title: An optical dynamic study of MAPbBr3single crystals passivated with MAPbCl3/I3-MAPbBr3heterojunctions.
abstract: Recently, perovskite based solar cells have attracted lots of research interest, some of which is in the passivation of perovskite surfaces, particularly the heterojunction based surface passivation. In this study, the optical dynamics of MAPbBr3single crystals with and without heterojunction passivation were studied systematically by means of a time-resolved spectroscopic technique for the first time. The emission lifetime of MAPbBr3single crystals under two-photon (1064 nm) excitation is a few orders of magnitude longer than that measured under one-photon (355 nm or 532 nm) excitation. Interestingly, with surface passivation, the lifetime measured at 355 nm excitations could be tuned significantly, whereas the lifetime change under 1064 nm excitations was considerably less. Our results give a direct evidence of surface quench by comparing the lifetimes before and after surface passivation. Furthermore, the results demonstrate that proper MAPbCl3-MAPbBr3heterojunctions can dramatically reduce the recombination channels in the surface region, which can be potentially useful for perovskite based solar cells, light emitting diodes (LED), and sensitive detectors.
authors.affiliation: State Key Laboratory of ASIC and System, SIST, Fudan University, Shanghai 200433, China. yqzhan@fudan.edu.cn lrzheng@fudan.edu.cn.
authors.forename: Haizhou
authors.identifier: http://orcid.org/0000-0001-9692-7860
authors.initials: H
authors.lastname: Lu
authors.affiliation: State Key Laboratory of ASIC and System, SIST, Fudan University, Shanghai 200433, China. yqzhan@fudan.edu.cn lrzheng@fudan.edu.cn.
authors.forename: Huotian
authors.initials: H
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of ASIC and System, SIST, Fudan University, Shanghai 200433, China. yqzhan@fudan.edu.cn lrzheng@fudan.edu.cn.
authors.forename: Sijian
authors.initials: S
authors.lastname: Yuan
authors.affiliation: State Key Laboratory of ASIC and System, SIST, Fudan University, Shanghai 200433, China. yqzhan@fudan.edu.cn lrzheng@fudan.edu.cn.
authors.forename: Jiao
authors.initials: J
authors.lastname: Wang
authors.affiliation: State Key Laboratory of ASIC and System, SIST, Fudan University, Shanghai 200433, China. yqzhan@fudan.edu.cn lrzheng@fudan.edu.cn.
authors.forename: Yiqiang
authors.initials: Y
authors.lastname: Zhan
authors.affiliation: State Key Laboratory of ASIC and System, SIST, Fudan University, Shanghai 200433, China. yqzhan@fudan.edu.cn lrzheng@fudan.edu.cn and Royal Inst Technol KTH, iPack VINN Excellence Ctr, S-16440 Stockholm, Sweden.
authors.forename: Lirong
authors.initials: L
authors.lastname: Zheng