Correlating Molecular Precursor Interactions with Device Performance in Solution-Processed CuZnSn(S,Se) Thin-Film Solar Cells.

Research efforts aimed at improving the crystal quality of solution-processed CuZnSn(S,Se) (CZTSSe) absorbers have largely employed delicate pre- and postprocessing strategies, such as multistep selenization, heat treatment in mixed chalcogen atmospheres, and multinary extrinsic doping that are often complex and difficult to reproduce. On the other hand, understanding and tuning chemical interactions in precursor inks prior to the thin-film deposition have received significantly less attention. Herein, we show for the first time how the complexation of metallic and chalcogen precursors in solution have a stark influence on the crystallization and optoelectronic quality of CZTSSe absorbers.