Veröffentlichungen
2016 |
O. Breitenstein, F. Frühauf, D. Hinken, and K. Bothe IEEE Journal of Photovoltaics 6 (5), 1243-1254, (2016). Abstract | Links | BibTeX | Schlagwörter: Current density, Effective diffusion length, electroluminescence imaging, Fuyuki approximation, Imaging, Limiting, luminescence, luminescence scaling factor, Nonhomogeneous media, Photovoltaic cells, saturation current density @article{Breitenstein2016,
title = {Effective diffusion length and bulk saturation current density imaging in solar cells by spectrally filtered luminescence imaging}, author = {O Breitenstein and F Frühauf and D Hinken and K Bothe}, doi = {10.1109/JPHOTOV.2016.2571621}, year = {2016}, date = {2016-09-01}, journal = {IEEE Journal of Photovoltaics}, volume = {6}, number = {5}, pages = {1243-1254}, abstract = {Most methods for interpreting electroluminescence (EL) or photoluminescence (PL) images of solar cells evaluate the local diode voltages but not the local luminescence intensity itself. One exception is the Fuyuki approximation, which assumes that the local value of the luminescence signal is proportional to the local effective diffusion length. This dependence has been derived for infinitely thick solar cells and neglects self-absorption of the luminescence photons. However, for real solar cells and imaging conditions, with increasing diffusion length, the luminescence signal approaches a limiting value; hence, the Fuyuki approximation no longer holds. In this paper, we compare EL and PL images of multicrystalline solar cells using different kinds of light filtering and find that gentle shortpass filtering is useful for avoiding optical artifacts. Based on earlier calculations, a physically founded formula for the dependence of the gently shortpass-filtered luminescence signal on the bulk diffusion length, for a given rear surface recombination velocity, is presented. Since this formula only barely allows us to calculate the diffusion length from the luminescence signal, a simplified approximate formula is proposed, and its accuracy is checked. This method is tested on EL and Voc PL images of solar cells. We find that for a typical industrial multicrystalline Albackside solar cell, the obtained effective diffusion length images correlate well with such images obtained by spectral LBIC image evaluation. In addition, the saturation current density images correlate well with such images obtained by dark lock-in thermography, which show a much lower spatial resolution. The main limitation of the proposed method is that it is basically approximate and needs some fitting parameters.}, keywords = {Current density, Effective diffusion length, electroluminescence imaging, Fuyuki approximation, Imaging, Limiting, luminescence, luminescence scaling factor, Nonhomogeneous media, Photovoltaic cells, saturation current density}, pubstate = {published}, tppubtype = {article} } Most methods for interpreting electroluminescence (EL) or photoluminescence (PL) images of solar cells evaluate the local diode voltages but not the local luminescence intensity itself. One exception is the Fuyuki approximation, which assumes that the local value of the luminescence signal is proportional to the local effective diffusion length. This dependence has been derived for infinitely thick solar cells and neglects self-absorption of the luminescence photons. However, for real solar cells and imaging conditions, with increasing diffusion length, the luminescence signal approaches a limiting value; hence, the Fuyuki approximation no longer holds. In this paper, we compare EL and PL images of multicrystalline solar cells using different kinds of light filtering and find that gentle shortpass filtering is useful for avoiding optical artifacts. Based on earlier calculations, a physically founded formula for the dependence of the gently shortpass-filtered luminescence signal on the bulk diffusion length, for a given rear surface recombination velocity, is presented. Since this formula only barely allows us to calculate the diffusion length from the luminescence signal, a simplified approximate formula is proposed, and its accuracy is checked. This method is tested on EL and Voc PL images of solar cells. We find that for a typical industrial multicrystalline Albackside solar cell, the obtained effective diffusion length images correlate well with such images obtained by spectral LBIC image evaluation. In addition, the saturation current density images correlate well with such images obtained by dark lock-in thermography, which show a much lower spatial resolution. The main limitation of the proposed method is that it is basically approximate and needs some fitting parameters.
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2014 |
D. Zielke, A. Pazidis, F. Werner, and J. Schmidt Organic-silicon heterojunction solar cells on n-type silicon wafers: the BackPEDOT concept Artikel Solar Energy Materials and Solar Cells 131 , 110-116, (2014), (SiliconPV 2014). Links | BibTeX | Schlagwörter: heterojunction, Organic-silicon, PEDOT:PSS, saturation current density, solar cell @article{Zielke2014b,
title = {Organic-silicon heterojunction solar cells on n-type silicon wafers: the BackPEDOT concept}, author = {D Zielke and A Pazidis and F Werner and J Schmidt}, doi = {10.1016/j.solmat.2014.05.022}, year = {2014}, date = {2014-12-01}, journal = {Solar Energy Materials and Solar Cells}, volume = {131}, pages = {110-116}, note = {SiliconPV 2014}, keywords = {heterojunction, Organic-silicon, PEDOT:PSS, saturation current density, solar cell}, pubstate = {published}, tppubtype = {article} } |
2012 |
H. Wagner, S. Steingrube, B. Wolpensinger, A. Dastgheib-Shirazi, R. Chen, S. T. Dunham, and P. P. Altermatt IEEE (Hrsg.): 2012 38th IEEE Photovoltaic Specialists Conference , 000313-000316, Austin, TX, USA, (2012), ISBN: 978-1-4673-0064-3. Links | BibTeX | Schlagwörter: Doping profiles, emitter dopant inhomogenities, Nonhomogeneous media, saturation current density, Semiconductor process modeling, silicon, simulations, Solid modeling, Surface texture, Surface treatment, textured surfaces @inproceedings{Wagner2012b,
title = {Analyzing emitter dopant inhomogeneities at textured Si surfaces by using 3D process and device simulations in combination with SEM imaging}, author = {H Wagner and S Steingrube and B Wolpensinger and A Dastgheib-Shirazi and R Chen and S T Dunham and P P Altermatt}, editor = {IEEE}, doi = {10.1109/PVSC.2012.6317625}, isbn = {978-1-4673-0064-3}, year = {2012}, date = {2012-06-01}, booktitle = {2012 38th IEEE Photovoltaic Specialists Conference }, pages = {000313-000316}, address = {Austin, TX, USA}, keywords = {Doping profiles, emitter dopant inhomogenities, Nonhomogeneous media, saturation current density, Semiconductor process modeling, silicon, simulations, Solid modeling, Surface texture, Surface treatment, textured surfaces}, pubstate = {published}, tppubtype = {inproceedings} } |