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Quantitative evaluation method for electroluminescence images of a‐Si:H thin‐film solar modules
Author(s) -
Tran T. M. H.,
Pieters B. E.,
Schneemann M.,
Müller T. C. M.,
Gerber A.,
Kirchartz T.,
Rau U.
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.201308039
Subject(s) - electroluminescence , sample (material) , diode , radiative transfer , voltage , materials science , optoelectronics , thin film , work (physics) , optics , physics , nanotechnology , layer (electronics) , quantum mechanics , thermodynamics
This work presents a method for extracting the absolute local junction voltage of a‐Si:H thin‐film solar cells and modules from electroluminescence (EL) images. It is shown that the electroluminescent emission of a‐Si:H devices follows a diode law with a radiative ideality factor n r larger than one. We introduce an evaluation method that allows us to determine the absolute local junction voltage in cases of n r > 1, while existing approaches rely on the assumption of n r = 1. Furthermore, we find that the experimentally determined values of n r vary from sample to sample. It is also explained why the derived radiative ideality factor is influenced by the spectral sensitivity of the camera system used in the experiment. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)