{"title":"Interface stoichiometry control in ZnO/Cu2O photovoltaic devices","authors":"S. Wilson, Y. Tolstova, H. Atwater","doi":"10.1109/PVSC.2013.6744960","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6744960","url":null,"abstract":"Cu2O is a potential earth-abundant alternative to established thin photovoltaic materials (CIGS, CdTe, etc.) because of its low cost, high availability, and inexpensive processing, but Cu2O has seen limited development as a photovoltaic device material owing to challenges in measurement and control of interface stoichiometry and doping. We report measurements of Cu2O interface stoichiometry and the effect of interface composition on heterojunction device performance. ZnO/Cu2O interface stoichiometry was varied by adjusting the ZnO window layer deposition conditions and stoichiometry was measured by X-ray photoelectron spectroscopy. Current-voltage characteristics of ZnO/Cu2O heterojunctions indicate open circuit voltages of Voc ~ 530 mV for devices where the Cu2O layer is stoichiometric at the interface and Voc ~ 100 mV for devices where Cu2O is nonstoichiometric at the interface.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"5 1","pages":"2410-2413"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75458411","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}
C. Peike, Lea Purschke, K. Weiß, Michael Kohl, M. Kempe
{"title":"Towards the origin of photochemical EVA discoloration","authors":"C. Peike, Lea Purschke, K. Weiß, Michael Kohl, M. Kempe","doi":"10.1109/PVSC.2013.6744447","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6744447","url":null,"abstract":"The root cause of the photochemical ethylene vinyl acetate (EVA) discoloration in photovoltaic (PV) modules was investigated. Laminates containing EVA foils with a systematic variation of the additive formulation, i.e. the crosslinking agents, ultraviolet (UV) absorber, hindered amine light stabilizers and antioxidants, were subjected to UV aging. The influence of the additive combination on the photochemical aging of EVA was investigated by Raman spectroscopy, Fourier transform infrared spectroscopy and UV/visible spectroscopy. The amount of EVA discoloration was found to be strongly depending on the additive formation. An important impact of the antioxidant in terms of chromophore formation inhibition could be found. Surprisingly, the highly stabilized EVA foils showed higher discoloration rates as well as a more intense fluorescence background in the Raman spectra.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"22 1","pages":"1579-1584"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78252223","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}
{"title":"Thermodynamic limits of solar cells with non-ideal optical response","authors":"M. Khan, P. Bermel, M. Alam","doi":"10.1109/PVSC.2013.6744318","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6744318","url":null,"abstract":"The Shockley-Queisser (S-Q) theory defines the thermodynamic upper limits for Jsc, Voc, FF, and efficiency of a solar cell. The classical calculation assumes an abrupt onset of absorption at the band-edge, perfect absorption for all energies above the bandgap, and absence of non-radiative recombination. These assumptions are never satisfied for any practical solar cell. In this paper, we explain how the S-Q limits are redefined in the presence of the non-ideal optical effects, and we provide closed-form analytical expressions for the new limits for Jsc, Voc, and FF. Remarkably, these new limits can be achieved to a very high degree, even with significantly imperfect materials.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"165 1","pages":"1036-1040"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75128325","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}
{"title":"Simulation and development of sub-wavelength grated dielectric ARCs for CPV applications","authors":"Wei Wang, A. Freundlich","doi":"10.1109/PVSC.2013.6745104","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6745104","url":null,"abstract":"Here, and in an attempt to identify a better alternative to the conventional dual layer ARCs for III-V multi-junction concentrator cells operating with or without protective cover glass in conjunction with wide acceptance angles, we have undertaken a systematic analysis of design parameters and angular dependent antireflective properties of dielectric grating formed, through the implementation of sub-wavelength arrays of 2D pyramidal gratings of ZnS and TiO2. Though the study indicated no or limited improvement for devices operating with a SiO2 like cover glass, in the absence of a cover the evaluation indicates that through a careful selection of the design these dielectric gratings can reduce reflection-loss related current losses by 2-3 fold by comparison to their planar double layer ARC counterparts. i.e. for a 3J metamorphic device this lead to a current improvement of 0.7 mA/cm2 for a 60 degree acceptance angles.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"12 1","pages":"3049-3052"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75260869","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}
{"title":"Commercial size multicrytalline silicon solar cell with ion implant emitter","authors":"A. Ebong, Yizhe Wang, Guangyao Jin, T. Zhou","doi":"10.1109/PVSC.2013.6744910","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6744910","url":null,"abstract":"This paper reports on the preliminary results of the first manufacturable ion implanted multicrystalline silicon solar cells with mean efficiency of 16.60%. The best efficiency of 16.83% is demonstrated, which is the highest reported ion implanted 243.4 cm2 multicrystalline silicon solar cell with Al back surface field. A dose of 2.8E15 atom.cm2 at 15-keV was used and annealed at implant anneal similar to the mono crystalline solar cell counterparts. The open circuit voltage of ~621 mV and the measured internal quantum efficiency (IQE) were similar to multicrystalline cells using POCl3 emitter. This results is very promising and confirms that the bulk lifetime does not degrade during the implant anneal.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"38 1","pages":"2191-2194"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75587474","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}
N. Nakagawa, S. Shibasaki, H. Hiraga, M. Yamazaki, Kazushige Yamamoto, S. Sakurada
{"title":"Feasibility study of homojunction CIGS solar cells","authors":"N. Nakagawa, S. Shibasaki, H. Hiraga, M. Yamazaki, Kazushige Yamamoto, S. Sakurada","doi":"10.1109/PVSC.2013.6744869","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6744869","url":null,"abstract":"The potential for high conversion efficiency of the homojunction Cu(In, Ga)Se2 (CIGS) solar cells was examined by device simulations and experimental approaches. The simulation results showed that many electrons in n-CIGS layers could compensate to some extent for the existence of interface states at i-ZnO/n-CIGS interfaces in the homojunction structure. In the case of using the partial electrolyte treatments of CIGS films to produce the n-type doping, the concentrations of the Cd dopants in the n-CIGS layer were 1016 cm-2. The conversion efficiency of 17.2% for this homojunction CIGS solar cell was obtained.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"34 1","pages":"2023-2025"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75642010","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}
S. Thibert, J. Jourdan, B. Bechevet, D. Chaussy, N. Reverdy-Bruas, D. Beneventi
{"title":"Influence of the Schottky barrier height on the silicon solar cells","authors":"S. Thibert, J. Jourdan, B. Bechevet, D. Chaussy, N. Reverdy-Bruas, D. Beneventi","doi":"10.1109/PVSC.2013.6745023","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6745023","url":null,"abstract":"With the recent introduction of ion implantation in the photovoltaic industry, it is now easier to carefully tailor the emitter doping profile. However the metallization layout should be optimized in the same time, as they are closely linked via the metal/silicon contact resistivity. In this work, an advanced co-optimization procedure allows finding out the influence of the Schottky barrier height on the metal grid design and the optimal doping profile. The theoretical electrical properties of a 2 × 2 cm2 ideal silicon solar cell are also computed for each optimal combination. According to this work, the maximal achievable efficiency decreases from 26.2 % to 25.3 % if the Schottky barrier height increases from 0.5 eV to 0.9 e V.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"54 1","pages":"2673-2676"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72890029","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}
M. Muller, T. Silverman, M. Deceglie, S. Kurtz, E. Menard, S. Burroughs
{"title":"Optical cell temperature measurements of multiple CPV technologies in outdoor conditions","authors":"M. Muller, T. Silverman, M. Deceglie, S. Kurtz, E. Menard, S. Burroughs","doi":"10.1109/PVSC.2013.6745184","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6745184","url":null,"abstract":"It is well known that photovoltaic performance is dependent on cell temperature. Although various methods have been explored to determine outdoor concentrating photovoltaic (CPV) cell temperature, no method has proven to work across all module technologies and result in desirable uncertainties. Menard (2012) has recently published results claiming accurate measurements of cell temperature using the wavelength shift of light emitted from the sub-cells of a Semprius CPV module. This work focuses on efforts to verify Menard's results using additional CPV technologies that are on-sun at NREL. Baseline electro-luminescence emission is recorded for modules under a low level forward bias and under isothermal conditions using thermal chambers. The same modules or sister modules are then placed on NREL's high accuracy two-axis tracker for outdoor measurements. Photo-luminescence emission peaks are measured for multiple modules at stable wind and irradiance conditions. Emission results from the sub-cells are compared to what is documented in the literature for the given semiconductor material. The signal to background ratio is analyzed and the possible broad applicability of this procedure is discussed.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"52 1","pages":"3426-3430"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72902051","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}
{"title":"Analysis, design, and evaluation of a high frequency inductor to reduce manufacturing cost, and improve the efficiency of a PV inverter","authors":"A. Alabakhshizadeh, O. Midtgård, K. Boysen","doi":"10.1109/PVSC.2013.6745064","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6745064","url":null,"abstract":"Photovoltaic inverters are the major functional units of the photovoltaic systems. Therefore, efficiency and cost are vitally important in the design, and operation of the PV system. Magnetic components are the bulkiest component and highly affect the efficiency of the galvanically isolated PV inverter and design of such component generally involves a compromise between the reduction of core loss at the expense of increased winding loss or vice versa. The loss characteristics of the magnetic material itself present a fundamental limitation on core loss reduction, implying that the intrinsic reduction of core loss density depends on magnetic material improvements. Hence, the essential tradeoff between cost, performance and physical size must be done by designers to make the most optimal inductor for their design. A high frequency magnetic powder core inductor used in galvanically isolated PV inverter is analyzed with commercially available finite element analysis software, Maxwell - Ansoft. Results obtained from simulation studies are compared with built prototype show good agreement.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"13 1","pages":"2845-2848"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73121413","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}
H. Sodabanlu, Yunpeng Wang, Shaojun Ma, Kentaroh Watanabe, M. Sugiyama, Y. Nakano
{"title":"Metalorganic vapor phase epitaxy growth of dual junction solar cell with InGaAs/GaAsP superlattice on Ge","authors":"H. Sodabanlu, Yunpeng Wang, Shaojun Ma, Kentaroh Watanabe, M. Sugiyama, Y. Nakano","doi":"10.1109/PVSC.2013.6744157","DOIUrl":"https://doi.org/10.1109/PVSC.2013.6744157","url":null,"abstract":"The impact of growth temperature was investigated on the quality and interface abruptness of InGaAs/GaAsP multiple quantum wells (MQWs) grown on various misoriented substrates. The growth of MQWs on substrates with a larger misoriented angle required a lower temperature. Non-radiative carrier lifetimes in MQWs strongly depended on the quality and abruptness of MQWs. On the basis of this understanding, a dual junction cell consisting of InGaAs/GaAsP superlattice top cell and Ge bottom cell was successfully fabricated. The result encourages the application of InGaAs/GaAsP superlattice for better current balancing and higher efficiency by III-V/Ge multiple junction solar cells.","PeriodicalId":6350,"journal":{"name":"2013 IEEE 39th Photovoltaic Specialists Conference (PVSC)","volume":"196 1","pages":"0318-0321"},"PeriodicalIF":0.0,"publicationDate":"2013-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74204899","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}