CZTS thin film solar cells utilizing sulfurization of metallic precursors

Abstract

During this decade, slow but steady progress in copper tin zinc sulfide (CZTS) photovoltaics can be seen as a deep research interest and an extensive development effort in the Earth-abundant and non-toxic thin-film solar cells have continued worldwide. Sulfurization of metallic precursors is one of the most promising preparation processes for this optical absorber because it is considered favorable from a productivity viewpoint. Two types of precursors were studied in this paper. One was a multiple stack of pure metal layers and the other was an alloy layer with or without an overlayer consisting of pure metal. By investigating how the stacking sequence of each metallic precursor layer and a heating rate for sulfurization had an influence on the formation of secondary phases on the CTZS surface and also in the bulk, we found that the sulfurization process of Zn-covered metallic precursors had a beneficial effect on the improvement of device performance.