Fast monolayer adsorption and slow energy transfer in CdSe quantum dot sensitized ZnO nanowires

Kaibo Zheng, Karel Žídek, Mohamed Abdellah, Magne Torbjörnsson, Pavel Chábera, Shuyan Shao, Fengling Zhang, Tõnu Pullerits

Research output: Contribution to journalArticlepeer-review

31 Citations (Scopus)

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.

Original languageEnglish
Pages (from-to)5919-5925
Number of pages7
JournalJournal of Physical Chemistry A
Volume117
Issue number29
DOIs
Publication statusPublished - Jul 25 2013
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry

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