Pub Date : 2012-06-03DOI: 10.1109/PVSC.2012.6317789
Xiaoqiang Li, Longzhong Tao, Zhengyue Xia, Zhuojian Yang, Jingbing Dong, Wentao Song, Bin Zhang, R. Sidhu, G. Xing
In this study, a well-controlled etch-back technique was developed using HF and HNO3 mixture solution to remove the boron depletion layer caused by post-oxidation step. The etching rate can be manipulated by changing HF proportion; meanwhile the sheet resistance variation can be maintained smaller than 10% after etching back. Nitric acid oxidation of Si technique was used to passivate the boron emitter before and after etch back. The presence of the surface boron depletion layer makes the surface boron concentration lower, which is better for low Dit at the surface after passivation, while it can also introduce extra recombination by making the electron and hole concentration closer at the surface. PC1D was used to simulate the results for further understanding the recombination in the whole emitter region.
{"title":"Boron diffused emitter etch back and passivation","authors":"Xiaoqiang Li, Longzhong Tao, Zhengyue Xia, Zhuojian Yang, Jingbing Dong, Wentao Song, Bin Zhang, R. Sidhu, G. Xing","doi":"10.1109/PVSC.2012.6317789","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317789","url":null,"abstract":"In this study, a well-controlled etch-back technique was developed using HF and HNO3 mixture solution to remove the boron depletion layer caused by post-oxidation step. The etching rate can be manipulated by changing HF proportion; meanwhile the sheet resistance variation can be maintained smaller than 10% after etching back. Nitric acid oxidation of Si technique was used to passivate the boron emitter before and after etch back. The presence of the surface boron depletion layer makes the surface boron concentration lower, which is better for low Dit at the surface after passivation, while it can also introduce extra recombination by making the electron and hole concentration closer at the surface. PC1D was used to simulate the results for further understanding the recombination in the whole emitter region.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89412989","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6317663
V. Velidandla, B. Garland, F. Cheung
Optimizing a solar cell manufacturing line must take into account a variety of issues. Wafers used for solar cells are typically thinner than those used in semiconductor IC manufacturing. This makes the solar cell wafers susceptible to surface and edge defects such as deep scratches and cracks. The wafer slicing operation can induce thickness non-uniformity as well as surface roughness variation. Wafer texturing (typically via etching) must result in an optimal pyramid height in the case of monocrystalline wafers and an optical grain size in the case of polycrystalline wafers. Silicon Nitride grown on the wafer can induce stress and eventual breakage of the wafer. An uneven nitride film can cause a drop in the overall efficiency of the wafer. The metal contact lines account for a significant cost in the production of a solar cell wafer. The process engineer must pay attention to the contact line height and width while minimizing the total amount of metal used. Based on all these requirements, an optical profiler, the Zeta-200, was developed to provide rapid and meaningful feedback to the process line. In this paper we present results from various process points in solar cell manufacturing, such as bare wafer roughness, silicon nitride film thickness and contact line dimensions.
{"title":"Automated process metrology in solar cell manufacturing","authors":"V. Velidandla, B. Garland, F. Cheung","doi":"10.1109/PVSC.2012.6317663","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317663","url":null,"abstract":"Optimizing a solar cell manufacturing line must take into account a variety of issues. Wafers used for solar cells are typically thinner than those used in semiconductor IC manufacturing. This makes the solar cell wafers susceptible to surface and edge defects such as deep scratches and cracks. The wafer slicing operation can induce thickness non-uniformity as well as surface roughness variation. Wafer texturing (typically via etching) must result in an optimal pyramid height in the case of monocrystalline wafers and an optical grain size in the case of polycrystalline wafers. Silicon Nitride grown on the wafer can induce stress and eventual breakage of the wafer. An uneven nitride film can cause a drop in the overall efficiency of the wafer. The metal contact lines account for a significant cost in the production of a solar cell wafer. The process engineer must pay attention to the contact line height and width while minimizing the total amount of metal used. Based on all these requirements, an optical profiler, the Zeta-200, was developed to provide rapid and meaningful feedback to the process line. In this paper we present results from various process points in solar cell manufacturing, such as bare wafer roughness, silicon nitride film thickness and contact line dimensions.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73542501","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6317856
J. Johnson, J. Kang
The 2011 National Electrical Code® Article 690.11 requires photovoltaic systems on or penetrating a building to include a DC arc-fault protection device. In order to satisfy this requirement, new Arc-Fault Detectors (AFDs) are being developed by multiple manufacturers including Sensata Technologies. Arc-fault detection algorithms often utilize the AC noise on the PV string to determine when arcing conditions exist in the DC system. In order to accelerate the development and testing of Sensata Technologies' arc-fault detection algorithm, Sandia National Laboratories (SNL) provided a number of data sets. These prerecorded 10 MHz baseline and arc-fault data sets included different inverter and arc-fault noise signatures. Sensata Technologies created a data evaluation method focused on regeneration of the prerecorded arcing and baseline test data with an arbitrary function generator, thereby reducing AFD development time.
{"title":"Arc-fault detector algorithm evaluation method utilizing prerecorded arcing signatures","authors":"J. Johnson, J. Kang","doi":"10.1109/PVSC.2012.6317856","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317856","url":null,"abstract":"The 2011 National Electrical Code® Article 690.11 requires photovoltaic systems on or penetrating a building to include a DC arc-fault protection device. In order to satisfy this requirement, new Arc-Fault Detectors (AFDs) are being developed by multiple manufacturers including Sensata Technologies. Arc-fault detection algorithms often utilize the AC noise on the PV string to determine when arcing conditions exist in the DC system. In order to accelerate the development and testing of Sensata Technologies' arc-fault detection algorithm, Sandia National Laboratories (SNL) provided a number of data sets. These prerecorded 10 MHz baseline and arc-fault data sets included different inverter and arc-fault noise signatures. Sensata Technologies created a data evaluation method focused on regeneration of the prerecorded arcing and baseline test data with an arbitrary function generator, thereby reducing AFD development time.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73496923","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6317837
P. kharangarh, D. Misra, G. Georgiou, A. Delahoy, Z. Cheng, G. Liu, H. Opyrchal, T. Gessert, K. Chin
Two sets of samples (CdTe solar cells) were investigated at -1V within a temperature range of 300K-393K. We discuss Shockley-Read-Hall recombination /generation (SRH R-G) as applied to CdTe and the assumptions used to yield trap energy levels in CdTe. Observed activation energies of the J-V characterization made with Cu-containing back contact in one sample shows one slope while in another sample shows two distinct slopes in Arrhenius plot of ln (J0T-2) vs. 1000/T. Using published identification of the physical trap with energy level, we conclude that one sample does not have hole traps while the other cell shows deep levels corresponding to substitutional impurities of Cu and positive interstitial Cui2+.
研究了两组样品(CdTe太阳能电池)在-1V下，300K-393K的温度范围内。我们讨论了应用于CdTe的Shockley-Read-Hall复合/生成(SRH R-G)和用于产生CdTe陷阱能级的假设。在ln (J0T-2) vs. 1000/T的Arrhenius图中，在一个样品中观察到含cu反接触的J-V表征活化能呈现出一个斜率，而在另一个样品中则呈现出两个不同的斜率。利用已发表的具有能级的物理陷阱鉴定，我们得出结论，一个样品没有空穴陷阱，而另一个电池显示出与Cu取代杂质和正间隙Cui2+对应的深能级。
{"title":"Investigation of defects in N+-CDS/P-CdTe solar cells","authors":"P. kharangarh, D. Misra, G. Georgiou, A. Delahoy, Z. Cheng, G. Liu, H. Opyrchal, T. Gessert, K. Chin","doi":"10.1109/PVSC.2012.6317837","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317837","url":null,"abstract":"Two sets of samples (CdTe solar cells) were investigated at -1V within a temperature range of 300K-393K. We discuss Shockley-Read-Hall recombination /generation (SRH R-G) as applied to CdTe and the assumptions used to yield trap energy levels in CdTe. Observed activation energies of the J-V characterization made with Cu-containing back contact in one sample shows one slope while in another sample shows two distinct slopes in Arrhenius plot of ln (J0T-2) vs. 1000/T. Using published identification of the physical trap with energy level, we conclude that one sample does not have hole traps while the other cell shows deep levels corresponding to substitutional impurities of Cu and positive interstitial Cui2+.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76634920","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6317740
S. Dongaonkar, E. Sheets, R. Agrawal, M. Alam
Partial shading in thin film solar panels can result in reverse bias stress across shaded cells. Therefore, it is important to understand the effect of such reverse stress in commercially competitive PV technologies such as CIGS. In this paper, we systematically investigate the effect of moderate reverse bias on solution-processed CIGS solar cells. We subject the solar cells to varying degrees of reverse biases and continuously monitor the impact of the stress on dark current. We also explore the relaxation behavior of dark current following passive storage and the long term effect of the shadow stress on power output of the cell. We find that the reverse stress affects only the localized shunt current paths, without affecting the bulk device characteristics. The shunt current exhibits a metastable change with reverse stress, and can increase or decrease on application of reverse stress. We analyze this phenomenon in detail, and discuss the hypothesis that can explain its characteristic features.
{"title":"Reverse stress metastability of shunt current in CIGS solar cells","authors":"S. Dongaonkar, E. Sheets, R. Agrawal, M. Alam","doi":"10.1109/PVSC.2012.6317740","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317740","url":null,"abstract":"Partial shading in thin film solar panels can result in reverse bias stress across shaded cells. Therefore, it is important to understand the effect of such reverse stress in commercially competitive PV technologies such as CIGS. In this paper, we systematically investigate the effect of moderate reverse bias on solution-processed CIGS solar cells. We subject the solar cells to varying degrees of reverse biases and continuously monitor the impact of the stress on dark current. We also explore the relaxation behavior of dark current following passive storage and the long term effect of the shadow stress on power output of the cell. We find that the reverse stress affects only the localized shunt current paths, without affecting the bulk device characteristics. The shunt current exhibits a metastable change with reverse stress, and can increase or decrease on application of reverse stress. We analyze this phenomenon in detail, and discuss the hypothesis that can explain its characteristic features.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76837489","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6318108
N. Feldberg, B. Keen, J. Aldous, D. Scanlon, P. Stampe, R. Kennedy, R. Reeves, T. Veal, S. M. Durbin
The Zn-IV-N2 semiconductor family represents a potential earth abundant element alternative for PV and lighting applications, with a predicted band gap range of ~0.6 to ~5 eV. While the Ge and Si containing members of the family have been successfully synthesized, little is known about the lower band gap energy members, in particular ZnSnN2. Here, we report the growth of this compound using a plasma-assisted molecular beam epitaxy technique, and compare experimental optical and structural properties to density functional theory predictions.
{"title":"ZnSnN2: A new earth-abundant element semiconductor for solar cells","authors":"N. Feldberg, B. Keen, J. Aldous, D. Scanlon, P. Stampe, R. Kennedy, R. Reeves, T. Veal, S. M. Durbin","doi":"10.1109/PVSC.2012.6318108","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318108","url":null,"abstract":"The Zn-IV-N2 semiconductor family represents a potential earth abundant element alternative for PV and lighting applications, with a predicted band gap range of ~0.6 to ~5 eV. While the Ge and Si containing members of the family have been successfully synthesized, little is known about the lower band gap energy members, in particular ZnSnN2. Here, we report the growth of this compound using a plasma-assisted molecular beam epitaxy technique, and compare experimental optical and structural properties to density functional theory predictions.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76965760","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6318211
K. Driscoll, S. Hubbard
Concentrator Photovoltaics (CPV) have emerged as a potential alternative energy source due to a favorable balance between cost and efficiency. In contrast to traditional flat panel systems, CPVs result in cheaper fabrication costs since a bulk of the pricey crystalline solar cell is replaced with less expensive light collection and concentrator materials. However, in order to remain competitive with other energy technologies, CPV systems require core solar cells with both high efficiencies and low temperature coefficients. To address the previous need, incorporating nanostructures, such as quantum wells (QW) and quantum dots (QD), into III-V solar cells has been proposed as a potential route towards achieving efficiencies well exceeding 50% under concentration. Hence, vital to the design process of this particular class of solar cells is the ability to accurately calculate nanostructure properties critical to the operation of CPV devices. Here, we have developed a modeling routine using the physics based software Crosslight to systematically study how quantum effects influence the performance of photovoltaics. In particular, this methodology can be applied to study how nanoscale variables, including size, shape and material compositions, can be used to tailor the electrical and optical properties at the device level. Finally, macro-level engineering of the nanostructures, such as the number of stacked layers as well as the position of these structures within the device, is explored in optimizing the overall device response.
{"title":"Modeling the optical and electrical response of nanostructured III–V solar cells","authors":"K. Driscoll, S. Hubbard","doi":"10.1109/PVSC.2012.6318211","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6318211","url":null,"abstract":"Concentrator Photovoltaics (CPV) have emerged as a potential alternative energy source due to a favorable balance between cost and efficiency. In contrast to traditional flat panel systems, CPVs result in cheaper fabrication costs since a bulk of the pricey crystalline solar cell is replaced with less expensive light collection and concentrator materials. However, in order to remain competitive with other energy technologies, CPV systems require core solar cells with both high efficiencies and low temperature coefficients. To address the previous need, incorporating nanostructures, such as quantum wells (QW) and quantum dots (QD), into III-V solar cells has been proposed as a potential route towards achieving efficiencies well exceeding 50% under concentration. Hence, vital to the design process of this particular class of solar cells is the ability to accurately calculate nanostructure properties critical to the operation of CPV devices. Here, we have developed a modeling routine using the physics based software Crosslight to systematically study how quantum effects influence the performance of photovoltaics. In particular, this methodology can be applied to study how nanoscale variables, including size, shape and material compositions, can be used to tailor the electrical and optical properties at the device level. Finally, macro-level engineering of the nanostructures, such as the number of stacked layers as well as the position of these structures within the device, is explored in optimizing the overall device response.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75169838","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6317591
P. Kobyakov, R. Geisthardt, T. Cote, W. Sampath
Expanded band gap ternary alloys, such as Cd1-xMgxTe, could be beneficial for formation of high-efficiency CdTe solar cells structures, such as multi-junction and electron reflector devices. Cd1-xMgxTe thin films were grown by side-by-side co-evaporation from CdTe and Mg precursors. Optical measurements reveal increased band gap with higher Mg incorporation and lateral band gap grading across the substrate. SEM imaging denotes a grain size decrease with Mg incorporation. XPS analysis indicates Mg directly replaces Cd in the film. TEC10/CdS/Cd1-xMgxTe structures with and without CdCl2 treatment demonstrate photovoltaic diode behavior similar to typical CdS/CdTe devices. LBIC and QE measurements register grading consistent with band gap grading of the film. Although successful, refinement of Cd1-xMgxTe thin film co-evaporation is needed to improve spatial uniformity for large area deposition.
{"title":"Growth and characterization of Cd1−xMgxTe thin films for possible application in high-efficiency solar cells","authors":"P. Kobyakov, R. Geisthardt, T. Cote, W. Sampath","doi":"10.1109/PVSC.2012.6317591","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317591","url":null,"abstract":"Expanded band gap ternary alloys, such as Cd1-xMgxTe, could be beneficial for formation of high-efficiency CdTe solar cells structures, such as multi-junction and electron reflector devices. Cd1-xMgxTe thin films were grown by side-by-side co-evaporation from CdTe and Mg precursors. Optical measurements reveal increased band gap with higher Mg incorporation and lateral band gap grading across the substrate. SEM imaging denotes a grain size decrease with Mg incorporation. XPS analysis indicates Mg directly replaces Cd in the film. TEC10/CdS/Cd1-xMgxTe structures with and without CdCl2 treatment demonstrate photovoltaic diode behavior similar to typical CdS/CdTe devices. LBIC and QE measurements register grading consistent with band gap grading of the film. Although successful, refinement of Cd1-xMgxTe thin film co-evaporation is needed to improve spatial uniformity for large area deposition.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77853844","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6317777
Z. R. Chowdhury, D. Stepanov, D. Yeghikyan, N. Kherani
Low temperature processing of silicon photovoltaic (PV) solar cells with excellent passivation quality enables the effective use of ultra-thin wafers for solar cell manufacturing, thus paving the way for high-efficiency low-cost silicon photovoltaics. This article presents Back Amorphous-Crystalline Silicon Heterojunction (BACH) cell performance using low temperature (<;= 400°C) facile native oxide-PECVD silicon nitride (SiNx) dual layer passivation scheme. The cell performance is also compared with the BACH cells fabricated using intrinsic hydrogenated amorphous silicon (i-aSi:H) and PECVD SiNx layer passivation. Reduced optical absorption in the native oxide-SiNx passivation layer resulted in a higher short-circuit current, JSC, compared to the i-aSi:H-SiNx passivated cells. The fill-factor also improved for the native oxide-SiNx passivated cells owing to the improved transport properties. The i-aSi:H-SiNx passivated cells exhibited optimum cell performance of 10.9% efficiency with VOC of 598.7 mV, JSC of 34.3 mA/cm2 and fill-factor of 0.531. In contrast, a maximum cell efficiency of 16% is obtained for native oxide-SiNx passivated cells with VOC of 651 mV, JSC of 35.4 mA/cm2 and fill-factor of 0.694 for a 1 cm2 untextured cell (all measurements having been performed under AM 1.5 global spectrum illumination). The above untextured cell performance is a record efficiency for a back amorphous-crystalline silicon heterojunction PV device synthesized using all low temperature processes, exceeding the previously reported highest cell efficiency of ~15%.
{"title":"Excellent low temperature passivation scheme with reduced optical absorption for back amorphous-crystalline silicon heterojunction (BACH) photovoltaic device","authors":"Z. R. Chowdhury, D. Stepanov, D. Yeghikyan, N. Kherani","doi":"10.1109/PVSC.2012.6317777","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317777","url":null,"abstract":"Low temperature processing of silicon photovoltaic (PV) solar cells with excellent passivation quality enables the effective use of ultra-thin wafers for solar cell manufacturing, thus paving the way for high-efficiency low-cost silicon photovoltaics. This article presents Back Amorphous-Crystalline Silicon Heterojunction (BACH) cell performance using low temperature (<;= 400°C) facile native oxide-PECVD silicon nitride (SiNx) dual layer passivation scheme. The cell performance is also compared with the BACH cells fabricated using intrinsic hydrogenated amorphous silicon (i-aSi:H) and PECVD SiNx layer passivation. Reduced optical absorption in the native oxide-SiNx passivation layer resulted in a higher short-circuit current, JSC, compared to the i-aSi:H-SiNx passivated cells. The fill-factor also improved for the native oxide-SiNx passivated cells owing to the improved transport properties. The i-aSi:H-SiNx passivated cells exhibited optimum cell performance of 10.9% efficiency with VOC of 598.7 mV, JSC of 34.3 mA/cm2 and fill-factor of 0.531. In contrast, a maximum cell efficiency of 16% is obtained for native oxide-SiNx passivated cells with VOC of 651 mV, JSC of 35.4 mA/cm2 and fill-factor of 0.694 for a 1 cm2 untextured cell (all measurements having been performed under AM 1.5 global spectrum illumination). The above untextured cell performance is a record efficiency for a back amorphous-crystalline silicon heterojunction PV device synthesized using all low temperature processes, exceeding the previously reported highest cell efficiency of ~15%.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75228139","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 : 2012-06-03DOI: 10.1109/PVSC.2012.6317882
M. Bokalič, U. Opara Krašovec, M. Hočevar, M. Topič
Spatial characterization techniques are applied to dye-sensitized solar cells (DSSCs). A comparison between transmittance imaging (TI), light-beam-induced-current (LBIC) scan and electroluminescence imaging is carried out. Detected types of inhomogeneities have different fingerprints by each applied technique. Electroluminescence (EL) is advantageous over TI because the electrical activity of the inhomogeneities influences the result. EL is also advantageous over the LBIC scan due to shorter acquisition time. Based on the above findings, EL has been used for characterization of DSSCs during outdoor short-term aging, showing that EL imaging is a proper method to follow the evolution of the inhomogeneities. Proof-of-concept EL inspection of a screen-printed dyesensitized solar module shows good uniformity.
{"title":"Spatial characterization techniques for dye-sensitized solar cells","authors":"M. Bokalič, U. Opara Krašovec, M. Hočevar, M. Topič","doi":"10.1109/PVSC.2012.6317882","DOIUrl":"https://doi.org/10.1109/PVSC.2012.6317882","url":null,"abstract":"Spatial characterization techniques are applied to dye-sensitized solar cells (DSSCs). A comparison between transmittance imaging (TI), light-beam-induced-current (LBIC) scan and electroluminescence imaging is carried out. Detected types of inhomogeneities have different fingerprints by each applied technique. Electroluminescence (EL) is advantageous over TI because the electrical activity of the inhomogeneities influences the result. EL is also advantageous over the LBIC scan due to shorter acquisition time. Based on the above findings, EL has been used for characterization of DSSCs during outdoor short-term aging, showing that EL imaging is a proper method to follow the evolution of the inhomogeneities. Proof-of-concept EL inspection of a screen-printed dyesensitized solar module shows good uniformity.","PeriodicalId":6318,"journal":{"name":"2012 38th IEEE Photovoltaic Specialists Conference","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2012-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75280565","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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