Li Liqi, Fang Yanjun, Yang Deren
State Key Laboratory of Silicon Materials and School of Materials Science and Engineering, Zhejiang University, Hangzhou 310027, P. R. China.
J Phys Chem Lett. 2022 Jun 23;13(24):5441-5450. doi: 10.1021/acs.jpclett.2c01389. Epub 2022 Jun 9.
All-inorganic perovskites are considered as preferred materials for next-generation X-ray detectors. However, preparing high-quality thick films by traditional solution-based methods remains challenging due to the low solubility of the precursors. In this work, chemical vapor deposition technology is employed to grow Si-based all-inorganic cesium-lead-bromide perovskite thick films. By introducing a SnO nanocrystal interlayer onto the Si substrate to facilitate the heterogeneous nucleation of the perovskite, we are able to grow high-quality films with a smooth surface and compact grains at a relatively low substrate temperature of 260 °C. The resultant X-ray detectors exhibit a decent sensitivity of 2930 μC Gy cm, a small dark current density of 1.5 nA cm, and a low detection limit of 120 nGy s. Moreover, the devices show excellent biasing stability with a record small baseline drift of 4.6 × 10 nA cm s V under a large electric field of 1100 V/cm among all perovskite polycrystalline film-based detectors ever reported.
全无机钙钛矿被认为是下一代X射线探测器的首选材料。然而，由于前驱体的低溶解度，通过传统的基于溶液的方法制备高质量厚膜仍然具有挑战性。在这项工作中，采用化学气相沉积技术生长硅基全无机铯-铅-溴钙钛矿厚膜。通过在硅衬底上引入SnO纳米晶体中间层以促进钙钛矿的异质成核，我们能够在相对较低的260°C衬底温度下生长出具有光滑表面和致密晶粒的高质量薄膜。所得的X射线探测器表现出2930 μC Gy cm的良好灵敏度、1.5 nA cm的小暗电流密度和120 nGy s的低检测限。此外，在所有报道的基于钙钛矿多晶膜的探测器中，该器件在1100 V/cm的大电场下表现出出色的偏置稳定性，基线漂移记录小至4.6×10 nA cm s V。
