高响应率石墨烯-CsPbBr3量子点光电探测器

Graphene-CsPbBr3 quantum dots photodetectors with high responsivity

摘要:

全无机金属卤化物钙钛矿材料CsPbX3 (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CsPbBr3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-CsPbBr3量子点复合光电探测器，光响应率高达3.5×104 A W-1. 研究表明引入石墨烯材料作为传输层后，CsPbBr3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.

Abstract:

All-inorganic perovskites, such as CsPbX3 (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, CsPbX3-based photodetector demonstrated a relatively low responsivity due to the low carrier mobility of perovskite films. In this work, we synthesize CsPbBr3 quantum dots and construct a hybrid graphene-CsPbBr3 quantum dots photodetector with a responsivity of 3.5×104 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.