Energetics of cdse quantum dots adsorbed on TiO2

Tal Z. Markus, Stella Itzhakov, Yafit Itzhaik Alkotzer, David Cahen, Gary Hodes, Dan Oron, Ron Naaman

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

Understanding how quantum dot (QD)-sensitized solar cells operate requires accurate determination of the offset between the lowest-unoccupied molecular orbital (LUMO) of the sensitizer quantum dot and the conduction band of the metal oxide electrode. We present detailed optical spectroscopy, low-energy photoelectron spectroscopy, and two-photon photoemission studies of the energetics of size-selected CdSe colloidal QDs deposited on TiO2 electrodes. Our experimental findings show that in contrast to the prediction of simplified models based on bulk band offsets and effective mass considerations, band alignment in this system is strongly modified by the interaction between the QDs and the electrode. In particular, we find relatively small conduction band- LUMO offsets, and near "pinning" of the QD LUMO relative to the conduction band of the TiO2 electrode, which is explained by the strongQD-electrode interaction. That interaction is the origin for the highly efficientQDto electrode charge transfer, and it also bears on the possibility of hot carrier injection in these types of cells.

Original languageEnglish
Pages (from-to)13236-13241
Number of pages6
JournalJournal of Physical Chemistry C
Volume115
Issue number27
DOIs
Publication statusPublished - Jul 14 2011

Fingerprint

Semiconductor quantum dots
quantum dots
Electrodes
electrodes
Molecular orbitals
Conduction bands
molecular orbitals
conduction bands
Hot carriers
carrier injection
Photoemission
interactions
Photoelectron spectroscopy
bears
Oxides
metal oxides
Charge transfer
Solar cells
photoelectric emission
Photons

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Energy(all)

Cite this

Markus, T. Z., Itzhakov, S., Alkotzer, Y. I., Cahen, D., Hodes, G., Oron, D., & Naaman, R. (2011). Energetics of cdse quantum dots adsorbed on TiO2 . Journal of Physical Chemistry C, 115(27), 13236-13241. https://doi.org/10.1021/jp2035955

Energetics of cdse quantum dots adsorbed on TiO2 . / Markus, Tal Z.; Itzhakov, Stella; Alkotzer, Yafit Itzhaik; Cahen, David; Hodes, Gary; Oron, Dan; Naaman, Ron.

In: Journal of Physical Chemistry C, Vol. 115, No. 27, 14.07.2011, p. 13236-13241.

Research output: Contribution to journalArticle

Markus, TZ, Itzhakov, S, Alkotzer, YI, Cahen, D, Hodes, G, Oron, D & Naaman, R 2011, 'Energetics of cdse quantum dots adsorbed on TiO2 ', Journal of Physical Chemistry C, vol. 115, no. 27, pp. 13236-13241. https://doi.org/10.1021/jp2035955
Markus TZ, Itzhakov S, Alkotzer YI, Cahen D, Hodes G, Oron D et al. Energetics of cdse quantum dots adsorbed on TiO2 . Journal of Physical Chemistry C. 2011 Jul 14;115(27):13236-13241. https://doi.org/10.1021/jp2035955
Markus, Tal Z. ; Itzhakov, Stella ; Alkotzer, Yafit Itzhaik ; Cahen, David ; Hodes, Gary ; Oron, Dan ; Naaman, Ron. / Energetics of cdse quantum dots adsorbed on TiO2 . In: Journal of Physical Chemistry C. 2011 ; Vol. 115, No. 27. pp. 13236-13241.
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