How grain boundaries affect the efficiency of poly-CdTe solar-cells

The Sunshot project scope is to develop next generation solar-cell devices with an installed cost for utility-scale solar systems of less than ~6¢ per kilowatt hour (kWh) or equivalently, $1 per watt for PV systems. In poly-crystalline CdTe PV devices, these goals can only be reached by developing a fundamentally new understanding of the role that grain boundaries play in limiting the efficiency to 17% and Voc to 850 mV. The aim of this collaborative research is to develop an atomic-scale understanding of the effects of grain boundaries in thin film CdTe on the minority carrier lifetime, Voc and Jsc, and thus the overall efficiency of the PV device. A collaborative research team (CRT) that combines their unique expertise in well-defined grain boundary fabrication at UT Dallas), II-VI thin film synthesis using molecular beam epitaxy (MBE) at UIC, atomic-resolution characterization in an aberration-corrected scanning transmission electron microscope (STEM) at UIC, as well as first-principles density functional theory (DFT) calculations at Argon National Lab).