Time-resolved terahertz spectroscopy reveals the influence of charged sensitizing quantum dots on the electron dynamics in ZnO

Sesha Bamini N., Hynek Němec, Karel Žídek, Mohamed Abdellah, Mohammed J. Al-Marri, Pavel Chábera, Carlito Ponseca, Kaibo Zheng, Tönu Pullerits

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Photoinitiated charge carrier dynamics in ZnO nanoparticles sensitized by CdSe quantum dots is studied using transient absorption spectroscopy and time-resolved terahertz spectroscopy. The evolution of the transient spectra shows that electron injection occurs in a two-step process, where the formation of a charge transfer state (occurring in several picoseconds) is followed by its dissociation within tens of picoseconds. The photoconductivity of electrons injected into the ZnO nanoparticles is lower than that of charges photogenerated directly in ZnO. We conclude that the motion of injected electrons in ZnO nanoparticles is strongly influenced by their interaction with positive charges left in the sensitizing quantum dots.

Original languageEnglish
Pages (from-to)6006-6012
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume19
Issue number8
DOIs
Publication statusPublished - 2017
Externally publishedYes

ASJC Scopus subject areas

  • General Physics and Astronomy
  • Physical and Theoretical Chemistry

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