Properties and characterization of CZTS nanoparticles prepared by microwave heating irradiation

Cu2ZnSnS4 (CZTS) nanoparticles suitable for solar cell absorber fabrication were synthesized by the microwave-assisted heating method. The influence of the reaction temperature, the temperature increase duration and post-annealing temperature on the chemical composition, crystallographic structure, phase purity and optical properties of CZTS nanocrystals has been investigated by means of XRD, Raman spectroscopy, scanning (SEM) and transmission electron microscopies (TEM), EDX and UV–Vis spectroscopies. The chemical composition of the CZTS nanoparticles synthesized at a temperature of 250°C and the temperature increase duration of 10 min are almost stoichiometric. The post-annealing process of CZTS has been investigated by means of the in situ XRD method. The results obtained point to the presence of a pure CZTS phase after annealing of the synthesized powder at a temperature of 550°C. The direct band gap energy (Eg) of the CZTS nanoparticles obtained depends on the post-annealing temperature and reaches nearly 1.5 eV at 550°C.