Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7750312
R. Zhou
Silicon Carbide (SiC) power devices can operate at higher temperatures, higher voltages and higher switching frequencies compared to existing silicon devices, resulting in greater power converter efficiency, smaller size and improved bandwidth. The SiC power device development at GE was launched in 2005 and is now starting transition from pilot production to high volume manufacturing. This talk will highlight GE's ongoing efforts to develop MW class PV inverter with best-in-class CEC efficiency approach 99%. The challenge of using SiC in those power applications is that the emphasis on reliability, ruggedness and cost is significantly higher. The extensive internal and external reliability testing of GE SiC MOSFETs has demonstrated reliability comparable to mature silicon power devices. In addition, extensive stress testing has mapped-out the device's safe operating area, such as: avalanche capability, short circuit ruggedness, body diode stability, and terrestrial cosmic radiation hardness.
与现有的硅器件相比，碳化硅(SiC)功率器件可以在更高的温度、更高的电压和更高的开关频率下工作，从而实现更高的功率转换器效率、更小的尺寸和改进的带宽。通用电气的SiC功率器件开发始于2005年，目前正开始从试点生产向大批量生产过渡。本次演讲将重点介绍GE正在努力开发的兆瓦级光伏逆变器，其CEC效率接近99%。在这些电源应用中使用SiC的挑战在于对可靠性、坚固性和成本的强调要高得多。GE SiC mosfet广泛的内部和外部可靠性测试表明，其可靠性可与成熟的硅功率器件相媲美。此外，广泛的压力测试已经绘制出设备的安全操作区域，例如:雪崩能力，短路坚固性，体二极管稳定性和地面宇宙辐射硬度。
{"title":"GE MW SiC PV inverter development","authors":"R. Zhou","doi":"10.1109/PVSC.2016.7750312","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7750312","url":null,"abstract":"Silicon Carbide (SiC) power devices can operate at higher temperatures, higher voltages and higher switching frequencies compared to existing silicon devices, resulting in greater power converter efficiency, smaller size and improved bandwidth. The SiC power device development at GE was launched in 2005 and is now starting transition from pilot production to high volume manufacturing. This talk will highlight GE's ongoing efforts to develop MW class PV inverter with best-in-class CEC efficiency approach 99%. The challenge of using SiC in those power applications is that the emphasis on reliability, ruggedness and cost is significantly higher. The extensive internal and external reliability testing of GE SiC MOSFETs has demonstrated reliability comparable to mature silicon power devices. In addition, extensive stress testing has mapped-out the device's safe operating area, such as: avalanche capability, short circuit ruggedness, body diode stability, and terrestrial cosmic radiation hardness.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"31 1","pages":"3470-3470"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75792543","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7749727
A. A. Baloch, H. Bahaidarah, P. Gandhidasan
Computational Fluid Dynamics (CFD) study to obtain uniform thermal characteristics on the front surface of solar cell module has been studied. The performance of PV panels significantly reduces with high temperature of solar cell and low temperature uniformity. For the optimization process, photovoltaic-thermal (PV/T) system has been analyzed in this paper for the meteorogical conditions of Dhahran. The effect of reducing heat exchanger's cross section area by changing the bas angle on the temperature profile has been studied using FLUENT software. Based on the CFD simulations of temperature profile, two degree angle was selected for the heat exchanger in PV/T system because of least mean temperature deviation. The temperature distribution for cooled PV showed an approximate uniform temperature profile and was able to reduce the cell temperature from 71°C to 45.2°C for the operating conditions in Dhahran in the month of June. From the electrical point of view, maximum energy yield increased from 11.9 W to 16.2W using the proposed uniform temperature heat exchanger.
{"title":"Computational fluid dynamics study for the optimization of surface temperature profile of photovoltaic/thermal system","authors":"A. A. Baloch, H. Bahaidarah, P. Gandhidasan","doi":"10.1109/PVSC.2016.7749727","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749727","url":null,"abstract":"Computational Fluid Dynamics (CFD) study to obtain uniform thermal characteristics on the front surface of solar cell module has been studied. The performance of PV panels significantly reduces with high temperature of solar cell and low temperature uniformity. For the optimization process, photovoltaic-thermal (PV/T) system has been analyzed in this paper for the meteorogical conditions of Dhahran. The effect of reducing heat exchanger's cross section area by changing the bas angle on the temperature profile has been studied using FLUENT software. Based on the CFD simulations of temperature profile, two degree angle was selected for the heat exchanger in PV/T system because of least mean temperature deviation. The temperature distribution for cooled PV showed an approximate uniform temperature profile and was able to reduce the cell temperature from 71°C to 45.2°C for the operating conditions in Dhahran in the month of June. From the electrical point of view, maximum energy yield increased from 11.9 W to 16.2W using the proposed uniform temperature heat exchanger.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"59 1","pages":"0847-0849"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90399999","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7749773
Jinjoo Park, S. M. Iftiquar, Youn-jung Lee, Chonghoon Shin, Shihyun Ahn, Junhee Jung, Sangho Kim, Taehee Kim, H. Kim, J. Yi
We employed a novel inorganic-organic hybrid triple junction solar cell (IOHTC), with an inorganic silicon tandem cell (ITC) that is series connected to an organic solar cell (OSC) at the back of the ITC. The ITC is used to absorb the short wavelength part of the solar spectrum, while the organic bottom cell utilizes the long wavelength part of the spectrum. The IOHTC was fabricated with hydrogenated amorphous silicon (a-Si:H) and PTB7:PCBM as active layers. The optical gap (Eg) of the active layers of the front to the back cells was 1.83 eV, 1.80 eV and 1.55 eV, respectively. The efficiency of the optimized IOHTC reached a maximum of 7.70% with high open circuit voltage (Voc) 2.33 V. The observed Voc of the IOHTC was 96.31% of the sum of the Voc of the individual component cells. In one of the IOHTC, the total current density (Jsc) increased by 11.19% and 14.13% as compared with total Jsc of the OSC and ITC, respectively.
{"title":"Advanced triple junction solar cell by employing inorganic-organic hybrid materials","authors":"Jinjoo Park, S. M. Iftiquar, Youn-jung Lee, Chonghoon Shin, Shihyun Ahn, Junhee Jung, Sangho Kim, Taehee Kim, H. Kim, J. Yi","doi":"10.1109/PVSC.2016.7749773","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749773","url":null,"abstract":"We employed a novel inorganic-organic hybrid triple junction solar cell (IOHTC), with an inorganic silicon tandem cell (ITC) that is series connected to an organic solar cell (OSC) at the back of the ITC. The ITC is used to absorb the short wavelength part of the solar spectrum, while the organic bottom cell utilizes the long wavelength part of the spectrum. The IOHTC was fabricated with hydrogenated amorphous silicon (a-Si:H) and PTB7:PCBM as active layers. The optical gap (Eg) of the active layers of the front to the back cells was 1.83 eV, 1.80 eV and 1.55 eV, respectively. The efficiency of the optimized IOHTC reached a maximum of 7.70% with high open circuit voltage (Voc) 2.33 V. The observed Voc of the IOHTC was 96.31% of the sum of the Voc of the individual component cells. In one of the IOHTC, the total current density (Jsc) increased by 11.19% and 14.13% as compared with total Jsc of the OSC and ITC, respectively.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"172 1","pages":"1055-1060"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83766147","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7749951
G. Hamon, J. Decobert, N. Vaissière, R. Lachaume, R. Cariou, W. Chen, J. Alvarez, N. Habka, J. Kleider, P. Roca i Cabarrocas
Monolithical integration of III-V and Si is of strong interest to produce tandem solar cells reaching high conversion efficiencies. In the context of the French ANR research project IMPETUS, an innovative approach for III-V/Si multijunction solar cells is studied. The targeted device is a tandem cell composed of a III-V top cell (AlGaAs) and a IV bottom cell (Si1-xGex). The choice of AlyGa1-yAs as the top material is justified because it provides the optimum bandgap combination with Si1-xGex (1.63 eV/0.96 eV), with theoretical efficiencies in excess of 42% for such a tandem configuration. In our inverted metamorphic approach, we first use MOVPE to grow the AlGaAs top cell on a lattice matched GaAs substrate, and then perform low temperature PECVD heteroepitaxial SiGe on top. We show here the first structural and electrical characterizations of Si(PECVD)/III-V(MOVPE) interfaces. Furthermore, the epitaxial growth of highly doped crystalline Si by low-temperature PECVD on GaAs enables us to fabricate hybrid tunnel junctions with low resistivity and a high current, suitable to interconnect the two subcells in the tandem III-V/Si solar cell.
{"title":"Direct growth of crystalline silicon on GaAs by low temperature PECVD: Towards hybrid tunnel junctions for III-V/Si tandem cells","authors":"G. Hamon, J. Decobert, N. Vaissière, R. Lachaume, R. Cariou, W. Chen, J. Alvarez, N. Habka, J. Kleider, P. Roca i Cabarrocas","doi":"10.1109/PVSC.2016.7749951","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749951","url":null,"abstract":"Monolithical integration of III-V and Si is of strong interest to produce tandem solar cells reaching high conversion efficiencies. In the context of the French ANR research project IMPETUS, an innovative approach for III-V/Si multijunction solar cells is studied. The targeted device is a tandem cell composed of a III-V top cell (AlGaAs) and a IV bottom cell (Si1-xGex). The choice of AlyGa1-yAs as the top material is justified because it provides the optimum bandgap combination with Si1-xGex (1.63 eV/0.96 eV), with theoretical efficiencies in excess of 42% for such a tandem configuration. In our inverted metamorphic approach, we first use MOVPE to grow the AlGaAs top cell on a lattice matched GaAs substrate, and then perform low temperature PECVD heteroepitaxial SiGe on top. We show here the first structural and electrical characterizations of Si(PECVD)/III-V(MOVPE) interfaces. Furthermore, the epitaxial growth of highly doped crystalline Si by low-temperature PECVD on GaAs enables us to fabricate hybrid tunnel junctions with low resistivity and a high current, suitable to interconnect the two subcells in the tandem III-V/Si solar cell.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"190 1","pages":"1895-1897"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76866348","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7750115
A. Manoussakis, Omar K. Abudayyeh, Nathan D. Gapp, D. Wilt
Solar cells used in space missions are the primary source for power on board the space vehicle. Space solar cells are becoming thinner for improved performance (W/kg) and are based on single crystalline materials where fracturing or cleaving can easily occur from packaging, deployment and constant temperature cycling in outer space. When the fracture in the semiconductor extends through the solar cell metallization, loss of power will occur and can hinder a mission. A novel semiconductor metallization is being developed that may enable the solar cells to be fully crack tolerant. The material consists of carbon nanotubes impregnated silver metallization, termed metal matrix composite, deposited by screen printing. The carbon nanotubes increase the fracture toughness of the metallization and also offers a redundant electrical path should the metal matrix fracture. In addition to these benefits, the use of screen printing will facilitate lower costs and ease of manufacturability by eliminating the expensive photolithography and evaporation steps used for conventional metallization. The inks that are being developed show promise of electrically bridging cracks and are further being tuned for screen printing processes.
{"title":"Screen printed metal matrix composite contacts for crack tolerant solar cells","authors":"A. Manoussakis, Omar K. Abudayyeh, Nathan D. Gapp, D. Wilt","doi":"10.1109/PVSC.2016.7750115","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7750115","url":null,"abstract":"Solar cells used in space missions are the primary source for power on board the space vehicle. Space solar cells are becoming thinner for improved performance (W/kg) and are based on single crystalline materials where fracturing or cleaving can easily occur from packaging, deployment and constant temperature cycling in outer space. When the fracture in the semiconductor extends through the solar cell metallization, loss of power will occur and can hinder a mission. A novel semiconductor metallization is being developed that may enable the solar cells to be fully crack tolerant. The material consists of carbon nanotubes impregnated silver metallization, termed metal matrix composite, deposited by screen printing. The carbon nanotubes increase the fracture toughness of the metallization and also offers a redundant electrical path should the metal matrix fracture. In addition to these benefits, the use of screen printing will facilitate lower costs and ease of manufacturability by eliminating the expensive photolithography and evaporation steps used for conventional metallization. The inks that are being developed show promise of electrically bridging cracks and are further being tuned for screen printing processes.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"34 1","pages":"2582-2585"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82718695","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7749895
Qiong Chen, Henan Liu, Hui‐Seon Kim, Yucheng Liu, Mengjin Yang, N. Yue, Gang Ren, K. Zhu, S. Liu, N. Park, Yong Zhang
By performing spatially resolved Raman and photoluminescence spectroscopy with different illumination conditions, we have achieved a unified understanding towards the spectroscopy signatures of the organic-inorganic hybrid perovskite, transforming from the pristine state (CH3NH3PbI3 or MAPbI3) to fully degraded state (i.e., PbI2), for samples with varying crystalline domain size from mesoscopic scale to macroscopic size, synthesized by three different techniques.
{"title":"Intrinsic Raman signatures of pristine hybrid perovskite CH3NH3PbI3 and its multiple stages of structure transformation","authors":"Qiong Chen, Henan Liu, Hui‐Seon Kim, Yucheng Liu, Mengjin Yang, N. Yue, Gang Ren, K. Zhu, S. Liu, N. Park, Yong Zhang","doi":"10.1109/PVSC.2016.7749895","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749895","url":null,"abstract":"By performing spatially resolved Raman and photoluminescence spectroscopy with different illumination conditions, we have achieved a unified understanding towards the spectroscopy signatures of the organic-inorganic hybrid perovskite, transforming from the pristine state (CH<sub>3</sub>NH<sub>3</sub>PbI<sub>3</sub> or MAPbI<sub>3</sub>) to fully degraded state (i.e., PbI<sub>2</sub>), for samples with varying crystalline domain size from mesoscopic scale to macroscopic size, synthesized by three different techniques.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"104 1","pages":"1620-1623"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82848005","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7750124
A. A. Shishavan, Eric C. Foresman, F. Toor
Iowa City is in the humid continental climate zone and the goal of this paper is to provide a thorough system performance analysis for PV systems installed in this climate zone. In this work we present the performance analysis of two photovoltaic (PV) systems installed at The University of Iowa in mid-2011. We analyze the system performance from mid-2011 to 2014. First system is a 39 kW-DC building-integrated amorphous silicon (a-Si) PV array. Second system is a 48.1 kW-DC solar charging station based on multicrystalline modules. We use National Renewable Energy Laboratory's System Advisor Model for the PV system performance analysis of the two systems and results of simulation are compared to measured energy yield. In addition, we compare PV system performance with the Iowa Energy Center Solar Calculator (IEC-SC) model for the mc-Si PV system. Our analysis indicates that the SAM model, with correct modeling parameters results in ±20% error relative to measured data whereas the IEC-SC model almost always over estimates the energy yield.
{"title":"Performance analysis of crystalline silicon and amorphous silicon photovoltaic systems in Iowa: 2011 to 2014","authors":"A. A. Shishavan, Eric C. Foresman, F. Toor","doi":"10.1109/PVSC.2016.7750124","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7750124","url":null,"abstract":"Iowa City is in the humid continental climate zone and the goal of this paper is to provide a thorough system performance analysis for PV systems installed in this climate zone. In this work we present the performance analysis of two photovoltaic (PV) systems installed at The University of Iowa in mid-2011. We analyze the system performance from mid-2011 to 2014. First system is a 39 kW-DC building-integrated amorphous silicon (a-Si) PV array. Second system is a 48.1 kW-DC solar charging station based on multicrystalline modules. We use National Renewable Energy Laboratory's System Advisor Model for the PV system performance analysis of the two systems and results of simulation are compared to measured energy yield. In addition, we compare PV system performance with the Iowa Energy Center Solar Calculator (IEC-SC) model for the mc-Si PV system. Our analysis indicates that the SAM model, with correct modeling parameters results in ±20% error relative to measured data whereas the IEC-SC model almost always over estimates the energy yield.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"3 1","pages":"2625-2630"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83303107","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7750268
Sarvagya Agrawal, S. Singh
In this paper a novel Multi-port converter interfacing a photovoltaic array, battery and a DC load is proposed It is composed of a two uni-directional DC port for interfacing photovoltaic array and DC load, and a bi-directional DC port for interfacing battery. Compared to the traditional stand-alone photovoltaic power system, this system shows the advantages of better protection and more efficient control on charge/discharge of the battery. Furthermore, it can make better use of solar energy and realize energy management of the system The key point of energy management for the system is to control the bi-directional converter efficiently, where bi-directional voltage and current must be controlled. In this paper, the control strategy of bi-directional converter is proposed, which operates at three operation modes: Buck (charge battery), Boost (discharge battery), and shut-down (SD). Maximum power point tracking control is used to extract the maximum power from the Photovoltaic array. Single power processing stage with multiple power ports offers an opportunity to make the whole system simpler, compact and more efficient. Finally, a simulation of 250 W and 5 hp converter is built to verify the theoretical analysis and the control strategies. The simulation is tested for variable irradiance and variable load.
{"title":"Multi-port converter for solar powered hybrid vehicle","authors":"Sarvagya Agrawal, S. Singh","doi":"10.1109/PVSC.2016.7750268","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7750268","url":null,"abstract":"In this paper a novel Multi-port converter interfacing a photovoltaic array, battery and a DC load is proposed It is composed of a two uni-directional DC port for interfacing photovoltaic array and DC load, and a bi-directional DC port for interfacing battery. Compared to the traditional stand-alone photovoltaic power system, this system shows the advantages of better protection and more efficient control on charge/discharge of the battery. Furthermore, it can make better use of solar energy and realize energy management of the system The key point of energy management for the system is to control the bi-directional converter efficiently, where bi-directional voltage and current must be controlled. In this paper, the control strategy of bi-directional converter is proposed, which operates at three operation modes: Buck (charge battery), Boost (discharge battery), and shut-down (SD). Maximum power point tracking control is used to extract the maximum power from the Photovoltaic array. Single power processing stage with multiple power ports offers an opportunity to make the whole system simpler, compact and more efficient. Finally, a simulation of 250 W and 5 hp converter is built to verify the theoretical analysis and the control strategies. The simulation is tested for variable irradiance and variable load.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"35 1","pages":"3258-3262"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91080414","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7749766
G. Scranton, T. P. Xiao, V. Ganapati, J. Holzrichter, P. Peterson, E. Yablonovitch
Thin-film photovoltaic cells with high reflectivity in the below-bandgap spectral region are ideally suited for thermophotovoltaics. This allows the below-bandgap radiation to be reflected back to the emitter, so that their energy can be used to reheat the source, rather than being lost. In this work, we present a substantial improvement in the theoretical thermophotovoltaic conversion efficiency in the presence of photon re-use. We also predict the achievable conversion efficiency for a system that uses In0.53Ga0.47As photovoltaic cells, and present an experimental optical cavity to be used for future efficiency measurements. Owing to recent advances in thin-film photovoltaics, thermophotovoltaic efficiencies above 50% may soon be realizable.
{"title":"Highly efficient thermophotovoltaics enabled by photon re-use","authors":"G. Scranton, T. P. Xiao, V. Ganapati, J. Holzrichter, P. Peterson, E. Yablonovitch","doi":"10.1109/PVSC.2016.7749766","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749766","url":null,"abstract":"Thin-film photovoltaic cells with high reflectivity in the below-bandgap spectral region are ideally suited for thermophotovoltaics. This allows the below-bandgap radiation to be reflected back to the emitter, so that their energy can be used to reheat the source, rather than being lost. In this work, we present a substantial improvement in the theoretical thermophotovoltaic conversion efficiency in the presence of photon re-use. We also predict the achievable conversion efficiency for a system that uses In0.53Ga0.47As photovoltaic cells, and present an experimental optical cavity to be used for future efficiency measurements. Owing to recent advances in thin-film photovoltaics, thermophotovoltaic efficiencies above 50% may soon be realizable.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"3 1","pages":"1026-1029"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84077454","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}
Pub Date : 2016-06-05DOI: 10.1109/PVSC.2016.7749560
X. Gu, Chiao-Chi Lin, Peter J. Krommenhoek, Yadong Lyu, Jae Hyun Kim, Li-Chieh Yu, T. Nguyen, S. Watson
The properties of the multilayer PV backsheets, including their interfaces, during weathering are not well-known. In this study, a commercial PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet films was selected as a model system for a depth profiling study of chemical and mechanical properties of a backsheet film during UV exposure. Cryo-microtomy was used to obtain cross-sectional PPE samples. 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 % (wet). Chemical and mechanical depth profiling of the aged and unaged samples was conducted by Raman microscopic mapping, nanoindentation and atomic force microscopy in quantitative nanomechanical mapping mode. The results indicated that non-uniform degradation took place across the thickness of the PPE backsheet with severe chemical and mechanical degradation observed on the outer pigmented PET layer, two adhesive layers, and the pigmented-EVA layer. The regions with the increase in the modulus detected by nanoindetation were consistent with those showing clear chemical degradation in Raman and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR). This depth profiling study brings new understanding to the mechanisms of failures observed in the backsheets during weathering.
{"title":"Depth profiling of chemical and mechanical degradation of UV-exposed PV backsheets","authors":"X. Gu, Chiao-Chi Lin, Peter J. Krommenhoek, Yadong Lyu, Jae Hyun Kim, Li-Chieh Yu, T. Nguyen, S. Watson","doi":"10.1109/PVSC.2016.7749560","DOIUrl":"https://doi.org/10.1109/PVSC.2016.7749560","url":null,"abstract":"The properties of the multilayer PV backsheets, including their interfaces, during weathering are not well-known. In this study, a commercial PPE (polyethylene terephthalate (PET)/PET/ethylene vinyl acetate (EVA)) backsheet films was selected as a model system for a depth profiling study of chemical and mechanical properties of a backsheet film during UV exposure. Cryo-microtomy was used to obtain cross-sectional PPE samples. 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 % (wet). Chemical and mechanical depth profiling of the aged and unaged samples was conducted by Raman microscopic mapping, nanoindentation and atomic force microscopy in quantitative nanomechanical mapping mode. The results indicated that non-uniform degradation took place across the thickness of the PPE backsheet with severe chemical and mechanical degradation observed on the outer pigmented PET layer, two adhesive layers, and the pigmented-EVA layer. The regions with the increase in the modulus detected by nanoindetation were consistent with those showing clear chemical degradation in Raman and Attenuated Total Reflection Fourier Transform Infrared Spectroscopy (ATR-FTIR). This depth profiling study brings new understanding to the mechanisms of failures observed in the backsheets during weathering.","PeriodicalId":6524,"journal":{"name":"2016 IEEE 43rd Photovoltaic Specialists Conference (PVSC)","volume":"34 1","pages":"0115-0120"},"PeriodicalIF":0.0,"publicationDate":"2016-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84798215","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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