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Bandgap imaging in Cu(In,Ga)Se 2 photovoltaic modules by electroluminescence
Author(s) -
Bokalič Matevž,
Pieters Bart E.,
Gerber Andreas,
Rau Uwe,
Topič Marko
Publication year - 2017
Publication title -
progress in photovoltaics: research and applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.286
H-Index - 131
eISSN - 1099-159X
pISSN - 1062-7995
DOI - 10.1002/pip.2846
Subject(s) - electroluminescence , band gap , photovoltaic system , calibration , materials science , optoelectronics , homogeneity (statistics) , optics , characterization (materials science) , computer science , physics , electrical engineering , nanotechnology , engineering , layer (electronics) , quantum mechanics , machine learning
Abstract A unique non‐destructive characterization method for apparent bandgap imaging in photovoltaic (PV) devices based on acquisition of two electroluminescence (EL) images in different spectral ranges is presented. The method consists of a calibration procedure and a bandgap imaging procedure. Calibration has to be performed once per module type and EL imaging setup, and must provide a relation between the bandgap and the ratio between two spectrally independent EL images. After calibration, bandgap imaging only requires acquisition of two spectrally independent EL images followed by image processing, making the method very fast and suitable for in‐line PV module characterization with regard to spatial (in)homogeneity and production process stability. The method is demonstrated on a commercial state‐of‐the‐art Cu(In,Ga)Se 2 PV module where apparent bandgap fluctuations between 1.07 and 1.15 eV are detected. Copyright © 2016 John Wiley & Sons, Ltd.