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Zero-Dimensional Cs2TeI6 Perovskite: Solution-Processed Thick Films with High X‑ray Sensitivity

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journal contribution
posted on 19.12.2018, 00:00 by Yadong Xu, Bo Jiao, Tze-Bin Song, Constantinos C. Stoumpos, Yihui He, Ido Hadar, Wenwen Lin, Wanqi Jie, Mercouri G. Kanatzidis
We demonstrate a potential candidate, the 0D “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 a low-temperature process using electrostatic-assisted spray technique under atmospheric conditions and achieved resistivity of 4.2 × 1010 Ω·cm. The resulting air- and water-stable Cs2TeI6 device exhibits a 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 ∼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.