K. Sakurai, A. Takano, Masayoshi Takani, A. Masuda
Current injected damp heat (CDH) test have been reported to accelerate certain type of long-term degradation observed in at least one prototype flexible thin film silicon photovoltaic (PV) modules deployed in field [1]. This report have raised a question that whether conventional DH tests should be combined with current injection or light illumination to better reproduce long-time degradations of flexible thin film modules. To answer this question, we have been testing multiple flexible products available in the market, as part of the activities of Japanese Task Group 8 of the International PV Quality Assurance Task Force (PVQAT) [2]. Here, we present some results of our damp (or dry) heat testing with light illumination on a flexible CIGS module product with relatively poor moisture barriers.
{"title":"Effects of light illumination during damp/dry heat tests on a flexible thin film photovoltaic module","authors":"K. Sakurai, A. Takano, Masayoshi Takani, A. Masuda","doi":"10.1117/12.2187891","DOIUrl":"https://doi.org/10.1117/12.2187891","url":null,"abstract":"Current injected damp heat (CDH) test have been reported to accelerate certain type of long-term degradation observed in at least one prototype flexible thin film silicon photovoltaic (PV) modules deployed in field [1]. This report have raised a question that whether conventional DH tests should be combined with current injection or light illumination to better reproduce long-time degradations of flexible thin film modules. To answer this question, we have been testing multiple flexible products available in the market, as part of the activities of Japanese Task Group 8 of the International PV Quality Assurance Task Force (PVQAT) [2]. Here, we present some results of our damp (or dry) heat testing with light illumination on a flexible CIGS module product with relatively poor moisture barriers.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114530167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
X. Gu, Peter J. Krommenhoek, Chiao-Chi Lin, Li-Chieh Yu, T. Nguyen, S. Watson
Polymeric multilayer backsheets protect the photovoltaic modules from damage of moisture and ultraviolet (UV) while providing electrical insulation. Due to the multilayer structures, the properties of the inner layers of the backsheets, including their interfaces, during weathering are not well known. In this study, a commercial type of PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet films was selected as a model system for a depth profiling study of mechanical properties of a backsheet film during UV exposure. The NIST SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) was used for the accelerated laboratory exposure of the materials with UV at 85°C and two relative humidities (RH) of 5 % (dry) and 60 % (humid). Cryomicrotomy was used to obtain cross-sectional PPE samples. Mechanical depth profiling of the cross-sections of aged and unaged samples was conducted by nanoindentation, and a peak-force based quantitative nanomechanical atomic force microscopy (QNM-AFM) mapping techniquewas used to investigate the microstructure and adhesion properties of the adhesive tie layers. The nanoindentation results show the stiffening of the elastic modulus in the PET outer and pigmented EVA layers. From QNM-AFM, the microstructures and adhesion properties of the adhesive layers between PET outer and core layers and between PET core and EVA inner layers are revealed and found to degrade significantly after aging under humidity environment. The results from mechanical depth profiling of the PPE backsheet are further related to the previous chemical depth profiling of the same material, providing new insights into the effects of accelerated UV and humidity on the degradation of multilayer backsheet.
{"title":"Depth profiling of mechanical degradation of PV backsheets after UV exposure","authors":"X. Gu, Peter J. Krommenhoek, Chiao-Chi Lin, Li-Chieh Yu, T. Nguyen, S. Watson","doi":"10.1117/12.2187171","DOIUrl":"https://doi.org/10.1117/12.2187171","url":null,"abstract":"Polymeric multilayer backsheets protect the photovoltaic modules from damage of moisture and ultraviolet (UV) while providing electrical insulation. Due to the multilayer structures, the properties of the inner layers of the backsheets, including their interfaces, during weathering are not well known. In this study, a commercial type of PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet films was selected as a model system for a depth profiling study of mechanical properties of a backsheet film during UV exposure. The NIST SPHERE (Simulated Photodegradation via High Energy Radiant Exposure) was used for the accelerated laboratory exposure of the materials with UV at 85°C and two relative humidities (RH) of 5 % (dry) and 60 % (humid). Cryomicrotomy was used to obtain cross-sectional PPE samples. Mechanical depth profiling of the cross-sections of aged and unaged samples was conducted by nanoindentation, and a peak-force based quantitative nanomechanical atomic force microscopy (QNM-AFM) mapping techniquewas used to investigate the microstructure and adhesion properties of the adhesive tie layers. The nanoindentation results show the stiffening of the elastic modulus in the PET outer and pigmented EVA layers. From QNM-AFM, the microstructures and adhesion properties of the adhesive layers between PET outer and core layers and between PET core and EVA inner layers are revealed and found to degrade significantly after aging under humidity environment. The results from mechanical depth profiling of the PPE backsheet are further related to the previous chemical depth profiling of the same material, providing new insights into the effects of accelerated UV and humidity on the degradation of multilayer backsheet.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129438416","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
W. Huang, S. Bringuier, J. Paul, K. Simmons-Potter, K. Muralidharan, B. G. Potter
An investigation of microindenter-induced crack evolution with independent variation of both temperature and relative humidity has been pursued in PV-grade Si wafers. Under static tensile strain conditions, an increase in subcritical crack elongation with increasing atmospheric water content was observed. To provide further insight into the potential physical and chemical conditions at the microcrack tip, micro-Raman measurements were performed. Preliminary results confirm a spatial variation in the frequency of the primary Si vibrational resonance within the cracktip region, associated with local stress state, whose magnitude is influenced by environmental conditions during the period of applied static strain. The experimental effort was paired with molecular dynamics (MD) investigations of microcrack evolution in single-crystal Si to furnish additional insight into mechanical contributions to crack elongation. The MD results demonstrate that crack-tip energetics and associated crack elongation velocity and morphology are intimately related to the crack and applied strain orientations with respect to the principal crystallographic axes. The resulting elastic strain energy release rate and the stress-strain response of the Si under these conditions form the basis for preliminary micro-scale peridynamics (PD) simulations of microcrack development under constant applied strain. These efforts will be integrated with the experimental results to further inform the mechanisms contributing to this important degradation mode in Si-based photovoltaics.
{"title":"Experimental and computational investigation of microcrack behavior under combined environments in monocrystalline Si","authors":"W. Huang, S. Bringuier, J. Paul, K. Simmons-Potter, K. Muralidharan, B. G. Potter","doi":"10.1117/12.2188521","DOIUrl":"https://doi.org/10.1117/12.2188521","url":null,"abstract":"An investigation of microindenter-induced crack evolution with independent variation of both temperature and relative humidity has been pursued in PV-grade Si wafers. Under static tensile strain conditions, an increase in subcritical crack elongation with increasing atmospheric water content was observed. To provide further insight into the potential physical and chemical conditions at the microcrack tip, micro-Raman measurements were performed. Preliminary results confirm a spatial variation in the frequency of the primary Si vibrational resonance within the cracktip region, associated with local stress state, whose magnitude is influenced by environmental conditions during the period of applied static strain. The experimental effort was paired with molecular dynamics (MD) investigations of microcrack evolution in single-crystal Si to furnish additional insight into mechanical contributions to crack elongation. The MD results demonstrate that crack-tip energetics and associated crack elongation velocity and morphology are intimately related to the crack and applied strain orientations with respect to the principal crystallographic axes. The resulting elastic strain energy release rate and the stress-strain response of the Si under these conditions form the basis for preliminary micro-scale peridynamics (PD) simulations of microcrack development under constant applied strain. These efforts will be integrated with the experimental results to further inform the mechanisms contributing to this important degradation mode in Si-based photovoltaics.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"66-69 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131018532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
G. Conibeer, S. Shrestha, Shujuan Huang, R. Patterson, H. Xia, Yu Feng, P. Zhang, N. Gupta, S. Smyth, Yuanxun Liao, Shu Lin, Pei Wang, X. Dai, S. Chung, Jianfeng Yang, Yi Zhang
The hot carrier cell aims to extract the electrical energy from photo-generated carriers before they thermalize to the band edges. Hence it can potentially achieve a high current and a high voltage and hence very high efficiencies up to 65% under 1 sun and 86% under maximum concentration. To slow the rate of carrier thermalisation is very challenging, but modification of the phonon energies and the use of nanostructures are both promising ways to achieve some of the required slowing of carrier cooling. A number of materials and structures are being investigated with these properties and test structures are being fabricated. Initial measurements indicate slowed carrier cooling in III-Vs with large phonon band gaps and in multiple quantum wells. It is expected that soon proof of concept of hot carrier devices will pave the way for their development to fully functioning high efficiency solar cells.
{"title":"Hot carrier solar cell absorbers: investigation of carrier cooling properties of candidate materials","authors":"G. Conibeer, S. Shrestha, Shujuan Huang, R. Patterson, H. Xia, Yu Feng, P. Zhang, N. Gupta, S. Smyth, Yuanxun Liao, Shu Lin, Pei Wang, X. Dai, S. Chung, Jianfeng Yang, Yi Zhang","doi":"10.1117/12.2187592","DOIUrl":"https://doi.org/10.1117/12.2187592","url":null,"abstract":"The hot carrier cell aims to extract the electrical energy from photo-generated carriers before they thermalize to the band edges. Hence it can potentially achieve a high current and a high voltage and hence very high efficiencies up to 65% under 1 sun and 86% under maximum concentration. To slow the rate of carrier thermalisation is very challenging, but modification of the phonon energies and the use of nanostructures are both promising ways to achieve some of the required slowing of carrier cooling. A number of materials and structures are being investigated with these properties and test structures are being fabricated. Initial measurements indicate slowed carrier cooling in III-Vs with large phonon band gaps and in multiple quantum wells. It is expected that soon proof of concept of hot carrier devices will pave the way for their development to fully functioning high efficiency solar cells.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114148604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hybrid photovoltaic/thermal (PV-T) solar collectors are capable of delivering heat and electricity concurrently. Implementing such receivers in linear concentrators for high temperature applications need special considerations such as thermal decoupling of the photovoltaic (pv) cells from the thermal receiver. Spectral beam splitting of concentrated light provides an option for achieving this purpose. In this paper we introduce a relatively simple hybrid receiver configuration that spectrally splits the light between a high temperature thermal fluid and silicon pv cells using volumetric light filtering by semi-conductor doped glass and propylene glycol. We analysed the optical performance of this device theoretically using ray tracing and experimentally through the construction and testing of a full scale prototype. The receiver was mounted on a commercial parabolic trough concentrator in an outdoor experiment. The prototype receiver delivered heat and electricity at total thermal efficiency of 44% and electrical efficiency of 3.9% measured relative to the total beam energy incident on the primary mirror.
{"title":"A high temperature hybrid photovoltaic-thermal receiver employing spectral beam splitting for linear solar concentrators","authors":"A. Mojiri, C. Stanley, G. Rosengarten","doi":"10.1117/12.2187869","DOIUrl":"https://doi.org/10.1117/12.2187869","url":null,"abstract":"Hybrid photovoltaic/thermal (PV-T) solar collectors are capable of delivering heat and electricity concurrently. Implementing such receivers in linear concentrators for high temperature applications need special considerations such as thermal decoupling of the photovoltaic (pv) cells from the thermal receiver. Spectral beam splitting of concentrated light provides an option for achieving this purpose. In this paper we introduce a relatively simple hybrid receiver configuration that spectrally splits the light between a high temperature thermal fluid and silicon pv cells using volumetric light filtering by semi-conductor doped glass and propylene glycol. We analysed the optical performance of this device theoretically using ray tracing and experimentally through the construction and testing of a full scale prototype. The receiver was mounted on a commercial parabolic trough concentrator in an outdoor experiment. The prototype receiver delivered heat and electricity at total thermal efficiency of 44% and electrical efficiency of 3.9% measured relative to the total beam energy incident on the primary mirror.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":" 20","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120827322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohamed Abusnina, M. Matin, H. Moutinho, M. Al‐Jassim
In this work, we report on the synthesis and characterization of Cu2ZnSnS4 (CZTS) thin films prepared by annealing of co-sputtered metal precursors in sulfur atmosphere. Radio-frequency magnetron sputtering was applied to deposit the metal layers from single metal targets on Mo-coated soda-lime glass substrates. The chemical composition of the precursors was controlled by varying the sputtering working power, resulting in films with various compositions. X-ray fluorescence was used to determine the elemental concentration of these metal films. The metal precursors were then converted into CZTS in a tube furnace using different sulfurization conditions to investigate the effect of the annealing process on the properties of the final CZTS films. Film structural characterization and phase identification results were supported by X-ray diffraction (XRD) and Raman spectroscopy. Surface and cross-sectional film morphology was carried out by scanning electron microscopy (SEM). For the sulfurized films, significant Sn loss was noticed. However, the loss of Sn was successfully controlled by depositing precursors with an excess of Sn. After optimizing the composition of the metal precursor, XRD and Raman scattering results revealed single-phase CZTS films without clear signs of secondary phases. SEM showed improved morphology in the form of dense structures and smooth surfaces for the films sulfurized at 600°C. Our first solar cell, based on a CZTS film originating from a precursor sulfurized at 550°C for 60 min, showed an open-circuit voltage of 471 mV, a short-circuit current density of 9.92 mA/cm-2, a fill factor of 36.9%, and an efficiency of 1.72%.
{"title":"Characterization of Cu2ZnSnS4 thin films prepared by the sulfurization of co-sputtered metal precursors","authors":"Mohamed Abusnina, M. Matin, H. Moutinho, M. Al‐Jassim","doi":"10.1117/12.2187315","DOIUrl":"https://doi.org/10.1117/12.2187315","url":null,"abstract":"In this work, we report on the synthesis and characterization of Cu2ZnSnS4 (CZTS) thin films prepared by annealing of co-sputtered metal precursors in sulfur atmosphere. Radio-frequency magnetron sputtering was applied to deposit the metal layers from single metal targets on Mo-coated soda-lime glass substrates. The chemical composition of the precursors was controlled by varying the sputtering working power, resulting in films with various compositions. X-ray fluorescence was used to determine the elemental concentration of these metal films. The metal precursors were then converted into CZTS in a tube furnace using different sulfurization conditions to investigate the effect of the annealing process on the properties of the final CZTS films. Film structural characterization and phase identification results were supported by X-ray diffraction (XRD) and Raman spectroscopy. Surface and cross-sectional film morphology was carried out by scanning electron microscopy (SEM). For the sulfurized films, significant Sn loss was noticed. However, the loss of Sn was successfully controlled by depositing precursors with an excess of Sn. After optimizing the composition of the metal precursor, XRD and Raman scattering results revealed single-phase CZTS films without clear signs of secondary phases. SEM showed improved morphology in the form of dense structures and smooth surfaces for the films sulfurized at 600°C. Our first solar cell, based on a CZTS film originating from a precursor sulfurized at 550°C for 60 min, showed an open-circuit voltage of 471 mV, a short-circuit current density of 9.92 mA/cm-2, a fill factor of 36.9%, and an efficiency of 1.72%.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"241 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124651914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The conductivity (i.e., n-type or p-type) of Cu2O films is controlled by the electrodeposition potential. A slightly acidic solution (pH 4.93) containing cupric acetate and sodium dodecyl sulfate (SDS) is used. Photoelectrochemical measurements at zero bias indicate that the Cu2O films deposited at the potentials of 0.00 V and -0.05 V generate the ntype photocurrents and the films deposited at the potentials negative than -0.10 V generate the p-type photocurrents. The X-ray diffraction (XRD) results show that the n-type films are pure Cu2O, however, the metallic copper appear in the ptype Cu2O films. Mott-Schottky measurements show that the donor concentrations of the n-type Cu2O films decrease and the acceptor concentrations of the p-type Cu2O films increase with the decrease of the deposition potential. The SDS molecules adsorbed on electrode surface and the SDS micelles block the diffusion of Cu2+ ions, resulting in a low diffusion rate of Cu2+ ions. Under this circumstance, the growth of Cu2O films are affected significantly by the overpotential. When the potential is positive than -0.05 V, oxygen vacancies are formed in the films leading to the n-type conductivity; however, when the potential is negative than -0.10 V, the Cu2+ ions are reduced to Cu+ rapidly and part of Cu2+ are reduced to metallic copper, the diffused Cu2+ ions to supply to the growth of Cu2O films are insufficient, hence copper vacancies are formed in the films resulting in the p-type conductivity.
{"title":"Effect of potential on the conductivity of electrodeposited Cu2O film","authors":"Ying Yang, Juan Han, X. Ning, Hongsheng Tang","doi":"10.1117/12.2189800","DOIUrl":"https://doi.org/10.1117/12.2189800","url":null,"abstract":"The conductivity (i.e., n-type or p-type) of Cu2O films is controlled by the electrodeposition potential. A slightly acidic solution (pH 4.93) containing cupric acetate and sodium dodecyl sulfate (SDS) is used. Photoelectrochemical measurements at zero bias indicate that the Cu2O films deposited at the potentials of 0.00 V and -0.05 V generate the ntype photocurrents and the films deposited at the potentials negative than -0.10 V generate the p-type photocurrents. The X-ray diffraction (XRD) results show that the n-type films are pure Cu2O, however, the metallic copper appear in the ptype Cu2O films. Mott-Schottky measurements show that the donor concentrations of the n-type Cu2O films decrease and the acceptor concentrations of the p-type Cu2O films increase with the decrease of the deposition potential. The SDS molecules adsorbed on electrode surface and the SDS micelles block the diffusion of Cu2+ ions, resulting in a low diffusion rate of Cu2+ ions. Under this circumstance, the growth of Cu2O films are affected significantly by the overpotential. When the potential is positive than -0.05 V, oxygen vacancies are formed in the films leading to the n-type conductivity; however, when the potential is negative than -0.10 V, the Cu2+ ions are reduced to Cu+ rapidly and part of Cu2+ are reduced to metallic copper, the diffused Cu2+ ions to supply to the growth of Cu2O films are insufficient, hence copper vacancies are formed in the films resulting in the p-type conductivity.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125224099","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tom H. Anderson, M. Faryad, T. Mackay, A. Lakhtakia, Rajendra Singh
A two-dimensional finite-element model was developed to simulate both the optical and electrical characteristics of thin-film, p-i-n junction, solar cells. For a preliminary assessment of the model’s capabilities, one or more p-i-n junctions were allowed to fill the region between the front and back surfaces; the semiconductor layers were taken to be made from mixtures of three different alloys of hydrogenated amorphous silicon; empirical relationships between the complex-valued relative optical permittivity and the bandgap were used; a transparent-conducting oxide layer was taken to be attached to the front surface of the solar cell; and a metallic reflector, which may be periodically corrugated, was supposed to be attached to the back surface. First the frequency-domain Maxwell postulates were solved in order to determine the absorption of solar photons and the subsequent generation of electron-hole pairs, with the AM1.5G solar spectrum taken to represent the incident solar flux. Next, the drift-diffusion equations were solved to track the evolution of electron and hole densities to a steady state. Preliminary numerical results from our model indicate that by increasing the number of p-i-n junctions from one to three, the solar-cell efficiency may be increased. The efficiency may be further increased by incorporating a periodically-corrugated back reflector, as opposed to a flat back reflector, in the case of a single p-i-n junction solar cell. We plan to apply the two-dimensional finite-element model for more complicated solar cells.
{"title":"Combined optical-electrical finite-element simulations of thin-film solar cells: preliminary results","authors":"Tom H. Anderson, M. Faryad, T. Mackay, A. Lakhtakia, Rajendra Singh","doi":"10.1117/12.2187778","DOIUrl":"https://doi.org/10.1117/12.2187778","url":null,"abstract":"A two-dimensional finite-element model was developed to simulate both the optical and electrical characteristics of thin-film, p-i-n junction, solar cells. For a preliminary assessment of the model’s capabilities, one or more p-i-n junctions were allowed to fill the region between the front and back surfaces; the semiconductor layers were taken to be made from mixtures of three different alloys of hydrogenated amorphous silicon; empirical relationships between the complex-valued relative optical permittivity and the bandgap were used; a transparent-conducting oxide layer was taken to be attached to the front surface of the solar cell; and a metallic reflector, which may be periodically corrugated, was supposed to be attached to the back surface. First the frequency-domain Maxwell postulates were solved in order to determine the absorption of solar photons and the subsequent generation of electron-hole pairs, with the AM1.5G solar spectrum taken to represent the incident solar flux. Next, the drift-diffusion equations were solved to track the evolution of electron and hole densities to a steady state. Preliminary numerical results from our model indicate that by increasing the number of p-i-n junctions from one to three, the solar-cell efficiency may be increased. The efficiency may be further increased by incorporating a periodically-corrugated back reflector, as opposed to a flat back reflector, in the case of a single p-i-n junction solar cell. We plan to apply the two-dimensional finite-element model for more complicated solar cells.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121798417","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
T. Thomas, K. R. Kumar, C. D. Kartha, K. Vijayakumar
Flexible semiconducting devices such as solar cells and displays have been a recent attraction. Unlike heavy, brittle glass substrates, plastics and metallic foils have advantage of flexibility. They also have added advantages like good thermal stability and high melting point. In this paper we present a very simple method for the growth of Copper Indium Sulphide (CIS) films by depositing merely Indium Sulphide (InS) directly over the Cu foil using simple and economical chemical spray pyrolysis technique. The effects of volume of precursor solution on structural and morphological properties of the films were studied. Finally trials on heterojunctions with a structure of Cu foil/CIS/InS/Ag were also employed. Further improvement on heterojunction is expected by optimizing the morphological and structural properties of the film.
{"title":"Simple one step spray process for CuInS2 / In2S3 heterojunctions on flexible substrates for photovoltaic applications","authors":"T. Thomas, K. R. Kumar, C. D. Kartha, K. Vijayakumar","doi":"10.1117/12.2187065","DOIUrl":"https://doi.org/10.1117/12.2187065","url":null,"abstract":"Flexible semiconducting devices such as solar cells and displays have been a recent attraction. Unlike heavy, brittle glass substrates, plastics and metallic foils have advantage of flexibility. They also have added advantages like good thermal stability and high melting point. In this paper we present a very simple method for the growth of Copper Indium Sulphide (CIS) films by depositing merely Indium Sulphide (InS) directly over the Cu foil using simple and economical chemical spray pyrolysis technique. The effects of volume of precursor solution on structural and morphological properties of the films were studied. Finally trials on heterojunctions with a structure of Cu foil/CIS/InS/Ag were also employed. Further improvement on heterojunction is expected by optimizing the morphological and structural properties of the film.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"7 5","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114028944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Antenna-coupled metal-insulator-metal devices are most potent candidate for future energy harvesting devices. The reason for that they are ultra-high speed devices that can rectify the electromagnetic radiation at high frequencies. In addition to their speed, they are also small devices that can have more number of devices in unit area. In this work, it is aimed design and develop a device which can harvest and detect IR radiation.
{"title":"Device characteristics of antenna-coupled metal-insulator-metal diodes (rectenna) using Al2O3, TiO2, and Cr2O3 as insulator layer for energy harvesting applications","authors":"M. Inac, A. Shafique, M. Ozcan, Y. Gurbuz","doi":"10.1117/12.2188161","DOIUrl":"https://doi.org/10.1117/12.2188161","url":null,"abstract":"Antenna-coupled metal-insulator-metal devices are most potent candidate for future energy harvesting devices. The reason for that they are ultra-high speed devices that can rectify the electromagnetic radiation at high frequencies. In addition to their speed, they are also small devices that can have more number of devices in unit area. In this work, it is aimed design and develop a device which can harvest and detect IR radiation.","PeriodicalId":142821,"journal":{"name":"SPIE Optics + Photonics for Sustainable Energy","volume":"9561 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2015-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130011399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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