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Portrait of Tönu Pullerits; Photo: Kennet Ruona

Tönu Pullerits

Professor

Portrait of Tönu Pullerits; Photo: Kennet Ruona

Hot electron and hole dynamics in thiol-capped CdSe quantum dots revealed by 2D electronic spectroscopy

Author

  • Nils Lenngren
  • Mohamed A. Abdellah
  • Kaibo Zheng
  • Mohammed J. Al-Marri
  • Donatas Zigmantas
  • Karel Zidek
  • Tõnu Pullerits

Summary, in English

Colloidal quantum dots (QDs) have attracted interest as materials for opto-electronic applications, wherein their efficient energy use requires the understanding of carrier relaxation. In QDs capped by bifunctional thiols, used to attach the QDs to a surface, the relaxation is complicated by carrier traps. Using 2D spectroscopy at 77 K, we follow excitations in thiol-capped CdSe QDs with state specificity and high time resolution. We unambiguously identify the lowest state as an optically allowed hole trap, and identify an electron trap with excited-state absorption. The presence of traps changes the initial dynamics entirely by offering a different relaxation channel. 2D electronic spectroscopy enables us to pinpoint correlations between states and to easily separate relaxation from different starting states. We observe the direct rapid trapping of 1S3/2, 2S3/2, and 1S1/2 holes, and several competing electron relaxation processes from the 1Pe state.

Department/s

  • Chemical Physics
  • NanoLund: Center for Nanoscience

Publishing year

2016

Language

English

Pages

26199-26204

Publication/Series

Physical Chemistry Chemical Physics

Volume

18

Issue

37

Document type

Journal article

Publisher

Royal Society of Chemistry

Topic

  • Physical Chemistry
  • Condensed Matter Physics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1463-9076