高响应率石墨烯-CsPbBr_(3)量子点光电探测器

Graphene-CsPbBr_(3) quantum dots photodetectors with high responsivity

全无机金属卤化物钙钛矿材料CsPbX_(3)(X=Cl,Br,I)不仅有优异光电特性,还有比有机-无机杂化钙钛矿更好的热稳定性,在光电探测器领域有很大应用前景.但由于全无机钙钛矿材料自身迁移率较低,直接用于光电探测器其光响应率也很低,难以满足实际应用.以热注入法合成高质量的CsPbBr_(3)钙钛矿量子点材料,再将其与高迁移率的单层石墨烯薄膜相结合,构建出石墨烯-CsPbBr_(3)量子点复合光电探测器,光响应率高达3.5×10^(4) A·W^(-1).研究表明引入石墨烯材料作为传输层后,CsPbBr_(3)量子点的光生电子空穴对得到有效分离并快速传输.两种材料界面处存在陷阱态,产生了光栅压效应,延长了载流子寿命.两种机制结合使复合光电探测器的光响应率大大提升.

All-inorganic perovskites,such as CsPbX_(3)(X=Cl,Br,I),are gaining increasing attention due to their outstanding optoelectronic properties,especially their higher thermal stability comparing with organic-inorganic hybrid perovskites.However,CsPbX_(3)-based photodetector demonstrated a relatively low responsivity due to the low carrier mobility of perovskite films.In this work,we synthesize CsPbBr_(3) quantum dots and construct a hybrid graphene-CsPbBr_(3) quantum dots photodetector with a responsivity of 3.5×10^(4) A·W^(-1),by introducing graphene as a transport layer.The unprecedented performance is attributed to the effective charge transfer and photogating effect,high mobility of graphene and prolonged carrier lifetime.