title: Auger-assisted electron transfer from photoexcited semiconductor quantum dots.
abstract: Although quantum confined nanomaterials, such as quantum dots (QDs) have emerged as a new class of light harvesting and charge separation materials for solar energy conversion, theoretical models for describing photoinduced charge transfer from these materials remain unclear. In this paper, we show that the rate of photoinduced electron transfer from QDs (CdS, CdSe, and CdTe) to molecular acceptors (anthraquinone, methylviologen, and methylene blue) increases at decreasing QD size (and increasing driving force), showing a lack of Marcus inverted regime behavior over an apparent driving force range of ∼0-1.3 V. We account for this unusual driving force dependence by proposing an Auger-assisted electron transfer model in which the transfer of the electron can be coupled to the excitation of the hole, circumventing the unfavorable Franck-Condon overlap in the Marcus inverted regime. This model is supported by computational studies of electron transfer and trapping processes in model QD-acceptor complexes.
authors.affiliation: Department of Chemistry, Emory University , Atlanta, Georgia 30322, United States.
authors.forename: Haiming
authors.initials: H
authors.lastname: Zhu
authors.forename: Ye
authors.initials: Y
authors.lastname: Yang
authors.forename: Kim
authors.initials: K
authors.lastname: Hyeon-Deuk
authors.forename: Marco
authors.initials: M
authors.lastname: Califano
authors.forename: Nianhui
authors.initials: N
authors.lastname: Song
authors.forename: Youwei
authors.initials: Y
authors.lastname: Wang
authors.forename: Wenqing
authors.initials: W
authors.lastname: Zhang
authors.forename: Oleg V
authors.initials: OV
authors.lastname: Prezhdo
authors.forename: Tianquan
authors.initials: T
authors.lastname: Lian