This document summarizes an undergraduate honors thesis that investigated the use of transition metal oxides as semiconductors in p-type dye-sensitized solar cells. The thesis synthesized oxides of manganese, cobalt, iron, and vanadium using sol-gel methods and characterized their structures and electrochemical properties. Solar cells were constructed using these oxides and tested under illumination to compare their performance to existing nickel oxide technologies. While the preliminary transition metal oxides did not perform similarly to nickel oxide, the thesis provided a first step in exploring their potential for solar cell applications.
This document summarizes research on the synthesis of copper nanoparticles through chemical reduction. A variety of copper salts, reducing agents, ligands, and solvents were tested. While color changes indicated reduction occurred in some experiments, UV-Vis analysis did not find evidence of copper nanoparticle formation due to degradation. The most promising results used copper(II) gluconate reduced by Surfonamine-L-100 in propylene carbonate, showing an absorbance peak that could represent large copper nanoparticles. Further optimization of parameters is needed to produce stable copper nanoparticles that can be characterized.
This document summarizes a study on the electrodeposition and characterization of copper oxide thin films for solar cell applications. The key points are:
1) Copper oxide thin films were electrodeposited on copper substrates using different deposition methods and parameters.
2) The films were characterized using EDS, FESEM, and Fischer Durlscope analysis to analyze their composition and structure.
3) Increasing the deposition time, temperature, copper sulfate concentration, and operating voltage increased the thickness of the copper oxide films.
4) The results indicate copper oxide films were successfully deposited and their properties evaluated, with future work aimed at developing them into commercial solar cells.
Thermal Oxidation of Copper for Favorable Formation of Cupric Oxide (CuO) Sem...IOSR Journals
Thermal oxidation of copper has been restudied to control the formation of photovoltaic active cupric oxide (CuO) phase against the cuprous oxide (Cu2O) phase. It has been established that the thermal oxidation of copper is governed by the outward lattice diffusion and grain boundary diffusion of copper ions at the interface. The lattice diffusion favors the formation of Cu2O phase whereas grain boundary diffusion favors the formation of CuO phase. In the present work, a fine copper powder is taken as starting material for thermal oxidation to increase the grain boundary diffusion and to study its on phase formation. Further, to suppress the grain boundary diffusion the starting material is chemically passivated with diethylenetriamine and olelamine to chameically passivated the surface defects. Thermal oxidation of these pre-treated materials is carried out in open air at temperature 500 oC and 700 oC to study the phase formation. The resulting materials are characterized by x-ray diffraction and scanning electron microscopy. These studies clearly confirm that grain boundary diffusion or defect mediated diffusion due to small particle size and more surface atoms of copper favor the formation of CuO at low temperature in case of pure copper, whereas the chemical passivation and high temperature heating favours the formation of Cu2O phase and hence the resulting material is biphasic. Hence, the present study is useful information in controlling the phase formation of copper oxide to obtain more photoactive material that is CuO.
Perovskite solar cells are a promising photovoltaic technology that has seen rapid increases in efficiency from 3.8% in 2009 to 19.3% in 2014. Perovskites have a unique crystal structure and can be prepared through various methods like spin coating and inkjet printing. They offer benefits such as high absorption, tunable bandgaps, and flexibility. However, challenges remain around stability issues from oxygen, moisture, UV light and heat that can be addressed through material engineering and encapsulation. With further research into replacing lead and improving stability, perovskite solar cells have the potential to become a leading solar technology of the future.
“Kinetics and mechanism of sulphuric acid oxidation of glycolic (ga) by selen...آفتاب حسین
This document provides an introduction to a study on the kinetics and mechanism of the oxidation of glycolic acid by selenium dioxide in an aqueous-acid medium. It discusses background information on chemical kinetics, oxidation-reduction reactions, and selenium dioxide as an oxidizing agent. Previous studies on the oxidation of various compounds like ketones using selenium dioxide are also summarized. The document lays out context for investigating the reaction kinetics and mechanism of glycolic acid oxidation.
This document discusses the structural, optical, and electronic properties of ZnO nanoparticles. It begins by describing various synthesis methods for ZnO nanoparticles, including liquid-phase, gas-phase, and vapor-phase methods. It then discusses the wurtzite crystal structure of ZnO and properties that arise from its structure like polarity and piezoelectricity. The document also covers optical and electronic properties of ZnO like its large exciton binding energy and potential optoelectronic applications. Finally, it briefly mentions some applications of ZnO nanoparticles in areas like electronics, optics, sensors, and more.
The document discusses using carbon nanotubes (CNTs) to remove heavy metals from wastewater. It notes that extensive industrialization has increased heavy metals in wastewater, which are toxic. While other adsorbents have been used for removal, CNTs have higher adsorption capacity due to their large surface area and interaction with pollutants. The document examines the structure and types of CNTs, as well as their characterization and ability to adsorb heavy metals through functional groups on their surface. Key factors affecting adsorption include surface acidity, pH, and temperature. The document concludes that CNTs are effective and future work could further enhance their adsorption properties and cost-effectiveness.
Optical studies of nano structured la-doped zn o prepared by combustion methodsuresh800
This document summarizes research on the optical properties of lanthanum-doped zinc oxide (ZnO) nanostructures prepared using a combustion synthesis method. Coral-shaped ZnO nanostructures with an average grain size of 15 nm were successfully synthesized. Transmission electron microscopy showed the nanostructures were porous with pore sizes of 10-50 nm. X-ray diffraction analysis confirmed the wurtzite crystal structure of both pure and lanthanum-doped ZnO. Doping with lanthanum altered the structural and optical properties of ZnO. Ultraviolet-visible spectroscopy showed the band gap of ZnO increased with higher lanthanum concentration. Photoluminescence spectra exhibited lanthanum characteristic emission and a
This document summarizes research on the synthesis of copper nanoparticles through chemical reduction. A variety of copper salts, reducing agents, ligands, and solvents were tested. While color changes indicated reduction occurred in some experiments, UV-Vis analysis did not find evidence of copper nanoparticle formation due to degradation. The most promising results used copper(II) gluconate reduced by Surfonamine-L-100 in propylene carbonate, showing an absorbance peak that could represent large copper nanoparticles. Further optimization of parameters is needed to produce stable copper nanoparticles that can be characterized.
This document summarizes a study on the electrodeposition and characterization of copper oxide thin films for solar cell applications. The key points are:
1) Copper oxide thin films were electrodeposited on copper substrates using different deposition methods and parameters.
2) The films were characterized using EDS, FESEM, and Fischer Durlscope analysis to analyze their composition and structure.
3) Increasing the deposition time, temperature, copper sulfate concentration, and operating voltage increased the thickness of the copper oxide films.
4) The results indicate copper oxide films were successfully deposited and their properties evaluated, with future work aimed at developing them into commercial solar cells.
Thermal Oxidation of Copper for Favorable Formation of Cupric Oxide (CuO) Sem...IOSR Journals
Thermal oxidation of copper has been restudied to control the formation of photovoltaic active cupric oxide (CuO) phase against the cuprous oxide (Cu2O) phase. It has been established that the thermal oxidation of copper is governed by the outward lattice diffusion and grain boundary diffusion of copper ions at the interface. The lattice diffusion favors the formation of Cu2O phase whereas grain boundary diffusion favors the formation of CuO phase. In the present work, a fine copper powder is taken as starting material for thermal oxidation to increase the grain boundary diffusion and to study its on phase formation. Further, to suppress the grain boundary diffusion the starting material is chemically passivated with diethylenetriamine and olelamine to chameically passivated the surface defects. Thermal oxidation of these pre-treated materials is carried out in open air at temperature 500 oC and 700 oC to study the phase formation. The resulting materials are characterized by x-ray diffraction and scanning electron microscopy. These studies clearly confirm that grain boundary diffusion or defect mediated diffusion due to small particle size and more surface atoms of copper favor the formation of CuO at low temperature in case of pure copper, whereas the chemical passivation and high temperature heating favours the formation of Cu2O phase and hence the resulting material is biphasic. Hence, the present study is useful information in controlling the phase formation of copper oxide to obtain more photoactive material that is CuO.
Perovskite solar cells are a promising photovoltaic technology that has seen rapid increases in efficiency from 3.8% in 2009 to 19.3% in 2014. Perovskites have a unique crystal structure and can be prepared through various methods like spin coating and inkjet printing. They offer benefits such as high absorption, tunable bandgaps, and flexibility. However, challenges remain around stability issues from oxygen, moisture, UV light and heat that can be addressed through material engineering and encapsulation. With further research into replacing lead and improving stability, perovskite solar cells have the potential to become a leading solar technology of the future.
“Kinetics and mechanism of sulphuric acid oxidation of glycolic (ga) by selen...آفتاب حسین
This document provides an introduction to a study on the kinetics and mechanism of the oxidation of glycolic acid by selenium dioxide in an aqueous-acid medium. It discusses background information on chemical kinetics, oxidation-reduction reactions, and selenium dioxide as an oxidizing agent. Previous studies on the oxidation of various compounds like ketones using selenium dioxide are also summarized. The document lays out context for investigating the reaction kinetics and mechanism of glycolic acid oxidation.
This document discusses the structural, optical, and electronic properties of ZnO nanoparticles. It begins by describing various synthesis methods for ZnO nanoparticles, including liquid-phase, gas-phase, and vapor-phase methods. It then discusses the wurtzite crystal structure of ZnO and properties that arise from its structure like polarity and piezoelectricity. The document also covers optical and electronic properties of ZnO like its large exciton binding energy and potential optoelectronic applications. Finally, it briefly mentions some applications of ZnO nanoparticles in areas like electronics, optics, sensors, and more.
The document discusses using carbon nanotubes (CNTs) to remove heavy metals from wastewater. It notes that extensive industrialization has increased heavy metals in wastewater, which are toxic. While other adsorbents have been used for removal, CNTs have higher adsorption capacity due to their large surface area and interaction with pollutants. The document examines the structure and types of CNTs, as well as their characterization and ability to adsorb heavy metals through functional groups on their surface. Key factors affecting adsorption include surface acidity, pH, and temperature. The document concludes that CNTs are effective and future work could further enhance their adsorption properties and cost-effectiveness.
Optical studies of nano structured la-doped zn o prepared by combustion methodsuresh800
This document summarizes research on the optical properties of lanthanum-doped zinc oxide (ZnO) nanostructures prepared using a combustion synthesis method. Coral-shaped ZnO nanostructures with an average grain size of 15 nm were successfully synthesized. Transmission electron microscopy showed the nanostructures were porous with pore sizes of 10-50 nm. X-ray diffraction analysis confirmed the wurtzite crystal structure of both pure and lanthanum-doped ZnO. Doping with lanthanum altered the structural and optical properties of ZnO. Ultraviolet-visible spectroscopy showed the band gap of ZnO increased with higher lanthanum concentration. Photoluminescence spectra exhibited lanthanum characteristic emission and a
The document summarizes research on the electrochemical deposition of lead dioxide nanostructured thin films. Key findings include:
- Lead dioxide nanostructures were successfully deposited on gold-coated substrates by anodic electrochemical deposition using nitric acid and lead chloride as reactants. The morphology was influenced by deposition parameters like potential, temperature, and pH.
- Deposition at higher temperatures (60°C vs room temperature) resulted in faster growth rates and denser nanostructures, as seen by SEM images.
- Both anodic and cathodic deposition were studied. Cathodic deposition allowed formation of different lead oxide phases depending on conditions, while anodic deposition selectively formed PbO2.
- The work provides a
Electrochemical Investigation of Electrolyte & Anodic Materials for Sodium Io...CrimsonPublishersRDMS
Electrochemical Investigation of Electrolyte & Anodic Materials for Sodium Ion Batteries by Majid Monajjemi* in Crimson Publishers: Peer Reviewed Material Science Journals
Carbon-cuprous oxide composite nanoparticles
were chemically deposited on surface of thin glass tubes of spent
energy saving lamps for solar heat collection. Carbon was
obtained from fly ash of heavy oil incomplete combustion in
electric power stations. Impurities in the carbon were removed by
leaching with mineral acids. The mineral free-carbon was then
wet ground to have a submicron size. After filtration, it was
reacted with concentrated sulfuric/fuming nitric acid mixture on
cold for 3-4 days. Potassium chlorate was then added drop wise on
hot conditions to a carbon slurry followed by filtration.
Nanocarbon sample was mixed with 5% by weight PVA to help
adhesion to the glass surface. Carbon so deposited was doped with
copper nitrate solution. After dryness, the carbon/copper nitrate
film was dipped in hydrazine hydrate to form cuprous oxide -
carbon composite, It was then roasted at 380-400 °C A heat
collector testing assembly was constructed of 5 glass coils
connected in series with a total surface area of 1250 cm2
. Heat
collection was estimated by water flowing in the glass coils that
are coated with the carbon/copper film,. Parameters affecting the
solar collection efficiency such as time of exposure and mass flow
rate of the water were studied. Results revealed that the prepared
glass coil has proven successful energy collector for solar heat.
Two-Dimensional Layered Materials for Battery Application--Yifei LiYifei Li
This document discusses the use of two-dimensional (2D) materials for lithium ion batteries and beyond. It introduces lithium ion batteries and motivations to explore batteries using alternative cations like sodium and magnesium. Various 2D materials are examined for their potential as electrodes, including graphite, dichalcogenides, and layered oxides. Challenges for sodium and magnesium ion batteries are also outlined. The document focuses on a novel electrode design using molybdenum disulfide (MoS2) intercalated with polyethylene oxide (PEO) to expand the interlayer distance and facilitate cation intercalation and diffusion for improved battery performance beyond lithium ion.
This document discusses different types of electrolyte materials that can be used for pseudocapacitors, including silver-doped manganese oxide, ruthenium oxides, solid electrolytes, liquid electrolytes, and ionic liquid electrolytes. It provides details on the properties and advantages of each material, such as manganese oxide having high capacitance but poor conductivity, which can be improved by doping with silver. It also discusses characteristics of solid electrolytes like high ionic conductivity and prevention of dendrite growth.
final accept-Optical and structural properties of TiO2 nanopowders with Co-Ce...nasrollah najibi ilkhchy
This document discusses a study on the optical and structural properties of TiO2 nanopowders doped with 2 mol% cerium and 4 mol% cobalt. X-ray diffraction analysis showed that cerium doping inhibited the formation of the rutile phase of titanium dioxide and promoted retention of the anatase phase at higher calcination temperatures. Optical absorption spectroscopy indicated that doping reduced the band gap of titanium dioxide from 3.21 eV to 3.14-3.20 eV. The crystallite size decreased with doping while the surface area increased compared to undoped titanium dioxide.
Direct Synthesis Carbon/Metal Oxide Composites for Electrochemical Capacitors...drboon
This paper deals with the study of the carbon/metal oxide composites synthesis for electrochemical capacitor electrode material. Transition metal salts, such as FeCl3 and TiCl3 act as activator in the synthesis of activated carbon from gelam wood sawdust (Melaleuca cajuputi Powell) which also have the functions as substrates for the composites. The surface functionalities of activated carbons were modified using oxidative treatments. The changes on crystallography and surface functionalities were analyzed based on XRD and FTIR data. The electrical conductivities and electrochemical properties were determined using kelvin and cyclic voltammetry methods, respectively. FTIR analyses showed that the activation and oxidation treatments affected their surface functionalities. The XRD analyses showed that oxidative treatments also affected carbons crystallite. The electrical conductivities and electrochemical properties were influenced by their crystallite and surface functionalities. The shape of the cyclic voltammograms varied according to the changes on the surface functionalities and on the metals loading. TEM analyses indicated the existence of nanoparticles metal oxides in the carbon samples.
2016 Journal of Power Sources 301 (2016) 35-40Alexis B. B
This document summarizes research on producing transparent thin-film electrodes of Li4Ti5O12 and LiMn2O4 via sol-gel dip coating. Key findings include:
1) Transparent and uniform Li4Ti5O12 and LiMn2O4 thin films were prepared on fluorine-doped tin oxide (FTO) substrates via sol-gel dip coating and heat treatment.
2) X-ray diffraction analysis confirmed the films had the target spinel crystal structures of Li4Ti5O12 and LiMn2O4.
3) Electrochemical characterization including cyclic voltammetry and galvanostatic charging/discharging demonstrated the films were electrochem
This document discusses nanostructures, their synthesis, and surface modification techniques. It defines nanostructures as having at least one dimension between 1-100 nm. Nanostructures are classified based on dimensionality as 0D, 1D, 2D, and 3D. Common synthesis methods include physical vapor deposition, chemical vapor deposition, and thermal spraying. Surface modification is done to change properties like reactivity, roughness, and corrosion protection. Common modification techniques are thermal spraying, PVD, and CVD.
This document discusses modern methods for recovering metals from effluents, specifically ion exchange chromatography and electrodialysis. Ion exchange chromatography separates ions and polar molecules using an ion exchange resin that retains analytes based on their charge. Electrodialysis uses an applied electric potential to transport ions through ion exchange membranes from a dilute solution to a concentrated brine solution. Both methods are effective at separating and recovering metal ions from industrial wastewater effluents.
Silicon is a chemical element with an atomic mass of 14 that occurs in crystal or amorphous form. It is a semiconductor used in electronic chips, solar cells, and other technologies due to its strength, thermal conductivity, and elasticity. Graphene is an allotrope of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It was discovered in 2004 by Andre Geim and Konstantin Novoselov, who won the Nobel Prize. Graphene has unique properties including high strength, thermal and electrical conductivity, and transparency. Potential uses include shielding, electronics, vehicles, and information technologies.
This document discusses copper (Cu) and Cu-based nanoparticles. It begins by defining nanoparticles and their classification. It then discusses the properties and synthesis of Cu nanoparticles specifically. Several methods for synthesizing Cu nanoparticles are described, including reduction of copper salts, using plant extracts, and underwater plasma. Characterization techniques like XRD and XPS are outlined. Applications of Cu nanoparticles include catalysis, antimicrobial uses, and biosensing. Methods of controlling size and shape during synthesis are also mentioned. In summary, the document provides an overview of Cu nanoparticles, including their synthesis, characterization, properties, and applications.
This document reports on a study investigating photoelectrolysis for hydrogen production. The researchers developed titanium dioxide and tungsten oxide photoanodes through anodization, creating nanostructures like nanopores, nanotubes, and nanoplatelets. They tested the photoanodes' ability to produce hydrogen and oxygen under illumination. The titanium dioxide nanotubes generated a small photocurrent without an applied voltage. While the efficiency was low, the study demonstrated photoelectrolysis using nanostructured metal oxides and laid the groundwork for further optimization of this hydrogen production method.
This document describes a study on developing a novel nanocomposite structure for dye-sensitized solar cells (DSSCs) consisting of zinc oxide (ZnO) nanorods coated with titanium dioxide (TiO2) nanoparticles. The ZnO nanorods provide fast electron transport while the TiO2 nanoparticles add high surface area for dye adsorption. Transient measurements show the composite film can transport electrons over 100 times faster than TiO2 nanoparticle films alone. When tested with an alternative redox couple that has fast recombination (ferrocene/ferrocenium), the ZnO-TiO2 films generate higher currents than TiO2 films, demonstrating their ability to better collect injected electrons. However, not all charges successfully transfer from TiO2 to Z
Characterization of Aluminum Doped Nanostructured ZnO/p-Si Heterojunctionstheijes
In this study we investigated electrical and optical properties of heterojunctions made of aluminum doped Zinc oxide (ZnO) nanorods and 4% Boron doped p-type silicon (p-Si). ZnOnanorods were grown by a chemical bath deposition (CBD) techniqueon a seed layer of ZnOsputtered on p-Si. Aluminum doping was achieved by incorporating 0-20% of aluminum nitrate in the chemical bath precursor solution. Room temperature photoluminescence showed a systematic decrease in the defect peak at 560 nm with increasing doping. Band gap was measured using UV-VIS spectroscopy shows that the band gap increased from 3.31 eV to 3.58 eV as the doping is varied from 0-20%. This increase in band gap could be due to the Burstein-Moss effect previously observed in heavily doped semiconductors. In addition, we also performed current-voltage (I-V), capacitancevoltage(C-V) measurements on Aluminum doped ZnO/p-Si nanorods samples under both dark and illumination conditions. I-V characteristics showed a good rectifying behavior under dark and illumination conditions. The saturation current, diode ideality factor, carrier concentrations, built in potential, and barrier height were calculated from I-V and C-V measurements for each sample. We will discuss the implications of the variations in band gap, I-V, and C-V measurements with variation in aluminum doping
Introduction of semiconductor oxides in photovoltaic devicesMuhammad Mudassir
This document discusses the incorporation of semiconductor oxides in photovoltaic devices. It explains that semiconductor oxides like ZnO, TiO2, and SnO2 can absorb solar energy due to their band gap. These metal oxide semiconductors can be used as n-type or p-type materials in organic solar cells depending on their conduction and valence bands. The document also discusses how ZnO and TiO2 can be used as photocatalysts in applications like wastewater treatment due to their photoinduced oxidation-reduction reactions when illuminated. Finally, it states that metal oxide semiconductors are useful in technologies involving photon-assisted processes like serving as scaffold layers in dye-sensitized solar cells and transport layers
Structure, Synthesis and Functionalization of CNTs & fullerene raosandy11
This document provides an overview of carbon nanotubes (CNTs) and fullerenes. It discusses the structure and properties of CNTs, including their mechanical, electrical, and thermal properties. It describes common synthesis methods for CNTs, such as arc discharge, laser ablation, and chemical vapor deposition. It also covers functionalization of CNTs through covalent and non-covalent methods. Applications of CNTs include use in batteries, electronics, and sensors. The document then discusses the structure and properties of fullerenes, as well as synthesis methods like arc discharge. It describes endohedral and exohedral fullerene modifications and applications in armor, materials, and lubricants.
The document discusses nanoparticles for small molecule electrocatalysis, specifically focusing on oxygen evolution reaction (OER) using Ni-Co hydroxides and oxides. It first provides background on OER and discusses how Co3O4, metal-doped Co3O4, and NiCo2O4 can be used as catalysts. It then outlines the purpose and scope of studying the composition dependence of Ni-Co hydroxides and oxides for OER using stainless steel mesh. The document reviews relevant theory around OER mechanisms and properties of different catalyst materials.
This document provides an overview of dye sensitized solar cells (DSSC). It discusses the principle and working of DSSCs, including the key components - a photosensitive dye, nanostructured semiconductor (typically TiO2), redox electrolyte, and two electrodes. Upon light absorption, electrons are injected from the dye into the semiconductor. The electrolyte regenerates the oxidized dye and transports electrons between the electrodes. The document outlines the preparation, applications, and commercial potential of DSSCs, noting their advantages over silicon solar cells.
This document analyzes the absorption properties and I-V characterization of a dye sensitized solar cell using a natural Ruthenium dye extracted from fruits. Anees Ur Rehman et al. fabricated a DSSC using Ruthenium dye extracted from fruits as a sensitizer on a titanium dioxide layer. They measured the cell's short circuit current, open circuit voltage, fill factor, and efficiency, finding values of 11.52 mA/cm2, 0.70V, 0.61, and 4.47% respectively under 110 mW/cm2 illumination. The dye was found to absorb visible light well and support electron transfer at the semiconductor interface, demonstrating the potential of natural dyes as lower-
The document summarizes research on the electrochemical deposition of lead dioxide nanostructured thin films. Key findings include:
- Lead dioxide nanostructures were successfully deposited on gold-coated substrates by anodic electrochemical deposition using nitric acid and lead chloride as reactants. The morphology was influenced by deposition parameters like potential, temperature, and pH.
- Deposition at higher temperatures (60°C vs room temperature) resulted in faster growth rates and denser nanostructures, as seen by SEM images.
- Both anodic and cathodic deposition were studied. Cathodic deposition allowed formation of different lead oxide phases depending on conditions, while anodic deposition selectively formed PbO2.
- The work provides a
Electrochemical Investigation of Electrolyte & Anodic Materials for Sodium Io...CrimsonPublishersRDMS
Electrochemical Investigation of Electrolyte & Anodic Materials for Sodium Ion Batteries by Majid Monajjemi* in Crimson Publishers: Peer Reviewed Material Science Journals
Carbon-cuprous oxide composite nanoparticles
were chemically deposited on surface of thin glass tubes of spent
energy saving lamps for solar heat collection. Carbon was
obtained from fly ash of heavy oil incomplete combustion in
electric power stations. Impurities in the carbon were removed by
leaching with mineral acids. The mineral free-carbon was then
wet ground to have a submicron size. After filtration, it was
reacted with concentrated sulfuric/fuming nitric acid mixture on
cold for 3-4 days. Potassium chlorate was then added drop wise on
hot conditions to a carbon slurry followed by filtration.
Nanocarbon sample was mixed with 5% by weight PVA to help
adhesion to the glass surface. Carbon so deposited was doped with
copper nitrate solution. After dryness, the carbon/copper nitrate
film was dipped in hydrazine hydrate to form cuprous oxide -
carbon composite, It was then roasted at 380-400 °C A heat
collector testing assembly was constructed of 5 glass coils
connected in series with a total surface area of 1250 cm2
. Heat
collection was estimated by water flowing in the glass coils that
are coated with the carbon/copper film,. Parameters affecting the
solar collection efficiency such as time of exposure and mass flow
rate of the water were studied. Results revealed that the prepared
glass coil has proven successful energy collector for solar heat.
Two-Dimensional Layered Materials for Battery Application--Yifei LiYifei Li
This document discusses the use of two-dimensional (2D) materials for lithium ion batteries and beyond. It introduces lithium ion batteries and motivations to explore batteries using alternative cations like sodium and magnesium. Various 2D materials are examined for their potential as electrodes, including graphite, dichalcogenides, and layered oxides. Challenges for sodium and magnesium ion batteries are also outlined. The document focuses on a novel electrode design using molybdenum disulfide (MoS2) intercalated with polyethylene oxide (PEO) to expand the interlayer distance and facilitate cation intercalation and diffusion for improved battery performance beyond lithium ion.
This document discusses different types of electrolyte materials that can be used for pseudocapacitors, including silver-doped manganese oxide, ruthenium oxides, solid electrolytes, liquid electrolytes, and ionic liquid electrolytes. It provides details on the properties and advantages of each material, such as manganese oxide having high capacitance but poor conductivity, which can be improved by doping with silver. It also discusses characteristics of solid electrolytes like high ionic conductivity and prevention of dendrite growth.
final accept-Optical and structural properties of TiO2 nanopowders with Co-Ce...nasrollah najibi ilkhchy
This document discusses a study on the optical and structural properties of TiO2 nanopowders doped with 2 mol% cerium and 4 mol% cobalt. X-ray diffraction analysis showed that cerium doping inhibited the formation of the rutile phase of titanium dioxide and promoted retention of the anatase phase at higher calcination temperatures. Optical absorption spectroscopy indicated that doping reduced the band gap of titanium dioxide from 3.21 eV to 3.14-3.20 eV. The crystallite size decreased with doping while the surface area increased compared to undoped titanium dioxide.
Direct Synthesis Carbon/Metal Oxide Composites for Electrochemical Capacitors...drboon
This paper deals with the study of the carbon/metal oxide composites synthesis for electrochemical capacitor electrode material. Transition metal salts, such as FeCl3 and TiCl3 act as activator in the synthesis of activated carbon from gelam wood sawdust (Melaleuca cajuputi Powell) which also have the functions as substrates for the composites. The surface functionalities of activated carbons were modified using oxidative treatments. The changes on crystallography and surface functionalities were analyzed based on XRD and FTIR data. The electrical conductivities and electrochemical properties were determined using kelvin and cyclic voltammetry methods, respectively. FTIR analyses showed that the activation and oxidation treatments affected their surface functionalities. The XRD analyses showed that oxidative treatments also affected carbons crystallite. The electrical conductivities and electrochemical properties were influenced by their crystallite and surface functionalities. The shape of the cyclic voltammograms varied according to the changes on the surface functionalities and on the metals loading. TEM analyses indicated the existence of nanoparticles metal oxides in the carbon samples.
2016 Journal of Power Sources 301 (2016) 35-40Alexis B. B
This document summarizes research on producing transparent thin-film electrodes of Li4Ti5O12 and LiMn2O4 via sol-gel dip coating. Key findings include:
1) Transparent and uniform Li4Ti5O12 and LiMn2O4 thin films were prepared on fluorine-doped tin oxide (FTO) substrates via sol-gel dip coating and heat treatment.
2) X-ray diffraction analysis confirmed the films had the target spinel crystal structures of Li4Ti5O12 and LiMn2O4.
3) Electrochemical characterization including cyclic voltammetry and galvanostatic charging/discharging demonstrated the films were electrochem
This document discusses nanostructures, their synthesis, and surface modification techniques. It defines nanostructures as having at least one dimension between 1-100 nm. Nanostructures are classified based on dimensionality as 0D, 1D, 2D, and 3D. Common synthesis methods include physical vapor deposition, chemical vapor deposition, and thermal spraying. Surface modification is done to change properties like reactivity, roughness, and corrosion protection. Common modification techniques are thermal spraying, PVD, and CVD.
This document discusses modern methods for recovering metals from effluents, specifically ion exchange chromatography and electrodialysis. Ion exchange chromatography separates ions and polar molecules using an ion exchange resin that retains analytes based on their charge. Electrodialysis uses an applied electric potential to transport ions through ion exchange membranes from a dilute solution to a concentrated brine solution. Both methods are effective at separating and recovering metal ions from industrial wastewater effluents.
Silicon is a chemical element with an atomic mass of 14 that occurs in crystal or amorphous form. It is a semiconductor used in electronic chips, solar cells, and other technologies due to its strength, thermal conductivity, and elasticity. Graphene is an allotrope of carbon consisting of a single layer of carbon atoms arranged in a hexagonal lattice. It was discovered in 2004 by Andre Geim and Konstantin Novoselov, who won the Nobel Prize. Graphene has unique properties including high strength, thermal and electrical conductivity, and transparency. Potential uses include shielding, electronics, vehicles, and information technologies.
This document discusses copper (Cu) and Cu-based nanoparticles. It begins by defining nanoparticles and their classification. It then discusses the properties and synthesis of Cu nanoparticles specifically. Several methods for synthesizing Cu nanoparticles are described, including reduction of copper salts, using plant extracts, and underwater plasma. Characterization techniques like XRD and XPS are outlined. Applications of Cu nanoparticles include catalysis, antimicrobial uses, and biosensing. Methods of controlling size and shape during synthesis are also mentioned. In summary, the document provides an overview of Cu nanoparticles, including their synthesis, characterization, properties, and applications.
This document reports on a study investigating photoelectrolysis for hydrogen production. The researchers developed titanium dioxide and tungsten oxide photoanodes through anodization, creating nanostructures like nanopores, nanotubes, and nanoplatelets. They tested the photoanodes' ability to produce hydrogen and oxygen under illumination. The titanium dioxide nanotubes generated a small photocurrent without an applied voltage. While the efficiency was low, the study demonstrated photoelectrolysis using nanostructured metal oxides and laid the groundwork for further optimization of this hydrogen production method.
This document describes a study on developing a novel nanocomposite structure for dye-sensitized solar cells (DSSCs) consisting of zinc oxide (ZnO) nanorods coated with titanium dioxide (TiO2) nanoparticles. The ZnO nanorods provide fast electron transport while the TiO2 nanoparticles add high surface area for dye adsorption. Transient measurements show the composite film can transport electrons over 100 times faster than TiO2 nanoparticle films alone. When tested with an alternative redox couple that has fast recombination (ferrocene/ferrocenium), the ZnO-TiO2 films generate higher currents than TiO2 films, demonstrating their ability to better collect injected electrons. However, not all charges successfully transfer from TiO2 to Z
Characterization of Aluminum Doped Nanostructured ZnO/p-Si Heterojunctionstheijes
In this study we investigated electrical and optical properties of heterojunctions made of aluminum doped Zinc oxide (ZnO) nanorods and 4% Boron doped p-type silicon (p-Si). ZnOnanorods were grown by a chemical bath deposition (CBD) techniqueon a seed layer of ZnOsputtered on p-Si. Aluminum doping was achieved by incorporating 0-20% of aluminum nitrate in the chemical bath precursor solution. Room temperature photoluminescence showed a systematic decrease in the defect peak at 560 nm with increasing doping. Band gap was measured using UV-VIS spectroscopy shows that the band gap increased from 3.31 eV to 3.58 eV as the doping is varied from 0-20%. This increase in band gap could be due to the Burstein-Moss effect previously observed in heavily doped semiconductors. In addition, we also performed current-voltage (I-V), capacitancevoltage(C-V) measurements on Aluminum doped ZnO/p-Si nanorods samples under both dark and illumination conditions. I-V characteristics showed a good rectifying behavior under dark and illumination conditions. The saturation current, diode ideality factor, carrier concentrations, built in potential, and barrier height were calculated from I-V and C-V measurements for each sample. We will discuss the implications of the variations in band gap, I-V, and C-V measurements with variation in aluminum doping
Introduction of semiconductor oxides in photovoltaic devicesMuhammad Mudassir
This document discusses the incorporation of semiconductor oxides in photovoltaic devices. It explains that semiconductor oxides like ZnO, TiO2, and SnO2 can absorb solar energy due to their band gap. These metal oxide semiconductors can be used as n-type or p-type materials in organic solar cells depending on their conduction and valence bands. The document also discusses how ZnO and TiO2 can be used as photocatalysts in applications like wastewater treatment due to their photoinduced oxidation-reduction reactions when illuminated. Finally, it states that metal oxide semiconductors are useful in technologies involving photon-assisted processes like serving as scaffold layers in dye-sensitized solar cells and transport layers
Structure, Synthesis and Functionalization of CNTs & fullerene raosandy11
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This document provides an overview of dye sensitized solar cells (DSSC). It discusses the principle and working of DSSCs, including the key components - a photosensitive dye, nanostructured semiconductor (typically TiO2), redox electrolyte, and two electrodes. Upon light absorption, electrons are injected from the dye into the semiconductor. The electrolyte regenerates the oxidized dye and transports electrons between the electrodes. The document outlines the preparation, applications, and commercial potential of DSSCs, noting their advantages over silicon solar cells.
This document analyzes the absorption properties and I-V characterization of a dye sensitized solar cell using a natural Ruthenium dye extracted from fruits. Anees Ur Rehman et al. fabricated a DSSC using Ruthenium dye extracted from fruits as a sensitizer on a titanium dioxide layer. They measured the cell's short circuit current, open circuit voltage, fill factor, and efficiency, finding values of 11.52 mA/cm2, 0.70V, 0.61, and 4.47% respectively under 110 mW/cm2 illumination. The dye was found to absorb visible light well and support electron transfer at the semiconductor interface, demonstrating the potential of natural dyes as lower-
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This document presents a student project on the effect of metal coupling on iron rusting. The student Mayank Chaudhary from JKG International School studied how coupling iron with more electropositive metals like zinc and magnesium prevents rusting, while coupling with less electropositive copper facilitates rusting. Through experimentation with iron nails wrapped in different metals, observation of color changes, and analysis, the student was able to conclude that metal coupling affects iron's corrosion, with more positive metals protecting iron and less positive metals increasing rusting.
Design and Simulation of Dye Sensitized Solar Cell as a Cost-Effective Alt...Scientific Review SR
The continuous research in the area of renewable energy technology to substitute the unsustainable nature of fossil
fuel in terms of it future availability and negative environmental impact created by fossil fuel has ensure the explore
of solar energy as a good alternative. Dye sensitized solar cells (DSSCs) serve to be a good alternative means of
producing photovoltaic solar cell. This work reports the working principle and construction process of dye-sensitized
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cell within 6:00am (GMT) and 6:00pm (GMT) for selected days. The results from the evaluation process show a
better performance of a dye-sensitized solar cell in low and normal sunny day. The solar cell has a good performance
at 12:00noon with a 0.5V output.
This document summarizes a project to prepare pure and magnesium-doped zinc oxide nanoparticles for photocatalytic degradation of endocrine disrupting chemicals. A group of 5 students will synthesize and characterize 1.5% Mg-doped ZnO using methods like X-ray diffraction and SEM. They will study the effect of time, catalyst loading on photocatalytic degradation of resorcinol. The goals are to prepare and analyze pure and doped ZnO nanoparticles to degrade chemicals like bisphenol and nonylphenol more efficiently through photocatalysis.
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This document discusses engineering the band edges of composite photoanodes for dye-sensitized solar cells through doping. Specifically, it doped ZnO nanorods with cobalt to lower its conduction band minimum and doped TiO2 nanoparticles with zirconium to raise its conduction band minimum in order to overcome an energy barrier preventing electron transfer. Characterization with diffuse reflectance spectroscopy and open circuit voltage measurements under illumination confirmed the doping shifted the band edges as intended. However, dye-sensitized solar cells fabricated with the composite nanostructures did not show improved performance. The paper details a methodology for producing and measuring band edge shifts but notes limitations in applying it to improve device operation.
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Potentiostatic Deposition of ZnO Nanowires: Effect of Applied Potential and Z...IJRES Journal
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The document discusses using X-ray diffraction (XRD) to analyze the molecular structure of nickel oxide (NiO) films annealed under different conditions. XRD patterns showed that films annealed for 60 minutes developed crystalline peaks, while shorter annealing durations resulted in amorphous structures. For films annealed at different temperatures, all showed crystallinity with larger crystallite sizes at higher temperatures. XRD thus provides a way to study how annealing conditions impact the structural properties of metal oxide thin films like NiO.
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Natural Dye-Sensitized Solar Cells (NDSSCs) From Opuntia Prickly Pear Dye Usi...IJERA Editor
Natural dye-sensitized solar cells (NDSSCs) have gained considerable attention in the field of solar energy due to their simple fabrication, good efficiency, and low production cost. Natural dyes are environmentally and economically superior to ruthenium-based dyes because they are nontoxic and cheap. However, the conversion efficiency of dye-sensitized solar cells based on natural dyes is low. One way to improve the DSSC performance is to enhance the absorptivity of extracted natural dyes. We investigated the influence of various factors in the extraction process, such as utilization of different extraction approaches, the acidity of extraction solvent, and different compounds of solvents on the optical absorption spectra. It was found that we could considerably enhance the optical absorptivity of dye and consequently the performance of DSSC by choosing a proper mixture of ethanol, methanol and water. In this study, a photo electrode using ZnO doped TiO2 nanoparticles was prepared by sol-gel method. In this paper we investigate the optical absorption, functional group, surface morphology and elementary composition of pure TiO2, ZnO doped TiO2 nanoparticles and opuntia prickly pear dye extract by using UV-Visible, PL-Studies, FT-IR, FE-SEM and EDS analysis. Finally photocurrent-voltaic characterization of nanocrystaline natural dye solar cell using I-V studies. It was found that the levels of short-circuit current (Jsc), open-circuit voltage (Voc), fill factor (FF) and overall conversion efficiency (η).
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were successfully reacted and deposited into electrochemically fabricated TiO2 nanotubes. Employing
vapor phase reaction deposition, the cavities of 100 mm long TiO2 nanotubes were infiltrated;
approximately 50% of the nanotube arrays were estimated to be infiltrated in the case of NaP7. Intensive
characterization of the hybrid materials with techniques including SEM, FIB, HR-TEM, Raman
spectroscopy, XRD, and XPS proved the successful vapor phase deposition and synthesis of the
substances on and inside the nanotubes. The polyphosphide@TiO2 hybrids exhibited superior water
splitting performance compared to pristine materials and were found to be more active at higher
wavelengths. SnIP@TiO2 emerged to be the most active among the polyphosphide@TiO2 materials. The
improved photocatalytic performance might be due to Fermi level re-alignment and a lower charge
transfer resistance which facilitated better charge separation from inorganic phosphides to TiO2.
This document summarizes a research paper on dye sensitized solar cells (DSSCs). It provides background on the development of DSSCs since 1991 and their advantages over traditional silicon solar cells in terms of lower cost and simpler preparation. However, liquid electrolytes used in early DSSCs limited long-term performance. Recent research has focused on improving electrolytes, particularly developing quasi-solid state electrolytes, to enhance photoelectric performance and stability for practical applications of DSSCs. The document reviews progress on quasi-solid state electrolytes and their advantages over liquid electrolytes for DSSCs.
This document is a student project on studying the effect of metal coupling on rusting of iron. It includes an introduction on corrosion, the electrochemical mechanism of rusting, and common prevention methods. The aim is to investigate how coupling iron with different metals affects rusting. The procedure involves coupling iron nails with zinc, copper, or magnesium and observing any rust formation. The results showed that coupling with more electropositive metals like zinc and magnesium prevented rusting, while coupling with less electropositive copper facilitated rusting.
1. An Investigation of Transition Metal Oxides in p-Type Dye-Sensitized Solar Cells
Undergraduate Honors Senior Thesis
Presented in Fulfillment of the Requirements for Honors Research Distinction in the
Undergraduate Chemical and Biomolecular Engineering School of The Ohio State University
By
Anna Dorfi, B.S
Chemical and Biomolecular Engineering
The Ohio State University
2014
Yiying Wu, Chemistry Research Advisor
2. Anna Dorfi, The Ohio State University
Page 1 of 27
ACKNOWLEDGMENTS
I would like to thank Dr. Yiying Wu for his support and the opportunity to do research under his
direction. I am also particularly grateful for the assistance given by Thomas Draskovic. He has
helped and guided me from the very beginning of my research and has been a wonderful
graduate research mentor. His willingness to give his time so generously has been very much
appreciated.
3. Anna Dorfi, The Ohio State University
Page 2 of 27
INTRODUCTION
The field of alternative energies is becoming increasingly important as conventional fossil
fuel sources are depleted, and the effects of global climate change are already being noted. In a
society greatly dependent on energy production, the need for alternative and renewable energy
forms is becoming a priority. Solar power is one of the most promising renewable energies,
however it is still somewhat more expensive than conventional sources of energy and it has not
yet been widely adopted [1]. In order for solar technologies to become a more viable energy
option, its production needs to be scaled-up in an economically efficient way. Thus, research
focused on low cost, high efficiency solar cells is necessary. It has been found that dye-sensitized
solar cell technology is promising in terms of high cell efficiencies, and their ability to be
manufactured from inexpensive materials [1]. Consequently, dye-sensitized solar cell (DSSC)
research is at the forefront of these technologies and could provide a way to more efficiently
capture solar energy for clean energy production.
In DSSCs light is absorbed by a sensitizer which is adhered to the surface of a wide band gap
semiconductor. The charge separation takes place at the interface via photo-induced charge
carrier injection from the dye into the semiconductor. The majority charge carriers are
transported through the semiconductor to the charge collector. DSSCs are characterized by the
nature of the semiconductor used. n-Type DSSCs (n-DSSC) use an n-type semiconductor (e.g.
TiO2, ZnO). Electrons are injected into the conduction band by the photo-excited dye and diffuse
to the external circuit. p-Type DSSCs (p-DSSC) use a p-type semiconductor (e.g. NiO). Holes
are injected into the valence band by the photo-excited dye and diffuse to the external circuit.
Research in Prof. Yiying Wu’s group has focused significantly on p-DSSCs, however
performances continue to be much less than those of n-DSSCs. The inherent properties of NiO as
4. Anna Dorfi, The Ohio State University
Page 3 of 27
a semiconductor appear to be the source of these problems, and current research is focused on
understanding the role of NiO as well as finding alternative semiconductors. While mainly the
focus of research on supercapacitors, transition metal oxides similar to NiO, specifically
manganese, cobalt, iron, and vanadium oxides, have not been thoroughly investigated for their
use in p-DSSCs. Fundamental research on these 3d transition metal oxides is needed to
understand their applicability and role in DSSCs.
BACKGROUND AND SIGNIFICANCE
Currently, nickel monoxide (NiO) is accepted as one of the few wide band-gap p-type
semiconductors, and is a pale, light color. However, due to defects from oxidation during
synthesis, it has been observed that the nickel oxidizes from 2+
to 3+
. This mixed oxidation state
is likely the reason NiO actually appears to be black. It is known that the higher edge of the
valence band in 3d metal oxides is heavily localized and holes created in the valence band are
not easily transported through the semiconductor [2]. The holes are more localized on individual
Ni atoms, due to their 3d orbital structure. It has been proposed that the holes are present as Ni3+
at the surface of NiO nanoparticles, and the charge transport involves hopping of charges at the
NiO/electrolyte interface. Ultimately, if a NiO p-DSSC essentially functions due to this hole
hopping mechanism induced by the oxidation of nickel by an excited dye molecule, then perhaps
other metal oxides in the same 3d transition metal row with oxidation potentials similar to the Ni
in NiO will work in p-DSSCs. These metal oxides should then theoretically function comparably
to NiO in p-DSSCs.
The transition metal oxides that will be investigated are in the 3d row of the periodic table
and exhibit many oxidations states, including 2+
. Therefore, they have the potential to behave
5. Anna Dorfi, The Ohio State University
Page 4 of 27
similarly to NiO, where the metal surface is oxidized by the dye sensitizer and can participate in
a redox reaction. The wide range of available oxidation states allows for easier oxidation of the
metal oxide surface by the dye. The project aims to construct DSSCs with these various oxides,
at varying oxidative states, in order to investigate their effectiveness for solar applications. When
a photoactive dye is absorbed onto the transition metal oxide, redox reactions between the dye,
electrolyte, and the oxide can be observed. A general equation that describes this aforementioned
phenomenon is shown below as Equation 1:
Equation 1: M2+
surf + Dye*
M3+
surf + Dye-
.
A simplified mechanism that also shows how this DSSC works by a redox reaction can be seen
below as Figure 1:
Figure 1: P-Type Dye-Sensitized Solar Cell Simplified Mechanism
This figure illustrates how a photoactive dye is excited by light energy and causes the electrons
to become excited from the highest occupied molecular orbit (HOMO) level to the lowest
occupied molecular orbit (LUMO) level. As mentioned before, the resulting positive charge from
the redox reaction, called the hole, is injected into the metal oxide which ultimately creates a
current through the semiconductor to the external circuit.
6. Anna Dorfi, The Ohio State University
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The significance of this project is the emphasis on the investigation of using relatively low
cost transition metal oxides made from metals in the 3d row of the periodic table, such as:
Manganese, Cobalt, Iron, and Vanadium in DSSCs. Fundamental research on transition metals
and their applicability for DSSCs has not been extensively explored. Again, the wide range of
oxidative states possible for these transition metal oxides makes them viable candidates, due to
the oxidation reactions that can occur from the excitation of an absorbed photoactive dye
sensitizer. The solar cells that are constructed for this project use a non-aqueous electrolyte
solution composed of the I-
/I3
-
redox couple. Research has shown that non-aqueous electrolyte
solutions achieve higher cell potentials than aqueous electrolytes, due to their ability to
encompass wider voltage windows and liquid ranges, thus leading to higher possible solar cell
efficiencies [3]. Specifically, the aforementioned transition metal oxides will be used in
preliminary constructions of non-aqueous DSSCs and their efficiencies will be compared to
existing technologies.
EXPERIMENTAL METHODOLOGY
Preliminary Oxides Methodology. The transition metal oxides of manganese, cobalt, iron, and
vanadium were synthesized via a modification of a previously developed sol-gel method for
synthesizing NiO thin films [4]. For each desired oxide, 7.72x10-3
moles of a soluble metal salt
precursor (Mn(NO3)3, Co(NO3)3, Fe(NO3)3, or VO(SO4)) was combined with 1 g of distilled
water, 3 g of ethanol, and 1 g of F108 polymer. The polymer was added to the solution to act as a
template for the oxide film formation and so that the film adheres to the substrates. The metal
salt polymer solution was then left to settle over three days. If any solids precipitated out, then
the solution was centrifuged and the resulting supernatant solution was kept. This was the
precursor solution used to make the metal oxide films.
7. Anna Dorfi, The Ohio State University
Page 6 of 27
Syntheses of Transition Metal Oxides with 2+
Oxidation States. Syntheses for the formation of
pure nano-scale lower oxidative transition metal oxides; specifically CoO and MnO were found
and used in order to have a direct comparison to NiO. All syntheses used to produce these
compounds were solvothermal methods and produced nanoparticles. The synthesis of CoO
consisted of combining cobalt acetate, ethanol and polyethylene glycols 4000 in an autoclave at
150 °C for 24 hours [5]. The resulting precipitate was washed with ethanol several times and
filtered by centrifugation before drying at room temperature. The resulting CoO precipitate was
dark blue. The dark brown MnO product was prepared similarly to the CoO product. In a glove
box, manganese acetate and ethanol were combined and transferred to a Teflon-lined stainless
steel autoclave. The autoclave was heated at 200 °C for 24 hours. The product was washed with
water and ethanol several times and filtered by centrifugation. The final washed MnO product
was then dried at 80 °C for 6 hours in a vacuum [6].
n-Type Semiconductors for Sensitized Photocathodes. It was attempted to replicate the tin-doped
indium oxide (ITO) results found from the lab group by creating small area films from
commercial ITO nanoparticle powder (NanoTek®, Alfa Aesar) suspended in ethanol. The Fe2O3
was synthesized using the aforementioned NiO sol-gel modification. WO3 was synthesized
according to previous literature reports [7]. A solvothermal synthesis used sodium tungstate
dehydrate dissolved in water. 2M HCL was added until the pH was 5 and it was then submerged
in a water bath at 80°C for four days. The resulting precipitate was washed and filtered by
centrifugation with distilled water various times. It was dried in the oven at 160°C for two hours.
Film and Cell Preparation. The general method for preparing films involved doctor-blading a
solution that contained the desired transition metal on a fluorine-doped tin oxide (FTO) glass
slide and then annealing the film at a high temperature. For the preliminary oxides, FTO slides
8. Anna Dorfi, The Ohio State University
Page 7 of 27
were cleaned and their conductive sides were marked for future use. Each slide was taped off to
form a “square well” area (around 1.3 mm2
for larger test films and around 0.5 mm2
for small
films) in the middle. 50 μL of each metal solution were deposited above the marked area, and a
microscope slide was used to doctor blade the film evenly. The solution was let dry for ten
minutes. The resulting film thicknesses ranged around two micrometers and were not less than a
micrometer thick. The thin film doctor blading technique was altered to ensure this standard. The
tape was then removed and the glass plates were put separately in an oven at three different
temperatures: 250 °C, 350 °C, and 450 °C.
Similarly for CoO, MnO, ITO and WO3, a solution of ethanol and their respective dry
nanoparticle powders were combined and sonicated for forty minutes to form a paste of
comparable viscosity to the sol-gel pastes. These pastes were then used to create films via the
doctor blading method previously described. All of the prepared CoO, MnO, ITO and WO3 films
were then annealed in a tube furnace under argon atmosphere at 450 °C at a heating rate of 2.5
°C/min and held for 30 minutes, in order to prevent further oxidation.
The film plates were then either sensitized or left bare for comparison studies. The
sensitization was accomplished by immersing the films in a dye-sensitizer for 15 hours to ensure
sufficient dye loading. The DSSCs were then assembled by placing a platinum-coated
conducting FTO glass plate with a hole drilled into it on the dye-sensitized film electrode. These
electrodes were joined using a 60 μm polymer spacer (Solaronix SA, Switzerland) that was
sealed first by heating at 120 °C for 5 minutes. An electrolyte was made with 1.0 M LiI and 0.1
M I2 in dry methoxypropionitrile and it was injected into the cell via vacuum backfilling through
the drilled hole. The hole was then sealed using the polymer film adhesive, a thin glass cover
slide and a quick-dry sealant.
9. Anna Dorfi, The Ohio State University
Page 8 of 27
Characterization. For the preliminary oxides, each metal film annealed at the various
temperatures was analyzed using x-ray powder diffraction (XRD, Rigaku) to confirm what
oxidative species were formed at the three temperatures and to determine at which temperature
each species needed to be annealed. Once the metal oxides films were made and characterized by
x-ray powder diffraction, their electrochemical properties were then evaluated using cyclic
voltammetry in a 0.01 M LiI, 0.001 M I2, and 0.1 M LiClO4 methoxypropionitrile electrolyte and
compared to the results obtained for the original NiO films. Cyclic Voltammetry (CV) is an
electrochemical test that ramps the potential of a working electrode against a reference electrode
for a certain range. The potential is ramped first in the negative direction and then backwards in
the positive direction. If there is any redox activity within the desired potential range, peaks can
be observed which account for the oxidation (peaks with positive currents) and reduction (peaks
with negative currents) activity of the material being tested. These tests allow each metal oxide
to be compared to NiO and its redox activity, so that conclusions can be drawn to how they will
perform when tested as a solar cell. Linear sweep voltammetry was used to test the solar cell
performances both in dark and under illumination from 1 sun AM 1.5G simulated sunlight
(Small-Area Class-B Solar Simulator, PV Measurements). Electrochemical data was collected
using a Gamry Instruments Reference 600. All potentials are reported with respect to the I-
/I3
-
redox couple.
RESULTS AND DISCUSSION
Preliminary Transition Metal Oxide Testing. Relatively pure phase oxides of each transition
metal were obtained at various film annealing temperatures: Mn3O4/Mn2O3 mixture was
confirmed at 450 °C, Co3O4 at 350 °C, Fe2O3 at 450 °C, and V2O5 at 450 °C. Their XRD results
can be seen in Appendix as Figures A1-A4. The oxides synthesized using the NiO sol-gel paper
10. Anna Dorfi, The Ohio State University
Page 9 of 27
adaptation were not directly comparable to Ni (II) as the states present for the cations in each
metal oxide were Manganese (III/IV), Cobalt (III/IV), Iron (III), and Vanadium (V). When
analyzing the CV’s of the preliminary oxides it is evident that they do not follow a similar CV
shape or activity to NiO. The CV’s of the preliminary metal oxides produced can be seen in
Appendix B as Figures B1-B4. This was to be expected, however, as these metal oxides are all
of higher oxidative states (III-V) than Ni (II) and likely do not have a similar charge hopping
mechanism. Linear sweep voltammetry tests were then done once the solar cells were assembled
in order to obtain the maximum current and voltage obtainable from a DSSC made of each
oxide. The first cells made were unsensitized and the metal oxide films were left bare. This was
done in order to see how the metal oxide itself acted in the DSSC. From the preliminary
unsensitized tests it is interesting to note that Fe2O3 exhibited anodic current when compared to
the other common oxides produced. Mn3O4 exhibited slight anodic current but the overall results
show that these common metal oxides produced did not exhibit any cathodic photocurrent on
their own. Thus, the DSSC photocurrent results of the sensitized cells were all due to the photo-
excitation of the sensitizer. A ruthenium-based dye was used for these sensitized cell tests. The
unsensitized results are shown below as Figure 2:
11. Anna Dorfi, The Ohio State University
Page 10 of 27
Figure 2: Non-sensitized DSSC results from metal oxides synthesized using NiO synthesis
modification
Using a ruthenium based dye, referred to as O3, solar cell tests were done in order to determine
the highest short circuit current (Isc, when the voltage is zero) and the highest open circuit
voltages (Voc, when the current is zero) produced by each cell. A graph of these results can be
seen below as Figure 3:
-0.010
0.000
0.010
0.020
0.030
0.040
0.050
-0.02 0.00 0.02 0.04 0.06 0.08 0.10
CurrentDensity(mA/cm2)
Potential (V vs I-/I-
3)
V2O5 Light Current
Density
V2O5 Dark Current
Density
Mn3O4 Light Current
Density
Mn3O4 Dark Current
Density
Co3O4 Light Current
Density
Co3O4 Dark Current
Density
Fe2O3 Light Current
Density
Fe2O3 Dark Current
Density
12. Anna Dorfi, The Ohio State University
Page 11 of 27
Figure 3: Comparison of Metal Oxides synthesized from NiO synthesis modification in O3 dye
The highest Voc’s were 77.7 mV for V2O5 and 74 mV for Mn3O4. The highest Isc densities (which
take into account the area of the films) were -0.0674 mA/cm2
for V2O5 and around -0.042
mA/cm2
for Co3O4. Even though V2O5 performed the best out of all the other oxides (highest Isc
and Voc), it was observed to undergo a color change from yellow to light green when it came in
contact with the I-
/I2/LiClO4 electrolyte. It was then determined to be unstable in the electrolyte
used for this study and no further investigation in regards to other vanadium oxides was done.
Vanadium (IV) is dark blue, so the combination of IV/V oxidation states could suggest that the
electrolyte was actually reducing the V2O5 film. Further research could be done with vanadium
oxides in differing electrolytes, but for the scope of this study it was not considered for further
testing. These results, however, when compared to the NiO results in the same O3 ruthenium-
based dye show that the currents and voltages produced are negligible. The graph comparing the
results to NiO data is shown below as Figure 4:
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02
0.04
0.06
-0.05 -0.03 -0.01 0.01 0.03 0.05 0.07 0.09
CurrentDensity(mA/cm2)
Potential (V vs I-/I-
3)
Co3O4 Light Current
Density
Co3O4 Dark Current
Density
Fe2O3 Light Current
Density
Fe2O3 Dark Current
Density
Mn3O4 Light Current
Density
Mn3O4 Dark Current
Density
V2O5 Light Current
Density
V2O5 Dark Current
Density
13. Anna Dorfi, The Ohio State University
Page 12 of 27
Figure 4: Comparison with NiO in O3 dye of Metal Oxides synthesized from NiO synthesis
modification.
This synthetic method was a starting point for the investigation but did not produce the
monoxides desired to directly compare to NiO. The overall aim was then to vary the procedure
by which the metal oxides were made, in order to produce metal oxide films of the 2+
state so
they could be directly compared to Ni2+
. Further research was then done to find various metal
oxide syntheses for lower metal oxide oxidative states. Syntheses were found for CoO and MnO
and their results are discussed in the following section.
Cobalt and Manganese Monoxide Investigation. CoO and MnO were also confirmed using XRD
(Rigaku) and be seen in Appendix A as Figures A5-A6, respectively. Due to the low oxidation
state in the monoxides, cobalt and manganese could easily be oxidized to 3+
during the synthesis
or film preparation. XRD shows there was some amount of Co3O4 and Mn3O4 in the products,
but it is believed that the monoxides were the dominant phase. Preliminary CV tests of CoO and
-2.300
-1.800
-1.300
-0.800
-0.300
0.200
0.700
1.200
1.700
-0.050 0.000 0.050 0.100 0.150
CurrentDensity(mA/cm2)
Voltage (V vs I-/I-
3)
Co3O4 Light Current
Density
Co3O4 Dark Current
Density
Fe2O3 Light Current
Density
Fe2O3 Dark Current
Density
Mn3O4 Light Current
Density
Mn3O4 Dark Current
Density
V2O5 Light Current
Density
V2O5 Dark Current
Density
NiO Light Current Density
14. Anna Dorfi, The Ohio State University
Page 13 of 27
MnO were done to compare to NiO’s results in order to determine their possible performance as
DSSCs. The CVs for CoO and MnO are seen below as Figure 5 and Figure 6, respectively:
Figure 5: CV of CoO (scan rate = 50 mV/s)
Figure 6: CV of MnO (scan rate = 50 mV/s)
-0.50
-0.30
-0.10
0.10
0.30
0.50
0.70
0.90
-1.70 -1.20 -0.70 -0.20 0.30 0.80 1.30
CurrentDensity(mA/cm2)
Voltage (V vs I-/I-
3)
CoO Current
Density
NiO Current
Density
-0.70
-0.50
-0.30
-0.10
0.10
0.30
0.50
0.70
0.90
1.10
-1.50 -1.00 -0.50 0.00 0.50 1.00 1.50 2.00
CurrentDensity(mA/cm2)
Voltage (V vs I-/I-
3)
MnO Current
Density
NiO Current
Density
15. Anna Dorfi, The Ohio State University
Page 14 of 27
Typically, the open-circuit voltage of a p-DSSC is determined be the potential of the
valance band edge with respect to the redox couple in the electrolyte. However, due to the
localized nature of the charge carriers, as discussed before, the Voc for NiO or similar oxides can
be viewed as the oxidation potential of the metal species with respect to the electrolyte.
From the CV’s it can be seen that the oxidative peaks for both CoO and MnO are slightly
more positively shifted than the oxidative peak for NiO and occur at a higher potential. This
should then directly correlate to a higher Voc than NiO for both CoO and MnO, with MnO
having the highest Voc. The shape of the CV’s for both monoxides are similar to that of NiO so it
is expected that their solar cell linear sweep voltammetry tests should yield comparable results to
NiO. Small area films of both CoO and MnO were then made into both un-sensitized and
sensitized cells and their performances were tested in both light and dark conditions. The
unsensitized DSSC results are shown in Figure 7 below and a clear view of the sensitized results
are shown in Figure 8. These results were then compared to NiO, as seen in Figure 9.
Figure 7: CoO and MnO Unsensitized Cell Performances
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
-0.10 -0.05 0.00 0.05 0.10 0.15
CurrentDensity(mA/cm2)
Potential (V vs I-/I-
3 )
CoO Light
Current Density
CoO Dark
Current Density
MnO Light
Current Density
MnO Dark
Current Density
16. Anna Dorfi, The Ohio State University
Page 15 of 27
Figure 8: CoO and MnO DSSC Results in O18 dye
Figure 9: CoO and MnO DSSC Results in O18 dye in comparison to NiO
-0.60
-0.40
-0.20
0.00
0.20
0.40
0.60
0.80
-0.03 0.02 0.07 0.12 0.17
CurrentDensity(mA/cm2)
Voltage (V vs I-/I3
-)
MnO Light
Current Density
MnO Dark
Current Density
CoO Light
Current Density
CoO Dark
Current Density
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
1.00
2.00
-0.03 0.02 0.07 0.12 0.17
CurrentDensity(mA/cm2)
Voltage (V vs I-/I3
-)
MnO Light
Current Density
MnO Dark
Current Density
CoO Light
Current Density
CoO Dark
Current Density
NiO Light
Current Density
17. Anna Dorfi, The Ohio State University
Page 16 of 27
The unsensitized DSSC results show that both CoO and MnO exhibit negligible
photocurrent themselves. They are slightly anodic and so they would only be marginally
inhibiting the photocurrent produced from the sensitized DSSC, but it can be safely interpreted
that no cathodic current produced from the sensitized DSSC is due to the metal oxides
themselves. When analyzing Figure 9 it was determined that the predicted trend from the CV’s
oxidative peaks did support the trend seen in the DSSC results. This also helps support the
hypothesis that the original mechanism for NiO p-DSSCs is also present in CoO and MnO
DSSCs. The cathodic current generated is due to the hopping mechanism of holes from the
oxidation of the monoxide cation from 2+
to 3+
. The Voc for NiO was 104 mV compared to the
highest Voc of 135 mV for MnO (Isc = -0.112 mA/cm2
) that was followed CoO with a Voc
112mV. The highest Isc density was -0.42mA/cm2
for CoO when comparing only CoO and MnO.
However, when analyzing the highest current densities achieved in comparison to NiO’s Isc of -
3.49mA/cm2
, Figure 9 shows that the currents are not comparable to NiO’s maximum current
density.
A further literature review was done in order to explain the discrepancy in current density
between the three monoxides. It was determined that the size of the cation decreases from
manganese to nickel and more oxygen overlap takes place in the metal-oxide of NiO compared
to MnO. This increased overlap of metal 3d and oxygen 2p orbitals correlates to higher hole
mobility as well as easier hopping [8]. This explains the slower hole mobility seen in MnO and
CoO, as the trends in the Isc results follow the aforementioned trend as well. Slower mobility
increases the probability for a hole in the metal oxide to interact with electrolyte and become
reduced, thus inhibiting the maximum current achievable in the DSSC. Furthermore, when
examining the 3d orbital configuration of the monoxides, it was determined that Co changes
18. Anna Dorfi, The Ohio State University
Page 17 of 27
from a high spin 2+
state to a low spin 3+
state. This also correlates to slow hole mobility and
hole hopping, as the change in spin inhibits this mechanism. This occurrence can be seen below
as Figure 10:
Figure 10: Cobalt d-orbital Configuration
Similarly, the oxidation from Mn2+
to Mn3+
results in a Jahn-Teller distortion in the MnO
structure. This phenomenon occurs frequently in d4
orbital configurations, which is the state Mn
(II) is oxidized to and becomes Mn (III). The ligands (oxygen) attached to the Manganese atoms
are stretched in the z-direction and have also shown to severely inhibit hole mobility [9]. This
depicted in Figure 11 below:
Figure 11: Manganese d-orbital configuration [9]
Co
3+
d6
Co
2+
d7
Mn
2+
d5
Mn
3+
d4
19. Anna Dorfi, The Ohio State University
Page 18 of 27
Lastly, when the d-orbital configurations for CoO and MnO are compared to NiO it can be
determined that when Ni (II) oxidizes to Ni (III) there is no significant chemical environmental
change for the monoxide. Only one electron is lost during the process but there are no spin
changes or deformations to the structure. This is clearly seen in Figure 12 below:
Figure 12: Ni d-orbital configuration
Use of n-Type Semiconductors in p-DSSCs. During the transition metal monoxide study, Prof.
Wu’s lab group, out of curiosity, had begun testing tin-doped indium oxide (ITO) as a possible
semiconductor for use in p-DSSCs in order to see if cathodic current would be produced, as ITO
is typically an n-Type semiconductor. ITO is also usually used as a coating for the glass plates
used in DSSC construction. They were able to achieve a relatively high cathodic short circuit
current density that was comparable to NiO. The hypothesized mechanism by which this cell
works is shown below as Figure 13:
Ni
2+
d8
Ni
3+
d7
20. Anna Dorfi, The Ohio State University
Page 19 of 27
Figure 13: Mechanism for ITO DSSC
There is cathodic current generated, even though ITO is an n-type semiconductor, because there
is hole injection into the conduction band of the ITO, rather than injection into the valence band
for a p-Type semiconductor. This is a very interesting mechanism so further research was done
in order to find other metal oxides with a similar conduction band position to ITO. Figure 14
below shows various metal oxides and their band gap positions.
Figure 14: Conduction band positions of various metal oxides [10].
This figure shows that tungsten oxide (WO3) and iron (III) oxide (Fe2O3) have similar
conduction band positions to tin oxide (SnO2) and so they would be interesting to synthesize for
21. Anna Dorfi, The Ohio State University
Page 20 of 27
further testing and comparison to ITO’s performance. Sensitized ITO cells with ruthenium O3
dye were assembled and tested in order to validate the previous results achieved by the lab
group. These results can be seen below as Figure 15:
Figure 15: O3 Dye DSSC ITO Results under Light
The Isc of the ITO cells is high compared to the monoxides but still slightly less than the NiO
results. The highest Isc density achieved was -2.69 mA/cm2
in O3 dye with a Voc of 104 mV.
However, the Isc is still promising and can be further improved. ITO showed the most promising
performance when compared to NiO and so the transition metals with similar conduction band
positions were also tested with dyes of various reductive potentials in order to analyze which dye
sensitizers maximized their performances. Two Ruthenium based dyes, O3 and O18, were used
as well as an organic dye referred to as “MC” [11, 12]. The reduction potentials of the dyes are
shown below in Table 1:
-3.00
-2.50
-2.00
-1.50
-1.00
-0.50
0.00
0.50
1.00
-0.03 -0.01 0.01 0.03 0.05 0.07 0.09 0.11 0.13 0.15
Currentdensity(mA/cm2)
Voltage (V vs I-/I3
-)
22. Anna Dorfi, The Ohio State University
Page 21 of 27
Table 1: Reduction Potentials of Dye Sensitizers
Dye Type Reduction Potentials
O18 0.106 V
O3 0.136 V
PMI-T2-TPA “MC” 1.046 V
DSSC’s of both WO3 and Fe2O3 were then constructed and tested with various dye sensitizers.
The results for WO3 can be seen below as Figure 16:
Figure 16: WO3 DSSC Results for various dyes
The highest Isc density was -1.20 mA/cm2
in O3 dye and the maximum Voc was 96.8mV.
However, the O18 dye did not perform as similarly to the O3 dye. This could be due to poor dye
-1.500
-1.000
-0.500
0.000
0.500
-0.03 -0.01 0.01 0.03 0.05 0.07 0.09 0.11 0.13
CurrentDensity(mA/cm2)
Voltage (V vs I-/I-
3)
WO3 MC Light
Current Density
WO3 O3 Light
Current Density
WO3 O18 Light
Current Density
23. Anna Dorfi, The Ohio State University
Page 22 of 27
loading or due to the fact that the O18 dye may have been old and somewhat degraded compared
to the freshly synthesized O3 dye that was tested. However, these results are more interesting in
regards to the organic dye performance. The organic dye produced anodic current rather than the
cathodic current produced for the ruthenium based dyes. This may be due to “MC”’s high
reduction potential which could be at a position too far into the band gap of WO3. Referring to
Figure 16, this seems like a plausible explanation, as the reduction potential of 1.046V falls in
the wide band gap of WO3. The lack of charge carrier density in that region would account for
the poor performance with the organic “MC” dye. This should be expected for Fe2O3 as well.
The results for Fe2O3 are seen below as Figure 17:
Figure 17: Fe2O3 DSSC Results for various dyes
-4.00E-05
-3.00E-05
-2.00E-05
-1.00E-05
0.00E+00
1.00E-05
2.00E-05
3.00E-05
4.00E-05
-0.300 -0.200 -0.100 0.000 0.100
Current(A)
Voltage (V vs I-/I-
3)
Fe2O3 MC Light
Current Density
Fe2O3 MC Dark
Current Density
Fe2O3 O18 Light
Current Density
Fe2O3 O18 Dark
Current Density
Fe2O3 O3 Light Current
Density
Fe2O3 O3 Dark Current
Density
Fe2O3 Unsensitized
Light Current Density
Fe2O3 Unsensitized
Dark Current Density
24. Anna Dorfi, The Ohio State University
Page 23 of 27
As stated in a previous section, Fe2O3 exhibited anodic current when assembled into an
unsensitized DSSC. The organic “MC” dye enhanced Fe2O3’s anodic current, most likely due to
the same reason it produced anodic current with WO3 (its reduction potential is in the band gap
of the metal oxide). The O3 dye, however, produced negligible cathodic current. This may be
due to the fact that the dye is balancing out the intrinsic anodic character of the Fe2O3, because
both the O3 and Fe2O3 are orange in color and could be competing for the same light absorption.
The O18 dye, on the other hand, is almost black and very dark in color. That would explain its
better performance with Fe2O3, although the current produced is still negligible in comparison to
ITO, WO3, and NiO.
CONCLUSIONS
Preliminary Transition Metal Oxide Tests. The short-circuit currents of the preliminary oxides
created using the NiO sol-gel modification were barely visible on the same scale with NiO’s
results. The open-circuit voltages were also significantly lower for every oxide in comparison to
NiO. However, no preliminary oxides created using this method were monoxides and thus did
not fit into the original hypothesis that directly compared the Ni (II) state. These results were not
useful for further analysis or investigation and further research was done to synthesize
monoxides of the transition metals in the 3d row that were similar to NiO, such as CoO and
MnO.
Cobalt and Manganese Monoxide Investigation. The highest Voc was for MnO and the lowest
was for NiO. This follows the trend shown by the CV tests, however the currents exhibited by
CoO and MnO are still essentially negligible in comparison to the NiO results. This discrepancy
was found to be due to the spin change from high spin to low spin that occurs when Co is
25. Anna Dorfi, The Ohio State University
Page 24 of 27
oxidized from 2+
to 3+
. This change accounts for low hole mobility. Subsequently, when Mn is
oxidized from 2+
to 3+
it changes to a d4 configuration and metals in d4 configurations are more
susceptible to Jahn Teller distortions. This Jahn Teller distortion also correlates to a significant
decrease in the hole mobility of the oxide. However, when NiO undergoes oxidation there is no
significant change to the chemical or physical environment of the oxide and so there is no impact
to the hole mobility of NiO, thus it outperforms CoO and MnO.
n-Type Semiconductors in p-DSSCs. The ITO and WO3 results seem to be the most promising for
future research in regards to p-DSSC research, as preliminary testing resulted in more than
double the magnitude of the Isc than compared to the Isc of the monoxides CoO and MnO. When
comparing the performances of the ruthenium-based dye sensitizers to the organic dye sensitizer
it was concluded that the organic dye HOMO reduction potential was too low into the band gap
of these oxides, thus there was very little to no charge carrier density available for WO3 and
Fe2O3. The organic “MC” dye produced anodic current for both WO3 and Fe2O3. It was also
interesting to note that the ruthenium O3 dye produced negligible cathodic current when tested
with Fe2O3 due to the competing light absorption of the dye with the metal oxide of similar color.
Optimizing the film thickness, uniformity, as well as the ruthenium based dyes used can further
increase the WO3 and ITO performances.
FUTURE WORK
Although WO3 did not produce results in a similar range to ITO or NiO, it shows promise
for improvement. The Isc produced was still double the magnitude of the Isc for CoO and MnO.
The ITO is also a heavily doped semiconductor and doping WO3 should be done to increase the
electron density of the Fermi level near the conduction band, which is higher for ITO than WO3,
26. Anna Dorfi, The Ohio State University
Page 25 of 27
due to the doping by tin. Similarly, a complete study of the 3d transition metal monoxides should
be done to compile a complete understanding of these monoxides, as well as compare their
performances to the more widely studied NiO. Thus, the next step in this investigation would be
to synthesize FeO and assemble DSSCs for comparison to CoO, MnO, and NiO. What is
particularly interesting about FeO is that there is no geometry distortion or change in spin when
it undergoes oxidation from 2+
to 3+
, as seen in the d-orbital configurations. It is high spin for
both the 2+
and 3+
states. Thus, charge transport may occur more similarly to NiO. The d-orbital
configuration for FeO is shown below in Figure 18:
Figure 18: Iron d-orbital configuration
REFERENCES
1. Ecole Polytechnique Fédérale de Lausanne. “Dye-sensitized solar cells rival conventional
cell efficiency.” Science Daily. 10. Jul. 2013. Web. 21. Jul. 2013. <
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2. Natu, Gayatri, Panitat Hasin, Zhongjie Huang, Zhiqiang Ji, Mingfu He, and Yiying Wu.
"Valence Band-Edge Engineering of Nickel Oxide Nanoparticles via Cobalt Doping for
Application in P-Type Dye-Sensitized Solar Cells." ACS Applied Materials & Interfaces
4.11 (2012): 5922-929. Print.
Fe
2+
d6
Fe
3+
d5
27. Anna Dorfi, The Ohio State University
Page 26 of 27
3. Gores, Heiner J., and Hans-Georg Schweiger. "Non-Aqueous Electrolyte Solutions." Non-
Aqueous Electrolyte Solutions. Ed. Robert F. Savinell, Ken-ichiro Ota, and Gerhard Kreysa.
Springer, n.d. Web. 09 Sept. 2013.
4. Sumikura, Seiichi, Shogo Mori, Shinya Shimizu, Hisanao Usami, and Eiji Suzuki.
"Syntheses of NiO Nanoporous Films Using Nonionic Triblock Co-polymer Templates and
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Photochemistry and Photobiology A: Chemistry 199.1 (2008): 1-7. Print.
5. Ye, Yin, Fangli Yuan, and Shaohua Li. "Synthesis of CoO Nanoparticles by Esterification
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Xiaotang Liu, and Yingliang Liu. "A Simple Additive-free Approach for the Synthesis of
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Research Letters 8.1 (2013): 166. Print.
7. Chiba, Yasuo, Ashraful Isham, Yuki Watanabe, Ryoichi Komiya, Naoke Koide, and Liyuan
Han. "Dye-Sensitized Solar Cells with Conversion Efficiency of 11.1%." Japanese Journal
of Applied Physics 45.25 (2006): n. pag. Web.
8. Shriver, D. F., P. W. Atkins, and Cooper Harold Langford. Inorganic Chemistry. New York:
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9. Jahn-Teller Distortions." UC Davis - Chemwiki. University of California, Davis, n.d. Web.
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_Chemistry/Coordination_Numbers/Jahn-Teller_Distortions>.
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Page 27 of 27
10. Shiyou Chen, Lin-Wang Wang “Thermodynamic Oxidation and Reduction Potentials of
Photocatalytic Semiconductors in Aqueous Solutions.” Chemistry of Materials 24 (2012):
3659-3666
11. He, Mingfu, Zhiqiang Ji, Zhongjie Huang, and Yiying Wu. "Molecular Orbital Engineering
of a Panchromatic Cyclometalated Ru(II) Dye for P-Type Dye-Sensitized Solar Cells."The
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29. Anna Dorfi, The Ohio State University
A1
Appendix A: XRD
Figure A1: XRD of Co3O4 (350°C) Film
Figure A2: XRD of Fe2O3 (450°C) Film
30. Anna Dorfi, The Ohio State University
A2
Figure A3: XRD of Mn3O4/Mn2O3 (450°C) Film
Figure A4: XRD of V2O5 (450°C) Film
31. Anna Dorfi, The Ohio State University
A3
Figure A6: XRD of MnO Precipitate
Figure A5: XRD of CoO precipitate
32. Anna Dorfi, The Ohio State University
A4
Figure A7: XRD of WO3 Precipitate
33. Anna Dorfi, The Ohio State University
B1
Appendix B: Cyclic Voltammetry
Figure B1: CV of CO3O4
Figure B2: CV of Fe2O3
34. Anna Dorfi, The Ohio State University
B2
Figure B3: CV of Mn3O4
Figure B4: CV of V2O5