title: Exploring the effect of band alignment and surface states on photoinduced electron transfer from CuInS2/CdS core/shell quantum dots to TiO2 electrodes.
abstract: Photoinduced electron transfer (ET) processes from CuInS2/CdS core/shell quantum dots (QDs) with different core sizes and shell thicknesses to TiO2 electrodes were investigated by time-resolved photoluminescence (PL) spectroscopy. The ET rates and efficiencies from CuInS2/CdS QDs to TiO2 were superior to those of CuInS2/ZnS QDs. An enhanced ET efficiency was surprisingly observed for 2.0 nm CuInS2 core QDs after growth of the CdS shell. On the basis of the experimental and theoretical analysis, the improved performances of CuInS2/CdS QDs were attributed to the passivation of nonradiative traps by overcoating shell and enhanced delocalization of electron wave function from core to CdS shell due to lower conduction band offset. These results indicated that the electron distribution regulated by the band alignment between core and shell of QDs and the passivation of surface defect states could improve ET performance between donor and acceptor.
authors.affiliation: State Key Laboratory of Luminescence and Applications, Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences , Changchun 130033, China.
authors.forename: Mingye
authors.initials: M
authors.lastname: Sun
authors.forename: Dehua
authors.initials: D
authors.lastname: Zhu
authors.forename: Wenyu
authors.initials: W
authors.lastname: Ji
authors.forename: Pengtao
authors.initials: P
authors.lastname: Jing
authors.forename: Xiuying
authors.initials: X
authors.lastname: Wang
authors.forename: Weidong
authors.initials: W
authors.lastname: Xiang
authors.forename: Jialong
authors.initials: J
authors.lastname: Zhao