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Photoconductivity as loss mechanism in organic solar cells
Author(s) -
Tress Wolfgang,
Leo Karl,
Riede Moritz
Publication year - 2013
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.201307039
Subject(s) - heterojunction , photoconductivity , optoelectronics , limiting , saturation (graph theory) , quantum efficiency , observable , materials science , voltage , solar cell , physics , mechanical engineering , mathematics , combinatorics , quantum mechanics , engineering
We observe that the reverse current under illumination in solar cells containing C 60 and ZnPc is dominated by a photoshunt. This shunt, not present in the dark, causes a linear current–voltage relation under illumination showing no saturation. Although observable in bulk heterojunctions, this effect is more pronounced in the presence of a pristine C 60 layer. An internal quantum efficiency larger than unity under an applied negative voltage and in the spectral range where C 60 absorbs identifies charges which are injected in addition to those photogenerated. The photoshunt is also present in the power‐generating region and represents a loss mechanism limiting the fill factor in particular for flat heterojunction devices. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)