Fabrication of Cu2ZnSn(SxSe1−x)4 thin film solar cell by single step sulfo-selenization of stacked metallic precursors

• Synthesis of Cu2ZnSn(SxSe1−x)4 absorbers using rapid thermal sulfo-selenization process.
• The mixed chalcogen annealing atmosphere enhances grain growth of the absorber.
• A CZTSSe solar cell with a ∼7% conversion efficiency is demonstrated.

We have synthesized an efficient Cu2ZnSn(SxSe1−x)4 (CZTSSe) absorbers by using single-step rapid thermal sulfo-selenization process of sputtered stack metallic precursor (Zn/Sn/Cu) films. The structural and morphological studies confirm that the suitability of the rapid thermal sulfo-selenization process for the synthesis of a CZTSSe absorber without any secondary phases with large grains. The annealing atmosphere with a mixed-chalcogen source enhances the grain growth of the CZTSSe absorber as compared with pure Cu2ZnSnS4 (CZTS) and Cu2ZnSnSe4 (CZTSe) absorbers. The CZTSSe thin film solar cell shows the best conversion efficiency of ∼7%.