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Separating the Influence of Material Composition and Local Defects on the Voc of CIGS Solar Modules
J. Hepp, A. Vetter, B. Hofbeck, C. Camus, J. Hauch, C.J. Brabec
Defects, Monitoring, Spectroscopy, Electroluminescence, CIGS
Thin Film Photovoltaics
Subtopic: CI(G)S, CdTe and Related Thin Film Solar Cells and Modules
Event: 33rd European Photovoltaic Solar Energy Conference and Exhibition
Session: 3AO.8.2
1010 - 1012
ISBN: 3-936338-47-7
Paper DOI: 10.4229/EUPVSEC20172017-3AO.8.2
0,00 EUR
Document(s): paper


In spite of the steadily improved quality of co-evaporated Cu(In,Ga)Se2 absorber layers, the existence of local defects affecting the module performance in large area production can still be an issue. Generally, both, lateral composition gradients and point defects can be found in those layers. We show the necessity to separate these two influences and propose two measurement techniques in order to asses the effect of the material and the defects individually. In oder to quantify the theoretical defect-free open circuit voltage (Voc), given by the material composition, we used luminescence spectroscopy. The additional effect on the Voc originating from local defects was determined using dark lock-in thermography. The combination of both these methods enables a local prediction of a module’s Voc. In the following, we conduct an indepth analysis of the determination of the material composition and its impact on the resulting Voc.