Zhu Wenjuan, Ma Wenbo, Su Yirong, Chen Zeng, Chen Xinya, Ma Yaoguang, Bai Lizhong, Xiao Wenge, Liu Tianyu, Zhu Haiming, Liu Xiaofeng, Liu Huafeng, Liu Xu, Yang Yang Michael
State Key Laboratory of Modern Optical Instrumentation, College of Optical Science and Engineering, International Research Center for Advanced Photonics, Zhejiang University, Hangzhou, Zhejiang China.
Center for Chemistry of High-Performance & Novel Materials, department of Chemistry, Zhejiang University, Hangzhou, Zhejiang China.
Light Sci Appl. 2020 Jun 30;9:112. doi: 10.1038/s41377-020-00353-0. eCollection 2020.
X-rays are widely used in probing inside information nondestructively, enabling broad applications in the medical radiography and electronic industries. X-ray imaging based on emerging lead halide perovskite scintillators has received extensive attention recently. However, the strong self-absorption, relatively low light yield and lead toxicity of these perovskites restrict their practical applications. Here, we report a series of nontoxic double-perovskite scintillators of CsAgNaInBiCl. By controlling the content of the heavy atom Bi, the X-ray absorption coefficient, radiative emission efficiency, light yield and light decay were manipulated to maximise the scintillator performance. A light yield of up to 39,000 ± 7000 photons/MeV for CsAgNaInBiCl was obtained, which is much higher than that for the previously reported lead halide perovskite colloidal CsPbBr (21,000 photons/MeV). The large Stokes shift between the radioluminescence (RL) and absorption spectra benefiting from self-trapped excitons (STEs) led to a negligible self-absorption effect. Given the high light output and fast light decay of this scintillator, static X-ray imaging was attained under an extremely low dose of ∼1 μGy, and dynamic X-ray imaging of finger bending without a ghosting effect was demonstrated under a low-dose rate of 47.2 μGy s. After thermal treatment at 85 °C for 50 h followed by X-ray irradiation for 50 h in ambient air, the scintillator performance in terms of the RL intensity and X-ray image quality remained almost unchanged. Our results shed light on exploring highly competitive scintillators beyond the scope of lead halide perovskites, not only for avoiding toxicity but also for better performance.
X射线被广泛用于无损探测内部信息，在医学放射成像和电子工业中有着广泛应用。基于新兴的卤化铅钙钛矿闪烁体的X射线成像最近受到了广泛关注。然而，这些钙钛矿的强自吸收、相对较低的光产额和铅毒性限制了它们的实际应用。在此，我们报道了一系列CsAgNaInBiCl无毒双钙钛矿闪烁体。通过控制重原子Bi的含量，对X射线吸收系数、辐射发射效率、光产额和光衰减进行了调控，以实现闪烁体性能的最大化。CsAgNaInBiCl的光产额高达39000±7000光子/兆电子伏，远高于先前报道的卤化铅钙钛矿胶体CsPbBr（21000光子/兆电子伏）。得益于自陷激子（STE），辐射发光（RL）和吸收光谱之间的大斯托克斯位移导致自吸收效应可忽略不计。鉴于这种闪烁体的高光输出和快速光衰减，在极低剂量约1微戈瑞下实现了静态X射线成像，并在47.2微戈瑞/秒的低剂量率下展示了手指弯曲的动态X射线成像且无重影效应。在85°C下热处理50小时，然后在环境空气中进行50小时的X射线辐照后，闪烁体在RL强度和X射线图像质量方面的性能几乎保持不变。我们的结果为探索超越卤化铅钙钛矿范围的极具竞争力的闪烁体提供了思路，不仅是为了避免毒性，也是为了获得更好的性能。
