Single molecule quantum-confined Stark effect measurements of semiconductor nanoparticles at room temperature

Kyoung Won Park, Zvicka Deutsch, J. Jack Li, Dan Oron, Shimon Weiss

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

Abstract

We investigate the quantum confined Stark effect (QCSE) of various nanoparticles (NPs) on the single molecule level at room temperature. We tested 8 different NPs with different geometry, material composition and electronic structure, and measured their QCSE by single molecule spectroscopy. This study reveals that suppressing the Coulomb interaction force between electron and hole by asymmetric type-II interface is critical for an enhanced QCSE. For example, ZnSe-CdS and CdSe(Te)-CdS-CdZnSe asymmetric nanorods (type-II) display respectively twice and more than three times larger QCSE than that of simple type-I nanorods (CdSe). In addition, wavelength blue-shift of QCSE and roughly linear Δλ-F (emission wavelength shift vs. the applied electric field) relation are observed for the type-II nanorods. Experimental results (Δλ-F or ΔE-F) are successfully reproduced by self-consistent quantum mechanical calculation. Intensity reduction in blue-shifted spectrum is also accounted for. Both calculations and experiments suggest that the magnitude of the QCSE is predominantly determined by the degree of initial charge separation in these structures.

Original languageEnglish
Title of host publicationColloidal Nanocrystals for Biomedical Applications VIII
DOIs
StatePublished - 2013
Externally publishedYes
EventColloidal Nanocrystals for Biomedical Applications VIII - San Francisco, CA, United States
Duration: 2 Feb 20134 Feb 2013

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume8595
ISSN (Print)1605-7422

Conference

ConferenceColloidal Nanocrystals for Biomedical Applications VIII
Country/TerritoryUnited States
CitySan Francisco, CA
Period2/02/134/02/13

Keywords

  • Blue-shift
  • Electric Field
  • Nano-rod
  • Quantum Confined Stark Effect
  • Quantum dot
  • Type-I
  • Type-II
  • Voltage sensing

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