The 0D Cs2TeI6 Perovskite: Solution Processed Thick Films with High X-Ray Sensitivity

摘要： We demonstrate a potential candidate the 0-D “all-inorganic” perovskite material Cs2TeI6 as a sensitive all-inorganic X-ray photoconductor for the development of the new generation of direct photon-to-current conversion flat panel X-Ray imagers. Cs2TeI6 consists of high atomic number elements, has high electrical resistance and exhibits high air and moisture stability making it suitable as a sensitive X-ray photoconductor. In addition, we identify that Cs2TeI6 film can be prepared under low temperature process using electrostatic assisted spray technique at atmospheric condition and achieved the resistivity of 4.2×1010 Ω·cm. The resulting air and water-stable Cs2TeI6 device exhibits strong photoresponse to X-ray radiation. An electron drift length on the order of 200 μm is estimated under an applied electrical field strength of 400 V·cm-1. A high sensitivity for Cs2TeI6 thick film device is realized, with the value of 192 nC·R-1cm-2 under 40 kVp X-rays at an electrical field of 250 V·cm-1, which is about 20 times higher than that of the hybrid 3D perovskite polycrystalline film X-ray detectors. X-ray imaging based on Cs2TeI6 perovskite films will require lower radiation doses in many medical and security check applications.