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: Contribution to journalArticle

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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
Electron energy levels
Semiconductor quantum dots
Lead
energy levels
Ligands
quantum dots
Thin films
ligands
thin films
shift
Surface chemistry
Electronic properties
electronics
Ultraviolet photoelectron spectroscopy
chemistry
Quantum confinement
Sulfides
lead sulfide
Dipole moment

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: Contribution to journalArticle

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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