Fabrication and characterization of Cu<inf>2−X</inf>Zn<inf>1.3</inf>SnS<inf>4</inf> Kesterite thin films synthesized by solvent based process method for photovoltaic solar energy applications

Solar has become one of the fastest growing renewable energy sources. With the push towards sustainability, it is an excellent solution to resolve the issue of our diminishing finite resources. Alternative photovoltaic systems are of much importance to utilize solar energy efficiently. The Cu-chalcopyrite compounds CuInS2 and CuInSe2 and their alloys provide absorber material of high absorption coefficients of the order of 105 cm−1. Cu2ZnSnS4 (CZTS) is more promising material for photovoltaic applications as Zn and Sn are abundant materials of earth’s crust. Further, the preparation of CZTS-ink facilitates the production of flexible solar cells. The device can be designed with Al doped ZnO as the front contact, n-type window layer (e.g. intrinsic ZnO); an n-type thin film buffer layer (e.g. CdS) and a p-type CZTS absorber layer with molybdenum (Mo) substrate as back contact. In this study, CZTS films were synthesized by a non-vacuum solvent based process technique from a molecular-ink using a non-toxic eco-friendly solvent dimethyl sulfoxide (DMSO). The deposited CZTS films were optimized and characterized by XRD, UV-visible spectroscopy and SEM.