A low-temperature-low-intensity study of flexible CIGS solar cells

Commercially available lightweight and flexible CIGS solar cells are investigated for their performance under low intensity low temperature (LILT) conditions governing outer planets Mars, Jupiter, and Saturn. Current density-voltage under varying temperatures and illumination intensities, including concentrated solar, as well as electroluminescence measurements is performed to investigate the effects of conditions in deep space. A barrier to minority carrier extraction is observed and attributed to the acceptor rich defect layer near the CIGS absorber/ CdS buffer interface. The effect of this barrier on power generation is presented and shown to decrease after light soaking, due to a transition between the so-called relaxed to metastable states. The power conversion efficiencies are shown to be higher for LILT conditions compared to terrestrial application.