Origin of high photoluminescence efficiencies in CdSe quantum belts

Yi Hsin Liu, Virginia L. Wayman, Patrick C. Gibbons, Richard A. Loomis, William E. Buhro

Research output: Contribution to journalArticle

89 Citations (Scopus)

Abstract

CdSe quantum belts (QBs) having lengths of 0.5-1μm and thicknesses of 1.5-2.0 nm exhibit high photoluminescence (PL) efficiencies of ∼30 %. Epifluorescence studies establish the PL spectra to be uniform along single QBs, and nearly the same from QB to QB. Photogenerated excitons are shown to be effectively delocalized over the entire QBs by position-selective excitation. Decoration of the QBs with gold nanoparticles indicates a low density of surface-trap sites, located primarily on the thin belt edges. The high PL efficiencies and effective exciton derealization are attributed to the minimization of defective {1100} edge surface area or edge-top/bottom (face) line junctions in QBs relative to quantum wires having roughly isotropic cross sections, for which very low PL quantum efficiencies have been reported. The results suggest that trap sites can be minimized in pseudo-one-dimensional nanocrystals, such that the facile transport of energy and charge along their long axes becomes possible.

Original languageEnglish
Pages (from-to)352-357
Number of pages6
JournalNano Letters
Volume10
Issue number1
DOIs
Publication statusPublished - 2010 Jan 13

Keywords

  • Decoration
  • Exciton diffusion
  • Quantum wires
  • Surface traps

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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  • Cite this

    Liu, Y. H., Wayman, V. L., Gibbons, P. C., Loomis, R. A., & Buhro, W. E. (2010). Origin of high photoluminescence efficiencies in CdSe quantum belts. Nano Letters, 10(1), 352-357. https://doi.org/10.1021/nl903740p