ABSTRACT
In this study single junction amorphous silicon (a-Si), CdTe and Cu(In,Ga)Se2 (CIGS) photovoltaic (PV) material samples were exposed to controlled light soaking. Controlled light soaking is used as a preconditioning step in the type approval testing of thin film photovoltaic modules. The controlled light soaking procedure is based on test experience gained from amorphous silicon modules. In this study two series of a-Si, CdTe and CIGS samples were exposed to light. The samples were measured for their electrical performance frequently during the exposure. As a result the a-Si degraded in performance, as expected from the literature. The CdTe samples degraded in maximum power but all the samples did not behave consistently during the test. The CIGS samples mostly gained in maximum power although there were inconsistencies in the behaviour also within these samples. As a conclusion because the behaviour of CdTe and CIGS materials differs radically from that of a-Si under light exposure, the description of the controlled light soaking procedure in the qualification standard requires some revision in order to be applied to these different thin film materials.
