title: Fast monolayer adsorption and slow energy transfer in CdSe quantum dot sensitized ZnO nanowires.
abstract: A method for CdSe quantum dot (QD) sensitization of ZnO nanowires (NW) with fast adsorption rate is applied. Photoinduced excited state dynamics of the quantum dots in the case of more than monolayer coverage of the nanowires is studied. Transient absorption kinetics reveals an excitation depopulation process of indirectly attached quantum dots with a lifetime of ~4 ns. Photoluminescence and incident photon-to-electron conversion efficiency show that this process consists of both radiative e-h recombination and nonradiative excitation-to-charge conversion. We argue that the latter occurs via interdot energy transfer from the indirectly attached QDs to the dots with direct contact to the nanowires. From the latter, fast electron injection into ZnO occurs. The energy transfer time constant is found to be around 5 ns.
authors.affiliation: Department of Chemical Physics, Lund University, Box 124, 22100, Lund, Sweden.
authors.forename: Kaibo
authors.initials: K
authors.lastname: Zheng
authors.forename: Karel
authors.initials: K
authors.lastname: Žídek
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abdellah
authors.forename: Magne
authors.initials: M
authors.lastname: Torbjörnsson
authors.forename: Pavel
authors.initials: P
authors.lastname: Chábera
authors.forename: Shuyan
authors.initials: S
authors.lastname: Shao
authors.forename: Fengling
authors.initials: F
authors.lastname: Zhang
authors.forename: Tõnu
authors.initials: T
authors.lastname: Pullerits