Synthesis and characterization of Cu₂ZnSnS₄ nanocrystals prepared by microwave irradiation method

In this study, we report a rapid and single-step synthesis of Cu₂ZnSnS₄ (CZTS) nanocrystals using microwave-assisted solution method. The influence of reaction temperature and reaction time on the phase purity, crystallographic structure, morphology and optical property of CZTS particles were investigated using X-ray diffraction, Raman spectroscopy, scanning electronic microscope, transmission electron microscopy and ultraviolet–visible spectrometer. Results revealed that the single kesterite CZTS particles with no secondary phase can be obtained by preparing samples at minimal temperature of 170 °C. The sphere-like particles, each of which contains many nanocrystals, decrease effectively in size when increasing the reaction temperature from 170 to 200 °C. The CZTS nanocrystals have an optical band gap around 1.5 eV, which is optimal for photovoltaic applications. In addition, minimal reaction time of 10 min is also essential for the growth of single kesterite CZTS. Our study demonstrated that appropriate reaction temperature and reaction time are crucial for the synthesis of high-quality CZTS by microwave irradiation method.