近日，中国工程物理研究院的郑霄家及其研究小组与吉林大学的沈亮等人合作并取得一项新进展。经过不懈努力，他们实现用于高性能X射线探测和成像的低维钙钛矿厚膜的自下而上构建。相关研究成果已于2024年7月23日在国际知名学术期刊《光：科学与应用》上发表。

该研究团队提出一种新的方法来调节Q-2D钙钛矿晶体在由甲胺(CH₃NH₂, MA)和氨(NH₃)组成的混合气氛中生长，从而成功地制备厚度为数百微米的高质量薄膜。随后，研究人员将钙钛矿层与二氧化钛(TiO₂)结合，构建了异质结X射线探测器。钙钛矿晶体生长的精确调控和器件结构的精心设计协同提高了X射线探测器的电阻率和载流子输运性能，实现了低维钙钛矿X射线探测器的超高灵敏度(29721.4μCGyair^-1cm^-2)和20.9nGyair s^-1的低检出限。

研究人员进一步展示了一种平板X射线成像仪(FPXI)，它具有3.6 lmpmm^-1的高空间分辨率，并且在低X射线剂量下具有出色的X射线成像能力。这项工作提出了一种实现高性能Q-2D钙钛矿FPXIs的有效方法，该方法在成像技术的各种应用中具有很大的前景。

据悉，准二维(Q-2D)钙钛矿表现出优异的光电性能，与3D钙钛矿相比，离子迁移减少，使其成为制造高灵敏度和稳定的X射线探测器的有前途的材料。然而，获得具有足够厚度的高质量钙钛矿薄膜以实现有效的X射线吸收仍然具有挑战性。

附：英文原文

Title: Bottom-up construction of low-dimensional perovskite thick films for high-performance X-ray detection and imaging

Author: Dong, Siyin, Fan, Zhenghui, Wei, Wei, Tie, Shujie, Yuan, Ruihan, Zhou, Bin, Yang, Ning, Zheng, Xiaojia, Shen, Liang

Issue&Volume: 2024-07-23

Abstract: Quasi-two-dimensional (Q-2D) perovskite exhibits exceptional photoelectric properties and demonstrates reduced ion migration compared to 3D perovskite, making it a promising material for the fabrication of highly sensitive and stable X-ray detectors. However, achieving high-quality perovskite films with sufficient thickness for efficient X-ray absorption remains challenging. Herein, we present a novel approach to regulate the growth of Q-2D perovskite crystals in a mixed atmosphere comprising methylamine (CH₃NH₂, MA) and ammonia (NH₃), resulting in the successful fabrication of high-quality films with a thickness of hundreds of micrometers. Subsequently, we build a heterojunction X-ray detector by incorporating the perovskite layer with titanium dioxide (TiO₂). The precise regulation of perovskite crystal growth and the meticulous design of the device structure synergistically enhance the resistivity and carrier transport properties of the X-ray detector, resulting in an ultrahigh sensitivity (29721.4μCGyair^-1cm^-2) for low-dimensional perovskite X-ray detectors and a low detection limit of 20.9nGyair s^-1. We have further demonstrated a flat panel X-ray imager (FPXI) showing a high spatial resolution of 3.6lpmm^-1 and outstanding X-ray imaging capability under low X-ray doses. This work presents an effective methodology for achieving high-performance Q-2D perovskite FPXIs that holds great promise for various applications in imaging technology.

DOI: 10.1038/s41377-024-01521-2

Source: https://www.nature.com/articles/s41377-024-01521-2