Chai Yingjun, Jiang Chaoyan, Hu Xudong, Han Jiguang, Wang Yao, Yang Wanqiu, Li Chongkang, Zeng Haibo, Li Xiaoming
MIIT Key Laboratory of Advanced Display Material and Devices, School of Material Science and Engineering, Nanjing University of Science and Technology, Nanjing, 210094, China.
School of Materials Science and Chemical Engineering, Ningbo University, Ningbo, 315211, China.
Small. 2023 Dec;19(52):e2305357. doi: 10.1002/smll.202305357. Epub 2023 Aug 27.
Solution-processed organic-inorganic hybrid perovskite polycrystalline thick films have shown great potential in X-ray detection. However, the preparation of compact perovskite thick films with large area is still challenging due to the limitation of feasible ink formulation and pinholes caused by solvent volatilization. Post-treatment and hot-pressing are usually involved to improve the film quality, which is however unsuitable for subsequent integration. In this work, a homogeneous bridging strategy is developed to prepare compact perovskite films directly. A stable perovskite slurry with suitable viscosity consisting of undissolved grains and supersaturated solution is formed by adding a weak coordination solvent to the pre-synthesized microcrystalline powders. Small perovskite grains in situ grow from the saturated solution during the annealing, filling the pinholes and connecting the surrounding original grains. As a result, large-area perovskite thick film with tight grain arrangement and ultralow current drift is blade-coated to achieve X-ray imaging. The optimal device displays an impressive mobility-lifetime product of 2.2 × 10 cm V and a champion ratio of sensitivity to the dark current density of 2.23 × 10 µC Gy A . This work provides a simple and effective route to prepare high-quality perovskite thick films, which is instructive for the development of perovskite-based X-ray flat-panel detectors.
溶液法制备的有机-无机杂化钙钛矿多晶厚膜在X射线检测中显示出巨大潜力。然而，由于可行的油墨配方的限制以及溶剂挥发导致的针孔问题，制备大面积致密的钙钛矿厚膜仍然具有挑战性。通常需要进行后处理和热压来提高膜质量，但这不适用于后续集成。在这项工作中，开发了一种均匀桥接策略来直接制备致密的钙钛矿膜。通过向预合成的微晶粉末中添加弱配位溶剂，形成了一种由未溶解的颗粒和过饱和溶液组成的具有合适粘度的稳定钙钛矿浆料。在退火过程中，小的钙钛矿晶粒从饱和溶液中原位生长，填充针孔并连接周围的原始晶粒。结果，通过刮涂制备出具有紧密晶粒排列和超低电流漂移的大面积钙钛矿厚膜以实现X射线成像。最佳器件显示出令人印象深刻的迁移率-寿命乘积为2.2×10 cm V，以及灵敏度与暗电流密度之比的最佳值为2.23×10 µC Gy A 。这项工作提供了一种简单有效的制备高质量钙钛矿厚膜的方法，对基于钙钛矿的X射线平板探测器的发展具有指导意义。
