Microwave heating synthesis and formation mechanism of chalcopyrite structured CuInS2 nanorods in deep eutectic solvent

Chalcopyrite structured CuInS2 nanorods were synthesized by an environmentally friendly microwave heating method in deep eutectic solvent. The as-synthesized CuInS2 nanorods were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. The results indicated that the obtained CuInS2 nanostructures display rod-like morphology with diameters of about 40 nm and lengths of about 400 nm. The influences of microwave heating time on the formation of CuInS2 phase were discussed. Ultraviolet–visible (UV–vis) and photoluminescence (PL) spectra were utilized to investigate the optical properties of CuInS2 nanorods. The results showed that the as-synthesized CuInS2 nanorods exhibit strong absorption from the entire visible light region to the near-infrared region beyond 1100 nm. PL spectrum of the as-synthesized CuInS2 nanorods displays an emission peak centered at 580 nm under excitation wavelength of 366 nm at room temperature. The possible growth mechanism of CuInS2 nanorods was discussed.