Synthesis of Nonstoichiometric Cu₂ZnSnS₄ from ZnS by Cation Exchange

Abstract

A cation exchange reaction of wide‐band‐gap crystalline ZnS with CuCl2 and SnCl4 in triethylene glycol was developed to synthesize nonstoichiometric Cu2ZnSnS4 with crystallite size more than 100 nm. The materials were characterized by powder X‐ray diffraction, electron microscopy, Raman, and energy dispersive X‐ray elemental mapping. The method allows the formation of Zn‐rich phases and good control of the crystal size and shape. No narrow‐band‐gap highly conductive CuxS impurities were observed.