摘要
Lead-halide perovskite single crystal(SC)heterojunctions have attracted significant attention for X-raydetection owing to their unique combination of high sensitivity,resolution,stability and low detection limit.However,the toxicity of lead in those perovskite heterojunctions limitstheir practical applications.Herein,we report the constructionof the first all-inorganic lead-free Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunctions with an area of 20×20 mm^(2)via a facile liquidphase epitaxial method through temperature-lowering crystallization.The epitaxial crystallization of the three-dimensional(3D)Cs_(2)AgBiBr_(6)SC film on a 2D Cs_(3)Bi_(2)Br_(9)SCsubstrate requires a large driving force for transitioning fromthe Volmer–Weber mode to the layer-by-layer growth modeunder a rapid cooling rate.The Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)SCheterojunction detector achieves a high sensitivity of1390μC Gy_(air)^(−1)cm^(−2)for 100 keV hard X-ray detection atroom temperature,which is enhanced to 2075μC Gy_(air)^(−1)cm^(−2)at 75℃,demonstrating impressive high-temperature stability.Moreover,the detector achieves a detection limit of37.48 nG_(yair)s^(−1)and excellent stability for 90 days without anyencapsulation.This work demonstrates the feasibility of usingthe epitaxial mechanism of perovskite formation on a highsurface-energy substrate for the controllable construction of a3D/2D heterojunction that significantly enhances X-ray detection performance.
卤化铅钙钛矿单晶异质结以其独特的高灵敏度、高分辨率、高稳定性和低检出限的特点,在X射线探测中受到了广泛关注.然而,这些钙钛矿异质结中Pb的毒性限制了它们的实际应用.本文采用降温结晶法构建了第一个面积为20×20 mm^(2)的全无机无铅Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)单晶异质结.3D Cs_(2)AgBiBr_(6)单晶薄膜在2D Cs_(3)Bi_(2)Br_(9)单晶衬底上的外延结晶需要更大的驱动力,我们通过大的冷却速率使其生长模式从Volmer-Weber过渡到逐层生长.Cs_(2)AgBiBr_(6)/Cs_(3)Bi_(2)Br_(9)单晶异质结探测器在100 keV硬X射线探测下,室温下灵敏度高达1390μC Gy_(air)^(−1)cm^(-2),75℃下增加到2075μC Gy_(air)^(−1)cm^(-2),且高温稳定性优异.此外,该探测器具有37.48 nGy_(air)S^(−1)的低检测限和长达90天的优异稳定性.
基金
financially supported by the National Natural Science Foundation of China(62274103 and 51972194)
the National Key Research and Development Program of China(2022YFB3204101)
the 111 Project 2.0(BP2018013)。
