The effect of polyvinylpyrrolidone (PVP) on thermochemical reaction of Cu2SnS3 nanoparticles: Shape and opto-crystalline structure

An attempt is made to resolve the controversy related to the difficulty in synthesizing the pure single crystalline phase of ternary Cu2SnS3 nanoparticles whereas the chemical bond and formation of crystalline structure and stoichiometry of nano-sized are strongly controlled by the surface of nano-sized particles. The related experimental results of X-ray diffraction, Raman active lattice mode, and UV-visible absorption were justified via solvothermal method resulted in the value of strain and the size of diameter. When the proper concentration of polyvinylpyrrolidone/ ethylene glycol (0.005gmL−1) as the capping agent was taken, the uniform size and shape of Cu2SnS3 nanoparticles with a sphere-like morphology were obtained. In the case of using copper chloride salt, the Cu2SnS3 nanoparticles with tetragonal phase and optical band gap energy of ~ 1.4 eV were obtained. Moreover, the Cu2SnS3 particles in the hexagonal phase were produced with the optical band gap of ~ 1.33 eV using copper acetate.