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

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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.

Details

Authors
Organisations
External organisations
  • South Valley University
  • Qatar University
  • University of Madras
  • Lund University
  • Institute of Physics of the Academy of Sciences of the Czech Republic
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry
Original languageEnglish
Pages (from-to)6006-6012
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume19
Issue number8
Publication statusPublished - 2017
Publication categoryResearch
Peer-reviewedYes