Effects of light-soaking and temperature on different PV technologies

A set of photovoltaic panels including CIGS, CdTe and c-Si were subjected to different light soaking conditions of varying irradiance, module temperature, light soaking under load and under open circuit. It was observed that for every technology, light soaking under load results in improved performance. This improvement is of the same order for CIGS and c-Si panels, and higher for CdTe. A calculation of the temperature coefficients based on each experiment allows the conclusion that the variations in performance with load are not due to thermal effects. Temperature coefficients are in general agreement with published values. Protocols developed for PV modules performance test should include a provision to always carry out measurements under load.