IOSR Journal of Applied Physics (IOSR-JAP) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of physics and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications in applied physics. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Study of Structural and Dielectric properties of BaTiO3 Doped with Mg-Cu-Zn F...IJSRD
The magnetoelectric (ME) composites having the general formula, (x) Mg0.25Cu0.25Zn0.5Fe2O4 + (1-x) BaTiO3 (x=15%, 30%, 45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO3 and highly magnetostrictive magnetic component Mg0.25Cu0.25Zn0.5Fe2O4. The presence of constituent phases of ferrite, ferroelectric and their composites were confirmed by X-ray diffraction (XRD) studies. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM), which revealed uniform mixing of two phases. The variations in dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz were measured in a Hioki LCR Hi-Tester. The dielectric constant and dielectric loss were found to decrease rapidly in the low frequency region and became almost constant in the high frequency region. The electrical conductivity deduced from the measured dielectric parameters has been analyzed and found that the conduction mechanism in these composites is in conformity with small polaron hopping model.
The document summarizes a study of the dielectric properties of nano-crystalline Mn-Zn ferrites. Samples of ZnxMn1-xFe2O4 where x ranges from 0.2 to 0.8 were synthesized using a solid-state route and characterized. The ac conductivity σ, dielectric constant ε', dielectric loss ε'', and loss tangent tan δ were measured from 100 Hz to 20 MHz. ε' and ε'' decreased with increasing frequency. σ was nearly frequency independent below 1 MHz and increased sharply above. The maximum dielectric constant and conductivity occurred for x=0.2, attributed to space charge polarization. The conduction mechanism was explained by electron hopping between Fe2+ and Fe
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
This document summarizes research on synthesizing polyaniline-clay nanocomposites using a mechanochemical method and studying their optical properties. Key findings include:
1) Polyaniline-clay nanocomposites were successfully synthesized via a mechanochemical polymerization of aniline monomer in the presence of clay.
2) Characterization using XRD, FT-IR, and optical measurements confirmed the formation of polyaniline-clay nanocomposites with an average grain size of 0.587 nm.
3) Optical properties such as refractive index, extinction coefficient, and optical band gap were determined from UV-visible spectroscopy measurements.
MECHANICAL & THERMAL PROPERTIES OF NANO COMPOSITESArjun K Gopi
This document discusses the mechanical and thermal properties of polymer nanocomposites. It explains that polymer nanocomposites consist of a polymer matrix reinforced with nanoparticles, which have high surface area. This results in enhanced bonding between the polymer and nanoparticles. As a result, polymer nanocomposites often demonstrate improved mechanical properties over micro-composites, such as increased elastic modulus. A key factor influencing the mechanical properties is the interphase layer that forms between the polymer matrix and nanoparticles. The properties of this interphase region, which can differ from the bulk materials, largely determine how stress is transferred between phases. Several experimental techniques for characterizing the structure and properties of polymer nanocomposites are described, including tensile testing,
Optical and Electrical Properties of TiO2 Doped Fe2O3 Thin Film Prepared by S...IJAEMSJORNAL
In this work, iron oxide (Fe2O3) and titanium oxide (TiO2) doping (Fe2O3) thin films have been prepared by spray pyrolysis technique (SPT) on a glass substrate. We have studied the effects of various doping percentage of (TiO2) on (Fe2O3) optical and electrical properties. The optical parameters of the prepared films as absorbance, absorption coefficient, optical energy gap and refractive index have been calculated for all prepared films. D.C conductivity and Hall effect for all films are measured. The results showed that absorbance of prepared films decreases with increasing percentage of (TiO2) this lead to increase the energy gap and conductivity decreased with increasing of percentage of (TiO2) as well as the results showed throughout the study that all films have tow activation energy, its value increase with increasing of percentage of (TiO2). Hall effect measurement showed all films have n-type conductivity.
STM Observation of the Si(111) - (7×7) Reconstructed Surface Modified by Exce...IJECEIAES
The electronic properties of semiconductor surfaces change readily upon changing the carrier densities by controlling the dopant concentration. Additionally, excess dopant atoms can exert electric field which would affect the molecular adsorption process and could be used to manipulate the dynamic movement of confined molecules. A mechanism can be developed to control the molecular dynamic movement on modified semiconductor surface by dopants thus changing the effect of the electric field on the active molecules. In this study, the Si(111) surface was doped with phosphorus excessively using thermal diffusion process. The surface was then reconstructed to the 7×7 configuration via heating under UHV conditions and then studied through STM and STS techniques. The protrusions due to surface and subsurface P atoms appear brighter due to the lone electron pair. The 7×7 reconstruction would be destabilized after a critical P substitution of Si-adatom concentration due to high surface strain result in P-terminated (6√3×6√3)R30º reconstruction.
Study of Polyaniline – Polymethylmethacraylate Blend Films for Amine SensorEditor IJMTER
Electrically conducting films are useful in many applications in the fields of sensors, and
nanoelectronics. However, it is very difficult to obtain fibers of conducting polymers like polyaniline
(PANI) and polypyrrole.Hence they are invariably mixed with other insulating polymers such as
polymethylmethacrylate (PMMA) to obtain a conducting composite depending on the percolation of the
conducting polymer. Here, we report the preparation of PANI-PMMA composite films by chemical
deposition method polymer fibers are investigated atroom temperature with different concentrations of
PANI (0.05M,0.1M,0.2M,0.5M,). It is observed that there is a significant enhancement in the
conductivity of these fibers with the increase in the concentration of PANI. Here to study the D.C.
conductivity, SEM, FTIR and Gas detecting properties of films.
Study of Structural and Dielectric properties of BaTiO3 Doped with Mg-Cu-Zn F...IJSRD
The magnetoelectric (ME) composites having the general formula, (x) Mg0.25Cu0.25Zn0.5Fe2O4 + (1-x) BaTiO3 (x=15%, 30%, 45%) were synthesized by sintering mixtures of highly ferroelectric BaTiO3 and highly magnetostrictive magnetic component Mg0.25Cu0.25Zn0.5Fe2O4. The presence of constituent phases of ferrite, ferroelectric and their composites were confirmed by X-ray diffraction (XRD) studies. Surface morphology of the samples has been investigated using Field Emission Scanning Electron Microscope (FESEM), which revealed uniform mixing of two phases. The variations in dielectric constant and dissipation factor as a function of frequency from 100 Hz to 1 MHz were measured in a Hioki LCR Hi-Tester. The dielectric constant and dielectric loss were found to decrease rapidly in the low frequency region and became almost constant in the high frequency region. The electrical conductivity deduced from the measured dielectric parameters has been analyzed and found that the conduction mechanism in these composites is in conformity with small polaron hopping model.
The document summarizes a study of the dielectric properties of nano-crystalline Mn-Zn ferrites. Samples of ZnxMn1-xFe2O4 where x ranges from 0.2 to 0.8 were synthesized using a solid-state route and characterized. The ac conductivity σ, dielectric constant ε', dielectric loss ε'', and loss tangent tan δ were measured from 100 Hz to 20 MHz. ε' and ε'' decreased with increasing frequency. σ was nearly frequency independent below 1 MHz and increased sharply above. The maximum dielectric constant and conductivity occurred for x=0.2, attributed to space charge polarization. The conduction mechanism was explained by electron hopping between Fe2+ and Fe
Study of Microstructural, Electrical and Dielectric Properties of La0.9Pb0.1M...Scientific Review SR
The present work studies the microstructural and electrical properties of La0.9Pb0.1MnO3 and La0.8Y0.1Pb0.1MnO3 ceramics synthesized by solid-state route method. Microstructure and elemental analysis of both samples were carried out by field emission scanning electron microscope (FESEM) and energy dispersive spectroscopy (EDS) method, respectively. Phase analysis by X-ray diffraction (XRD) indicated formation of single phase distorted structure. The XRD data were further analyzed by Rietveld refinement technique. Raman analysis reveals that Y atom substitutes La site into the LPMO with shifting of phonon modes. The temperature variation of resistivity of undoped and Y-doped La0.9Pb0.1MnO3 samples have been investigated. The electrical resistivity as a function of temperature showed that all samples undergo an metal-insulator (M-I) transition having a peak at transition temperature TMI. Y-doping increases the resistivity and the metal-insulator transition temperature (TMI) shifts to lower temperature. The temperature-dependent resistivity for temperatures less than metal-insulator transition is explained in terms the quadratic temperature dependence and for T > TMI, thermally activated conduction (TAC) is appropriate. Variation of frequency dispersion in permittivity and loss pattern due to La-site substitution in LPMO was observed in the dielectric response curve.
This document summarizes research on synthesizing polyaniline-clay nanocomposites using a mechanochemical method and studying their optical properties. Key findings include:
1) Polyaniline-clay nanocomposites were successfully synthesized via a mechanochemical polymerization of aniline monomer in the presence of clay.
2) Characterization using XRD, FT-IR, and optical measurements confirmed the formation of polyaniline-clay nanocomposites with an average grain size of 0.587 nm.
3) Optical properties such as refractive index, extinction coefficient, and optical band gap were determined from UV-visible spectroscopy measurements.
MECHANICAL & THERMAL PROPERTIES OF NANO COMPOSITESArjun K Gopi
This document discusses the mechanical and thermal properties of polymer nanocomposites. It explains that polymer nanocomposites consist of a polymer matrix reinforced with nanoparticles, which have high surface area. This results in enhanced bonding between the polymer and nanoparticles. As a result, polymer nanocomposites often demonstrate improved mechanical properties over micro-composites, such as increased elastic modulus. A key factor influencing the mechanical properties is the interphase layer that forms between the polymer matrix and nanoparticles. The properties of this interphase region, which can differ from the bulk materials, largely determine how stress is transferred between phases. Several experimental techniques for characterizing the structure and properties of polymer nanocomposites are described, including tensile testing,
Optical and Electrical Properties of TiO2 Doped Fe2O3 Thin Film Prepared by S...IJAEMSJORNAL
In this work, iron oxide (Fe2O3) and titanium oxide (TiO2) doping (Fe2O3) thin films have been prepared by spray pyrolysis technique (SPT) on a glass substrate. We have studied the effects of various doping percentage of (TiO2) on (Fe2O3) optical and electrical properties. The optical parameters of the prepared films as absorbance, absorption coefficient, optical energy gap and refractive index have been calculated for all prepared films. D.C conductivity and Hall effect for all films are measured. The results showed that absorbance of prepared films decreases with increasing percentage of (TiO2) this lead to increase the energy gap and conductivity decreased with increasing of percentage of (TiO2) as well as the results showed throughout the study that all films have tow activation energy, its value increase with increasing of percentage of (TiO2). Hall effect measurement showed all films have n-type conductivity.
STM Observation of the Si(111) - (7×7) Reconstructed Surface Modified by Exce...IJECEIAES
The electronic properties of semiconductor surfaces change readily upon changing the carrier densities by controlling the dopant concentration. Additionally, excess dopant atoms can exert electric field which would affect the molecular adsorption process and could be used to manipulate the dynamic movement of confined molecules. A mechanism can be developed to control the molecular dynamic movement on modified semiconductor surface by dopants thus changing the effect of the electric field on the active molecules. In this study, the Si(111) surface was doped with phosphorus excessively using thermal diffusion process. The surface was then reconstructed to the 7×7 configuration via heating under UHV conditions and then studied through STM and STS techniques. The protrusions due to surface and subsurface P atoms appear brighter due to the lone electron pair. The 7×7 reconstruction would be destabilized after a critical P substitution of Si-adatom concentration due to high surface strain result in P-terminated (6√3×6√3)R30º reconstruction.
Study of Polyaniline – Polymethylmethacraylate Blend Films for Amine SensorEditor IJMTER
Electrically conducting films are useful in many applications in the fields of sensors, and
nanoelectronics. However, it is very difficult to obtain fibers of conducting polymers like polyaniline
(PANI) and polypyrrole.Hence they are invariably mixed with other insulating polymers such as
polymethylmethacrylate (PMMA) to obtain a conducting composite depending on the percolation of the
conducting polymer. Here, we report the preparation of PANI-PMMA composite films by chemical
deposition method polymer fibers are investigated atroom temperature with different concentrations of
PANI (0.05M,0.1M,0.2M,0.5M,). It is observed that there is a significant enhancement in the
conductivity of these fibers with the increase in the concentration of PANI. Here to study the D.C.
conductivity, SEM, FTIR and Gas detecting properties of films.
This document presents preliminary findings from a study preparing doped polyaniline (PANI) as a filler for vulcanized latex. Different types of PANI (undoped and doped) were prepared through polymerization with aniline, surfactants, oxidizing agents, and metal oxides or cellulose. PANI was then dispersed in pre-vulcanized latex to produce modified cast films. Analysis found that PANI-ZnO gave the best mechanical properties and thermal resistance of the films. Visual inspection showed homogenizing PANI in latex with potassium hydroxide improved dispersion. While conductivity was not measured in the films, doped PANI templates showed increased conductivity. The study successfully prepared various PANI templates and
OPTICAL PROPERTIES OF MDMO-PPV AND MDMO-PPV/ [6,6]-PHENYL C61-BUTYRIC ACID 3-...ijoejournal
Thin films of a conjugated polymer Poly [2-methoxy-5-(3’,7’-dimethyloctyloxy)-1,4-phenylenevinylene]
(MDMO-PPV) were prepared from chloroform, 1,2dichlorobenzene and toluene solutions by spin coating
technique on quartz substrates. Absorption and photoluminescence (PL) spectra of the polymer thin films
prepared from different solvents were measured. The UV-vis absorption and PL spectra of MDMO-PPV
films was affected by solvents used for spin coating. Further, with Atomic Force Microscope (AFM) it has
been demonstrated that the surface morphology of MDMO-PPV: [6,6]-Phenyl C61-butyric Acid 3-
ethylthiophene Ester thin films depends strongly on preparation condition (solvents).
The influence of ambient conditions on properties of MgxZn1-xO films by sputt...M.I. Joaquin Torres Salas
The document summarizes research on the influence of ambient conditions on properties of MgxZn1-xO films prepared by magnetron sputtering. It finds that increasing the ratio of oxygen to argon and oxygen during the sputtering process:
1) Improves the crystal quality of the films and increases the magnesium content in the films.
2) Increases the band gap of the films, with band gaps ranging from 3.5 to 3.83 eV depending on the magnesium content.
3) Does not change the wurtzite structure of the films but increases the lattice constant, with the largest lattice constant seen in the film with the highest magnesium content.
This document provides an overview of magnetic nanocomposite materials. It discusses how nanocomposite materials with magnetic particles embedded in a matrix can have properties different from conventional composites due to interactions at the nanoscale. The document then reviews the history of magnetic nanocomposites, including early amorphous alloys and more recent developments like FINEMET, NANOPERM, and HITPERM which use crystalline nanoparticles embedded in an amorphous matrix. Recent advances in preparation of functional nanocomposites and hybrid materials are also summarized, including core-shell nanoparticles, colloidal crystals, mesoporous composites, and functional magnetic polymers.
This document summarizes a seminar on magnetic nanocomposites. It discusses how nanocomposites have particles mixed at the nanoscale, including magnetic nanocomposites containing ferromagnetic particles. The history of magnetic nanocomposites is reviewed, from early amorphous alloys to developments in the 1980s-1990s of alloys like FINEMET, NANOPERM, and HITPERM. Recent developments discussed include core-shell nanoparticles, colloidal crystals, mesoporous nanocomposites, and functional polymers. Applications mentioned are using magnetic fields to destroy tumor cells, transformers, and DC-DC power converters. Challenges remaining are controlled synthesis, understanding mechanisms, cost, toxicity
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
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This document summarizes a study that evaluated the influence of different curing methods on the post-polymerization shrinkage stress of a composite resin. Specifically, it:
1) Compared stress levels immediately after curing and after 5 minutes using different curing methods (continuous QTH light, soft-start QTH light, intermittent QTH light, and xenon plasma arc light).
2) Found that all curing methods resulted in significantly higher stress levels after 5 minutes compared to immediately after curing.
3) Determined that xenon plasma arc light resulted in the greatest increase in stress over 5 minutes, while continuous QTH light produced the smallest increase.
Effect of calcination on the electrical properties and quantum confinement of...eSAT Journals
Abstract Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven. X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample. Calcined samples were obtained by annealing the as-prepared sample at different temperatures, viz. 400, 500, 600 and 700oC. Transmission electron microscopic images indicate that all the five samples are spherical in shape. AC electrical measurements were carried out on pelletized samples by the parallel plate capacitor method at various temperatures ranging from 40-130oC and frequencies ranging from 100 Hz -1 MHz. Results indicate low AC electrical conductivities and consequently show the occurrence of nano confined states. The exciton Bohr radii obtained from the dielectric constant values at 40oC temperature and 1 kHz frequency are 41.8, 54.8, 55.3, 56.3 and 27.0 respectively for the as-prepared sample and samples calcined at 400, 500, 600 and 700oC which indicate a strong quantum confinement effect. The impedance spectra observed exhibit non-ideal behavior. Keywords: Semiconductors, Magnetic materials, Nanoparticles, Electrical properties
Effect of calcination on the electrical properties and quantum confinement of...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
The document summarizes research on cobalt-carbon nanocomposites prepared by RF sputtering and RF plasma-enhanced chemical vapor deposition. Three cobalt-carbon nanocomposite films were prepared under different deposition pressures. Atomic force microscopy showed the average particle size and surface roughness decreased with increasing pressure. X-ray diffraction identified cobalt nanoparticles in the FCC phase and cobalt oxide. Optical absorbance measurements showed the surface plasmon resonance band shifted to higher wavelengths with decreasing pressure, indicating larger particle sizes. The composition of the films was confirmed with EDX to contain cobalt, oxygen, and carbon from the matrix. In conclusion, lower deposition pressures favored the formation of larger cobalt nanoparticles while higher pressures increased cobalt oxide formation.
The document describes the synthesis and characterization of a composite material made of polyaniline and ferric oxide. Polyaniline and ferric oxide were mixed in a 1:1 ratio by weight and heat treated to form the composite. The composite was characterized using X-ray diffraction, UV-visible spectroscopy, and vibrating sample magnetometry. XRD analysis confirmed the crystalline structure of the composite and determined a particle size of 126 nm. UV-visible spectroscopy showed optical absorption peaks related to electronic transitions in polyaniline and charge transfer in ferric oxide. Magnetic characterization found the composite exhibited ferromagnetism at room temperature with a saturation magnetization of 0.136 emu, indicating the composite has magnetic properties.
Role of Environmental Factors on the Structure and Spectroscopic ResponseAngela Mammana
We have explored the utility,
strength, and limitation of throughspace
exciton-coupled circular dichroism
in determination of the secondary
structure of optically active chromophoric
nanoarrays using the example of
end-capped porphyrin– and metalloporphyrin–
oligodeoxynucleotide conjugates.
We put special emphasis on the
explanation of the origin and significance
of the distinctive multiple bands
in the CD spectra (trisignate and tetrasignate
CD bands). Such CD profiles
are often observed in chiral aggregates
or multichromophoric arrays but have
never before been studied in detail. We
found that variation of temperature
and ionic strength has a profound
effect on the geometry of the porphyrin–
DNA conjugates and thus the
nature of electronic interactions. At
lower temperatures and in the absence
of NaCl all three 5’-DNA–porphyrin
conjugates display negative bisignate
CD exciton couplets of variable intensity
in the Soret region resulting from
through-space interaction between the
electric transition dipole moments of
the two end-capped porphyrins. As the
temperature is raised these exciton
couplets are transformed into single
positive bands originating from the
porphyrin–single-strand DNA interactions.
At higher ionic strengths and low
temperatures, multisignate CD bands
are observed in the porphyrin Soret
region. These CD signature bands originate
from a combination of intermolecular,
end-to-end porphyrin–porphyrin
stacking between duplexes and porphyrin–
DNA interactions. The intermolecular
aggregation was confirmed
by fluorescence and absorption spectroscopy
and resonance light scattering.
DeVoe theoretical CD calculations, in
conjunction with molecular dynamics
simulations and Monte Carlo conformational
searches, were used to mimic
the observed bisignate exciton-coupled
CD spectra as well as multiple CD
bands. Calculations correctly predicted
the sign and shape of the experimentally
observed CD spectra. These studies
reveal that the exciton-coupled circular
dichroism is a very useful technique for
the determination of the structure of
optically active arrays.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Optical properties of (polystyrene wood buckthorn peel) compositesAlexander Decker
This document summarizes research on the optical properties of polystyrene composites doped with wood buckthorn peel at different concentrations. Samples of pure polystyrene and polystyrene with 2%, 4%, and 6% wood buckthorn peel were created using casting. Absorption coefficient, energy gap, refractive index, and extinction coefficient were determined for the samples using spectroscopy. The results showed the optical constants changed with increased wood buckthorn peel concentration. Absorption decreased with increasing wavelength. Energy gap and optical constants generally depended on crystal structure and atom arrangement. Refractive index increased with photon energy while extinction coefficient varied more at high energies.
This document summarizes a study investigating compositional modulations in AlxGa1-xAs thin films using solid-state NMR and DFT calculations. The researchers were able to identify all possible As coordination sites in AlxGa1-xAs using 75As NMR experiments. Spectral deconvolution complied with an absence of long-range ordering, but an unconstrained fit showed a deviation from the imposed ordering parameter. NMR and DFT showed that the electric field gradients experienced by arsenic sites are distributed due to compositional variation in the higher coordination spheres of Al and Ga atoms. DFT calculations reproduced the experimentally observed electric field gradient distributions and showed NMR is sensitive to compositional modulations up to the 7th coordination shell
This document discusses the chemistry of nanoscale materials including their synthesis, properties, and applications. Key points include:
- Nanoparticles exhibit unusual properties due to their small size such as changes in melting points, optical properties, and surface reactivity.
- Semiconductor nanoparticles known as quantum dots exhibit quantum confinement effects which alter their band gap.
- Common synthetic methods for nanoparticles include chemical reduction, sonochemistry, and electrochemical routes. Stabilization is needed to prevent aggregation.
- Dendrimers can template the synthesis of metal nanoclusters within their cores. Monitoring by UV-vis spectroscopy allows observation of cluster formation.
This document summarizes work done on finite element analysis of polymer nano composites. Objectives include analyzing polymer nanocomposites using ABAQUS software and studying how nanofillers affect mechanical properties. Work completed includes learning ABAQUS tutorials, literature review, and geometric modeling of nanofillers. Future work plans to compare results of spherical and ellipsoidal inclusions and extend the study to fracture mechanics. Representative volume elements are generated and analyzed to determine properties like Young's modulus at varying nanofiller weight fractions and shapes.
High-Gradient Magnetic Separation Method for Weakly Magnetic Particles: an In...Barhm Mohamad
The high-gradient magnetic separation process is a technique used in heavy industries, particularly steel mills, to extract magnetic particles from mixtures. The difficulty of separating the slightly magnetic particles from the nonmagnetic ones lies in the distribution of the magnetic field and the fineness of their class to be separated. A use of different separation matrix profile is implemented, making it possible to act on the value of the gradient of the inhomogeneous magnetic field. Different matrixes are tested and the results obtained experimentally allows to choose the most efficient matrix form in the operation of extraction which increased by 11% in magnetic fraction yield, 15% iron content and 17% of extraction degree relative to the John’s matrix. This matrix used is consistent with that cited in literatures. The separation technology used can extend its useful application to small particles from very weakly magnetic materials. Its exploitation will result in the method of reducing the degree of pollution and improvement the process of extraction of minerals that has an impact on the environment and on human health as a result a high level of extraction.
This document presents a study of the electrical properties of chemically treated coir fiber-reinforced epoxy composites. Coir fiber was chemically treated using ferric nitrate and ammonium chloride, then composites were fabricated using a hand molding method. The dielectric constant, dissipation factor, and AC conductivity of the composites were measured at room temperature and different frequencies. The results showed that the electrical properties of the composites were dependent on fiber concentration and frequency. An artificial neural network model was also able to predict the electrical properties measured experimentally. Scanning electron microscopy and X-ray diffraction analysis confirmed the crystalline nature and poor fiber-matrix bonding of the chemically treated coir fiber reinforced epoxy
This document discusses the use of positron annihilation spectroscopy to analyze the free volume nanohole distribution in polymers and its correlation to the physico-chemical properties of polymers. It provides background on positron annihilation spectroscopy and how it can be used to measure free volume in polymers. The document then describes several studies that use this technique to analyze the influence of free volume properties on the swelling of polymer hydrogels, structure-property relationships in modified epoxy resins, and free volume and interfacial interactions in epoxy clay composites.
Study of highly broadening Photonic band gaps extension in one-dimensional Me...IOSR Journals
This document discusses the theoretical study of enhancing the reflectance spectra of one-dimensional metallo-organic multilayer photonic structures. It examines structures composed of alternating thin layers of silver and the organic material N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine. The transfer matrix method is used to calculate the reflectance spectra for different configurations of layer thicknesses and incident angles of light. Tuning of the photonic band gap is observed by varying the thickness of either the metal or organic layers. Broadening and shifting of the band edges from ultraviolet to visible and infrared regions occurs due to the optical absorption properties of both the
11.the optical constants of highly absorbing films using the spectral reflect...Alexander Decker
This document summarizes a study that determined the optical constants of thin films of rhodium metal using spectral reflectance measurements. The researchers measured the reflectance of rhodium films of varying thicknesses using a double beam spectrophotometer. They then used Kramers-Kronig relations to calculate the phase angle from the reflectance data and determine the real refractive index and extinction coefficient. Their method provides accurate optical constants without needing transmission measurements. They found the refractive index and extinction coefficient were nearly equal for thin films and that their method compared well to values from other interference-based techniques.
This document presents preliminary findings from a study preparing doped polyaniline (PANI) as a filler for vulcanized latex. Different types of PANI (undoped and doped) were prepared through polymerization with aniline, surfactants, oxidizing agents, and metal oxides or cellulose. PANI was then dispersed in pre-vulcanized latex to produce modified cast films. Analysis found that PANI-ZnO gave the best mechanical properties and thermal resistance of the films. Visual inspection showed homogenizing PANI in latex with potassium hydroxide improved dispersion. While conductivity was not measured in the films, doped PANI templates showed increased conductivity. The study successfully prepared various PANI templates and
OPTICAL PROPERTIES OF MDMO-PPV AND MDMO-PPV/ [6,6]-PHENYL C61-BUTYRIC ACID 3-...ijoejournal
Thin films of a conjugated polymer Poly [2-methoxy-5-(3’,7’-dimethyloctyloxy)-1,4-phenylenevinylene]
(MDMO-PPV) were prepared from chloroform, 1,2dichlorobenzene and toluene solutions by spin coating
technique on quartz substrates. Absorption and photoluminescence (PL) spectra of the polymer thin films
prepared from different solvents were measured. The UV-vis absorption and PL spectra of MDMO-PPV
films was affected by solvents used for spin coating. Further, with Atomic Force Microscope (AFM) it has
been demonstrated that the surface morphology of MDMO-PPV: [6,6]-Phenyl C61-butyric Acid 3-
ethylthiophene Ester thin films depends strongly on preparation condition (solvents).
The influence of ambient conditions on properties of MgxZn1-xO films by sputt...M.I. Joaquin Torres Salas
The document summarizes research on the influence of ambient conditions on properties of MgxZn1-xO films prepared by magnetron sputtering. It finds that increasing the ratio of oxygen to argon and oxygen during the sputtering process:
1) Improves the crystal quality of the films and increases the magnesium content in the films.
2) Increases the band gap of the films, with band gaps ranging from 3.5 to 3.83 eV depending on the magnesium content.
3) Does not change the wurtzite structure of the films but increases the lattice constant, with the largest lattice constant seen in the film with the highest magnesium content.
This document provides an overview of magnetic nanocomposite materials. It discusses how nanocomposite materials with magnetic particles embedded in a matrix can have properties different from conventional composites due to interactions at the nanoscale. The document then reviews the history of magnetic nanocomposites, including early amorphous alloys and more recent developments like FINEMET, NANOPERM, and HITPERM which use crystalline nanoparticles embedded in an amorphous matrix. Recent advances in preparation of functional nanocomposites and hybrid materials are also summarized, including core-shell nanoparticles, colloidal crystals, mesoporous composites, and functional magnetic polymers.
This document summarizes a seminar on magnetic nanocomposites. It discusses how nanocomposites have particles mixed at the nanoscale, including magnetic nanocomposites containing ferromagnetic particles. The history of magnetic nanocomposites is reviewed, from early amorphous alloys to developments in the 1980s-1990s of alloys like FINEMET, NANOPERM, and HITPERM. Recent developments discussed include core-shell nanoparticles, colloidal crystals, mesoporous nanocomposites, and functional polymers. Applications mentioned are using magnetic fields to destroy tumor cells, transformers, and DC-DC power converters. Challenges remaining are controlled synthesis, understanding mechanisms, cost, toxicity
Welcome to International Journal of Engineering Research and Development (IJERD)IJERD Editor
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This document summarizes a study that evaluated the influence of different curing methods on the post-polymerization shrinkage stress of a composite resin. Specifically, it:
1) Compared stress levels immediately after curing and after 5 minutes using different curing methods (continuous QTH light, soft-start QTH light, intermittent QTH light, and xenon plasma arc light).
2) Found that all curing methods resulted in significantly higher stress levels after 5 minutes compared to immediately after curing.
3) Determined that xenon plasma arc light resulted in the greatest increase in stress over 5 minutes, while continuous QTH light produced the smallest increase.
Effect of calcination on the electrical properties and quantum confinement of...eSAT Journals
Abstract Fe2O3 nanoparticles have been prepared by a simple solvothermal method using a domestic microwave oven. X-ray powder diffraction measurement indicates the amorphous nature of the as-prepared sample. Calcined samples were obtained by annealing the as-prepared sample at different temperatures, viz. 400, 500, 600 and 700oC. Transmission electron microscopic images indicate that all the five samples are spherical in shape. AC electrical measurements were carried out on pelletized samples by the parallel plate capacitor method at various temperatures ranging from 40-130oC and frequencies ranging from 100 Hz -1 MHz. Results indicate low AC electrical conductivities and consequently show the occurrence of nano confined states. The exciton Bohr radii obtained from the dielectric constant values at 40oC temperature and 1 kHz frequency are 41.8, 54.8, 55.3, 56.3 and 27.0 respectively for the as-prepared sample and samples calcined at 400, 500, 600 and 700oC which indicate a strong quantum confinement effect. The impedance spectra observed exhibit non-ideal behavior. Keywords: Semiconductors, Magnetic materials, Nanoparticles, Electrical properties
Effect of calcination on the electrical properties and quantum confinement of...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
The document summarizes research on cobalt-carbon nanocomposites prepared by RF sputtering and RF plasma-enhanced chemical vapor deposition. Three cobalt-carbon nanocomposite films were prepared under different deposition pressures. Atomic force microscopy showed the average particle size and surface roughness decreased with increasing pressure. X-ray diffraction identified cobalt nanoparticles in the FCC phase and cobalt oxide. Optical absorbance measurements showed the surface plasmon resonance band shifted to higher wavelengths with decreasing pressure, indicating larger particle sizes. The composition of the films was confirmed with EDX to contain cobalt, oxygen, and carbon from the matrix. In conclusion, lower deposition pressures favored the formation of larger cobalt nanoparticles while higher pressures increased cobalt oxide formation.
The document describes the synthesis and characterization of a composite material made of polyaniline and ferric oxide. Polyaniline and ferric oxide were mixed in a 1:1 ratio by weight and heat treated to form the composite. The composite was characterized using X-ray diffraction, UV-visible spectroscopy, and vibrating sample magnetometry. XRD analysis confirmed the crystalline structure of the composite and determined a particle size of 126 nm. UV-visible spectroscopy showed optical absorption peaks related to electronic transitions in polyaniline and charge transfer in ferric oxide. Magnetic characterization found the composite exhibited ferromagnetism at room temperature with a saturation magnetization of 0.136 emu, indicating the composite has magnetic properties.
Role of Environmental Factors on the Structure and Spectroscopic ResponseAngela Mammana
We have explored the utility,
strength, and limitation of throughspace
exciton-coupled circular dichroism
in determination of the secondary
structure of optically active chromophoric
nanoarrays using the example of
end-capped porphyrin– and metalloporphyrin–
oligodeoxynucleotide conjugates.
We put special emphasis on the
explanation of the origin and significance
of the distinctive multiple bands
in the CD spectra (trisignate and tetrasignate
CD bands). Such CD profiles
are often observed in chiral aggregates
or multichromophoric arrays but have
never before been studied in detail. We
found that variation of temperature
and ionic strength has a profound
effect on the geometry of the porphyrin–
DNA conjugates and thus the
nature of electronic interactions. At
lower temperatures and in the absence
of NaCl all three 5’-DNA–porphyrin
conjugates display negative bisignate
CD exciton couplets of variable intensity
in the Soret region resulting from
through-space interaction between the
electric transition dipole moments of
the two end-capped porphyrins. As the
temperature is raised these exciton
couplets are transformed into single
positive bands originating from the
porphyrin–single-strand DNA interactions.
At higher ionic strengths and low
temperatures, multisignate CD bands
are observed in the porphyrin Soret
region. These CD signature bands originate
from a combination of intermolecular,
end-to-end porphyrin–porphyrin
stacking between duplexes and porphyrin–
DNA interactions. The intermolecular
aggregation was confirmed
by fluorescence and absorption spectroscopy
and resonance light scattering.
DeVoe theoretical CD calculations, in
conjunction with molecular dynamics
simulations and Monte Carlo conformational
searches, were used to mimic
the observed bisignate exciton-coupled
CD spectra as well as multiple CD
bands. Calculations correctly predicted
the sign and shape of the experimentally
observed CD spectra. These studies
reveal that the exciton-coupled circular
dichroism is a very useful technique for
the determination of the structure of
optically active arrays.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
Optical properties of (polystyrene wood buckthorn peel) compositesAlexander Decker
This document summarizes research on the optical properties of polystyrene composites doped with wood buckthorn peel at different concentrations. Samples of pure polystyrene and polystyrene with 2%, 4%, and 6% wood buckthorn peel were created using casting. Absorption coefficient, energy gap, refractive index, and extinction coefficient were determined for the samples using spectroscopy. The results showed the optical constants changed with increased wood buckthorn peel concentration. Absorption decreased with increasing wavelength. Energy gap and optical constants generally depended on crystal structure and atom arrangement. Refractive index increased with photon energy while extinction coefficient varied more at high energies.
This document summarizes a study investigating compositional modulations in AlxGa1-xAs thin films using solid-state NMR and DFT calculations. The researchers were able to identify all possible As coordination sites in AlxGa1-xAs using 75As NMR experiments. Spectral deconvolution complied with an absence of long-range ordering, but an unconstrained fit showed a deviation from the imposed ordering parameter. NMR and DFT showed that the electric field gradients experienced by arsenic sites are distributed due to compositional variation in the higher coordination spheres of Al and Ga atoms. DFT calculations reproduced the experimentally observed electric field gradient distributions and showed NMR is sensitive to compositional modulations up to the 7th coordination shell
This document discusses the chemistry of nanoscale materials including their synthesis, properties, and applications. Key points include:
- Nanoparticles exhibit unusual properties due to their small size such as changes in melting points, optical properties, and surface reactivity.
- Semiconductor nanoparticles known as quantum dots exhibit quantum confinement effects which alter their band gap.
- Common synthetic methods for nanoparticles include chemical reduction, sonochemistry, and electrochemical routes. Stabilization is needed to prevent aggregation.
- Dendrimers can template the synthesis of metal nanoclusters within their cores. Monitoring by UV-vis spectroscopy allows observation of cluster formation.
This document summarizes work done on finite element analysis of polymer nano composites. Objectives include analyzing polymer nanocomposites using ABAQUS software and studying how nanofillers affect mechanical properties. Work completed includes learning ABAQUS tutorials, literature review, and geometric modeling of nanofillers. Future work plans to compare results of spherical and ellipsoidal inclusions and extend the study to fracture mechanics. Representative volume elements are generated and analyzed to determine properties like Young's modulus at varying nanofiller weight fractions and shapes.
High-Gradient Magnetic Separation Method for Weakly Magnetic Particles: an In...Barhm Mohamad
The high-gradient magnetic separation process is a technique used in heavy industries, particularly steel mills, to extract magnetic particles from mixtures. The difficulty of separating the slightly magnetic particles from the nonmagnetic ones lies in the distribution of the magnetic field and the fineness of their class to be separated. A use of different separation matrix profile is implemented, making it possible to act on the value of the gradient of the inhomogeneous magnetic field. Different matrixes are tested and the results obtained experimentally allows to choose the most efficient matrix form in the operation of extraction which increased by 11% in magnetic fraction yield, 15% iron content and 17% of extraction degree relative to the John’s matrix. This matrix used is consistent with that cited in literatures. The separation technology used can extend its useful application to small particles from very weakly magnetic materials. Its exploitation will result in the method of reducing the degree of pollution and improvement the process of extraction of minerals that has an impact on the environment and on human health as a result a high level of extraction.
This document presents a study of the electrical properties of chemically treated coir fiber-reinforced epoxy composites. Coir fiber was chemically treated using ferric nitrate and ammonium chloride, then composites were fabricated using a hand molding method. The dielectric constant, dissipation factor, and AC conductivity of the composites were measured at room temperature and different frequencies. The results showed that the electrical properties of the composites were dependent on fiber concentration and frequency. An artificial neural network model was also able to predict the electrical properties measured experimentally. Scanning electron microscopy and X-ray diffraction analysis confirmed the crystalline nature and poor fiber-matrix bonding of the chemically treated coir fiber reinforced epoxy
This document discusses the use of positron annihilation spectroscopy to analyze the free volume nanohole distribution in polymers and its correlation to the physico-chemical properties of polymers. It provides background on positron annihilation spectroscopy and how it can be used to measure free volume in polymers. The document then describes several studies that use this technique to analyze the influence of free volume properties on the swelling of polymer hydrogels, structure-property relationships in modified epoxy resins, and free volume and interfacial interactions in epoxy clay composites.
Study of highly broadening Photonic band gaps extension in one-dimensional Me...IOSR Journals
This document discusses the theoretical study of enhancing the reflectance spectra of one-dimensional metallo-organic multilayer photonic structures. It examines structures composed of alternating thin layers of silver and the organic material N,N'-bis-(1-naphthyl)-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine. The transfer matrix method is used to calculate the reflectance spectra for different configurations of layer thicknesses and incident angles of light. Tuning of the photonic band gap is observed by varying the thickness of either the metal or organic layers. Broadening and shifting of the band edges from ultraviolet to visible and infrared regions occurs due to the optical absorption properties of both the
11.the optical constants of highly absorbing films using the spectral reflect...Alexander Decker
This document summarizes a study that determined the optical constants of thin films of rhodium metal using spectral reflectance measurements. The researchers measured the reflectance of rhodium films of varying thicknesses using a double beam spectrophotometer. They then used Kramers-Kronig relations to calculate the phase angle from the reflectance data and determine the real refractive index and extinction coefficient. Their method provides accurate optical constants without needing transmission measurements. They found the refractive index and extinction coefficient were nearly equal for thin films and that their method compared well to values from other interference-based techniques.
Preparation of (pomegranate peel polystyrene) composites and study their opt...Alexander Decker
This document summarizes research on preparing composites of polystyrene doped with pomegranate peel and studying their optical properties. Samples of pure polystyrene and polystyrene with 2%, 4%, and 6% by weight pomegranate peel were created. Testing showed that optical constants like absorption coefficient, energy gap, refractive index, and extinction coefficient changed with increased pomegranate peel concentration. Absorbance decreased with increasing wavelength. The composites exhibited low absorption at low photon energies that increased at different rates depending on structure. Optical properties generally increased with higher photon energy.
The absorption spectrum of poly(3-hexylthiophene-2,5-diyl), or P3HT, shows a wide peak from 500-550 nm with a maximum at 526 nm corresponding to an energy of 2.36 eV. This peak is attributed to a 0-3' vibronic state. A shoulder is also observed from 590-610 nm with a critical point at 607 nm of 2.04 eV energy, likely due to a secondary vibronic excitation state. The peaks match those found in crystalline P3HT and are broader than solution spectra due to intermolecular interactions in the film.
Characterization of Polyaniline for Optical and Electrical PropertiesIOSR Journals
This document characterizes polyaniline for its optical and electrical properties. Polyaniline was synthesized through the oxidation of aniline using hydrochloric acid and ammonium persulfate. It was characterized using various techniques. XRD analysis showed the polymer was semi-crystalline with a crystal size of 2.10nm. UV-visible spectroscopy identified peaks corresponding to the aniline moiety and benzenoid group, and the band gap was calculated to be 3.73eV. FT-IR spectroscopy confirmed the presence of functional groups. SEM images showed the polyaniline had a fibrous structure with fiber lengths around 800nm. The characterization demonstrated polyaniline has properties suitable for uses in hybrid solar cells, batteries,
Copper indium sulphide films were deposited by the
pulse plating technique with different OFF times in the range of
5s – 30s and at a constant current density of 5 mA cm-2. The
films exhibited single phase copper indium sulphide. The grain
size increased with decrease of OFF time. Optical band gap of the
films increased from 1.44– 1.497 eV with decrease of OFF time.
Optical constants (refractive index, n, and extinction co-efficient,
k) of the films have been obtained in the wavelength range 800 -
1700 nm by using spectrophotometric measurement. The
obtained results concerning the absorption index yield the energy
gap in addition to the type of the allowed optical transitions.
N/m* ratio has been obtained from refractive index data. The
dispersion of refractive index is analyzed by using a single
oscillator model.
The International Journal of Engineering and Sciencetheijes
This document summarizes a study on enhancing the properties of porous gallium nitride (GaN) using different intensities of ultraviolet (UV) electrochemical etching. GaN samples were etched at various current densities of UV illumination and characterized using scanning electron microscopy, photoluminescence spectroscopy, and Raman spectroscopy. The results showed that increasing the current density led to larger pore sizes, higher photoluminescence intensity, and small blue shifts and peak broadening in the Raman spectra, indicating relaxation of stress in the porous GaN layers.
Spectral studies of praseodymium doped heavy metal borate glass systemsinventy
Praseodymium doped HMO glasses are fabricated with the following compositions using conventional melt quenching technique. The compositions of the glass systems are 12 ZnO + 33 B2O3 + (50-x) PbO + (x+10) CaO + 4 Al2O3 + 1 Pr6O11 where (x = 0,10,20,30 and 40 mol %.). Certain physical properties of these systems have been evaluated and reported. Spectral data for all these systems were recorded for X-ray diffraction, Optical absorption and Fluorescence properties. The Judd-Ofelt intensity parameters Ωλ ( λ = 2,4,6) were evaluated from the spectral data and in turn employed to evaluate the lasing parameters of Pr3+ HMO glass systems such as radiative transition probabilities (A), radiative life-times (τR), branching ratios (βR) absorption cross-sections (σa) and Stimulated emission cross-sections (σe). The experimental and calculated branching ratios (βR) for the lasing transitions 3P0 3H4, 3P0 3H6, and 3P0 3F2 are found to be in good agreement in the present work.
Study the physical properties of some alloy materials and effect of gamma rad...Alexander Decker
This document discusses a study on the physical properties of alloy materials containing tellurium, germanium, selenium, and arsenic. Specifically, it examines the effect of replacing selenium with tellurium in TexGe20Se(60-x)As20 thin films at concentrations of 0, 10, 15 and 20 atomic %. The key findings are:
1) Increasing the tellurium content decreases the average heat of atomization, cohesive energy, and optical band gap of the alloy materials.
2) Optical absorption measurements show the fundamental absorption edge decreases with higher tellurium content, indicating allowed direct transitions.
3) The decrease in optical band gap with increasing tellurium can be
This document summarizes the optical, electrical, and dielectric properties of a novel organic-inorganic hybrid material (C6H10N2)(Hg2Cl5)2.3H2O. X-ray diffraction was used to determine the crystal structure, which crystallizes in the monoclinic system. UV-Vis spectroscopy was used to study the optical properties in both liquid and solid states. The optical band gap was determined to be 2.37 eV for the liquid and 4.33 eV for the solid using the Tauc model. Impedance spectroscopy was used to study the electrical and dielectric properties as functions of temperature and frequency. The conductivity behavior was represented by an equivalent circuit model consisting of bulk and grain boundary components
Surface and volume energy loss , optical conductivity of rhodamine 6 g dye (...Alexander Decker
Rhodamine 6G dye thin films were prepared and their optical properties were investigated using transmittance spectra from 200-900nm. The dye's optical energy gap was determined to be 2.2eV from direct allowed transitions and 1.3eV from indirect transitions. Dispersion parameters like the oscillation energy Eo, dispersion energy Ed, and refractive index no were calculated using Wemple-DiDomenico and single oscillator models. The optical conductivity and dielectric constant were also determined from the dispersion parameters and transmittance data.
TUNABLE BROADBAND ALL-DIELECTRIC PERFECT ABSORBER BASED ON PHASE CHANGE MATERIALoptljjournal
This work reported a polarization-independent, all-dielectric perfect absorber based on phase-change material. Broadband (in the wavelength range of 400-1000 nm) absorption of higher than 90% has been realized in our designed absorber. Moreover, absorption bandwidth and absorptivity can be tuned via structural parameters (such as the period, height and radius of nanopillars, the thicknesses of TiO2 and bottom GeTe films) and phase-change process. The underlying physical mechanism of the absorber is analyzed in detail. The proposed all-dielectric perfect absorber has potential applications in solar energy harvesting.
TUNABLE BROADBAND ALL-DIELECTRIC PERFECT ABSORBER BASED ON PHASE CHANGE MATERIALoptljjournal
This work reported a polarization-independent, all-dielectric perfect absorber based on phase-change material. Broadband (in the wavelength range of 400-1000 nm) absorption of higher than 90% has been realized in our designed absorber. Moreover, absorption bandwidth and absorptivity can be tuned via structural parameters (such as the period, height and radius of nanopillars, the thicknesses of TiO2 and bottom GeTe films) and phase-change process. The underlying physical mechanism of the absorber is analyzed in detail. The proposed all-dielectric perfect absorber has potential applications in solar energy harvesting.
This document summarizes an article that appeared in a journal published by Elsevier. The attached copy is provided to the author for non-commercial research and education purposes only. Other uses such as reproduction, distribution, selling, or posting to third party websites are prohibited without permission. Authors are generally allowed to post their article in Word or Tex format to their personal or institutional website. Further information about Elsevier's archiving and manuscript policies can be found at the provided URL.
This document summarizes restrictions on sharing and distributing an article from a journal published by Elsevier. It states that the attached copy is for the author's internal non-commercial use, including for instruction and sharing with colleagues. It prohibits other uses without permission, including reproduction, distribution, selling or licensing copies, or posting to personal, institutional or third party websites. It notes that in most cases authors can post their version of the article to their personal website or institutional repository.
This document summarizes restrictions on sharing and distributing an article from a journal published by Elsevier. It states that the attached copy is for the author's internal non-commercial use, including for instruction and sharing with colleagues. It prohibits other uses without permission, including reproduction, distribution, selling or licensing copies, or posting to personal, institutional or third party websites. It notes that in most cases authors can post their version of the article to their personal website or institutional repository.
ELECTRICAL AND STRUCTURAL PROPERTIES OF ZnSe THIN FILMS BY ELECTRODEPOSITION ...IKHIOYA IMOSOBOMEH LUCKY
The document summarizes research on producing zinc selenide (ZnSe) thin films through an electrodeposition technique. X-ray diffraction analysis showed the films had a cubic structure and preferred orientation along the (111) plane. Optical analysis found the band gap was between 2.1-2.3 eV and the films had high transmittance in the visible-near infrared range, making ZnSe suitable as a glazing material. Electrical analysis measured the resistivity of the films to be in the range of 104-1012 Ωm, indicating ZnSe is suitable as a buffer layer in thin film technologies.
ELECTRICAL AND STRUCTURAL PROPERTIES OF ZnSe THIN FILMS BY ELECTRODEPOSITION ...IKHIOYA IMOSOBOMEH LUCKY
The document summarizes research on producing zinc selenide (ZnSe) thin films through an electrodeposition technique. X-ray diffraction analysis showed the films had a cubic structure and preferred orientation along the (111) plane. Optical analysis found the band gap energy was between 2.1-2.3 eV. Electrical measurements showed the films had high resistivity, making ZnSe suitable as a buffer layer in thin film technologies. Overall, the research aimed to characterize ZnSe thin films produced through an inexpensive electrodeposition method for potential optoelectronic and photovoltaic device applications.
This document summarizes research on photovoltaic structures using thermally evaporated tin sulfide thin films. Key points:
- Tin sulfide films were deposited by thermal evaporation onto glass substrates in thicknesses ranging from 100-300nm.
- The films exhibited n-type conductivity at low thicknesses, transitioning to p-type at higher thicknesses. Bandgaps ranged from 2.1-1.7eV.
- CdS/SnS photovoltaic cells showed open circuit voltages up to 400mV, short circuit current densities up to 0.061mA/cm2, and conversion efficiencies up to 1.49% under 106mW/cm2 illumination.
Similar to Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties of Polystyrene Films (20)
An Examination of Effectuation Dimension as Financing Practice of Small and M...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Does Goods and Services Tax (GST) Leads to Indian Economic Development?iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Childhood Factors that influence success in later lifeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Emotional Intelligence and Work Performance Relationship: A Study on Sales Pe...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Customer’s Acceptance of Internet Banking in Dubaiiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study of Employee Satisfaction relating to Job Security & Working Hours amo...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumer Perspectives on Brand Preference: A Choice Based Model Approachiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Student`S Approach towards Social Network Sitesiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Broadcast Management in Nigeria: The systems approach as an imperativeiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study on Retailer’s Perception on Soya Products with Special Reference to T...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
A Study Factors Influence on Organisation Citizenship Behaviour in Corporate ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Consumers’ Behaviour on Sony Xperia: A Case Study on Bangladeshiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Design of a Balanced Scorecard on Nonprofit Organizations (Study on Yayasan P...iosrjce
1. The document describes a study that designed a balanced scorecard for a nonprofit organization called Yayasan Pembinaan dan Kesembuhan Batin (YPKB) in Malang, Indonesia.
2. The balanced scorecard translated YPKB's vision and mission into strategic objectives across four perspectives: financial, customer, internal processes, and learning and growth.
3. Key strategic objectives included donation growth, budget effectiveness, customer satisfaction, reputation, service quality, innovation, and employee development. Customers perspective had the highest weighting, suggesting a focus on public service over financial growth.
Public Sector Reforms and Outsourcing Services in Nigeria: An Empirical Evalu...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Media Innovations and its Impact on Brand awareness & Considerationiosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Customer experience in supermarkets and hypermarkets – A comparative studyiosrjce
- The document examines customer experience in supermarkets and hypermarkets in India through a survey of 418 customers.
- It finds that in supermarkets, previous experience, atmosphere, price, social environment and experience in other channels most influence customer experience, while in hypermarkets, previous experience, product assortment, social environment and experience in other channels are most influential.
- The study provides insights for retailers on key determinants of customer experience in each format to help them improve strategies and competitive positioning.
Social Media and Small Businesses: A Combinational Strategic Approach under t...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Secretarial Performance and the Gender Question (A Study of Selected Tertiary...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Implementation of Quality Management principles at Zimbabwe Open University (...iosrjce
This document discusses the implementation of quality management principles at Zimbabwe Open University's Matabeleland North Regional Centre. It begins with background information on ZOU and the importance of quality management in open and distance learning institutions. The study aimed to determine if quality management and its principles were being implemented at the regional centre. Key findings included that the centre prioritized customer focus and staff involvement. Decisions were made based on data analysis. The regional centre implemented a quality system informed by its policy documents. The document recommends ensuring staffing levels match needs and providing sufficient resources to the regional centre.
Organizational Conflicts Management In Selected Organizaions In Lagos State, ...iosrjce
IOSR Journal of Business and Management (IOSR-JBM) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of business and managemant and its applications. The journal welcomes publications of high quality papers on theoretical developments and practical applications inbusiness and management. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
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BREEDING METHODS FOR DISEASE RESISTANCE.pptxRASHMI M G
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Slides from talk:
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https://www.etran.rs/2024/en/home-english/
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Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties of Polystyrene Films
1. IOSR Journal of Applied Physics (IOSR-JAP)
e-ISSN: 2278-4861.Volume 7, Issue 6 Ver. II (Nov. - Dec. 2015), PP 64-70
www.iosrjournals
DOI: 10.9790/4861-07626470 www.iosrjournals.org 64 | Page
Investigation of the Effects of Fullerene addition and Plasma
Exposure on Optical Properties of Polystyrene Films
N. M. Elsayed*, O. F. Farag, M. H. Elghazaly and D. A. Nasrallah
Physics Department, Faculty of Science, Zagazig University, Egypt
Abstract: In the present study, two different methods of modification (Fullerene addition and plasma exposure)
were applied to tune the basic optical properties and optical constants of the polystyrene films with thickness in
the range (0.22-0.25 mm). The samples have been investigated via absorbance, transmittance and reflectance
spectra, and characterized in the wavelength range 200–900 nm. The optical band gap Eg is found to be
decreased after Fullerene addition while it is not changed with plasma exposure. The optical constants
(refractive index, extinction coefficient, and real and imaginary parts of the dielectric constant) showed clear
changes with Fullerene addition and plasma exposure.
Keywords: polystyrene/ fullerene/ plasma exposure/ optical constants/ optical band gap/ doping
I. Introduction
In recent years, polymers with different optical properties have been attracted much attentions due to
their applications in the sensors, light-emitting diodes and others [1]. The optical study is very interesting
because it provides an important information about the absorbance, transmittance and reflectance of the
observed polymeric films [2]. The optical absorption and especially the absorption edge present a useful method
for the investigation of optically induced transition and for getting information about the band structure, the
band tail and the energy gap of the polymeric materials under consideration [3].
The optical properties of polymeric materials can be easily tuned by controlling contents of the
different concentrations [1] and by physical surface modification. Physical surface modification by flame,
corona treatment, UV, gamma-ray, electron beam irradiations, ion beam, plasma, and laser treatments [4, 5, 6, 7]
lead the breakage of covalent bonds, promotion of cross linkages, formation of carbon clusters, liberation of
volatile species and in certain cases creation of new chemical bonds [8]. All these processes introduce so-called
defects inside the material that are responsible for change in the optical, electrical, mechanical and chemical
properties of the material [9].
Polystyrene (PS) is amorphous polymer with bulky side groups. General purposes PS are hard, rigid,
and transparent at room temperature and glass like thermoplastic material which can be soften and distort under
heat. It is soluble in aromatic hydrocarbon solvents, cyclohexane and chlorinated hydrocarbons [10].
Fullerene (C60) is a widely studied material due to its unique optical, electrical, and chemical properties
[11]. It has potential applications in hetero-junction solar cell as well as medical sciences [12]. Incorporation of
fullerene and nanotubes into chemical composition of polymers gives one more opportunities for their study and
application as composite materials, films, and fibers serving different purposes [13].
Plasma treatment have distinct advantages over other methods, modifications are limited to the surface
layer to a depth of typically 0.005 to 0.05 μm without affecting the bulk properties of the polymer [14].
Moreover, it is a rabid and environmentally friendly process [15]. The effect of plasma treatment depends on a
verity of parameters such as kind of plasma (DC, radio frequency (RF) or microwave (MW)), the discharge
power, the pressure of the gas, as well as exposure time [16].
In the present paper, we study the effects of fullerene addition and DC N2 plasma on the basic optical
properties and optical constants of the polystyrene films.
II. Materials And Methods
1. Samples preparation
The studied samples were prepared by the casting technique. PS of molecular weight 192,000 in the
form of grains and Fullerene (C60) of molecular weight 720.64 were supplied by Sigma- Aldrich Company. PS
and Fullerene (C60) were dissolved in toluene with purity 99.99 %, the complete dissolution was obtained using
a magnetic stirrer at room temperature for half-hour. A mixture of the solution was cast onto a clean glass Petri
dish. The whole assembly was placed in a dust free chamber and allowed to evaporate the solvent slowly in air
at room temperature for one week. The thickness of the films was in the range of (0.22-0.25 mm), it was
determined using micrometer at different places in each film and an average was taken.
The Fullerene content in films prepared in this study are 0, 1× 10-5
, 5 × 10-5
, 1× 10-4
, 5 × 10-4
and 1× 10-3
mol.
%.
2. Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties…
DOI: 10.9790/4861-07626470 www.iosrjournals.org 65 | Page
2. Plasma treatment
Figure (1) represents a schematic diagram of the DC glow discharge setup used for surface treatment of
the PS films. The setup consists of a Pyrex tube of (18 cm) long and (13 cm) diameter closed at each end with
aluminum plate. Two planes circular stainless steel plates of (5 cm radius) represent the two electrodes are
connected to each other with four isolated rods keeping the spacing constant at (7 cm). The two electrodes move
axially forward and backward as a unit controlled by a handle outside the tube. The base pressure is attained into
the tube at (10-3
Torr) by using a rotary pump (Edwards H. vacuum pump, model ED 200) then the N2 gas is
allowed to inter the tube throw a controllable needle valve. Plasma properties were kept constant during the
experiment, as the gas pressure was 0.4 Torr, and the discharge power was about 3.5 W. The exposure time was
varied from 15 to 120 minutes.
The films were cut to give sample size (1.5 x 2 cm). The samples were supported on a glass rode and put in front
of the cathode at the edge of the negative glow.
3. UV-Visible Spectroscopy
Ultra violet and visible (UV/VIS) absorbance, transmittance and reflectance spectra of pristine and
plasma treated PS and pristine (PS-C60) films were recorded over a wavelength range 200–900 nm using a
Perkin–Elmer Lambda 950 spectrophotometer. The optical absorption and reflectance spectra were analyzed to
determine optical constants such as refractive index n, extinction coefficient k, and absorption coefficient α.
Analysis of the absorption coefficient was also carried out to determine the optical band gap.
III. Results And Discussion
1. Optical absorption spectra
Figure (2.a) shows UV-Visible spectra of the PS films filled with different concentrations of Fullerene
(C60). Pure PS exhibit strong absorption over the 200-280 nm range (max 240 nm). The peak at 240 nm can be
attributed to the phenyl ring in each repeat unit [17]. On the other hand, Fullerene (C60) exhibit strong
absorption peak at 335 nm and two weak-broad bands between 450 and 640 nm which are attributed to the π-π
transition and the transition from HOMO to LUMO, respectively [18].
UV-Visible spectra recorded for the plasma treated PS films are displayed in Figure (2.b) for different
durations. An increase of absorbance is observed in spectra of samples exposed to plasma, which indicates that
absorbing photoproducts (e.g. conjugated double bonds) are present in PS [17].
2. Optical energy gap
The variation of the optical bulk absorption coefficient, α, with wavelength is a unique parameter of the
medium. The importance of the absorption coefficient is related to the valuable information that can be
obtained, such as the electronic band structure and the optical energy band gap. The absorption coefficient can
be estimated from the optical absorption spectrum owing to the following equation [3]:
dA /303.2)( (1)
where A is the absorbance and d is the film thickness.
Figure (2): The UV-Visible absorption spectra, (a) for PS films filled with different
concentrations of C60 and (b) for pristine and plasma treated PS films for different durations.
3. Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties…
DOI: 10.9790/4861-07626470 www.iosrjournals.org 66 | Page
Figure (2): The UV-Visible absorption spectra, (a) for PS films filled with different concentrations of C60
and (b) for pristine and plasma treated PS films for different durations.
The relation between the optical energy band gap, absorption coefficient and energy (hv) of the
incident photon is given by [19,20]:
r
g
EhBh )( (2)
where α is the absorption coefficient, ν is the frequency, h is the Planck’s constant, B is a constant, Eg
is the optical energy band gap between the valence and the conduction bands and r is the power that
characterizes the transition process. Specifically, r can take the values 1/2, 3/2, 2, and 3 for transitions
designated as direct allowed, direct forbidden, indirect allowed and indirect forbidden, respectively.
The usual method to determine the optical energy band gap is to plot a graph between (hνα)1/r
and hv.
The best fit of indirect transitions is obtained for r = 2, meanwhile for a direct transition the best fit is obtained
for r = 1/2 . The indirect optical energy band gap is determined by plotting (α hν)1/2
against the photon energy
(hv). The extrapolation of the straight parts of the curves to the energy axis (hv) yields the indirect optical
energy band gap.
The variation of the absorption coefficient (α) versus photon energy (hν) for pure and doped PS with
C60 of different concentrations is shown in Figure (3.a). The absorption coefficient of samples increased with
increasing C60 concentrations in the film. Also, it can be seen that the behavior of (α) is similar to the absorption
spectra.
Figure (3.b) shows the absorption coefficient (α) as function of photon energy (hν) for pristine and
nitrogen plasma treated PS films at different durations. It is clear from this figure that the values of (α) showed
increase with increase in the exposure time. The increase in (α) with increasing the exposure time is attributed to
same reasons that were discussed for the increase in the absorbance of UV-Visible spectra.
Figure (4) displays the C60 content dependence of Eg and the results are listed in table 1. It is clear that
the values of indirect optical energy band gap are decreased with increasing C60 content in PS films. Such
behavior is in accordance with those reported previously [21, 22]. The decrease in the optical energy band gap
with filling may be explained by increasing the incorporation of C60 contents in the polymeric host matrix. This
4. Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties…
DOI: 10.9790/4861-07626470 www.iosrjournals.org 67 | Page
introduces additional absorption bands in the UV and visible regions of the optical spectra as shown in UV-
Visible spectra (fig. 2a).
The values of optical energy band gap for pristine and plasma treated samples are tabulated in Table II.
As can be seen the values of indirect optical energy band gap are not changed with the increase in the exposure
time. This may be due to low power of the applied plasma [23].
Table I: Displays the C60 content dependence of Eg values of indirect transition.
C60 Concentration ( mol. %) Eg (indirect) (eV)
0 4.22
1×10-5
4.14
5×10-5
3.56
1×10-4
3.26
5×10-4
2.42
1×10-3
2.38
Table II: Displays the values of optical energy band gaps for pristine and plasma treated samples.
3. The Refractive index (n)
The index of refraction of a material is the ratio of the velocity of the light in vacuum to that of the
specimen. The refractive index of the films was calculated by the following equation [24]:
2
2
)1(
4
1
1
k
R
R
R
R
n
(3)
where R is the reflectance and k is the extinction coefficient.
The extinction coefficient (k) describes the properties of the material with respect to light of a given wavelength
and indicates the absorption changes when the electromagnetic wave propagates through the material. The
extinction coefficient (k) was calculated using the following equation [23]:
4/k (4)
where λ is the wavelength and α is the absorption coefficient.
Figure (5.a) shows the refractive index as function of wavelength for pure and doped PS with C60 of
different concentrations. In this figure, (n) exhibits to decrease with λ for pure and doped films. Also the values
of (n) showed increase with increasing C60 concentrations. Moreover, (n) increases from 1.45 to 2.45 at λ = 625
Exposure Time (min.) Eg (indirect) (eV)
0 4.22
15 4.22
30 4.22
60 4.22
120 4.22
Figure (4): The dependence of (α hν)1/2
on the photon energy for PS films filled with
different concentrations of C60.
5. Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties…
DOI: 10.9790/4861-07626470 www.iosrjournals.org 68 | Page
nm (when C60 concentration increases from (0 to 1 × 10-3
) mol. %. This is a result of increasing the number of
atomic refractions due to the increase of the C60 concentrations in the films.
Figure (5.b) shows the refractive index as function of wavelength for pristine and nitrogen plasma
treated PS films at different durations. It is clear from this figure, that the refractive index for pristine and
nitrogen plasma treated PS films decrease with increasing λ. Also the values of (n) showed increase with the
increase in the exposure time. This increase in refractive index with increasing the exposure time may be
attributed the etching action of the plasma which increase roughness of film surface.
Figure (6.a) shows the variations of (k) with λ of pure and doped PS with C60. (k) shows an increasing
with increasing C60 concentration. This increase in the values of (k) can be ascribed to high absorption
coefficient [25]. This result indicates that the dopant atoms of C60 will modify the structure of PS. C60 dopant
has increased the absorbance in the visible region.
Figure (6.b) shows (k) as function of wavelength for pristine and nitrogen plasma treated PS films at
different durations. It is clear from this figure, that the values of the extinction coefficient showed increase with
the increase in the exposure time. The increase in extinction coefficient with increasing the exposure time is
attributed to same reason that was discussed for the increase in the absorbance of UV-Visible spectra.
IV. Complex dielectric function
The complex dielectric constant is defined as the response of the material toward the incident
electromagnetic field. The complex dielectric constant of compound ε is divided into two parts real εr, and
imaginary εi. The real and imaginary parts of dielectric constant (εr and εi) were calculated by the following
equations [26, 27]:
6. Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties…
DOI: 10.9790/4861-07626470 www.iosrjournals.org 69 | Page
nk
kn
i
r
2
,
22
(5)
Figures (7.a and b) show the real and imaginary parts of dielectric constant (εr and εi) as function of
wavelength for pure and doped PS with C60 of different concentrations. From Figures 7a and b it is seen that the
real and imaginary parts of the dielectric constant decrease with increasing the wavelength. The real part of the
dielectric constant is higher than the imaginary part.
Figures (8.a and b) show the real and imaginary parts of dielectric constant (εr and εi) as function of
wavelength for pristine and nitrogen plasma treated PS films at different durations. It is clear from these figures,
that (εr and εi) for pristine and nitrogen plasma treated PS films decrease with increasing λ. Also the values of (εr
and εi) showed increase with the increase in the exposure time.
It is concluded that the variation of εr mainly depends on n2
because of small values of k2
, while εi
mainly depends on the k values which are related to the variation of absorption coefficients.
V. Conclusion
The present study revealed the significant effects of varying Fullerene content and plasma exposure on
optical properties of the polystyrene films. From the experimental results we can conclude that:
(1) The values of indirect optical energy band gap are decreased with the increase in the Fullerene content.
Meanwhile their values are not changed with the increase in the plasma exposure time.
(2) The Refractive index (n) increases by increasing both Fullerene content and plasma exposure time.
7. Investigation of the Effects of Fullerene addition and Plasma Exposure on Optical Properties…
DOI: 10.9790/4861-07626470 www.iosrjournals.org 70 | Page
(3) The real and imaginary parts of the dielectric constant were showed clear changes with Fullerene addition
and plasma exposure.
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