卤化物单晶质量的精细调控阀及高性能X射线探测

Fine-control-valve of halide perovskite single crystal quality for high performance X-ray detection

钙钛矿单晶为研究卤化物钙钛矿这种新兴的半导体材料的光电特性提供了一个独特的平台,而温度诱导的晶体生长方法往往增加溶质沉积速度或者造成不可避免的溶质消耗,这容易导致晶体生长速率飙升或者下降.本文开发了一种通用且易做到的溶剂挥发限制生长策略来动态抑制卤化物钙钛矿单晶晶体生长速率的上升或降低,晶体生长速率的上升或降低通常分别是由于溶质沉积速度的增加或不可避免的溶质消耗造成的.溶剂挥发限制生长策略可以通过精细控制阀精细控制晶体生长速率,通过溶液过程生长出高质量的晶体.通过溶剂挥发限制生长方法生长的卤化物钙钛矿单晶显示出的缺陷态密度低至2.8×10^(8)cm^(-3),其载流子迁移率-载流子寿命乘积高达0.021 cm^(2)/V,说明晶体质量优良.晶体表面被含氧官能团的供体作为路易斯碱进一步钝化,并且在低剂量的X射线中表面泄漏电流被抑制了2倍,钙钛矿单晶X射线探测器对120 ke V硬X射线显示的灵敏度高达1274μC/(Gyair s),最低可检测剂量率为0.56μC/(Gyair s).钙钛矿单晶X射线探测器被进一步应用于合金成分分析和金属探伤,不仅为产品质量检测和无损材料分析开辟了广阔的前景,而且为生产高质量单晶和制备多晶薄膜铺平了道路.

Halide perovskite single crystals(HPSCs)provide a unique platform to study the optoelectronic properties of such emerging semiconductor materials,while the temperature induced crystal growth method often has an increased solute integration speed and/or unavoidable solute consumption,resulting in a soaring or slumping crystal growth rate of HPSCs.Here,we developed a universal and facile solvent-vola tilization-limited-growth(SVG)strategy to finely control the crystal growth rate by the fine-control-valve for high quality crystal grown through solution processes.The grown HPSCs by SVG method exhibited a record low trap density of 2.8×10^(8)cm^(-3)and a high charge carrier mobility-lifetime product(μτproduct)of 0.021 cm2/V,indicating the excellent crystal quality.The crystal surface defects were further passivated by oxygen suppliers as Lewis base,which led to a reduction of surface leakage current by two times when using for low dose rate X-ray detection.Such HPSC X-ray detector displayed a high sensitivity of 1274μC/(Gyair cm^(2))with a lowest detectable dose rate of 0.56μGyair/s under 120 keV hard X-ray.Further applications including alloy composition analysis and metal flaw detection by HPSC detectors were also demonstrated,which not only shows the bright future for product quality inspection and non-destructive materials analysis,but also paves the way for growing high quality single crystals and fabricating polycrystalline films.