CIGS-based solar cells prepared from electrodeposited precursor films

Previously, we reported 15.4%-efficient [1] copper indium gallium diselenide (CIGS)-based photovoltaic devices from electrodeposited precursor films in which the final film composition was adjusted using the physical vapor deposition (PVD) method. At present, we are fabricating CIGS-based solar cells directly from electrodeposited precursor films, eliminating the expensive PVD step. Electrodeposited CIGS absorber layers are fabricated by a three-stage electrodeposition process in which: (a) CIGS is electrodeposited in the first stage, (b) Cu is electrodeposited in the second stage, and (c) an In layer is deposited in the final third stage. All films are electrodeposited from an aqueous-based solution at room temperature in a two-electrode cell configuration, with platinum gauze as the counter electrode and a glass/MO substrate as the working electrode. The substrate is DC-sputtered with about 1 μm of Mo. The electrodeposited films are selenized at high temperature (∼550 °C) to obtain a 10.9%-efficient device.