Extremely long-lived charge separation and related carrier spin excitation in CsPbBr3 perovskite quantum dots with an electron acceptor benzoquinone
Lin Cheng, Rongrong Hu, Meizhen Jiang, Yumeng Men, Yang Wang, Jinlei Li, Tianqing Jia, Zhenrong Sun, Donghai Feng
Abstract
The formation and evolution dynamics of charge separation (CS) in a complex of CsPbBr3 quantum dots (QDs) and 1,4-benzoquinone (BQ) molecules are measured with a high-sensitive pump-orientation-probe technique by which spin signals of the CS state are monitored. An extraordinarily long-lasting CS is observed, with a characteristic time being up to a dozen days under ambient conditions, due to electron transferring from QDs to BQ molecules. Upon the long-lived CS, spin coherences of both electrons and holes are detected at room temperature, with a spin dephasing time of 420 and 26 ps, respectively. The long-lived CS and spin coherence have important implications for applications of perovskite nanomaterials in photocatalysis, photovoltaics, and spintronics.