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Updated: Mar 7, 2026
All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
Time-resolved terahertz spectroscopy reveals the influence of charged sensitizing quantum dots on the electron
Sesha Bamini N1, Hynek Němec2, Karel Žídek3
1Department of Chemical Physics and NanoLund, Lund University, Box 124, 22100 Lund, Sweden. kaibo.zheng@chemphys.lu.se tonu.pullerits@chemphys.lu.se and National Center for Ultrafast Processes, University of Madras, Chennai 600113, India.
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.
