铯铅溴X射线面阵探测器研究：准单晶生长策略及缺陷性能调控

X射线探测技术是医学诊断、无损检测的重要手段。然而，我国X射线探测器专利被封锁，为“卡脖子”技术；现有探测器技术存在灵敏度低、成像辐射剂量高的问题，无法满足病变监测、低辐射损害等动态成像需求。新一代无机铯铅溴X射线探测器具有灵敏度高、检测限低、稳定性好等优异性能，有望用于动态成像；但亟需解决缺陷抑制的科学难题和大面积制备的技术瓶颈。本项目基于申请人在X射线探测器的研究积累，拟利用定向凝固策略制备大面积铯铅溴厚膜，解析其在热场下的流变行为，确保准单晶性、消除纵向晶界；以化学势调控和异质外延钝化为指导，综合最小化体相、横向晶界缺陷，建立化学势与体缺陷的定量关系，阐明异质外延钝化机理；进一步地，将铯铅溴准单晶膜与TFT集成，构筑10×10 cm2面阵探测原型器件。最终实现灵敏度超过10000 μC Gy-1 cm-2、3dB带宽>200Hz、低辐射剂量的X射线动态成像，达到国际领先水平。

X-ray detection is of great significance for medical diagnosis and non-destructive inspection. However, X-ray detection technology in China currently is still a bottleneck. Also, the detectors are confronted with the issue of low detection sensitivity and high radiation dosage, which can not satisfy the requirements of real-time monitoring and low radiation damage for dynamic X-ray imaging. The novel inorganic CsPbBr3 perovskite based X-ray detector has advantages of high sensitivity, low detection limit and good stability, and thus is promising for dynamic X-ray imaging. However, the rational passivation of defect states and fabrication of large area detectors are urgent to be addressed. Based on the previous research of the applicant, this project aims to achieve large area CsPbBr3 thick film through controlled directional solidification method and study the rheology behavior of CsPbBr3 under the thermal field, guaranteeing the removal of vertical grain boundaries. In terms of defects, we will utilize the strategy of controlling the chemical potential and heteroepitaxial passivation to minimize the defects within the bulk phase and horizontal grain boundaries. This project will also establish the relationship between the chemical potential and the defect concentration, and illustrate the mechanism of heteroepitaxial passivation. Ultimately, we expect to integrate the detector with TFT back-end circuits, and realize the flat panel X-ray detector with an area of 10×10 cm2. The flat panel detector is expected to achieve a high sensitivity over 10000 μC Gy-1 cm-2, 3dB bandwidth over 200 Hz and low radiation dosage. Thereby, the detector can fulfill the requirements of the dynamic X-ray imaging and reach the international leading level.