Energy level modification in lead sulfide quantum dot thin films through ligand exchange

Patrick R. Brown, Donghun Kim, Richard R. Lunt, Ni Zhao, Moungi G. Bawendi, Jeffrey C. Grossman, Vladimir Bulović

    Research output: Research - peer-reviewArticle

    • 216 Citations

    Abstract

    The electronic properties of colloidal quantum dots (QDs) are critically dependent on both QD size and surface chemistry. Modification of quantum confinement provides control of the QD bandgap, while ligand-induced surface dipoles present a hitherto underutilized means of control over the absolute energy levels of QDs within electronic devices. Here, we show that the energy levels of lead sulfide QDs, measured by ultraviolet photoelectron spectroscopy, shift by up to 0.9 eV between different chemical ligand treatments. The directions of these energy shifts match the results of atomistic density functional theory simulations and scale with the ligand dipole moment. Trends in the performance of photovoltaic devices employing ligand-modified QD films are consistent with the measured energy level shifts. These results identify surface-chemistry-mediated energy level shifts as a means of predictably controlling the electronic properties of colloidal QD films and as a versatile adjustable parameter in the performance optimization of QD optoelectronic devices.

    LanguageEnglish (US)
    Pages5863-5872
    Number of pages10
    JournalACS Nano
    Volume8
    Issue number6
    DOIs
    StatePublished - Jun 24 2014

    Profile

    lead sulfides
    energy levels
    quantum dots
    ligands
    thin films
    Electron energy levels
    Semiconductor quantum dots
    Lead
    Ligands
    Thin films
    Sulfides
    lead sulfide
    shift
    electronics
    chemistry
    Surface chemistry
    Electronic properties
    ultraviolet spectroscopy
    optoelectronic devices
    dipole moments

    Keywords

    • density functional theory
    • lead sulfide
    • ligands
    • nanocrystals
    • photovoltaics
    • quantum dots
    • solar cells
    • ultraviolet photoelectron spectroscopy

    ASJC Scopus subject areas

    • Engineering(all)
    • Materials Science(all)
    • Physics and Astronomy(all)

    Cite this

    Brown, P. R., Kim, D., Lunt, R. R., Zhao, N., Bawendi, M. G., Grossman, J. C., & Bulović, V. (2014). Energy level modification in lead sulfide quantum dot thin films through ligand exchange. ACS Nano, 8(6), 5863-5872. DOI: 10.1021/nn500897c

    Energy level modification in lead sulfide quantum dot thin films through ligand exchange. / Brown, Patrick R.; Kim, Donghun; Lunt, Richard R.; Zhao, Ni; Bawendi, Moungi G.; Grossman, Jeffrey C.; Bulović, Vladimir.

    In: ACS Nano, Vol. 8, No. 6, 24.06.2014, p. 5863-5872.

    Research output: Research - peer-reviewArticle

    Brown, PR, Kim, D, Lunt, RR, Zhao, N, Bawendi, MG, Grossman, JC & Bulović, V 2014, 'Energy level modification in lead sulfide quantum dot thin films through ligand exchange' ACS Nano, vol 8, no. 6, pp. 5863-5872. DOI: 10.1021/nn500897c
    Brown PR, Kim D, Lunt RR, Zhao N, Bawendi MG, Grossman JC et al. Energy level modification in lead sulfide quantum dot thin films through ligand exchange. ACS Nano. 2014 Jun 24;8(6):5863-5872. Available from, DOI: 10.1021/nn500897c
    Brown, Patrick R. ; Kim, Donghun ; Lunt, Richard R. ; Zhao, Ni ; Bawendi, Moungi G. ; Grossman, Jeffrey C. ; Bulović, Vladimir. / Energy level modification in lead sulfide quantum dot thin films through ligand exchange. In: ACS Nano. 2014 ; Vol. 8, No. 6. pp. 5863-5872
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