Color homogeneity is one of the goals to continuously improve WLED. Among the methods for enhancing the color uniformity of WLEDs, improving scattering in phosphor layer is considered to be the most effective. In this paper, ZnO is used for that purpose. The results show that ZnO particle size significantly affects scattering in the phosphor layer, which is a vital factor to analyze scattering, scattering sand surface, scattering coefficient and scattered phase function C sca (D, λ), μ ( λ ) and ρ(θ, λ). In addition, the concentration of ZnO was also analyzed with values from 2% to 22%. Color homogeneity depends not only on size but also on the concentration of added ZnO. Therefore, color homogeneity control is the control of ZnO size and concentration. The proposed result is 10% ZnO for the highest lumen of LED. With 14% and 500 nm of ZnO particles, ΔCCT reaches the lowest. Depending on the production needs, manufacturers can choose the most appropriate way. However, with both required lumen and ΔCCT, 14% ZnO is suitable for ZnO sizes. sca
Utilizing CaCO 3 , CaF 2 , SiO 2 , and TiO 2 particles to enhance color hom...IJECEIAES
The chromatic homogeneity and luminous efficiency are two crucial elements for determining a high-quality phosphor-converted LEDs (pc-LEDs). Thus, this paper provides essential information in choosing the particles to enhance lighting properties of high performance pc-LEDs. Scattering enhancement particles (SEP) such as CaCO 3 , CaF 2 , SiO 2 , and TiO 2 , are combined with yellow phosphor Y 3 Al 5 O 12 :Ce 3+ and applied to the lighting devices. Initially, optical simulations are carried out with the support of LightTools program. Next, the Mie-theory is applied to calculate and confirm the results. The calculation subjects are SEPs scattering properties within the band 455 -595 nm. The scattering results of TiO 2 suggest it is the optimal choice for pc-LEDs color quality in comparison to the other SEPs; however, it causes the luminous flux to decrease significantly along with the increase in its concentration. Besides, with the addition of SiO 2 grains, we can accomplish higher lumen output at all particle sizes. Meanwhile, the application of 30% CaCO 3 can decreas the CCT deviation by 620 K making CaCO 3 the potential particle to be selected for chromatic quality and light output enhancement of pc-LEDs.
The influences of calcium fluoride and silica particles on improving color ho...TELKOMNIKA JOURNAL
The LEDs lighting device with phosphor ingredient (pcLEDs) is among the most common lighting methods in recent years and evaluated by chromatic uniformity and lighting capacity. Therefore, we introduce the phosphor particles that can improve the scattering efficiency (SEPs) to apply in pcLEDs at 8500 K correlated color temperature (CCT) with the expectation to produce better pcLEDs by enhancing both quantity and quality of emitted light. Combining various materials such as CaF2 and SiO2 with yellow Y3Al5O12:Ce3+ phosphor composition in the pcLEDs simulation created by the LightTools program is the mechanism of this research. The simulated pcLEDs are tested and the results will be verified with Mie-scattering theory. The observation of the simulation leads to the conclusion about the scattering coefficients of SEPs at 455 nm and 595 nm wavelengths. The calculation showed that CaF2 is better for color homogeneity yet suffer from luminous flux deficiency as the concentration gets higher. On the other hand, SiO2 is the scattering enhancement material that can maintain high luminous flux regardless of its concentration.
Using SiO 2 nano-particles for better color uniformity and lumen output in 8...IJECEIAES
In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO 2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO 2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO 2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO 2 -doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO 2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO 2 -doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO 2 . These experimental outcomes suggest that SiO 2 is an effective material to add in WLEDs structure for better lighting efficiency.
Enhancing light sources color homogeneity in high-power phosphor-based white ...TELKOMNIKA JOURNAL
Color uniformity is one of the essentials for the on-going development of WLED. To achieve a high color uniformity index, increasing the scattering events within the phosphor layers was reported to be the most efficient method and in this article, ZnO is the chosen material to apply in this method. After analyzing the scattering properties through the scattering cross-section , scattering coefficient and scattering phase function , the which outcomes comfirm that ZnO can enhance the scattered light in the phosphor layers. Moreover, the findings from the study of ZnO concentration from 2% to 26% suggest that color uniformity also depends on the fluctuation of ZnO concentration, therefore, to control color uniformity the focus should be implied on both size and concentration of ZnO. The experimental results from this research show that the luminous flux of WLED is at the peak if the concentration of ZnO is at 6%, and when the concentration of ZnO is at 18% and has 100 nm particles size, the ΔCCT reaches the lowest level. The final choice should be based on the desired characteristic of WLEDs, however, if the WLED need to excel in both luminous flux and ΔCCT then 6% ZnO concentration with particles size from 100 nm-300 nm is the optimal choice.
The effectiveness of MgCeAl 11 O 19 :Tb phosphor in enhancing the luminous e...IJECEIAES
In this research paper, we introduced yellow-green MgCeAl 11 O 19 :Tb as a new phosphor ingredient to adapt to the quality requirements on the chromatic homogeneity and emitted luminous flux of modern multi-chip white LED lights (MCW-LEDs). The results from experiments and simulation show that employing MgCeAl 11 O 19 :Tb 3+ phosphor can lead to much better optical properties and therefore is a perfect supporting material to achieve the goals of the research. When the MgCeAl 11 O 19 :Tb phosphor is added into the phosphorus composite which already contains YAG: Ce particles, and the silicone glue, it affects the optical properties significantly. In other words, the concentration of this phosphor can determine the efficiency of lumen output and chromatic homogeneity of WLEDs. In specific, as the concentration of MgCeAl 11 O 19 :Tb 3+ go up, the luminous yield will increase accordingly, though there is an insignificant decrease in CQS. Moreover, if the MgCeAl 11 O 19 :Tb 3+ concentration reduce a little bit, it is possible to better the correlated color temperature uniformity and lumen efficacy of LED packages. In addition, the Mie scattering theory, Monte Carlo simulation and LightTools 8.3.2 software are employed to analyze and simulate the LED packages’ structure as well as the phosphor compound.
The application of double-layer remote phosphor structures in increasing WLED...IJECEIAES
The remote phosphor structure often has inferior color quality but better luminous flux in than conformal or in-cup configurations. Therefore, numerous researches study remote phosphor structure for methods to enhance it chromatic quality. This study introduces the use of dual-layer remote phosphor structure in WLEDs with identical structure but at different color temperature, 6600 K and 7700 K, to demonstrate their effect on quality indicators. The concept is placing a green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb or a red phosphor layer MgSr 3 Si 2 O 8 :Eu on the layer of yellow-emitting phosphor YAG:Ce 3+ and find the suitable concentration of the additional phosphor to create the best color quality. The results showed that the increase of CRI and CQS are affected by MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ , in particular, the higher the concentration of red phosphor gets the better CRI and CQS because the emitted red light in enhanced. The green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb, on the other hand, is beneficial for the luminous flux. The concentration of MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ and (Ce,Tb)MgAl 11 O 19 :Ce:Tb, however, need to be adjusted properly to avoid decreasing the luminous flux due to overgrowth. The Mie scattering theory and Beer’s law are the verification tools for these conclusions, which gives them the credibility to be applied in producing better quality WLEDs. 2+ ,Mn 2+
SrBaSiO 4 :Eu 2+ phosphor: a novel application for improvingthe luminous flu...IJECEIAES
This paper described in detail the chromatic homogeneity and luminous flux influences in producing better quality white LED devices with various phosphor layers (MCW-LEDs). The method is to let Eu -activated strontium–barium silicate (SrBaSiO 4 :Eu 2+ ) mixed with their phosphor compounding, which results in notable impact on lighting performance. The increase in concentration of yellow-green-emitting SrBaSiO 4 :Eu phosphor also promotes the color performance and lumen output of WLED devices at high correlated color temperature around 8500K. This is the first time this approach is applied and it results can be utilized for better understanding of optical properties interaction with phosphor materials. Although SrBaSiO 4 :Eu 2+ receives many positive responses, we still need to limit it concentration for high SrBaSiO 4 :Eu 2+ concentration is detrimental to CQS. The appropriate choice of concentration and size of SrBaSiO 4 :Eu is the principal factor to decide the performance of MCW-LEDs. 2+ 2+ 2+
Improving optical properties of remote phosphor LED using green Y2O3:Ho3+ and...TELKOMNIKA JOURNAL
The lighting device that employs diodes to create white light (WLEDs) with quantum dots (QDs) and phosphor layers is a promising lighting method that is increasingly used in many fields on account of the remarkable color expressing ability. The QDs film is usually placed apart from the phosphor layer according to the packaging configuration to prevent light loss due to backscattering as well as preserve the consistency of the ligands on the QDs surface. The article also conducted experiments to compare the lighting properties and thermal output of the two packaging orders of QDs and phosphor. The heat discharing ranges were simulated with thermography technology, moreover, other parameters such as light energy emission and PL spectra are acquired to evaluate the efficiency of the packaging order. The results from the practical experiment show that while under 10% wt., the luminous output (LO) of green QDs-on-phosphor structure reaches 1130 lm, higher than the red QDs-on-phosphor structure with 878 lm, and the color rendering value in the configuration with red QDs on phosphor is Ra = 74 are higher than Ra = 68 index of the green QDs-on-phosphor structure. As a result, the QDs-on-phosphor is determined as the better packaging configuration to choose to achieve an overall improvement in lighting efficiency, color rendering index
Utilizing CaCO 3 , CaF 2 , SiO 2 , and TiO 2 particles to enhance color hom...IJECEIAES
The chromatic homogeneity and luminous efficiency are two crucial elements for determining a high-quality phosphor-converted LEDs (pc-LEDs). Thus, this paper provides essential information in choosing the particles to enhance lighting properties of high performance pc-LEDs. Scattering enhancement particles (SEP) such as CaCO 3 , CaF 2 , SiO 2 , and TiO 2 , are combined with yellow phosphor Y 3 Al 5 O 12 :Ce 3+ and applied to the lighting devices. Initially, optical simulations are carried out with the support of LightTools program. Next, the Mie-theory is applied to calculate and confirm the results. The calculation subjects are SEPs scattering properties within the band 455 -595 nm. The scattering results of TiO 2 suggest it is the optimal choice for pc-LEDs color quality in comparison to the other SEPs; however, it causes the luminous flux to decrease significantly along with the increase in its concentration. Besides, with the addition of SiO 2 grains, we can accomplish higher lumen output at all particle sizes. Meanwhile, the application of 30% CaCO 3 can decreas the CCT deviation by 620 K making CaCO 3 the potential particle to be selected for chromatic quality and light output enhancement of pc-LEDs.
The influences of calcium fluoride and silica particles on improving color ho...TELKOMNIKA JOURNAL
The LEDs lighting device with phosphor ingredient (pcLEDs) is among the most common lighting methods in recent years and evaluated by chromatic uniformity and lighting capacity. Therefore, we introduce the phosphor particles that can improve the scattering efficiency (SEPs) to apply in pcLEDs at 8500 K correlated color temperature (CCT) with the expectation to produce better pcLEDs by enhancing both quantity and quality of emitted light. Combining various materials such as CaF2 and SiO2 with yellow Y3Al5O12:Ce3+ phosphor composition in the pcLEDs simulation created by the LightTools program is the mechanism of this research. The simulated pcLEDs are tested and the results will be verified with Mie-scattering theory. The observation of the simulation leads to the conclusion about the scattering coefficients of SEPs at 455 nm and 595 nm wavelengths. The calculation showed that CaF2 is better for color homogeneity yet suffer from luminous flux deficiency as the concentration gets higher. On the other hand, SiO2 is the scattering enhancement material that can maintain high luminous flux regardless of its concentration.
Using SiO 2 nano-particles for better color uniformity and lumen output in 8...IJECEIAES
In the effort of improving the performance of white light LEDs devices (WLEDs), the SiO 2 nano-particles were applied and have shown a significant impact on the optical properties. Specifically, the light output of the lighting devices is enhanced when a mixture of SiO 2 particles and silicone gel is diffused on the encapsulation layer surface. This enhancement is the result of light scattering from SiO 2 that strengthens the emitted blue light at further angles and reduces the color discrepancy. The evidence is that CCT deviation in SiO 2 -doped structure decline from 1000 K to 420 K in -70° to 70°. In addition, the SiO 2 with refractive index in between the phosphor material and outside environment allows light to be emitted outward more effectively. This lighting enhancement of SiO 2 -doped structure increases the lumen output by 2.25% at 120 mA power source in comparison to structure without SiO 2 . These experimental outcomes suggest that SiO 2 is an effective material to add in WLEDs structure for better lighting efficiency.
Enhancing light sources color homogeneity in high-power phosphor-based white ...TELKOMNIKA JOURNAL
Color uniformity is one of the essentials for the on-going development of WLED. To achieve a high color uniformity index, increasing the scattering events within the phosphor layers was reported to be the most efficient method and in this article, ZnO is the chosen material to apply in this method. After analyzing the scattering properties through the scattering cross-section , scattering coefficient and scattering phase function , the which outcomes comfirm that ZnO can enhance the scattered light in the phosphor layers. Moreover, the findings from the study of ZnO concentration from 2% to 26% suggest that color uniformity also depends on the fluctuation of ZnO concentration, therefore, to control color uniformity the focus should be implied on both size and concentration of ZnO. The experimental results from this research show that the luminous flux of WLED is at the peak if the concentration of ZnO is at 6%, and when the concentration of ZnO is at 18% and has 100 nm particles size, the ΔCCT reaches the lowest level. The final choice should be based on the desired characteristic of WLEDs, however, if the WLED need to excel in both luminous flux and ΔCCT then 6% ZnO concentration with particles size from 100 nm-300 nm is the optimal choice.
The effectiveness of MgCeAl 11 O 19 :Tb phosphor in enhancing the luminous e...IJECEIAES
In this research paper, we introduced yellow-green MgCeAl 11 O 19 :Tb as a new phosphor ingredient to adapt to the quality requirements on the chromatic homogeneity and emitted luminous flux of modern multi-chip white LED lights (MCW-LEDs). The results from experiments and simulation show that employing MgCeAl 11 O 19 :Tb 3+ phosphor can lead to much better optical properties and therefore is a perfect supporting material to achieve the goals of the research. When the MgCeAl 11 O 19 :Tb phosphor is added into the phosphorus composite which already contains YAG: Ce particles, and the silicone glue, it affects the optical properties significantly. In other words, the concentration of this phosphor can determine the efficiency of lumen output and chromatic homogeneity of WLEDs. In specific, as the concentration of MgCeAl 11 O 19 :Tb 3+ go up, the luminous yield will increase accordingly, though there is an insignificant decrease in CQS. Moreover, if the MgCeAl 11 O 19 :Tb 3+ concentration reduce a little bit, it is possible to better the correlated color temperature uniformity and lumen efficacy of LED packages. In addition, the Mie scattering theory, Monte Carlo simulation and LightTools 8.3.2 software are employed to analyze and simulate the LED packages’ structure as well as the phosphor compound.
The application of double-layer remote phosphor structures in increasing WLED...IJECEIAES
The remote phosphor structure often has inferior color quality but better luminous flux in than conformal or in-cup configurations. Therefore, numerous researches study remote phosphor structure for methods to enhance it chromatic quality. This study introduces the use of dual-layer remote phosphor structure in WLEDs with identical structure but at different color temperature, 6600 K and 7700 K, to demonstrate their effect on quality indicators. The concept is placing a green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb or a red phosphor layer MgSr 3 Si 2 O 8 :Eu on the layer of yellow-emitting phosphor YAG:Ce 3+ and find the suitable concentration of the additional phosphor to create the best color quality. The results showed that the increase of CRI and CQS are affected by MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ , in particular, the higher the concentration of red phosphor gets the better CRI and CQS because the emitted red light in enhanced. The green phosphor layer (Ce,Tb)MgAl 11 O 19 :Ce:Tb, on the other hand, is beneficial for the luminous flux. The concentration of MgSr 3 Si 2 O 8 :Eu 2+ ,Mn 2+ and (Ce,Tb)MgAl 11 O 19 :Ce:Tb, however, need to be adjusted properly to avoid decreasing the luminous flux due to overgrowth. The Mie scattering theory and Beer’s law are the verification tools for these conclusions, which gives them the credibility to be applied in producing better quality WLEDs. 2+ ,Mn 2+
SrBaSiO 4 :Eu 2+ phosphor: a novel application for improvingthe luminous flu...IJECEIAES
This paper described in detail the chromatic homogeneity and luminous flux influences in producing better quality white LED devices with various phosphor layers (MCW-LEDs). The method is to let Eu -activated strontium–barium silicate (SrBaSiO 4 :Eu 2+ ) mixed with their phosphor compounding, which results in notable impact on lighting performance. The increase in concentration of yellow-green-emitting SrBaSiO 4 :Eu phosphor also promotes the color performance and lumen output of WLED devices at high correlated color temperature around 8500K. This is the first time this approach is applied and it results can be utilized for better understanding of optical properties interaction with phosphor materials. Although SrBaSiO 4 :Eu 2+ receives many positive responses, we still need to limit it concentration for high SrBaSiO 4 :Eu 2+ concentration is detrimental to CQS. The appropriate choice of concentration and size of SrBaSiO 4 :Eu is the principal factor to decide the performance of MCW-LEDs. 2+ 2+ 2+
Improving optical properties of remote phosphor LED using green Y2O3:Ho3+ and...TELKOMNIKA JOURNAL
The lighting device that employs diodes to create white light (WLEDs) with quantum dots (QDs) and phosphor layers is a promising lighting method that is increasingly used in many fields on account of the remarkable color expressing ability. The QDs film is usually placed apart from the phosphor layer according to the packaging configuration to prevent light loss due to backscattering as well as preserve the consistency of the ligands on the QDs surface. The article also conducted experiments to compare the lighting properties and thermal output of the two packaging orders of QDs and phosphor. The heat discharing ranges were simulated with thermography technology, moreover, other parameters such as light energy emission and PL spectra are acquired to evaluate the efficiency of the packaging order. The results from the practical experiment show that while under 10% wt., the luminous output (LO) of green QDs-on-phosphor structure reaches 1130 lm, higher than the red QDs-on-phosphor structure with 878 lm, and the color rendering value in the configuration with red QDs on phosphor is Ra = 74 are higher than Ra = 68 index of the green QDs-on-phosphor structure. As a result, the QDs-on-phosphor is determined as the better packaging configuration to choose to achieve an overall improvement in lighting efficiency, color rendering index
This document discusses the performance of dye-sensitized solar cells that use different types of titanium dioxide photoelectrodes. Nanocrystalline and nanotube anatase TiO2 photoelectrodes were fabricated using a hydrothermal technique and their morphological characteristics were analyzed using scanning electron microscopy. The nanotube-based dye-sensitized solar cell was found to have a higher efficiency of 7.28% compared to the 6.6% efficiency of the nanocrystalline anatase-based cell, as measured by current density-voltage curves and incident photon to current conversion efficiency spectra. The nanotube structure allows for illumination from both the front and back sides.
The application of (Y,Gd)BO3:Tb3+ and CaGa2S4:Mn2+ phosphors to remote white ...TELKOMNIKA JOURNAL
The remote phosphor structure is superior to the conformal phosphor and the in-cup phosphor in terms of lighting efficiency; however, managing the color quality of the remote phosphor structure has been a nuisance to the manufacturers. To address this problem, many researches were conducted and the results suggested that using dual-layer phosphor structure and triple-layer phosphor structure could improve the color quality in remote phosphor structures. The purpose of this article is to study which one between the two configurations mentioned above allows multi-chip white LEDs (WLEDs) to reach highest indexes in color rendering index (CRI), color quality scale (CQS), luminous flux (LF), and color uniformity. The color temperature of the WLEDs used for the experiments in this article is 8500 K. The result of this research shows that the triple-layer phosphor configuration has higher CRI, CQS, and LE and also able to reduce color deviation resulting in better color uniformity. This conclusion can be verified by analyzing the scattering features of the phosphor layers using the Mie-theory. Being verifiable increases the reliability of the research result and makes it a valuable reference for producing better quality WLEDs.
Charge Transport in organic semiconductorsTauqueer Khan
This document summarizes research on synthesizing cadmium telluride (CdTe) nanocrystals directly within a poly(3-hexylthiophene) (P3HT) matrix for use in photovoltaic devices. The in situ growth improves the polymer-nanoparticle interface facilitating efficient charge transfer. Spectral results suggest CdTe forms a charge transfer complex with P3HT via dipole-dipole interaction. Structural studies show CdTe facilitates charge transport pathways between polymer chains. Photovoltaic devices using P3HT-CdTe nanocomposites demonstrated enhanced current density and open circuit voltage compared to P3HT:PCBM devices due to increased energy level offset between donor and
Natural Dye-Sensitized Solar Cells (NDSSCs) From Opuntia Prickly Pear Dye Usi...IJERA Editor
Natural dye-sensitized solar cells (NDSSCs) have gained considerable attention in the field of solar energy due to their simple fabrication, good efficiency, and low production cost. Natural dyes are environmentally and economically superior to ruthenium-based dyes because they are nontoxic and cheap. However, the conversion efficiency of dye-sensitized solar cells based on natural dyes is low. One way to improve the DSSC performance is to enhance the absorptivity of extracted natural dyes. We investigated the influence of various factors in the extraction process, such as utilization of different extraction approaches, the acidity of extraction solvent, and different compounds of solvents on the optical absorption spectra. It was found that we could considerably enhance the optical absorptivity of dye and consequently the performance of DSSC by choosing a proper mixture of ethanol, methanol and water. In this study, a photo electrode using ZnO doped TiO2 nanoparticles was prepared by sol-gel method. In this paper we investigate the optical absorption, functional group, surface morphology and elementary composition of pure TiO2, ZnO doped TiO2 nanoparticles and opuntia prickly pear dye extract by using UV-Visible, PL-Studies, FT-IR, FE-SEM and EDS analysis. Finally photocurrent-voltaic characterization of nanocrystaline natural dye solar cell using I-V studies. It was found that the levels of short-circuit current (Jsc), open-circuit voltage (Voc), fill factor (FF) and overall conversion efficiency (η).
Ba[Mg2Al2N4]Eu2+ phosphor for enhancing the optical quality of the 6600K CPW-...TELKOMNIKA JOURNAL
Compared with conventional lamps, LED-based light sources have a superior lifetime, efficiency, and reliability, which promise significant reductions in power consumption and pollution from fossil fuel power plants. The main purpose of this paper is proposed and investigated the effect of the concentration of Ba[Mg2Al2N4]Eu2+conversion phosphor on the CCT deviation (D-CCT) and lumen output (LO) of the 6600 K conformal-packaging white LEDs (CPW-LEDs). For this purpose, we used the Light Tools and Mat Lab software to investigate this problem. From the research results, we can state that the concentration of the red phosphor crucially influenced on the optical quality of the 6600 K CPW-LEDs. The D-CCT can be decreased from 4700K to 2500K, and the LO can be increased from 600 lm. to 1200 lm. This research can provide the new recommendation for LEDs industry at this time.
A review on graphene based light emitting functional devicesJournal Papers
The document reviews recent developments in graphene-based light-emitting devices. It discusses how light emissions from graphene have been observed through thermal emission, electroluminescence, and plasmon-assisted emission. The review covers the device structures, fabrication methods, optical and electronic properties related to these light emission mechanisms. It also discusses potential applications for graphene light emitters and current technological challenges in the field.
Decreasing CCT deviation of white light emitting diodes by employing SiO2 nan...journalBEEI
In this research, the SiO2 nano-particles (NPs) usage in enhancing optical performances of InGaN/GaN-based white light-emitting diodes (WLEDs) with remote phosphor structure. The research subject shows better lighting capacity than the white LEDs devices without the space between the layers. The adjustment in development process resulted in enhancements of internal quantum efficiency (IQE) and light extraction efficiency (LEE) that lead to 13.5% luminous efficacy improvement. From the experiments, it can be concluded that the LEE is affected by the trapped light and enhancing the light output with SiO2 scattering properties reduce the amount of trapped light. These results confirm that SiO2 nano-particles is effective in enhancing the optical performance of WLEDs and can be considered for production of higher quality devices.
Optical Studies of Ni and Fe Doped Tin Oxide Nanoparticles by Co-Precipitatio...IRJET Journal
This document describes a study on the synthesis and characterization of pure, nickel-doped, and iron-doped tin oxide nanoparticles. The nanoparticles were synthesized via a co-precipitation method and analyzed using various techniques. X-ray diffraction analysis showed that the nanoparticles crystallized in the tetragonal rutile structure. UV-visible spectroscopy revealed that doping reduced the optical band gap. Fourier transform infrared spectroscopy confirmed the incorporation of nickel and iron into the tin lattice. Photoluminescence spectra exhibited blue emission peaks attributed to electron transitions involving defect levels. Scanning electron microscopy images displayed nanoparticle morphology and energy-dispersive X-ray spectroscopy confirmed the presence of tin, oxygen, and dopants in the samples.
Spectroscopic studies on Mn2+ ions doped Cadmium Aluminum Fluoro Lead Borate ...IJERA Editor
This document summarizes a study on the optical properties of manganese ion (Mn2+)-doped cadmium aluminum fluoro lead borate glass. The glass was prepared with the composition 49.5B2O3-10PbO-30CdO-10AlF3 doped with 0.5% Mn2+. Optical absorption spectroscopy showed a broad absorption band at 473 nm, confirming the presence of Mn2+ ions. Photoluminescence spectroscopy revealed a red emission at 618 nm under excitation at 467 nm, attributed to the 4T1g(G) → 6A1g(S) transition of Mn2+ ions in an octahedral environment. The
The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote ...TELKOMNIKA JOURNAL
Remote phosphor structure is commonly limited in color quality, but has greater luminous flux when comparing to structures with in-cup or conformal coating. From this dilemma, various researches with advance modifications have been proposed to perfect the chromatic performance of remote structure. In this research, we reach higher color quality by obtaining better values in quality indcators such as color rendering index (CRI) and color quality scale (CQS) with the dual-layer phosphor in our remote white light-emitting diodes (WLEDs). The idea is to ultize WLEDs with 7000 K correlated color temperature (CCT) and create dual-layer configuration with yellow phosphor YAG:Ce3+ under green phosphor YPO4:Ce3+,Tb3+ or red phosphor LiLaO2:Eu3+. After that, we search for suitable concentration of LiLaO2:Eu3+ for addition in order to acquire the finest color quality. The result shows that WLED with LiLaO2:Eu3+ has better CRI and CQS as the higher the concentration of LiLaO2:Eu3+, the larger CRI and CQS due to increased light scattered in WLEDs. Meanwhile, the green phosphor layer YPO4:Ce3+,Tb3+ give advantages to luminous flux. However, the reduction in luminous flux and color quality occurs when the concentration of LiLaO2:Eu3+ and YPO4:Ce3+,Tb3+ over increase. Results are verified by Mie theory and Beer’s Law and can be applied to practical manufacturing of high quality WLEDs.
(Y,Gd)BO3:Eu red phosphor for dual-layer phosphor structure to enhance the op...journalBEEI
Among the structures using for fabricating white light-emitting diodes (WLEDs) such as the conformal coating or in-cup geometries, the remote phosphor structure gives the highest luminous efficacy. However, in terms of color quality, its performance is not as good as the others. The red-light compensation has been reported as the effective solution for enhancing the color quality of WLEDs. Hence, this study adopted the idea and applied to the dual-layer phosphor structure. The phosphor used to boost the red color in light formation is (Y,Gd)BO3:Eu particle. The dual-layer remote phosphor structure was simulated with the red (Y,Gd)BO3:Eu phosphor layer above the original yellow phosphor YAG:Ce3+ one. The WLEDs with different correlated color temperatures of 5600 K, 6600 K and 7700K were experimented. Mie-theory and Lambert-Beer law were applied to examine the results. The growth in color rendering index (CRI) and color quality scale (CQS) with the increase of (Y,Gd)BO3:Eu phosphor concentration was observed. Nevertheless, the lumen efficacy would be degraded if the concentration was over a certain number. The information provided in this article is useful for the development of high-power WLED production with greater color quality.
Improving color quality and luminous flux of white LED utilizing triple-layer...IJECEIAES
In this manuscript, we presented a research that enhance the performance of WLED using the multi-phosphor configuration. The phosphor layers in the research are separated from each other to achieved better luminous efficiency, however, it makes controlling color light quality more complex. Another issue is finding out the whether two layers of phosphor or three layers of phosphor is better in improving color quality. The research addressed this issue by analyzing the optical aspects of the respective WLEDs that employ these structure. The studied aspects are quality indicators such as luminous efficacy (LE), and color uniformity, color rendering index (CRI), color quality scale (CQS). The results of the experiments in this research, which come from the employment of WLEDs with 2 color temperatures 5600 K and 8500 K, suggest that WLED with three phosphor layers is better in CRI, CQS, LE. This type of phosphor structure also limits the color deviation significantly, thus, improves the color uniformity. This results is verifies with Mie theory, therefore, can be applied as reference or guideline for production of better WLEDs.
Indium Doped Zinc Oxide Thin Films: Effect on Structural, Optical and Electri...IRJET Journal
This document summarizes research on indium-doped zinc oxide thin films deposited using spray pyrolysis. Key findings include:
1) XRD analysis showed the films were polycrystalline and doping led to a decrease in average grain size and a reorientation of crystal planes.
2) Optical band gap increased from 3.06 eV to 3.6 eV with doping due to the Burstein-Moss effect. Transmittance remained above 80% in the visible region.
3) Electrical resistivity decreased from 45.07 Ω-cm in undoped films to a minimum of 0.1 Ω-cm with doping, increasing conductivity. The highest figure of merit
Long Term Stability of Solid State Dye Sensitized Solar Cellrehman1oo
This document summarizes research on developing a solid-state dye-sensitized solar cell (ss-DSSC) with improved long-term stability using a solid-state polymerized hole-transporting material (HTM). Key findings:
1) A conductive polymer, poly-3,4-ethylenedioxythiophene (PEDOT), was synthesized via a solid-state polymerization (SSP) method using 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) as the monomer.
2) SSP-PEDOT exhibited higher conductivity than other preparation methods and was used as the HTM in an ss-DSS
Fabrication of (Polymer Blend-magnesium Oxide) Nanoparticle and Studying thei...journalBEEI
The document summarizes research on fabricating nanocomposites from a polymer blend of polyvinyl pyrrolidone (PVP) and carboxymethyl cellulose (CMC) with varying concentrations of magnesium oxide (MgO) nanoparticles. The optical properties of the nanocomposites, including absorbance, transmittance, absorption coefficient, refractive index, extinction coefficient, dielectric constant, optical conductivity, and energy bandgap were studied. The results showed that these optical properties generally increased with higher MgO nanoparticle concentration, while transmittance and energy bandgap decreased. The nanocomposites showed high absorbance in the UV region, indicating potential use for applications like radiation shielding.
Synthesis and characterization of zno thin films deposited by chemical bath t...eSAT Journals
Abstract ZnO thin films have been deposited on silica glass substrate using the chemical bath deposition technique. The precursors used were zinc chloride and aqueous ammonia. The solution was stirred continuously with the help of a magnetic stirrer at a bath temperature of 70 oC and a deposition time of 70 minutes. The elemental composition and the surface morphology were studied using energy dispersive and scanning electron microscopy. The band gap was 2.72, 2.66, 2.60 eV for as-deposited, annealed at 200 oC and 300 oC respectively. There was a red shift in the band gap energy as the annealing temperature was increased. This might be due to an improvement in the crystallinity of the ZnO thin films. Index Terms: Zinc oxide, chemical bath, band gap, annealing
Enhancing the CRI and lumen output for the 6600 K WLED with convex-dual-layer...IJECEIAES
The traditional white LED product established with a single chip and a single phosphor results in a low color rendering index (CRI). The upgrade of LED package is comprised of two chips and one phosphor material and gives the higher CRI while keeping high luminous efficiency. Based on previous findings, the research paper performs the application of the two chips and two phosphors to enhance the color tunability of LEDs with different amounts and intensities of the two employed phosphors. Additionally, a color design model is built to serve the purpose of bettering the color fine-tuning of the white-light LED module. The maximum value of the difference between the measured CIE 1931 color coordinates and that of the simulated model is approximately 0.0063 around the 6600 K correlated color temperature (CCT). From the results, this study offers a quick approach to achieve the color fine tuning of a white-light LED module with a high CRI and luminous efficiency.
The document summarizes research on the effects of ion irradiation and high temperature annealing on nanocrystalline graphene grown directly on quartz and sapphire substrates. It finds that nanocrystalline graphene can withstand fairly high doses of ion irradiation without losing conductivity, but at higher doses it rapidly becomes insulating. Annealing can restore the conductivity of irradiated graphene. Ion irradiation also enhances graphene's adhesion to substrates and increases the substrate's ability to nucleate graphene deposition. These effects could enable new methods for patterning and imprint lithography of graphene on insulating substrates.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The options in remote phosphor structure for better white LEDs color qualityTELKOMNIKA JOURNAL
The WLEDs configuration with remote phosphor layers has higher luminescent performance than WLEDs with dispense coating or conformal coating and is applied for many modern devices. However, managing the chromatic performance of lighting structure with remote phosphor materials is a challenging objective that demands more research. This has inspired the usage of multi phosphor configurations with distance in between the layers to improve color quality. The results of this manuscript can support the manufacturers in choosing the optimal configuration for optical performance in LEDs devices with more than one phosphor material. The simulated model used in the experments is 6500 K CCT WLEDs, which results show the triple-layers structure is more favorable in terms of color quality and light output. Besides, a notable reduction occurs in color deviation means that chromatic stability is also enhanced in WLEDs with three phosphor layers. Through experimental results, which were confirmed by the Mie-scattering theory, this research offers valuable approach and details to produce better WLEDs.
Y 2 O 3 :Ho 3+ and ZnO:Bi 3+ : a selection for enhancing color quality and ...IJECEIAES
As the luminescence industry develops, the white light light-emitting diode (LED) package with a single chip and a single phosphor although produces good luminous flux but has a poor color rendering index (CRI) can no longer fulfill the requirements of modern lighting applications. Therefore, this research is conducted to response to the urgent demands of improving other lighting qualities of WLED while maintaining high luminous efficiency. To achieve this target, we applied the new WLED package, which contains multi-chips and multi-phosphor layers, and have obtained outstanding results in both CRI and luminous efficacy. Two types of phosphor used in the WLED package are Y 2 O 3 :Ho 3+ and ZnO:Bi 3+ . A color configuration model is also developed to adjust the shading of the white-light LED module. The results of this research show that the triple-layer phosphorhas the best performance when applied in a white-light LED package, which is demonstrated through better color quality, CRI and luminous efficacy. The manufacturers can rely on this research to produce the optimal-quality WLED, or WLED that is appropriate to their quality demands.
Chroma consistency and luminous efficacy for a WLED using remote phosphor con...TELKOMNIKA JOURNAL
The light quality of white-light-emitting diodes (WLEDs), an essential element for the improvement of WLEDs performance, can now be estimated by the angular color uniformity (ACU). In this study, a single
micro-patterned layer is used to compare the variations between the traditional remote phosphor (RP) layer and the remote phosphor layer (single remote micro-patterned phosphor film (RMPP) layer). Furthermore,
we investigate the application of a novel triple remote phosphor layer to improve the ACU in RP down-light lamps. Besides, the optical efficiency of the layers as well as the distribution for the angular correlated color temperature (ACCT) were also measured experimentally. According to the findings, the dual-RMPP-layer structure can achieve better chromatic uniformity with just 441 K of correlated color temperature (CCT) variance. Meanwhile, the single RMPP layer shows an ACCT deviation of 556 K and RP film structure of 1390 K. The simulation incorporating e finite-difference time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in ACU. Furthermore, compare to the traditional RP layer,
the single and dual RMPP layers configuration result in respective luminous efficiency ameliorations of 6.68% and 4.69%. The scattering principle and combining influence from the micro-molded layer may explain the enhancement in ACU as well as lumen.
This document discusses the performance of dye-sensitized solar cells that use different types of titanium dioxide photoelectrodes. Nanocrystalline and nanotube anatase TiO2 photoelectrodes were fabricated using a hydrothermal technique and their morphological characteristics were analyzed using scanning electron microscopy. The nanotube-based dye-sensitized solar cell was found to have a higher efficiency of 7.28% compared to the 6.6% efficiency of the nanocrystalline anatase-based cell, as measured by current density-voltage curves and incident photon to current conversion efficiency spectra. The nanotube structure allows for illumination from both the front and back sides.
The application of (Y,Gd)BO3:Tb3+ and CaGa2S4:Mn2+ phosphors to remote white ...TELKOMNIKA JOURNAL
The remote phosphor structure is superior to the conformal phosphor and the in-cup phosphor in terms of lighting efficiency; however, managing the color quality of the remote phosphor structure has been a nuisance to the manufacturers. To address this problem, many researches were conducted and the results suggested that using dual-layer phosphor structure and triple-layer phosphor structure could improve the color quality in remote phosphor structures. The purpose of this article is to study which one between the two configurations mentioned above allows multi-chip white LEDs (WLEDs) to reach highest indexes in color rendering index (CRI), color quality scale (CQS), luminous flux (LF), and color uniformity. The color temperature of the WLEDs used for the experiments in this article is 8500 K. The result of this research shows that the triple-layer phosphor configuration has higher CRI, CQS, and LE and also able to reduce color deviation resulting in better color uniformity. This conclusion can be verified by analyzing the scattering features of the phosphor layers using the Mie-theory. Being verifiable increases the reliability of the research result and makes it a valuable reference for producing better quality WLEDs.
Charge Transport in organic semiconductorsTauqueer Khan
This document summarizes research on synthesizing cadmium telluride (CdTe) nanocrystals directly within a poly(3-hexylthiophene) (P3HT) matrix for use in photovoltaic devices. The in situ growth improves the polymer-nanoparticle interface facilitating efficient charge transfer. Spectral results suggest CdTe forms a charge transfer complex with P3HT via dipole-dipole interaction. Structural studies show CdTe facilitates charge transport pathways between polymer chains. Photovoltaic devices using P3HT-CdTe nanocomposites demonstrated enhanced current density and open circuit voltage compared to P3HT:PCBM devices due to increased energy level offset between donor and
Natural Dye-Sensitized Solar Cells (NDSSCs) From Opuntia Prickly Pear Dye Usi...IJERA Editor
Natural dye-sensitized solar cells (NDSSCs) have gained considerable attention in the field of solar energy due to their simple fabrication, good efficiency, and low production cost. Natural dyes are environmentally and economically superior to ruthenium-based dyes because they are nontoxic and cheap. However, the conversion efficiency of dye-sensitized solar cells based on natural dyes is low. One way to improve the DSSC performance is to enhance the absorptivity of extracted natural dyes. We investigated the influence of various factors in the extraction process, such as utilization of different extraction approaches, the acidity of extraction solvent, and different compounds of solvents on the optical absorption spectra. It was found that we could considerably enhance the optical absorptivity of dye and consequently the performance of DSSC by choosing a proper mixture of ethanol, methanol and water. In this study, a photo electrode using ZnO doped TiO2 nanoparticles was prepared by sol-gel method. In this paper we investigate the optical absorption, functional group, surface morphology and elementary composition of pure TiO2, ZnO doped TiO2 nanoparticles and opuntia prickly pear dye extract by using UV-Visible, PL-Studies, FT-IR, FE-SEM and EDS analysis. Finally photocurrent-voltaic characterization of nanocrystaline natural dye solar cell using I-V studies. It was found that the levels of short-circuit current (Jsc), open-circuit voltage (Voc), fill factor (FF) and overall conversion efficiency (η).
Ba[Mg2Al2N4]Eu2+ phosphor for enhancing the optical quality of the 6600K CPW-...TELKOMNIKA JOURNAL
Compared with conventional lamps, LED-based light sources have a superior lifetime, efficiency, and reliability, which promise significant reductions in power consumption and pollution from fossil fuel power plants. The main purpose of this paper is proposed and investigated the effect of the concentration of Ba[Mg2Al2N4]Eu2+conversion phosphor on the CCT deviation (D-CCT) and lumen output (LO) of the 6600 K conformal-packaging white LEDs (CPW-LEDs). For this purpose, we used the Light Tools and Mat Lab software to investigate this problem. From the research results, we can state that the concentration of the red phosphor crucially influenced on the optical quality of the 6600 K CPW-LEDs. The D-CCT can be decreased from 4700K to 2500K, and the LO can be increased from 600 lm. to 1200 lm. This research can provide the new recommendation for LEDs industry at this time.
A review on graphene based light emitting functional devicesJournal Papers
The document reviews recent developments in graphene-based light-emitting devices. It discusses how light emissions from graphene have been observed through thermal emission, electroluminescence, and plasmon-assisted emission. The review covers the device structures, fabrication methods, optical and electronic properties related to these light emission mechanisms. It also discusses potential applications for graphene light emitters and current technological challenges in the field.
Decreasing CCT deviation of white light emitting diodes by employing SiO2 nan...journalBEEI
In this research, the SiO2 nano-particles (NPs) usage in enhancing optical performances of InGaN/GaN-based white light-emitting diodes (WLEDs) with remote phosphor structure. The research subject shows better lighting capacity than the white LEDs devices without the space between the layers. The adjustment in development process resulted in enhancements of internal quantum efficiency (IQE) and light extraction efficiency (LEE) that lead to 13.5% luminous efficacy improvement. From the experiments, it can be concluded that the LEE is affected by the trapped light and enhancing the light output with SiO2 scattering properties reduce the amount of trapped light. These results confirm that SiO2 nano-particles is effective in enhancing the optical performance of WLEDs and can be considered for production of higher quality devices.
Optical Studies of Ni and Fe Doped Tin Oxide Nanoparticles by Co-Precipitatio...IRJET Journal
This document describes a study on the synthesis and characterization of pure, nickel-doped, and iron-doped tin oxide nanoparticles. The nanoparticles were synthesized via a co-precipitation method and analyzed using various techniques. X-ray diffraction analysis showed that the nanoparticles crystallized in the tetragonal rutile structure. UV-visible spectroscopy revealed that doping reduced the optical band gap. Fourier transform infrared spectroscopy confirmed the incorporation of nickel and iron into the tin lattice. Photoluminescence spectra exhibited blue emission peaks attributed to electron transitions involving defect levels. Scanning electron microscopy images displayed nanoparticle morphology and energy-dispersive X-ray spectroscopy confirmed the presence of tin, oxygen, and dopants in the samples.
Spectroscopic studies on Mn2+ ions doped Cadmium Aluminum Fluoro Lead Borate ...IJERA Editor
This document summarizes a study on the optical properties of manganese ion (Mn2+)-doped cadmium aluminum fluoro lead borate glass. The glass was prepared with the composition 49.5B2O3-10PbO-30CdO-10AlF3 doped with 0.5% Mn2+. Optical absorption spectroscopy showed a broad absorption band at 473 nm, confirming the presence of Mn2+ ions. Photoluminescence spectroscopy revealed a red emission at 618 nm under excitation at 467 nm, attributed to the 4T1g(G) → 6A1g(S) transition of Mn2+ ions in an octahedral environment. The
The application of green YPO4:Ce3+,Tb3+ and red LiLaO2:Eu3+ layers to remote ...TELKOMNIKA JOURNAL
Remote phosphor structure is commonly limited in color quality, but has greater luminous flux when comparing to structures with in-cup or conformal coating. From this dilemma, various researches with advance modifications have been proposed to perfect the chromatic performance of remote structure. In this research, we reach higher color quality by obtaining better values in quality indcators such as color rendering index (CRI) and color quality scale (CQS) with the dual-layer phosphor in our remote white light-emitting diodes (WLEDs). The idea is to ultize WLEDs with 7000 K correlated color temperature (CCT) and create dual-layer configuration with yellow phosphor YAG:Ce3+ under green phosphor YPO4:Ce3+,Tb3+ or red phosphor LiLaO2:Eu3+. After that, we search for suitable concentration of LiLaO2:Eu3+ for addition in order to acquire the finest color quality. The result shows that WLED with LiLaO2:Eu3+ has better CRI and CQS as the higher the concentration of LiLaO2:Eu3+, the larger CRI and CQS due to increased light scattered in WLEDs. Meanwhile, the green phosphor layer YPO4:Ce3+,Tb3+ give advantages to luminous flux. However, the reduction in luminous flux and color quality occurs when the concentration of LiLaO2:Eu3+ and YPO4:Ce3+,Tb3+ over increase. Results are verified by Mie theory and Beer’s Law and can be applied to practical manufacturing of high quality WLEDs.
(Y,Gd)BO3:Eu red phosphor for dual-layer phosphor structure to enhance the op...journalBEEI
Among the structures using for fabricating white light-emitting diodes (WLEDs) such as the conformal coating or in-cup geometries, the remote phosphor structure gives the highest luminous efficacy. However, in terms of color quality, its performance is not as good as the others. The red-light compensation has been reported as the effective solution for enhancing the color quality of WLEDs. Hence, this study adopted the idea and applied to the dual-layer phosphor structure. The phosphor used to boost the red color in light formation is (Y,Gd)BO3:Eu particle. The dual-layer remote phosphor structure was simulated with the red (Y,Gd)BO3:Eu phosphor layer above the original yellow phosphor YAG:Ce3+ one. The WLEDs with different correlated color temperatures of 5600 K, 6600 K and 7700K were experimented. Mie-theory and Lambert-Beer law were applied to examine the results. The growth in color rendering index (CRI) and color quality scale (CQS) with the increase of (Y,Gd)BO3:Eu phosphor concentration was observed. Nevertheless, the lumen efficacy would be degraded if the concentration was over a certain number. The information provided in this article is useful for the development of high-power WLED production with greater color quality.
Improving color quality and luminous flux of white LED utilizing triple-layer...IJECEIAES
In this manuscript, we presented a research that enhance the performance of WLED using the multi-phosphor configuration. The phosphor layers in the research are separated from each other to achieved better luminous efficiency, however, it makes controlling color light quality more complex. Another issue is finding out the whether two layers of phosphor or three layers of phosphor is better in improving color quality. The research addressed this issue by analyzing the optical aspects of the respective WLEDs that employ these structure. The studied aspects are quality indicators such as luminous efficacy (LE), and color uniformity, color rendering index (CRI), color quality scale (CQS). The results of the experiments in this research, which come from the employment of WLEDs with 2 color temperatures 5600 K and 8500 K, suggest that WLED with three phosphor layers is better in CRI, CQS, LE. This type of phosphor structure also limits the color deviation significantly, thus, improves the color uniformity. This results is verifies with Mie theory, therefore, can be applied as reference or guideline for production of better WLEDs.
Indium Doped Zinc Oxide Thin Films: Effect on Structural, Optical and Electri...IRJET Journal
This document summarizes research on indium-doped zinc oxide thin films deposited using spray pyrolysis. Key findings include:
1) XRD analysis showed the films were polycrystalline and doping led to a decrease in average grain size and a reorientation of crystal planes.
2) Optical band gap increased from 3.06 eV to 3.6 eV with doping due to the Burstein-Moss effect. Transmittance remained above 80% in the visible region.
3) Electrical resistivity decreased from 45.07 Ω-cm in undoped films to a minimum of 0.1 Ω-cm with doping, increasing conductivity. The highest figure of merit
Long Term Stability of Solid State Dye Sensitized Solar Cellrehman1oo
This document summarizes research on developing a solid-state dye-sensitized solar cell (ss-DSSC) with improved long-term stability using a solid-state polymerized hole-transporting material (HTM). Key findings:
1) A conductive polymer, poly-3,4-ethylenedioxythiophene (PEDOT), was synthesized via a solid-state polymerization (SSP) method using 2,5-dibromo-3,4-ethylenedioxythiophene (DBEDOT) as the monomer.
2) SSP-PEDOT exhibited higher conductivity than other preparation methods and was used as the HTM in an ss-DSS
Fabrication of (Polymer Blend-magnesium Oxide) Nanoparticle and Studying thei...journalBEEI
The document summarizes research on fabricating nanocomposites from a polymer blend of polyvinyl pyrrolidone (PVP) and carboxymethyl cellulose (CMC) with varying concentrations of magnesium oxide (MgO) nanoparticles. The optical properties of the nanocomposites, including absorbance, transmittance, absorption coefficient, refractive index, extinction coefficient, dielectric constant, optical conductivity, and energy bandgap were studied. The results showed that these optical properties generally increased with higher MgO nanoparticle concentration, while transmittance and energy bandgap decreased. The nanocomposites showed high absorbance in the UV region, indicating potential use for applications like radiation shielding.
Synthesis and characterization of zno thin films deposited by chemical bath t...eSAT Journals
Abstract ZnO thin films have been deposited on silica glass substrate using the chemical bath deposition technique. The precursors used were zinc chloride and aqueous ammonia. The solution was stirred continuously with the help of a magnetic stirrer at a bath temperature of 70 oC and a deposition time of 70 minutes. The elemental composition and the surface morphology were studied using energy dispersive and scanning electron microscopy. The band gap was 2.72, 2.66, 2.60 eV for as-deposited, annealed at 200 oC and 300 oC respectively. There was a red shift in the band gap energy as the annealing temperature was increased. This might be due to an improvement in the crystallinity of the ZnO thin films. Index Terms: Zinc oxide, chemical bath, band gap, annealing
Enhancing the CRI and lumen output for the 6600 K WLED with convex-dual-layer...IJECEIAES
The traditional white LED product established with a single chip and a single phosphor results in a low color rendering index (CRI). The upgrade of LED package is comprised of two chips and one phosphor material and gives the higher CRI while keeping high luminous efficiency. Based on previous findings, the research paper performs the application of the two chips and two phosphors to enhance the color tunability of LEDs with different amounts and intensities of the two employed phosphors. Additionally, a color design model is built to serve the purpose of bettering the color fine-tuning of the white-light LED module. The maximum value of the difference between the measured CIE 1931 color coordinates and that of the simulated model is approximately 0.0063 around the 6600 K correlated color temperature (CCT). From the results, this study offers a quick approach to achieve the color fine tuning of a white-light LED module with a high CRI and luminous efficiency.
The document summarizes research on the effects of ion irradiation and high temperature annealing on nanocrystalline graphene grown directly on quartz and sapphire substrates. It finds that nanocrystalline graphene can withstand fairly high doses of ion irradiation without losing conductivity, but at higher doses it rapidly becomes insulating. Annealing can restore the conductivity of irradiated graphene. Ion irradiation also enhances graphene's adhesion to substrates and increases the substrate's ability to nucleate graphene deposition. These effects could enable new methods for patterning and imprint lithography of graphene on insulating substrates.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
The options in remote phosphor structure for better white LEDs color qualityTELKOMNIKA JOURNAL
The WLEDs configuration with remote phosphor layers has higher luminescent performance than WLEDs with dispense coating or conformal coating and is applied for many modern devices. However, managing the chromatic performance of lighting structure with remote phosphor materials is a challenging objective that demands more research. This has inspired the usage of multi phosphor configurations with distance in between the layers to improve color quality. The results of this manuscript can support the manufacturers in choosing the optimal configuration for optical performance in LEDs devices with more than one phosphor material. The simulated model used in the experments is 6500 K CCT WLEDs, which results show the triple-layers structure is more favorable in terms of color quality and light output. Besides, a notable reduction occurs in color deviation means that chromatic stability is also enhanced in WLEDs with three phosphor layers. Through experimental results, which were confirmed by the Mie-scattering theory, this research offers valuable approach and details to produce better WLEDs.
Y 2 O 3 :Ho 3+ and ZnO:Bi 3+ : a selection for enhancing color quality and ...IJECEIAES
As the luminescence industry develops, the white light light-emitting diode (LED) package with a single chip and a single phosphor although produces good luminous flux but has a poor color rendering index (CRI) can no longer fulfill the requirements of modern lighting applications. Therefore, this research is conducted to response to the urgent demands of improving other lighting qualities of WLED while maintaining high luminous efficiency. To achieve this target, we applied the new WLED package, which contains multi-chips and multi-phosphor layers, and have obtained outstanding results in both CRI and luminous efficacy. Two types of phosphor used in the WLED package are Y 2 O 3 :Ho 3+ and ZnO:Bi 3+ . A color configuration model is also developed to adjust the shading of the white-light LED module. The results of this research show that the triple-layer phosphorhas the best performance when applied in a white-light LED package, which is demonstrated through better color quality, CRI and luminous efficacy. The manufacturers can rely on this research to produce the optimal-quality WLED, or WLED that is appropriate to their quality demands.
Chroma consistency and luminous efficacy for a WLED using remote phosphor con...TELKOMNIKA JOURNAL
The light quality of white-light-emitting diodes (WLEDs), an essential element for the improvement of WLEDs performance, can now be estimated by the angular color uniformity (ACU). In this study, a single
micro-patterned layer is used to compare the variations between the traditional remote phosphor (RP) layer and the remote phosphor layer (single remote micro-patterned phosphor film (RMPP) layer). Furthermore,
we investigate the application of a novel triple remote phosphor layer to improve the ACU in RP down-light lamps. Besides, the optical efficiency of the layers as well as the distribution for the angular correlated color temperature (ACCT) were also measured experimentally. According to the findings, the dual-RMPP-layer structure can achieve better chromatic uniformity with just 441 K of correlated color temperature (CCT) variance. Meanwhile, the single RMPP layer shows an ACCT deviation of 556 K and RP film structure of 1390 K. The simulation incorporating e finite-difference time-domain (FDTD) as well as the approach of ray-tracing ensures an increase in ACU. Furthermore, compare to the traditional RP layer,
the single and dual RMPP layers configuration result in respective luminous efficiency ameliorations of 6.68% and 4.69%. The scattering principle and combining influence from the micro-molded layer may explain the enhancement in ACU as well as lumen.
LaSiO 3 Cl:Ce 3+ ,Tb 3+ and Mg 2 TiO 4 :Mn 4+ : quantum dot phosphors for im...IJECEIAES
In this research, we focus on the solutions to enhance the lighting properties as well as the heat regulation of the white light-emitting diodes (WLEDs) with conventional phosphor and quantum dots (QDs). Although receiving lots of attention for being an innovative lighting solution with good color rendering index, the potentials of WLEDs conjugated with quantum dots (QDS), especially the QDs-phosphor mixed nanocomposites ones, are restrained due to the lacking performance in the aspects mentioned above. The crucial requirement to produce better WLEDs is finding solutions that improve the lacking aspects, therefore, through observing previous studies and applying advanced technique, this research suggest an effective and unique packaging configuration, in which the nanocomposites QDs-phosphor layer is set horizontally to the WLED. This novel packaging configuration allow WLED performance in terms of lighting and heating to reach it peaks. This is the first time four different types of WLEDs, singlelayer phosphor, dual-layer remote phosphor with yellow-red and yellow-green, and triple-layer phosphor, were simulated, utilized and compared in one study to decide the best WLED configuration. The results show that the triple-layer phosphor configurations improve the color rendering ability and lumen output better than the other configurations.
LaSiO 3 Cl:Ce 3+ ,Tb 3+ and Mg 2 TiO 4 :Mn 4+ : quantum dot phosphors for im...IJECEIAES
In this research, we focus on the solutions to enhance the lighting properties as well as the heat regulation of the white light-emitting diodes (WLEDs) with conventional phosphor and quantum dots (QDs). Although receiving lots of attention for being an innovative lighting solution with good color rendering index, the potentials of WLEDs conjugated with quantum dots (QDS), especially the QDs-phosphor mixed nanocomposites ones, are restrained due to the lacking performance in the aspects mentioned above. The crucial requirement to produce better WLEDs is finding solutions that improve the lacking aspects, therefore, through observing previous studies and applying advanced technique, this research suggest an effective and unique packaging configuration, in which the nanocomposites QDs-phosphor layer is set horizontally to the WLED. This novel packaging configuration allow WLED performance in terms of lighting and heating to reach it peaks. This is the first time four different types of WLEDs, singlelayer phosphor, dual-layer remote phosphor with yellow-red and yellow-green, and triple-layer phosphor, were simulated, utilized and compared in one study to decide the best WLED configuration. The results show that the triple-layer phosphor configurations improve the color rendering ability and lumen output better than the other configurations.
Excellent color quality of phosphor converted white light emitting diodes wit...TELKOMNIKA JOURNAL
The remote phosphor structure is disadvantageous in color quality but more convenient in luminous flux when compared to conformal phosphor or in-cup phosphor structure. From this disadvantage, there are many studies to improve the color quality of the remote phosphor structure. This research will propose a dual-layer remote phosphor structure to improve color rendering index (CRI) and color quality scale (CQS) of WLEDs. The WLED package with color temperature of 8500 K is utilized in this study. The idea of the study is to locate a layer of phosphor green Y2O2S:Tb3+ or red ZnS:Sn2+ on the yellow phosphor YAG:Ce3+ film, and then finding the suitable added concentration of ZnS:Sn2+ to match the highest color quality. The results showed that ZnS:Sn2+ brings great benefits to increase CRI and CQS. The greater the ZnS:Sn2+ concentration is, the higher the CRI and CQS become owing to the rise in red light components in WLEDs. Meanwhile, the green Y2O2S:Tb3+ phosphor brings benefits to luminous flux. However, the decrease in luminous flux and color quality occurs when the concentration of ZnS:Sn2+ and Y2O2S:Tb3+ exceeds the corresponding level. This is proved by applying Mie-scattering theory and Lambert-Beer's law. The results of articles are important for WLEDs’ fabrication having higher white light quality.
LED technology had a huge development in recent years with major benefits: long-life, high-efficiency, excellent performance, compactness. In this work, an innovative method for improving the performance of multi-chip white LED lamps (MCW-LEDs) by adding the green Ce0.67 Tb0.33 MgAl11 O19:Ce,Tb (CeTb) phosphor to their in-cup phosphor compounding is proposed, investigated and demonstrated. Firstly, CeTb was mixed to the in-cup phosphor package of MCW-LEDs. Then by varying CeTb concentration, lumen output and angular color uniformity (ACU) of MCW-LEDs was calculated and analyzed. The results showed that the lumen output and the ACU of 7000 K and 8500 K MCW-LEDs increased significantly in comparison with others related works. This method is a prospective ideal for future improving LED manufacture.
Comparison of calcium carbonate and titania particles on improving color homo...TELKOMNIKA JOURNAL
1) The document compares the effects of adding calcium carbonate (CaCO3) and titania (TiO2) particles to yellow phosphor in phosphor-converted LEDs (pc-LEDs) to improve color uniformity and luminous flux.
2) Simulation results show that pc-LEDs with 30% CaCO3 concentration have a 620K lower correlated color temperature deviation compared to no additional particles, indicating better color uniformity. In contrast, increasing TiO2 concentration sharply reduces luminous flux.
3) CaCO3 particles are recommended for achieving both higher color homogeneity and lumen output in pc-LEDs due to their scattering properties being more equal between blue and yellow light wavelengths.
OLED Device Review and A Summary of the Plasmonic Enhancement thereofAI Publications
Within this work the major breakthroughs in the development of OLED technologies are described. There is a strong emphasis placed upon materials discovery. The basic OLED structure is shown and the plasmonic effect is detailed in the context of OLED technologies.
Employing SiO2 nano-particles in conformal and in-cup structures of 8500 K wh...journalBEEI
SiO2 nano-particles have been examined in a distant phosphor structure for the elevated luminous quality and better consistency of white light-emitting diodes with angular-dependent associated color temperature (CCT). The luminous scattering ability could be increased by applying SiO2 nano-particles contain silicone to the outside of the phosphorus coating. In specific, the strength of blue light at wide angles is increased and differences in CCT can be minimized. In addition, owing to the sufficient refractive indices of silicone-containing SiO2 nanoparticles between the air and phosphorus layers, the luminous flux was improved. This new configuration decreases angular-dependent CCT deviations in the range of -700 to 700 from 1000 to 420 K. In comparison, at a 120 mA driving current, the rise of lumen flux increased by 2.25% relative to an usual distant phosphor structure without SiO2 nano-particles. As a result, in a distant phosphor structure, the SiO2 nano-particles could not only enhance the uniformity of illumination but also enhance the output of light.
IRJET - Review on Ameliorated in the Life, and Calibrated the OledIRJET Journal
This document summarizes research on improving the lifespan of OLED (organic light-emitting diode) displays. It discusses how OLED degradation occurs through chemical breakdown processes involving radical species. Methods to improve OLED lifetime are proposed, including using thermally activated delayed fluorescent materials and adding a thin lithium-containing layer. The document also reviews the structure and functioning of OLEDs, different degradation mechanisms, and potential future applications and challenges of OLED technology.
Dual-layer remote phosphor structure: a novel technique to enhance the color ...IJECEIAES
The effects of red light-emitting phosphor CaMgSi2O6:Eu2+,Mn2+ on the optical properties of single-layer remote phosphor structure (SRPS) and dual-layer remote phosphor structure (DRPS) are the focus of this study. The differences in color quality and luminous flux (LF) of white lightemitting diodes (WLEDs) between these two structures are also revealed and demonstrated based on the Mie theory. SRPS consists of one mixed phosphor layer betweenCaMgSi2O6:Eu2+,Mn2+ andYAG:Ce3+particles, while DRPS includes two separated layers: red phosphor layer and yellow phosphor layer. In this work, 5% SiO2 is added into the phosphor layers to increase scattering abilities. Discrepancies in structures greatly affect the optical characteristics of WLEDs. The results showed that the color rendering index (CRI) increased with the concentration in both structures with nearly equal values. Meanwhile, color quality scale (CQS) of DPRS is 74 at ACCTs ranging from 5600K to 8500K, higher than CQS of SRPS which is only 71 at 8500K. In addition, the luminous flux of DRPS is significantly higher than SRPS at 2% -14% of CaMgSi2O6:Eu2+,Mn2+. In summary, DRPS is better for color quality and lumen outputin comparison to SRPS and adding the right amount of red phosphor can enhance CQS and LF.
Enhance the chromatic uniformity and luminous efficiency of WLEDs with triple...IJECEIAES
The angular color uniformity (ACU) with the ability to evaluate chromatic performance of WLED has become an important target to achieve in producing higher-quality WLEDs. This paper studies the ACU enhancing effects of novel triple-phosphor configuration in lighting devices with remote phosphor structure. Moreover, the optical influences of remote phosphor structure with three phosphor layers (TL) on WLEDs properties are calculated and compared to the dual-layer (DL) one for reference. The experiments are applied to devices at 5 distinct correlated color temperature ranging from 5600-8500 K. The results presented that DL structure attains better color rendering index (CRI) than the TL one. Meanwhile, in terms of color quality scales (CQS), TL model shows higher values at all ACCTs, compared to the DL. Moreover, the luminous flux of DL configuration is lower than that of TL structure. In addition, the diversion of color temperature depicts as D-CCT in TL structure is much better than the value in DL structure, especially at high ACCT as 8500 K, which means TL is good for chromatic uniformity of high ACCTs WLEDs. These results proved that the triple-layer structure is superior and more effective to apply for acquiring the enhancement of WLEDs package.
IRJET-A Review on Utilization of Waste Heat from Automobile Based on Thermoel...IRJET Journal
This document discusses using metal-doped zinc oxide nanoparticles for water treatment in industries. It begins by introducing zinc oxide nanoparticles and the need to dope them with metals like magnesium to modify their properties. It then describes how magnesium-doped zinc oxide nanoparticles were synthesized using a sol-gel method. Characterization of the nanoparticles showed they were uniform in size and distribution. Experiments were conducted using these nanoparticles to degrade methylene blue dye in water via a photocatalytic process when exposed to light. The mechanism of photocatalysis is explained where light generates electron-hole pairs that initiate degradation reactions on the nanoparticle surfaces. The goal is to use this process to treat wastewater from industries in an efficient and environmentally friendly
Fabrication of zn o nanorod modified ITOViolet Flower
This document discusses the fabrication and characterization of zinc oxide (ZnO) nanorod arrays deposited on indium tin oxide (ITO) glass substrates via chemical bath deposition. Key points:
- ZnO nanorods were grown on ITO-coated glass by immersing the substrates in solutions containing zinc nitrate and hexamethylenetetramine at 80°C for varying times.
- Scanning electron microscopy images showed the diameter of the ZnO nanorods increased with higher solution concentration and longer growth time.
- X-ray diffraction analysis identified the crystal structure of the ZnO nanorods. Electrochemical measurements including cyclic voltammetry and electrochemical impedance spectroscopy were used to characterize the electron transfer properties of
Effects of NaB2O4:Mn2+ and Ba2Li2Si2O7:Sn3+,Mn2+ phosphors and remote structu...journalBEEI
In order to increase the optical features of white light-emitting diodes (WLEDs), quantum dots (QDs) and phosphor materials have been proposed because of outstanding performance. The configuration of WLEDs with QDs layer and phosphor-silicone layer suggested placing these components separately to limit light loss, and enhance consistency at contact surface of QDs. In this research, the effects of QDs and phosphor on the performance of WLEDs are concluded through experiments. The emitted light and PL spectra were examined thoroughly, and infrared thermal imagers were applied to simulate the heat generation of an actual WLED device. The results show that with the configuration of 60 mA energy source, WLEDs which has the QDs-on-phosphor form attained luminous efficiency (LE) of 110 lm/W, with color rendering index (CRI) of Ra=92 and R9=80, whereas the WLEDs which has the phosphor-on-QDs form only has 68 lm/W in LE, Ra=57 and R9=24. Furthermore, WLEDs which has the QDs-on-phosphor form has less high temperature generated at the components’ conjunction in comparison to the counterpart, the peak generated heat in QDs-on-phosphor WLEDs is also lower and the heating capacity gap between 2 structures can go up to 12.3°C.
Research on advancing chromatic reproduction and luminosity of a WLED using t...TELKOMNIKA JOURNAL
In this study, the use of triple-sheet phosphor arrangement (TRP) in performing significant improvements to both color quality and luminous flux of white light emitting diode (WLEDs) is introduced. The phosphor layer of CaLaB3O7:Ce3+,Mn2+ is to accomplish green-spectra enhancement for the boost of luminous efficacy (LE), while MgB2O4:Mn2+ red phosphor layer is for red-spectra enhancement to better color rendering index (CRI) of WLEDs. The changes in these two phosphors’ concentrations present considerable effects on the yellow phosphor YAG:Ce3+ concentration, the color quality scale (CQS), CRI, and LE. Findings display the decrease of YAG:Ce3+ concentration accompanying the increase of red and green phosphor concentrations, for the stabilized average correlated color temperatures (ACCTs) between 6000 and 8500 K. Results also reveal that greater content of MgB2O4:Mn2+ leads to greater CRI value. Meanwhile using the increasing CaLaB3O7:Ce3+,Mn2+ concentration, the CRI lowers considerably. CQS, on the other hand, can increase with CaLaB3O7:Ce3+,Mn2+ concentration from 10% to 14%. Especially, given the enhancement for the CRI as well as CQS, LE value will surge to more than 40% due to the reduction of scattering light and the addition of green light. The outcome of the study is a priceless reference for light emitting diode (LED) producers.
Improvement of double-layer phosphor structure WLEDS in color homogeneity and...journalBEEI
The concept of the analysis is to put a CaAl2O4:Mn2+ green phosphor layer on top of the YAG:Ce3+ yellow phosphor layer. After that, find the added CaAl2O4:Mn2+ concentration appropriate for the highest luminous flux (LF) and color homogeneity (CH). In this analysis, five equivalent WLEDs were applied but with distinct color temperatures, including 5600 K - 8500 K. The findings showed that CaAl2O4:Mn2+ brings great benefits to increase not only the luminous flux but also the color homogeneity. Especially, the higher the CaAl2O4:Mn2+ concentration, the more the luminous flux released by WLEDs, owing to the risen content of the light of green in WLEDs. Nevertheless, as the CaAl2O4:Mn2+ concentration raised significantly, a small reduction in the color rendering metric (CRI) and color quality scale (CQS) occurred. This is supported by simulation and calculation according to the theory of Monte Carlo. The paper results are the crucial contribution to the manufacture of WLEDs with better optical performance and color homogeneity of remote phosphor configurations.
The improvement of the color rendering index using convex-dual-layer remote p...TELKOMNIKA JOURNAL
White-light emitting diodes (WLEDs) are semiconductor light sources whose construction design is usually made up of a single pumping chip and a single light-conversion film of phosphor compound. The outstanding problem of this traditional setting is the inadequate chroma rendering index (CRI). Introducing a cluster of multiple blue chips with more than one phosphor layer is demonstrated to address that flaw of W-LEDs. This package is called the dual-film remote-phosphor multi-chip WLED. As a consequence, both the light brightness and the CRI are improved. However, for the maximum results, the test on the second layer of phosphor has been performed to continually alter the proportions and densities of phosphor within the silicone. The researchers employed a unique hue design to control the white-light light emitting diode (LED) module. When comparing the actual result to the simulated color coordinates under the hue standard of international commission on illumination (CIE) 1931, the highest difference is found to be around 0.0063 for correlated color temperatures (CCT) of 6600 K and 7700 K. Experiments indicate that the setting of multi-chip and dual-phosphorus is the optimal design for supporting CRI quality and luminous intensity.
Application of green-emitting ZnS:Eu2+ for boosting the spectrum of white li...IJECEIAES
Through utilizing a nonlinear application to acquire the best lumen efficiency (LE) for radiation (also known as LER) when color rendering index (CRI) value, especially CRI of R9 for strong red exceeds 90 with correlated color temperature (CCT) range of 2700-6500 K, the white light emitting diodes (WLED) package with adjustable CCT value and comprised of mixed-type light-emitting diodes (LEDs) can be acquired. The WLED model here contains blue and red LEDs with direct emission and a phosphorconversion blue LED or pc/B-LED (including orange and green phosphors mixed with blue LED colorant). The peak wavelengths of each LED constituent are 465 and 628 nm for LEDs in blue and red, 452 nm for the blue LED colorant, 530 and 586 nm for the phosphors exhibiting green and orange colors. Under the CCT of 2722-6464 K, the attained actual LED package, either with conversion phosphor, in red or in blue, possibly displays both CRI and R9 values measured from 90 to 96, color quality scale (CQS) values measured from 89 to 94, with LERs and LEs of 303-358 lm/W and 105-119 lm/W, respectively.
Similar to The effects of ZnO particles on the color homogeneity of phosphor-converted high-power white led light sources (20)
Redefining brain tumor segmentation: a cutting-edge convolutional neural netw...IJECEIAES
Medical image analysis has witnessed significant advancements with deep learning techniques. In the domain of brain tumor segmentation, the ability to
precisely delineate tumor boundaries from magnetic resonance imaging (MRI)
scans holds profound implications for diagnosis. This study presents an ensemble convolutional neural network (CNN) with transfer learning, integrating
the state-of-the-art Deeplabv3+ architecture with the ResNet18 backbone. The
model is rigorously trained and evaluated, exhibiting remarkable performance
metrics, including an impressive global accuracy of 99.286%, a high-class accuracy of 82.191%, a mean intersection over union (IoU) of 79.900%, a weighted
IoU of 98.620%, and a Boundary F1 (BF) score of 83.303%. Notably, a detailed comparative analysis with existing methods showcases the superiority of
our proposed model. These findings underscore the model’s competence in precise brain tumor localization, underscoring its potential to revolutionize medical
image analysis and enhance healthcare outcomes. This research paves the way
for future exploration and optimization of advanced CNN models in medical
imaging, emphasizing addressing false positives and resource efficiency.
Embedded machine learning-based road conditions and driving behavior monitoringIJECEIAES
Car accident rates have increased in recent years, resulting in losses in human lives, properties, and other financial costs. An embedded machine learning-based system is developed to address this critical issue. The system can monitor road conditions, detect driving patterns, and identify aggressive driving behaviors. The system is based on neural networks trained on a comprehensive dataset of driving events, driving styles, and road conditions. The system effectively detects potential risks and helps mitigate the frequency and impact of accidents. The primary goal is to ensure the safety of drivers and vehicles. Collecting data involved gathering information on three key road events: normal street and normal drive, speed bumps, circular yellow speed bumps, and three aggressive driving actions: sudden start, sudden stop, and sudden entry. The gathered data is processed and analyzed using a machine learning system designed for limited power and memory devices. The developed system resulted in 91.9% accuracy, 93.6% precision, and 92% recall. The achieved inference time on an Arduino Nano 33 BLE Sense with a 32-bit CPU running at 64 MHz is 34 ms and requires 2.6 kB peak RAM and 139.9 kB program flash memory, making it suitable for resource-constrained embedded systems.
Advanced control scheme of doubly fed induction generator for wind turbine us...IJECEIAES
This paper describes a speed control device for generating electrical energy on an electricity network based on the doubly fed induction generator (DFIG) used for wind power conversion systems. At first, a double-fed induction generator model was constructed. A control law is formulated to govern the flow of energy between the stator of a DFIG and the energy network using three types of controllers: proportional integral (PI), sliding mode controller (SMC) and second order sliding mode controller (SOSMC). Their different results in terms of power reference tracking, reaction to unexpected speed fluctuations, sensitivity to perturbations, and resilience against machine parameter alterations are compared. MATLAB/Simulink was used to conduct the simulations for the preceding study. Multiple simulations have shown very satisfying results, and the investigations demonstrate the efficacy and power-enhancing capabilities of the suggested control system.
Neural network optimizer of proportional-integral-differential controller par...IJECEIAES
Wide application of proportional-integral-differential (PID)-regulator in industry requires constant improvement of methods of its parameters adjustment. The paper deals with the issues of optimization of PID-regulator parameters with the use of neural network technology methods. A methodology for choosing the architecture (structure) of neural network optimizer is proposed, which consists in determining the number of layers, the number of neurons in each layer, as well as the form and type of activation function. Algorithms of neural network training based on the application of the method of minimizing the mismatch between the regulated value and the target value are developed. The method of back propagation of gradients is proposed to select the optimal training rate of neurons of the neural network. The neural network optimizer, which is a superstructure of the linear PID controller, allows increasing the regulation accuracy from 0.23 to 0.09, thus reducing the power consumption from 65% to 53%. The results of the conducted experiments allow us to conclude that the created neural superstructure may well become a prototype of an automatic voltage regulator (AVR)-type industrial controller for tuning the parameters of the PID controller.
An improved modulation technique suitable for a three level flying capacitor ...IJECEIAES
This research paper introduces an innovative modulation technique for controlling a 3-level flying capacitor multilevel inverter (FCMLI), aiming to streamline the modulation process in contrast to conventional methods. The proposed
simplified modulation technique paves the way for more straightforward and
efficient control of multilevel inverters, enabling their widespread adoption and
integration into modern power electronic systems. Through the amalgamation of
sinusoidal pulse width modulation (SPWM) with a high-frequency square wave
pulse, this controlling technique attains energy equilibrium across the coupling
capacitor. The modulation scheme incorporates a simplified switching pattern
and a decreased count of voltage references, thereby simplifying the control
algorithm.
A review on features and methods of potential fishing zoneIJECEIAES
This review focuses on the importance of identifying potential fishing zones in seawater for sustainable fishing practices. It explores features like sea surface temperature (SST) and sea surface height (SSH), along with classification methods such as classifiers. The features like SST, SSH, and different classifiers used to classify the data, have been figured out in this review study. This study underscores the importance of examining potential fishing zones using advanced analytical techniques. It thoroughly explores the methodologies employed by researchers, covering both past and current approaches. The examination centers on data characteristics and the application of classification algorithms for classification of potential fishing zones. Furthermore, the prediction of potential fishing zones relies significantly on the effectiveness of classification algorithms. Previous research has assessed the performance of models like support vector machines, naïve Bayes, and artificial neural networks (ANN). In the previous result, the results of support vector machine (SVM) were 97.6% more accurate than naive Bayes's 94.2% to classify test data for fisheries classification. By considering the recent works in this area, several recommendations for future works are presented to further improve the performance of the potential fishing zone models, which is important to the fisheries community.
Electrical signal interference minimization using appropriate core material f...IJECEIAES
As demand for smaller, quicker, and more powerful devices rises, Moore's law is strictly followed. The industry has worked hard to make little devices that boost productivity. The goal is to optimize device density. Scientists are reducing connection delays to improve circuit performance. This helped them understand three-dimensional integrated circuit (3D IC) concepts, which stack active devices and create vertical connections to diminish latency and lower interconnects. Electrical involvement is a big worry with 3D integrates circuits. Researchers have developed and tested through silicon via (TSV) and substrates to decrease electrical wave involvement. This study illustrates a novel noise coupling reduction method using several electrical involvement models. A 22% drop in electrical involvement from wave-carrying to victim TSVs introduces this new paradigm and improves system performance even at higher THz frequencies.
Electric vehicle and photovoltaic advanced roles in enhancing the financial p...IJECEIAES
Climate change's impact on the planet forced the United Nations and governments to promote green energies and electric transportation. The deployments of photovoltaic (PV) and electric vehicle (EV) systems gained stronger momentum due to their numerous advantages over fossil fuel types. The advantages go beyond sustainability to reach financial support and stability. The work in this paper introduces the hybrid system between PV and EV to support industrial and commercial plants. This paper covers the theoretical framework of the proposed hybrid system including the required equation to complete the cost analysis when PV and EV are present. In addition, the proposed design diagram which sets the priorities and requirements of the system is presented. The proposed approach allows setup to advance their power stability, especially during power outages. The presented information supports researchers and plant owners to complete the necessary analysis while promoting the deployment of clean energy. The result of a case study that represents a dairy milk farmer supports the theoretical works and highlights its advanced benefits to existing plants. The short return on investment of the proposed approach supports the paper's novelty approach for the sustainable electrical system. In addition, the proposed system allows for an isolated power setup without the need for a transmission line which enhances the safety of the electrical network
Bibliometric analysis highlighting the role of women in addressing climate ch...IJECEIAES
Fossil fuel consumption increased quickly, contributing to climate change
that is evident in unusual flooding and draughts, and global warming. Over
the past ten years, women's involvement in society has grown dramatically,
and they succeeded in playing a noticeable role in reducing climate change.
A bibliometric analysis of data from the last ten years has been carried out to
examine the role of women in addressing the climate change. The analysis's
findings discussed the relevant to the sustainable development goals (SDGs),
particularly SDG 7 and SDG 13. The results considered contributions made
by women in the various sectors while taking geographic dispersion into
account. The bibliometric analysis delves into topics including women's
leadership in environmental groups, their involvement in policymaking, their
contributions to sustainable development projects, and the influence of
gender diversity on attempts to mitigate climate change. This study's results
highlight how women have influenced policies and actions related to climate
change, point out areas of research deficiency and recommendations on how
to increase role of the women in addressing the climate change and
achieving sustainability. To achieve more successful results, this initiative
aims to highlight the significance of gender equality and encourage
inclusivity in climate change decision-making processes.
Voltage and frequency control of microgrid in presence of micro-turbine inter...IJECEIAES
The active and reactive load changes have a significant impact on voltage
and frequency. In this paper, in order to stabilize the microgrid (MG) against
load variations in islanding mode, the active and reactive power of all
distributed generators (DGs), including energy storage (battery), diesel
generator, and micro-turbine, are controlled. The micro-turbine generator is
connected to MG through a three-phase to three-phase matrix converter, and
the droop control method is applied for controlling the voltage and
frequency of MG. In addition, a method is introduced for voltage and
frequency control of micro-turbines in the transition state from gridconnected mode to islanding mode. A novel switching strategy of the matrix
converter is used for converting the high-frequency output voltage of the
micro-turbine to the grid-side frequency of the utility system. Moreover,
using the switching strategy, the low-order harmonics in the output current
and voltage are not produced, and consequently, the size of the output filter
would be reduced. In fact, the suggested control strategy is load-independent
and has no frequency conversion restrictions. The proposed approach for
voltage and frequency regulation demonstrates exceptional performance and
favorable response across various load alteration scenarios. The suggested
strategy is examined in several scenarios in the MG test systems, and the
simulation results are addressed.
Enhancing battery system identification: nonlinear autoregressive modeling fo...IJECEIAES
Precisely characterizing Li-ion batteries is essential for optimizing their
performance, enhancing safety, and prolonging their lifespan across various
applications, such as electric vehicles and renewable energy systems. This
article introduces an innovative nonlinear methodology for system
identification of a Li-ion battery, employing a nonlinear autoregressive with
exogenous inputs (NARX) model. The proposed approach integrates the
benefits of nonlinear modeling with the adaptability of the NARX structure,
facilitating a more comprehensive representation of the intricate
electrochemical processes within the battery. Experimental data collected
from a Li-ion battery operating under diverse scenarios are employed to
validate the effectiveness of the proposed methodology. The identified
NARX model exhibits superior accuracy in predicting the battery's behavior
compared to traditional linear models. This study underscores the
importance of accounting for nonlinearities in battery modeling, providing
insights into the intricate relationships between state-of-charge, voltage, and
current under dynamic conditions.
Smart grid deployment: from a bibliometric analysis to a surveyIJECEIAES
Smart grids are one of the last decades' innovations in electrical energy.
They bring relevant advantages compared to the traditional grid and
significant interest from the research community. Assessing the field's
evolution is essential to propose guidelines for facing new and future smart
grid challenges. In addition, knowing the main technologies involved in the
deployment of smart grids (SGs) is important to highlight possible
shortcomings that can be mitigated by developing new tools. This paper
contributes to the research trends mentioned above by focusing on two
objectives. First, a bibliometric analysis is presented to give an overview of
the current research level about smart grid deployment. Second, a survey of
the main technological approaches used for smart grid implementation and
their contributions are highlighted. To that effect, we searched the Web of
Science (WoS), and the Scopus databases. We obtained 5,663 documents
from WoS and 7,215 from Scopus on smart grid implementation or
deployment. With the extraction limitation in the Scopus database, 5,872 of
the 7,215 documents were extracted using a multi-step process. These two
datasets have been analyzed using a bibliometric tool called bibliometrix.
The main outputs are presented with some recommendations for future
research.
Use of analytical hierarchy process for selecting and prioritizing islanding ...IJECEIAES
One of the problems that are associated to power systems is islanding
condition, which must be rapidly and properly detected to prevent any
negative consequences on the system's protection, stability, and security.
This paper offers a thorough overview of several islanding detection
strategies, which are divided into two categories: classic approaches,
including local and remote approaches, and modern techniques, including
techniques based on signal processing and computational intelligence.
Additionally, each approach is compared and assessed based on several
factors, including implementation costs, non-detected zones, declining
power quality, and response times using the analytical hierarchy process
(AHP). The multi-criteria decision-making analysis shows that the overall
weight of passive methods (24.7%), active methods (7.8%), hybrid methods
(5.6%), remote methods (14.5%), signal processing-based methods (26.6%),
and computational intelligent-based methods (20.8%) based on the
comparison of all criteria together. Thus, it can be seen from the total weight
that hybrid approaches are the least suitable to be chosen, while signal
processing-based methods are the most appropriate islanding detection
method to be selected and implemented in power system with respect to the
aforementioned factors. Using Expert Choice software, the proposed
hierarchy model is studied and examined.
Enhancing of single-stage grid-connected photovoltaic system using fuzzy logi...IJECEIAES
The power generated by photovoltaic (PV) systems is influenced by
environmental factors. This variability hampers the control and utilization of
solar cells' peak output. In this study, a single-stage grid-connected PV
system is designed to enhance power quality. Our approach employs fuzzy
logic in the direct power control (DPC) of a three-phase voltage source
inverter (VSI), enabling seamless integration of the PV connected to the
grid. Additionally, a fuzzy logic-based maximum power point tracking
(MPPT) controller is adopted, which outperforms traditional methods like
incremental conductance (INC) in enhancing solar cell efficiency and
minimizing the response time. Moreover, the inverter's real-time active and
reactive power is directly managed to achieve a unity power factor (UPF).
The system's performance is assessed through MATLAB/Simulink
implementation, showing marked improvement over conventional methods,
particularly in steady-state and varying weather conditions. For solar
irradiances of 500 and 1,000 W/m2
, the results show that the proposed
method reduces the total harmonic distortion (THD) of the injected current
to the grid by approximately 46% and 38% compared to conventional
methods, respectively. Furthermore, we compare the simulation results with
IEEE standards to evaluate the system's grid compatibility.
Enhancing photovoltaic system maximum power point tracking with fuzzy logic-b...IJECEIAES
Photovoltaic systems have emerged as a promising energy resource that
caters to the future needs of society, owing to their renewable, inexhaustible,
and cost-free nature. The power output of these systems relies on solar cell
radiation and temperature. In order to mitigate the dependence on
atmospheric conditions and enhance power tracking, a conventional
approach has been improved by integrating various methods. To optimize
the generation of electricity from solar systems, the maximum power point
tracking (MPPT) technique is employed. To overcome limitations such as
steady-state voltage oscillations and improve transient response, two
traditional MPPT methods, namely fuzzy logic controller (FLC) and perturb
and observe (P&O), have been modified. This research paper aims to
simulate and validate the step size of the proposed modified P&O and FLC
techniques within the MPPT algorithm using MATLAB/Simulink for
efficient power tracking in photovoltaic systems.
Adaptive synchronous sliding control for a robot manipulator based on neural ...IJECEIAES
Robot manipulators have become important equipment in production lines, medical fields, and transportation. Improving the quality of trajectory tracking for
robot hands is always an attractive topic in the research community. This is a
challenging problem because robot manipulators are complex nonlinear systems
and are often subject to fluctuations in loads and external disturbances. This
article proposes an adaptive synchronous sliding control scheme to improve trajectory tracking performance for a robot manipulator. The proposed controller
ensures that the positions of the joints track the desired trajectory, synchronize
the errors, and significantly reduces chattering. First, the synchronous tracking
errors and synchronous sliding surfaces are presented. Second, the synchronous
tracking error dynamics are determined. Third, a robust adaptive control law is
designed,the unknown components of the model are estimated online by the neural network, and the parameters of the switching elements are selected by fuzzy
logic. The built algorithm ensures that the tracking and approximation errors
are ultimately uniformly bounded (UUB). Finally, the effectiveness of the constructed algorithm is demonstrated through simulation and experimental results.
Simulation and experimental results show that the proposed controller is effective with small synchronous tracking errors, and the chattering phenomenon is
significantly reduced.
Remote field-programmable gate array laboratory for signal acquisition and de...IJECEIAES
A remote laboratory utilizing field-programmable gate array (FPGA) technologies enhances students’ learning experience anywhere and anytime in embedded system design. Existing remote laboratories prioritize hardware access and visual feedback for observing board behavior after programming, neglecting comprehensive debugging tools to resolve errors that require internal signal acquisition. This paper proposes a novel remote embeddedsystem design approach targeting FPGA technologies that are fully interactive via a web-based platform. Our solution provides FPGA board access and debugging capabilities beyond the visual feedback provided by existing remote laboratories. We implemented a lab module that allows users to seamlessly incorporate into their FPGA design. The module minimizes hardware resource utilization while enabling the acquisition of a large number of data samples from the signal during the experiments by adaptively compressing the signal prior to data transmission. The results demonstrate an average compression ratio of 2.90 across three benchmark signals, indicating efficient signal acquisition and effective debugging and analysis. This method allows users to acquire more data samples than conventional methods. The proposed lab allows students to remotely test and debug their designs, bridging the gap between theory and practice in embedded system design.
Detecting and resolving feature envy through automated machine learning and m...IJECEIAES
Efficiently identifying and resolving code smells enhances software project quality. This paper presents a novel solution, utilizing automated machine learning (AutoML) techniques, to detect code smells and apply move method refactoring. By evaluating code metrics before and after refactoring, we assessed its impact on coupling, complexity, and cohesion. Key contributions of this research include a unique dataset for code smell classification and the development of models using AutoGluon for optimal performance. Furthermore, the study identifies the top 20 influential features in classifying feature envy, a well-known code smell, stemming from excessive reliance on external classes. We also explored how move method refactoring addresses feature envy, revealing reduced coupling and complexity, and improved cohesion, ultimately enhancing code quality. In summary, this research offers an empirical, data-driven approach, integrating AutoML and move method refactoring to optimize software project quality. Insights gained shed light on the benefits of refactoring on code quality and the significance of specific features in detecting feature envy. Future research can expand to explore additional refactoring techniques and a broader range of code metrics, advancing software engineering practices and standards.
Smart monitoring technique for solar cell systems using internet of things ba...IJECEIAES
Rapidly and remotely monitoring and receiving the solar cell systems status parameters, solar irradiance, temperature, and humidity, are critical issues in enhancement their efficiency. Hence, in the present article an improved smart prototype of internet of things (IoT) technique based on embedded system through NodeMCU ESP8266 (ESP-12E) was carried out experimentally. Three different regions at Egypt; Luxor, Cairo, and El-Beheira cities were chosen to study their solar irradiance profile, temperature, and humidity by the proposed IoT system. The monitoring data of solar irradiance, temperature, and humidity were live visualized directly by Ubidots through hypertext transfer protocol (HTTP) protocol. The measured solar power radiation in Luxor, Cairo, and El-Beheira ranged between 216-1000, 245-958, and 187-692 W/m 2 respectively during the solar day. The accuracy and rapidity of obtaining monitoring results using the proposed IoT system made it a strong candidate for application in monitoring solar cell systems. On the other hand, the obtained solar power radiation results of the three considered regions strongly candidate Luxor and Cairo as suitable places to build up a solar cells system station rather than El-Beheira.
An efficient security framework for intrusion detection and prevention in int...IJECEIAES
Over the past few years, the internet of things (IoT) has advanced to connect billions of smart devices to improve quality of life. However, anomalies or malicious intrusions pose several security loopholes, leading to performance degradation and threat to data security in IoT operations. Thereby, IoT security systems must keep an eye on and restrict unwanted events from occurring in the IoT network. Recently, various technical solutions based on machine learning (ML) models have been derived towards identifying and restricting unwanted events in IoT. However, most ML-based approaches are prone to miss-classification due to inappropriate feature selection. Additionally, most ML approaches applied to intrusion detection and prevention consider supervised learning, which requires a large amount of labeled data to be trained. Consequently, such complex datasets are impossible to source in a large network like IoT. To address this problem, this proposed study introduces an efficient learning mechanism to strengthen the IoT security aspects. The proposed algorithm incorporates supervised and unsupervised approaches to improve the learning models for intrusion detection and mitigation. Compared with the related works, the experimental outcome shows that the model performs well in a benchmark dataset. It accomplishes an improved detection accuracy of approximately 99.21%.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapte...University of Maribor
Slides from talk presenting:
Aleš Zamuda: Presentation of IEEE Slovenia CIS (Computational Intelligence Society) Chapter and Networking.
Presentation at IcETRAN 2024 session:
"Inter-Society Networking Panel GRSS/MTT-S/CIS
Panel Session: Promoting Connection and Cooperation"
IEEE Slovenia GRSS
IEEE Serbia and Montenegro MTT-S
IEEE Slovenia CIS
11TH INTERNATIONAL CONFERENCE ON ELECTRICAL, ELECTRONIC AND COMPUTING ENGINEERING
3-6 June 2024, Niš, Serbia
International Conference on NLP, Artificial Intelligence, Machine Learning an...gerogepatton
International Conference on NLP, Artificial Intelligence, Machine Learning and Applications (NLAIM 2024) offers a premier global platform for exchanging insights and findings in the theory, methodology, and applications of NLP, Artificial Intelligence, Machine Learning, and their applications. The conference seeks substantial contributions across all key domains of NLP, Artificial Intelligence, Machine Learning, and their practical applications, aiming to foster both theoretical advancements and real-world implementations. With a focus on facilitating collaboration between researchers and practitioners from academia and industry, the conference serves as a nexus for sharing the latest developments in the field.
Low power architecture of logic gates using adiabatic techniquesnooriasukmaningtyas
The growing significance of portable systems to limit power consumption in ultra-large-scale-integration chips of very high density, has recently led to rapid and inventive progresses in low-power design. The most effective technique is adiabatic logic circuit design in energy-efficient hardware. This paper presents two adiabatic approaches for the design of low power circuits, modified positive feedback adiabatic logic (modified PFAL) and the other is direct current diode based positive feedback adiabatic logic (DC-DB PFAL). Logic gates are the preliminary components in any digital circuit design. By improving the performance of basic gates, one can improvise the whole system performance. In this paper proposed circuit design of the low power architecture of OR/NOR, AND/NAND, and XOR/XNOR gates are presented using the said approaches and their results are analyzed for powerdissipation, delay, power-delay-product and rise time and compared with the other adiabatic techniques along with the conventional complementary metal oxide semiconductor (CMOS) designs reported in the literature. It has been found that the designs with DC-DB PFAL technique outperform with the percentage improvement of 65% for NOR gate and 7% for NAND gate and 34% for XNOR gate over the modified PFAL techniques at 10 MHz respectively.
A review on techniques and modelling methodologies used for checking electrom...nooriasukmaningtyas
The proper function of the integrated circuit (IC) in an inhibiting electromagnetic environment has always been a serious concern throughout the decades of revolution in the world of electronics, from disjunct devices to today’s integrated circuit technology, where billions of transistors are combined on a single chip. The automotive industry and smart vehicles in particular, are confronting design issues such as being prone to electromagnetic interference (EMI). Electronic control devices calculate incorrect outputs because of EMI and sensors give misleading values which can prove fatal in case of automotives. In this paper, the authors have non exhaustively tried to review research work concerned with the investigation of EMI in ICs and prediction of this EMI using various modelling methodologies and measurement setups.
Introduction- e - waste – definition - sources of e-waste– hazardous substances in e-waste - effects of e-waste on environment and human health- need for e-waste management– e-waste handling rules - waste minimization techniques for managing e-waste – recycling of e-waste - disposal treatment methods of e- waste – mechanism of extraction of precious metal from leaching solution-global Scenario of E-waste – E-waste in India- case studies.
2. ISSN: 2088-8708
Int J Elec & Comp Eng, Vol. 10, No. 5, October 2020 : 5155 - 5561
5156
between metals such as TiO2, ZrO2 and SiO2 have been utilized in several LED configuration to stabilize
the CTT [17-21]. Chen and his partners applied TiO2 diffuser-loaded encapsulation to accomplish
the enhancement in CCT uniformity as well as the reduction in CCT variance of remote phosphor white
LEDs. Their research demonstrated the increases of angular color uniformity and luminous flux by 31.82%
and 8.65%, respectively, when TiO2 diffuser is utilized. Another paper of Liang et al. considered TiO2 as
a potential element to proposed UV/TiO2, a treatment for hazardous organic pollutants, because it is a catalyst
that can give a constant oxidant source to water without having to be replenished. Besides, the team of Geng
and Xu has already practiced the application of SiO2 by forming the composition QDs-SiO2-BNAs and used
it to create QDs-SiO2-BN nanoplate, which can eliminate thermal quenching, an effect induced by inadequate
heat conduction and the high heat retaining limit in QDs-SiO2 material, and improve the stability of QDs in
LEDs. In addition to these aforementioned materials, researchers also interested in combining CaF2 with
other phosphor patterns to enhance the performance of WLEDs, owing to the outstanding optical properties
and high thermal conductivity of this particle. Bhanvase’s team is one of those researchers, and in their 2018
paper, they exhibited the optical and structural properties of CaF2:Eu3+
synthesized by using ultrasound
assisted method. According to their researches, the new synthesized CaF2:Eu3+
phosphor has excitation band
that agrees with the excitation range of LED; moreover, the Eu3+
ions elements has the peak excitation
at 394 nm and exhibits 591 nm and 612 nm emission bands. Thus, they concluded that this CaF2:Eu3+
can
be a good red emitting material. In 2019, continuing investigating the application of CaF2, Xie and
Wang and their partners proposed CaF2-YAG:Ce phosphor ceramic, which includes yellow-emitting YAG:Ce
particles mixed with a non-luminescent CaF2 ceramic matrix. The results from their study showed that
CaF2-YAG:Ce phosphor ceramic increase the optical performance of WLEDs, specifically, the increased
luminous flux, CCT and CRI are 359.7 lm, 4021-7941 K and 70.1-82.7, respectively. The potential to boost
the effectiveness of these nanoparticles is high as they are compact and flexible which open directions for
alterations yet there are not many manuscripts on utilizing nanoparticles in a creative structure as most
research concentrate on how WLEDs react to the particles [22-24]. In the meantime, because of the lack of
concentrated speculations and complex specialized direction, choosing an optimal nanoparticles material to
effectively enhance the CCT is quite confusing and repetitive, especially for manufacturers.
As the search continues, nanostructure containing ZnO came across as a preferable solution above
considering how easy it is to operate, manufacture and monitor [25, 26]. The nanostructure containing ZnO
with the refractive index of (n= 2.0) can act as a slope refractive record layer between GaN and air with
refractive indices respectively being (n = 2.5) and (n = 1), providing that other elements that follow such as
thermal performance, duration, and antecedent focus are accounted for. The finding in recent research that
prove the use of ZnO in enhancing the effective of light extraction process in LEDs devices through
experiments integrating ZnO in specialized nanostructure has inspired many innovative applications.
Yet many possibilities are still neglected for ZnO utilization in improving other lighting criteria with Drove
bundling beside the light output, specifically the effects of different ZnO particles structure on light power
and CCT consistency. With that being said, the focus of research should be moved to these area for new
discovery of ZnO nanostructure potential to improve light energy and CCT. Hence, acknowledging
the remaining issues, this paper will present the effect of ZnO on the performance of WLEDs based on
an analysis of ZnO morphologies, which has not been done in any aforementioned studies. Particularly,
the impacts of the particle size and concentration of ZnO are investigated and demonstrated through
mathematic system and figures. The attain results will provide a basis for selecting suitable ZnO’s parameters
that serve the demands of improving lumen efficacy and color homogeneity of WLED. Through
measurement of scattering events in the WLED, the effect of size and concentration of ZnO is clarified.
Research results are valuable reference for the application of ZnO.
2. RESEARCH METHOD
2.1. Physical and optoelectronic characterization
From Figure 1(a), we can observe the physical model of WLED with ZnO traits that is used in all
the experiments presented in this research. The schematic image of WLED cross-section in Figure 1(b)
demonstrates how arrangement of the component inside the device. The constructing process of this WLED
model is conducted in the following sequence: first, a blue chip with GaN traits which emits at 450 nm and
has the appraised intensity of 1 W at a 350 mA current was put in the business lead-outline bundle.
Then, a composition of YAG:Ce yellow phosphor (D half, 13 ± 2 µm) and silicone glue is form in
12 minutes with a vacuum homogenizer running at 1360 rpm and 0.2 MPa (the weight proportion between
the yellow phosphor and the silicone is 3:8). The composition is diffused on the surrounding of the blue chip
and dried at 120°C for 3 hours to form a phosphor coating layer. A glass hemisphere is put above
the compound to protect it from contamination and impact. The final step would be curing the ZnO
3. Int J Elec & Comp Eng ISSN: 2088-8708
The effects of ZnO particles on the color homogeneity of phosphor-converted... (Nguyen Thi Phuong Loan)
5157
nanoparticles by blending vacuumed environment and degassed before inserting them into the phosphor
structure. The final mixture should be left till dried in room temperature at approximately 25°C. The field
emission scanning electron microscope (FE-SEM, Merlin) is the tool to draft the surface structure of ZnO.
The UV-Vis spectrometer (UV-Vis, Agilent Cary 5000) is used for the calculation of the transmission
efficiency in films with ZnO. The Electro-optical values in flims and WLEDs with ZnO were achieved using
a specialized system (Multi Spectrums T-950/930). The conducting process of measuring the mentioned
value are carried out in the same condition which is in the air and under consistent thermal condition (25°C).
(a) (b)
Figure 1. (a) Photograph of 9W WLED device and
(b) schematic cross-sectional view of ZnO-doped WLED devices
2.2. Mie-scattering analysis
To calculate the scattered quantum-dot-converted elements (QDCEs), we can utilized the equation
from Monte Carlo model [27] and apply the same way to measure the phosphor conversion in WLED.
The equation below expressed the scattering coefficient and scattering phase function, which can be
described as µsca and µsca (𝜆) respectively:
𝜇 𝑠𝑐𝑎 =
𝑐
𝑚̅
∫ 𝑓(𝐷) 𝐶𝑠𝑐𝑎(𝐷, 𝜆)𝑑𝐷 (1)
The scattering coefficient is the possibility that a scattering event occurs. The elements contribute to this
value which presented above are 𝑐 𝑚̅⁄ for the thickness of QDs particles; c describes the QD concentration
(mg/cm3
); D is the magnitude of particle in nm; 𝜆 is the measurement of wavelength in nm; f(D) is
the distribution function of QD particle in size; 𝑚̅ depicts QD’s mass (mg) in the QDCE, which can be
calculated by integrating over f(D); Csca(D, 𝜆) is the QD’s scattering cross-section, respectively, and can be
calculated by:
𝐶𝑠𝑐𝑎(𝐷, 𝜆) =
𝑃𝑠𝑐𝑎(𝐷, 𝜆)
𝑃𝑖𝑛𝑐(𝜆)
=
∫ 𝑃𝑠𝑐𝑎(𝐷, 𝜆)𝑑𝜃
𝑃𝑖𝑛𝑐(𝜆)
(2)
In which, 𝑃𝑖𝑛𝑐(𝜆) is the source incident radiation (W/m2
); 𝑃𝑠𝑐𝑎(𝐷, 𝜆)is the scattering energy (W), when light
transmits through the QD; 𝑃𝑠𝑐𝑎(𝜃, 𝐷, 𝜆) is the scattering power (W). The phase function of scattering that
depicts the distribution of scattered energy meets the normalization conditions and can be observed in
simplified form below:
𝜌(𝜃, 𝜆) =
∫ 𝑓(𝐷)𝜌𝑠𝑐𝑎(𝜃, 𝐷, 𝜆) 𝑃𝑠𝑐𝑎(𝐷, 𝜆)𝐶𝑠𝑐𝑎(𝐷, 𝜆)𝑑𝐷⁄
∫ 𝑓(𝐷) 𝐶𝑠𝑐𝑎(𝐷, 𝜆)𝑑𝐷
(3)
3. RESULTS AND ANALYSIS
To assess the effects of ZnO particles size on the scattering efficiency of WLED, we must consider
different magnitude of ZnO particles with each distinct scattering feature. For example, the scattering
cross-section of the ZnO particles, 𝐶𝑠𝑐𝑎(𝐷, 𝜆) with the size varies from 400 nm, 500 nm to 600 nm,
are shown in Figure 2(a-c). As the ZnO size increases, 𝐶𝑠𝑐𝑎(𝐷, 𝜆) also increases, resulting in stronger
scattering ability. Light tends to transmit straight to larger particles, which is beneficial to luminous flux.
In contrast, light scatters in all directions with small particles. This is conducive to color uniformity but not
4. ISSN: 2088-8708
Int J Elec & Comp Eng, Vol. 10, No. 5, October 2020 : 5155 - 5561
5158
conducive to luminous flux. Dependent values 𝐶𝑠𝑐𝑎(𝐷, 𝜆) and wavelength values 𝐶𝑠𝑐𝑎(𝐷, 𝜆) decrease as
the wavelength increases. Moreover, it is noticed that within the 380 nm wavelength, the maximum value
𝐶𝑠𝑐𝑎(𝐷, 𝜆) can be achieved with all particle sizes. The scattering phase distributions are also measured
responding to the size of ZnO particles of 400 nm, 500 nm, and 600 nm to determine the influences on
scattering intensity.
(a) (b)
(c)
Figure 2. Scattering and cross-sections of ZnO particles with various sizes:
(a) 400 nm, (b) 500 nm, (c) 600 nm
Similar to 𝐶𝑠𝑐𝑎(𝐷, 𝜆), 𝜇 𝑠𝑐𝑎(𝜆) the value increases when the ZnO particle size increases.
This further confirmed the scattering ability of ZnO particles increased. However, the larger the wavelength
is, the smaller 𝜇 𝑠𝑐𝑎(𝜆) becomes. The maximum value is accomplished at 380 nm, which is suitable for
the application of ZnO particles to improve light quality. It is possible to explain this phenomenon to
𝐶𝑠𝑐𝑎(𝐷, 𝜆), 𝜇 𝑠𝑐𝑎(𝜆), like this:
- We need to increase the scattering ability in the layers of phosphor so that the emitted light are mixed
more times to make the white light emit color copper.
- Scattering value peaks at 380 nm, then gradually decreasing, and eventually reaching the smallest value at
780 nm. Meanwhile, the wavelength of the LED chip is 453 nm, which means that ZnO is suitable for
advanced scattering in phosphor layers.
The results of Figure 2 confirm that the larger the ZnO particle size, the greater the scattering
capacity. To determine which ZnO size is suitable for application, 𝜌(𝜃, 𝜆) should be considered. 𝜌(𝜃, 𝜆)
shows the angle of scattering intensity, thus selecting suitable ZnO particle size depends on scattering and
scattering ability. For large-sized particles, lights will be transmitted straight through them, leading to
the benefited lumen. With a smaller particle size, the light is dispersed in many directions, meaning that
5. Int J Elec & Comp Eng ISSN: 2088-8708
The effects of ZnO particles on the color homogeneity of phosphor-converted... (Nguyen Thi Phuong Loan)
5159
the scattering angle is large, and the energy of light is reduced by back scattering to the LED chip, resulting
in lower lumen output. However, due to this multiple light scattering, blue and yellow rays are mixed more
times before emitting from the phosphor layer to form white light.
Blue rays can be scattered more often with small ZnO particles. And these blue rays are sent to more
LED chip sides. At this point, there is a combination of blue rays and "yellow ring" to form white light.
The result are a reduction in the "yellow ring" effect and an improvement in color uniformity. The value
𝜌(𝜃, 𝜆) is clearly shown in Figure 3. The larger the ZnO particle size, the greater the intensity of scattering
but the smaller the scattering angle. These findings clearly demonstrate the significant effects of ZnO particle
sizes on two crucial optical properties of WLEDs, color uniformity and luminous flux. Thus, this helps
manufacturers figure out the suitable size of ZnO particles when applied them in production.
(a) (b)
(c)
Figure 3. Scattering phase distributions of ZnO particles with various sizes:
(a) 400 nm, (b) 500 nm, and (c) 600 nm
However, to investigate the lumen emitted, the size information is not enough. The emitted lumen
is also influenced by the concentration of ZnO in the phosphor layer, as presented in Figure 4.
As the concentration of ZnO increases, the passing lumen tends to decrease significantly at any size.
As the ZnO concentration increases, the scattering capacity also increases, and the energy for this large
scattering reduces the energy of light emitted. Therefore, choosing the right size and concentration of ZnO
becomes very important in production. Based on the result of Figure 4, ZnO concentration of about 10% can
be selected at any size to achieve the highest lumen. However, the goal of the study is not only the lumen
emitted, but also the color uniformity, so we continue to consider the results in Figure 5 which depicts
the reponse of ΔCCT in WLED to different size and concentration of ZnO.
With 14% ZnO, though ΔCCT does not reach the lowest level, it decreases significantly. Moreover,
ΔCCT has the lowest value with 500 nm ZnO at 14% concentration. In addition, it is easy to realize that
ΔCCT tends to decrease with the increasing concentration of ZnO. This can be explained by excessive
scattering in the phosphor layer, from which the amount of scattered blue light becomes redundant, especially
6. ISSN: 2088-8708
Int J Elec & Comp Eng, Vol. 10, No. 5, October 2020 : 5155 - 5561
5160
with smaller size of ZnO particles. To achieve color uniformity, which means that ΔCCT must be low, there
must be a balance between the intensity of blue and yellow. Calibration of the size and ZnO concentration
also aims at this. When the golden light prevailed, the "yellow ring" phenomenon appeared, the white light
emitted was warm white light. At this time, the scattering of blue light is next feature to improve. Therefore,
based on ZnO particle scattering survey through values 𝐶𝑠𝑐𝑎(𝐷, 𝜆), 𝜇 𝑠𝑐𝑎(𝜆) and 𝜌(𝜃, 𝜆), as well as
the investigation in the concentration of ZnO, we can fully select the suitable ZnO particle parameters for
application. If the manufacturer's request is a lumen emitted, 10% ZnO can be added to the phosphor layer
regardless of particles’ sizes. If the manufacturers aim to achieve the color uniformity, it is possible to choose
14% ZnO. And, if the manufacturer's goal is the enhancement in both lumen and color copper, 14% ZnO is
the most suitable option.
Figure 4. Lumen output of WLED as a function of the size and concentration of ZnO particles
Figure 5. ΔCCT of WLED as a function of the size and concentration of ZnO particles
4. CONCLUSION
The paper successfully presents the effects of ZnO particles in two aspects of WLED, color uniformity
and lumen output. In this study, we apply the mixture of ZnO and YAG:Ce in which the 400-600 nm ZnO were
added to YAG:Ce to increase the scattering in phosphor layer. Increased scattering is an idea to improve color
uniformity. However, it is necessary to select roofing to prevent excessive lumen emission. Through value
𝐶𝑠𝑐𝑎(𝐷, 𝜆), 𝜇 𝑠𝑐𝑎(𝜆) and 𝜌(𝜃, 𝜆) analysis, the paper analyzed the scattering of ZnO particles by size clearly.
Moreover, ZnO concentration is also mentioned so that producers have an overview of ZnO application.
In other words, this article analyzed the two important factors of ZnO application which are the size and
concentration through mathematic system and experiments. The proposed results show that lumen output of
WLED can achieve the highest value with 10% ZnO. Meanwhile, with 14% concentration and 500 nm particle
size of ZnO, ΔCCT reaches the lowest level. Depending on the production needs, manufacturers can choose
the most suitable concentration of ZnO. However, with both the required lumen and ΔCCT required, 14% ZnO
is suitable for applied ZnO sizes. With the useful information provided in this paper, we believe that
manufacturer can improve their WLED products by selecting suitable ZnO particles’ parameters.
7. Int J Elec & Comp Eng ISSN: 2088-8708
The effects of ZnO particles on the color homogeneity of phosphor-converted... (Nguyen Thi Phuong Loan)
5161
REFERENCES
[1] S. K. Abeysekera, et al., “Impact of circadian tuning on the illuminance and color uniformity of a multichannel
luminaire with spatially optimized LED placement,” Optics Express. vol. 28, issue 1, pp. 130-145, 2020.
[2] Q. W. Xu, et al., “Nanocrystal-filled polymer for improving angular color uniformity of phosphor-converted white
LEDs,” Applied Optics. vol. 58, issue 27, pp. 7649-7654, 2019.
[3] R. E. Christiansen, et al., “Inverse design of nanoparticles for enhanced Raman scattering,” Optics Express. vol. 28,
issue 4, pp. 4444-4462, 2020.
[4] Jiasheng, et al., “Color uniformity enhancement for COB WLEDs using a remote phosphor film with two freeform
surfaces,” Optics Express, vol. 24, issue 1, pp. 23685-23696, 2016.
[5] Yongzhang, et al., “Luminescence of Tb3+
/Eu3+
codoped LiYF4 single crystals under UV excitation for white-light
LEDs,” Chinese Optics Letters, vol. 13, issue 7, pp. 071601, 2015.
[6] Xiangtian, et al., “Improving the modulation bandwidth of LED by CdSe/ZnS quantum dots for visible light
communication,” Optics Express, vol. 24, issue 19, pp. 21577-21586, 2016.
[7] Yu, et al., “Phosphor-free Monolithic High-Efficiency White Light-Emitting-Diodes on Ternary InGaN
Substrates,” CLEO: OSA Technical Digest, pp. 1-2, 2015.
[8] Yanru, et al., “Composite phase ceramic phosphor of Al2O3-Ce:YAG for high efficiency light emitting,” Optics
Express, vol. 23, issue 14, pp. 17923-17928, 2015.
[9] Haibo, et al., “Cymbal-shaped phosphor structure for phosphor-converted white LEDs,” Optics Express, vol. 23,
no. 15, pp. A949-A956, 2015.
[10] Yun, et al., “Energy transfer induced improvement of luminescent efficiency and thermal stability in phosphate
phosphor,” Optics Express, vol. 24, issue 4, pp. 4316-4330, 2016.
[11] C. Fu, et al., “Raman determination of carrier concentration in ZnO-based heterostructure light-emitting diodes,”
Optics Letters, vol. 44, issue 7, pp. 1576-1579, 2019.
[12] Y. J. Park, et al., “Development of high luminous efficacy red-emitting phosphor-in-glass for high-power LED
lighting systems using our original low Tg and Ts glass,” Optics Letters, vol. 44, issue 24, pp. 6057-6060, 2019.
[13] Chiang, et al., “Effects of phosphor distribution and step-index remote configuration on the performance of white
light-emitting diodes,” Optics Letters, vol. 40, issue 12, pp. 2830-2833, 2015.
[14] Michael, et al., “High luminous flux from single crystal phosphor-converted laser-based white lighting system,”
Optics Express, vol. 24, issue 2, pp. A215-A221, 2016.
[15] Bin, et al., “Structural optimization for remote white light-emitting diodes with quantum dots and phosphor:
packaging sequence matters,” Optics Express, vol. 24, issue 26, pp. A1560-A1570, 2016.
[16] Le, et al., “Highly efficient narrow-band green and red phosphors enabling wider color-gamut LED backlight for
more brilliant displays,” Optics Express, vol. 23, issue 22, pp. 28707-28717, 2015.
[17] Shaojun, et al., “Energy transfer between Ce3+
and Tb3+
and the enhanced luminescence of a green phosphor
SrB2O4:Ce3+
, Tb3+
, Na+
,” Optical Materials Express, vol. 6, issue 4, pp. 1172-1185, 2016.
[18] Shudong, et al., “Angular color uniformity enhancement of white light-emitting diodes by remote micro-patterned
phosphor film,” Photonics Research, vol. 4, issue 4, pp. 140-145, 2016.
[19] Huajuan, et al., “Close-relationship between the luminescence and structural characteristics in efficient nano-
phosphor Y2Mo4O15:Eu3+
,” Optical Materials Express, vol. 5, issue 3, pp. 490-496, 2015.
[20] Linlin, et al., “Near-infrared quantum cutting in Nd3+
and Yb3+
Doped BaGd2ZnO5 phosphors,” Optical Materials
Express, vol. 5, issue 4, pp. 756-763, 2015.
[21] Hirokazu, et al., “High energy-transfer rate from Sn2+ to Mn2+ in phosphate glasses,” Optical Materials Express,
vol. 5, issue 3, pp. 617-622, 2015.
[22] Hiroyo, et al., “Europium-doped SiAlON and borosilicate glass composites for white light-emitting diode,” Applied
Optics, vol. 54, issue 29, pp. 8727-8730, 2015.
[23] Dick, et al., “High-brightness source based on luminescent concentration,” Optics Express, vol. 24, issue 14,
pp. A1069-A1074, 2016.
[24] Chen, et al., “Efficient hybrid white light-emitting diodes by organic-inorganic materials at different CCT from
3000K to 9000K,” Optics Express, vol. 23, issue 7, pp. A204-A210, 2015.
[25] S. -J. Kim, et al., “Enhanced performance of InGaN/GaN MQW LED with strain-relaxing Ga-doped ZnO
transparent conducting layer,” Optics Express, vol. 27, issue 8, pp. A458-A467, 2019.
[26] Z. Huang, et al., “Investigation on the p-type formation mechanism of nitrogen ion implanted ZnO thin films
induced by rapid thermal annealing,” Optical Materials Express, vol. 9, issue 7, pp. 3098-3108, 2019.
[27] J. X. Chen, et al., “Electroluminescence from light-emitting devices based on erbium-doped ZnO/n-Si
heterostructures: Enhancement effect of fluorine co-doping,” Optics Express, vol. 27, issue 21, pp. 30919-30930,
2019.