Non-vacuum synthesis of CZTS by sulphurization of electrochemically layered zinc and tin on copper

Sequential layering of Zn and Sn on Cu foil by electrolysis of appropriate salt solution is carried out. The layered metals are annealed at 350 °C to form Cu-Zn-Sn alloy. To the alloy, 30 g of (excess) elemental sulphur powder is added and sulphurized at 350°, 450°, 550° and 650 °C. Structural, morphological, optical and electrochemical investigations revealed CZTS as favourable phase at all sulphurization temperatures. Electrochemical Impedance studies in conjunction with Raman spectroscopy indicated negligible secondary phases for CZTS-550 °C when compared to CZTS synthesized at other temperatures. For CZTS-550 °C, UV–vis DRS studies depicted 1.51 eV as band gap and high absorption coefficient of 105 cm−1. Thus CZTS synthesized by the demonstrated procedure can be suitable for optoelectronic applications.