Solvothermal synthesis and optical characterization of chalcopyrite CuInSe2 microspheres

CuInSe2 microspheres were synthesized by a solvothermal method with a mixed solvent of ethylenediamine and ethanol (1:1, v/v). Besides, other morphological CuInSe2 such as platelets and rods were obtained by selecting different solvothermal conditions. The crystalline structure and morphology of the as-obtained products were characterized by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The effects of the experimental parameters including solvents, reaction time, and reactant concentration have also been studied. The near IR absorption spectra showed that CuInSe2 microstructures had strong absorption and their energy band gaps were tunable in the range of 1.03–1.13 eV, which was somewhat relevant to the size and morphology.