The exposure of CIGS solar cells to different electrical biases in a damp-heat illumination environment

Two hybrid degradation setups, allowing exposure of solar cells and modules to elevated temperatures and humidity as well as illumination have been built. CIGS solar cells were placed in the degradation setups, allowing real time monitoring of their electrical properties. Under open circuit conditions, the efficiency of alkali-rich CIGS solar cells quickly decreased due to the occurrence of shunts. Electrical loads were built and implemented in order to allow exposure of CIGS solar cells to alternative bias voltages, including maximum power point (MPP) conditions and negative voltages. Preliminary studies indicated an influence of the both negative and positive electrical bias on CIGS solar cell stability.