![]() The basic principle of X-ray imaging is to record the attenuation of X-rays after penetrating subjects. (30−32)Īmong the present applications, high-energy radiation (e.g., X-ray) detection is of particular importance in a variety of fields related to daily life. Furthermore, these remarkable properties also made perovskite materials promising candidates for optoelectronic applications, including light-emitting diodes (LEDs), (21−23) photodetectors, (24,25) irradiation detectors, (26,27) lasers, (28,29) and many others to be discovered. in 2009, (19) the power conversion efficiency of single-junction perovskite solar cell has rapidly increased to reach 25.5%, (20) which is comparable to the efficiencies of CdTe, CuInGaSe, and silicon-based photovoltaic devices. (15−18) Specifically, since the first report of using halide perovskite as light absorber for solar cells by Kojima et al. (12−14) By virtue of these excellent optical and transport properties, halide perovskites have demonstrated huge successes in photovoltaics. Halide perovskite materials generally possess low trap densities, (9) high charge-carrier mobilities, (10) long minority carrier diffusion lengths, (11) and high photoluminescence quantum yields (PLQYs) especially for nanocrystals counterparts. (6,8) Note that the nomenclature of 3D, 2D, 1D, and 0D herein means the structural dimensionality of halide perovskites at the molecular level. (6,7) Further structural reduction of the 2D perovskite generates structurally 1D and 0D halide perovskites such as (C 7H 16N)PbBr 3 and Cs 4PbBr 6. ![]() Reducing the structural 3D to 2D perovskites produces a general chemical formula of A′ 2A n–1B nX 3 n+1 or A′A n–1B nX 3 n+1 (A′ = 1+ or 2+ cation, A = MA +, FA +, Cs +). (1−5) The 3D halide perovskite has a general chemical formula of ABX 3, in which A is a small organic cation (e.g., MA + = methylammonium, FA + = formamidinium) or an inorganic cation (e.g., Cs +, Rb +), B is a metal cation (e.g., Pb 2+, Sn 2+), and X is a halide anion (I –, Br –, Cl –). Metal halide perovskites have attracted worldwide attention in the research field of materials science, physics, and optoelectronics largely because of their solution processability for cost-effective synthesis, tunable bandgaps, and structure dimensionality as well as the outstanding photophysical properties. We further discuss the recent advancements in this promising research area, pointing out the remaining challenges and our perspective for future research directions toward perovskite-based X-ray applications. ![]() In this review, we explore and decipher the working mechanism of scintillators and direct conversion detectors as well as the key advantages of halide perovskites for both detection approaches. Metal halide perovskite-based high-resolution scintillation-imaging screens or direct conversion detectors are promising candidates for such applications, because they have high absorption cross sections for X-rays due to their heavy atom (e.g., Pb 2+, Bi 3+, I –) compositions moreover, these materials are solution-processable at low temperature, possessing tunable bandgaps, near-unity photoluminescence quantum yields, low trap density, high charge carrier mobility, and fast photoresponse. Radiation detection, using materials to convert high-energy photons to low-energy photons (X-ray imaging) or electrical charges (X-ray detector), has become essential for a wide range of applications including medical diagnostic technologies, computed tomography, quality inspection and security, etc.
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