CsMX<sub>3</sub>(M = Sn, Pb; X = Cl, Br, I) are strong candidates for the fast high energy irradiation detectors, ionic conductors, and optoelectronic devices. There are many experimental and theoretical investigations devoted to the study of perovskites ABX<sub>3</sub> (A is a cation with different valence, B is a transition metal and X is oxides, halides or chlorides). But there is no systematic study of CsMX<sub>3</sub> using HSE approximation particularly. In this paper, the band structures, density of states and optical properties of CsMX<sub>3</sub>(M = Sn, Pb; X = Cl, Br, I) have been studied by first-principles calculations using both the hybrid functional (HSE) approximation and the PBE-GGA approximation. The results of both approximations are compared with the experimental values. The results of HSE are closer to the experimental values. The changes of properties have been founded by comparing the band structures, density of states and optical properties of this series of thin film materials respectively. The trend of impact on these properties by replace elements has also been found. Our results provide a basis for the design of specific performance thin film materials.
CdZnTe thin films were deposited on FTO (SnO<sub>2</sub>: F)-coated glass substrates by close-spaced sublimation method and then annealed under three different conditions. The influences of the three thermal treatments on the structure, morphology, composition and optical properties of the CdZnTe thin films were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy disperse spectra (EDS) and photoluminescence (PL) spectroscopy. The XRD results show that the films are (111) preferred orientation. The SEM and PL spectroscopy results show the better crystalline quality after any of three thermal treatments than that of as-deposited sample. The EDS analysis indicates that the Zn composition decreases for the sample with CdCl<sub>2</sub> annealing, but increases for the sample annealing directly and ZnCl<sub>2</sub> annealing. The same results are also obtained by XRD and PL spectroscopy.