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*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

90 Scopus citations


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 (US)
Pages (from-to)5455-5460
Number of pages6
JournalNano letters
Issue number12
StatePublished - Dec 14 2011


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

ASJC Scopus subject areas

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


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