A molecule to detect and perturb the confinement of charge carriers in quantum dots

Matthew T. Frederick, Victor A. Amin, Laura C. Cass, Emily A Weiss

Research output: Contribution to journalArticle

74 Citations (Scopus)

Abstract

This paper describes unprecedented bathochromic shifts (up to 970 meV) of the optical band gaps of CdS, CdSe, and PbS quantum dots (QDs) upon adsorption of an organic ligand, phenyldithiocarbamate (PTC), and the use of PTC to map the quantum confinement of specific charge carriers within the QDs as a function of their radius. For a given QD material and physical radius, R, the magnitude of the increase in apparent excitonic radius (ΔR) upon delocalization by PTC directly reflects the degree of quantum confinement of one or both charge carriers. The plots of ΔR vs R for CdSe and CdS show that exciton delocalization by PTC occurs specifically through the excitonic hole. Furthermore, the plot for CdSe, which spans a range of R over multiple confinement regimes for the hole, identifies the radius (R ∼ 1.9 nm) at which the hole transitions between regimes of strong and intermediate confinement. This demonstration of ligand-induced delocalization of a specific charge carrier is a first step toward eliminating current-limiting resistive interfaces at organic-inorganic junctions within solid-state hybrid devices. Facilitating carrier-specific electronic coupling across heterogeneous interfaces is especially important for nanostructured devices, which comprise a high density of such interfaces.

Original languageEnglish
Pages (from-to)5455-5460
Number of pages6
JournalNano Letters
Volume11
Issue number12
DOIs
Publication statusPublished - Dec 14 2011

Fingerprint

Plasma confinement
Charge carriers
Semiconductor quantum dots
charge carriers
Quantum confinement
quantum dots
Molecules
radii
Ligands
molecules
plots
Optical band gaps
Excitons
ligands
Demonstrations
Adsorption
excitons
solid state
adsorption
shift

Keywords

  • charge carrier
  • delocalization
  • dithiocarbamate
  • organic adlayer
  • quantum confinement
  • Quantum dot

ASJC Scopus subject areas

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

Cite this

A molecule to detect and perturb the confinement of charge carriers in quantum dots. / Frederick, Matthew T.; Amin, Victor A.; Cass, Laura C.; Weiss, Emily A.

In: Nano Letters, Vol. 11, No. 12, 14.12.2011, p. 5455-5460.

Research output: Contribution to journalArticle

Frederick, Matthew T. ; Amin, Victor A. ; Cass, Laura C. ; Weiss, Emily A. / A molecule to detect and perturb the confinement of charge carriers in quantum dots. In: Nano Letters. 2011 ; Vol. 11, No. 12. pp. 5455-5460.
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