Synthesis of copper zinc tin sulfide nanocrystal films by solution-based methods and study of their photoelectrochemical properties

Due to the difficulties in achieving high purity, high dispersion, and uniform size distribution, solvothermal synthesis has been seldom employed to fabricate Cu₂ZnSnS₄ (CZTS) nanocrystals for photoelectrochemical applications. Herein, a facile approach has been adopted for preparing CZTS nanocrystals using a solvothermal method. Employing various characterizations, and a thorough analysis of the photoelectrochemical performance, the impacts of different sulfur sources and surfactants on the products were investigated. High-quality CZTS nanocrystal films with small particle size, high dispersion, and hydrophilic surfaces were developed by utilizing proper solvents, cheap metallic ions, surfactants, and right sulfur source. The product that employed Na₂S as its sulfur source had the highest phase purity and the closest stoichiometric ratio. The photoelectrochemical tests showed that CZTS nanocrystal films using polyvinylpyrrolidone as a surfactant had quicker light responsiveness and smaller dark current.