An Efficient S and Se Co-Annealing Strategy for Performance Enhancement of Solution-Processed Submicron CuIn(S,Se)2 Solar Cells

Solution-processed CuIn(S,Se) ₂ (CISSe) solar cells with a submicron absorber (500 nm < thickness < 1 μm) can effectively reduce the deposition time and manufacturing cost. However, both, sensitive shunt paths and serious rear interface recombination limit the performance of submicron CISSe solar cells. In this work, Cu-In-S precursor films are comparatively annealed under Se or Se and S conditions. When the precursor films are annealed in pure Se, the efficiency of the CISSe solar cells can significantly improve from 7.51% to 8.57% with increasing Se content. The Se and S annealing condition enables further efficiency improvement, CISSe solar cell with an efficiency of 10.44% is achieved with the absorber annealed in high Se and S content. The origins of the efficiency enhancement may be found in a widened bandgap and effectively passivated shunt paths, resulting in a significant improvement of V _oc (601.2 mV) and FF (68%).