Enhanced light trapping in thin amorphous silicon solar cells by directionally selective optical filters
Ulbrich C, Peters M, Tayyib M, Blaesi B, Kirchartz T, Gerber A, Rau U (2010)
Publication Type: Conference contribution
Publication year: 2010
Journal
Book Volume: 7725
Conference Proceedings Title: Proceedings of SPIE - The International Society for Optical Engineering
Event location: BEL
ISBN: 9780819481986
DOI: 10.1117/12.853799
Abstract
Optical absorption losses limit the efficiency of thin-film solar cells. We demonstrate how to increase the absorption in hydrogenated amorphous silicon solar cells by using a directionally selective optical multilayer filter covering the front glass. The filter transmits perpendicularly incident photons in the wavelength range 350 nm - 770 nm. In the regime of low absorptance, i.e. large optical absorption lengths, however, it blocks those photons impinging under oblique angles. Thus, the incoming radiation is transmitted with almost no loss while the emitted radiation is mostly blocked due to its wider angle distribution. We determine the enhancement in the optical path length from reflectivity measurements. In the weakly absorbing high wavelength range (650 nm - 770 nm) we observe a peak optical path length enhancement of κ ∼3.5. The effective path length enhancement κ ∼ calculated from the external quantum efficiency of the solar cell with filter, however, peaks at a lower value of only κ ∼1.5 in the same wavelength range. Parasitic absorption in the layers adjacent to the photovoltaic absorber limit the increase in the effective light path enhancement. Nonetheless we determine an increase of 0.2 mAcm-2 in the total short circuit current density. © 2010 Copyright SPIE - The International Society for Optical Engineering.
Involved external institutions
Forschungszentrum Jülich / Research Centre Jülich (FZJ)
Germany (DE)
Fraunhofer-Institut für Solare Energiesysteme (ISE) / Fraunhofer Institute for Solar Energy Systems
Germany (DE)
Germany (DE)
Fraunhofer-Institut für Solare Energiesysteme (ISE) / Fraunhofer Institute for Solar Energy Systems
Germany (DE)
How to cite
APA:
Ulbrich, C., Peters, M., Tayyib, M., Blaesi, B., Kirchartz, T., Gerber, A., & Rau, U. (2010). Enhanced light trapping in thin amorphous silicon solar cells by directionally selective optical filters. In Proceedings of SPIE - The International Society for Optical Engineering. BEL.
MLA:
Ulbrich, Carolin, et al. "Enhanced light trapping in thin amorphous silicon solar cells by directionally selective optical filters." Proceedings of the Photonics for Solar Energy Systems III, BEL 2010.
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