Lead-free halide perovskite Cs3Bi2Br9 single crystals for high-performance X-ray detection

Abstract

All-inorganic lead-free halide perovskites have attracted interest owing to their high ambient and thermal stabilities, excellent optoelectronic properties, and environmental friendliness. Herein, the bismuth-based halide perovskite Cs 3 Bi 2 Br 9 single crystals were successfully grown to a diameter of 12 mm and length of 40 mm using a modified Bridgman method for the first time. The resistivity and transmittance of transparent and crack-free Cs 3 Bi 2 Br 9 single crystal are ~6.8×10 11 Ω cm and ~80%, respectively. The carrier mobility of the (−120) plane is 0.17 cm 2 V −1 s −1 along the [010] orientation ( b axis), and the trap density is 9.7×10 10 cm −3 . Moreover, Cs 3 Bi 2 Br 9 single crystals exhibit excellent potential for X-ray detection, including a high absorption coefficient, a superior X-ray sensitivity of ~230.4 µC Gy air −1 cm −2 , and an ultra-low and no-drift dark current density of ~17.8 pA mm −2 , which enables lower noise and is also beneficial to the ultra-low detection limit for X-ray detectors. Our study shows that Cs 3 Bi 2 Br 9 is a promising candidate for X-ray detection applications. 近年来, 全无机无铅卤化物钙钛矿以其良好的环境稳定性和热 稳定性、优异的光电性能以及环境友好性而受到广泛关注. 本文采 用改进的垂直布里奇曼法首次生长出直径12 mm、长度约40 mm、 透明性良好的Cs 3 Bi 2 Br 9 单晶. 生长的Cs 3 Bi 2 Br 9 单晶的电阻率约为 6.8×1011 Ω cm, 透过率约为80%. 在(−120)晶面内, 载流子迁移率为 0.17 cm 2 V −1 s −1 , 缺陷态密度为9.7×1010 cm −3 . 在X射线探测方面, Cs 3 Bi 2 Br 9 单晶最大灵敏度约为230.4 μC Gy air −1 cm −2 ; 暗电流密度约为 17.8 pA mm −2 , 且没有漂移现象, 这表明Cs 3 Bi 2 Br 9 单晶具有更小的暗 电流噪声, 有利于获得更低的检测限.