Study on Structural and Optical Properties of Wurtzite Cu2ZnSnS4 Nanocrystals Synthesized via Solvothermal Method

A simple low-cost solvothermal method was applied to synthesize hexagonal wurtzite Cu2ZnSnS4 (CZTS) nanoparticles with different morphologies using Polyvinylpyrrolidone (PVP) as a capping ligand and copper and zinc acetate salts at 180 and 220 ℃. The resulting sphere-like and flower-like nanoparticles synthesized at 180 and 220℃, respectively, indicated thecalculated optical band gaps of 1.45 and 1.28 eV, respectively. Where both samples indicated the metastable wurtzite phase. The main Raman peaks were observed at 333 and 371 cm-1, was indicating the wurtzite phase of CZTS nanocrystals. The phase of the wurtzite CZTS nanoparticles was successfully controlled by using zinc acetate salt, which affected the reaction rate between Zn and S sources. In addition, reaction temperature was found as an effective factor on the morphology, elemental ratio, reaction kinetic, crystallinity, and size of the CZTS nanoparticles. Photoresponse of the CZTS thin films were confirmed by I-V measurements under dark and light illumination. All these results imply the potential of these nanoparticles for solar cell applications.