Reducing series resistance in CuZnSn(S,Se) nanoparticle ink solar cells on flexible molybdenum foil substrates.

Earth abundant CuZnSnS nanoparticle inks were deposited on molybdenum foil substrates and subsequently converted to high quality thin film CuZnSn(S,Se) photovoltaic absorbers. Integration of these absorbers within a thin film solar cell device structure yields a solar energy conversion efficiency which is comparable to identical devices processed on rigid glass substrates. Importantly, this is only achieved when a thin layer of molybdenum is first applied directly to the foil. The layer limits the formation of a thick Mo(S,Se) layer resulting in a substantially reduced series resistance.