A 3.2% efficient Kesterite device from electrodeposited stacked elemental layers

An improved electrodeposition-annealing route for preparing films of the Kesterite Cu2ZnSnS4 (CZTS) for thin film solar cell absorber layers is demonstrated. The material is prepared by sequential electrodeposition of a metallic precursor stack in the order Cu/Sn/Cu/Zn and subsequent annealing of the stack in an atmosphere containing sulfur. The new precursor is demonstrably more uniform on both macro-and microscopic scales, and this translates to enhanced lateral uniformity of the photoresponse of the CZTS film. Photovoltaic devices were prepared from the films, with the best cell having an efficiency of 3.2%.