Hot-electron transfer from semiconductor nanocrystals

William A. Tisdale, Kenrick J. Williams, Brooke A. Timp, David J. Norris, Eray S. Aydil, X. Y. Zhu

Research output: Contribution to journalArticlepeer-review

Abstract

In typical semiconductor solar cells, photons with energies above the semiconductor bandgap generate hot charge carriers that quickly cool before all of their energy can be captured, a process that limits device efficiency. Although fabricating the semiconductor in a nanocrystalline morphology can slow this cooling, the transfer of hot carriers to electron and hole acceptors has not yet been thoroughly demonstrated. We used time-resolved optical second harmonic generation to observe hot-electron transfer from colloidal lead selenide (PbSe) nanocrystals to a titanium dioxide (TiO2) electron acceptor. With appropriate chemical treatment of the nanocrystal surface, this transfer occurred much faster than expected. Moreover, the electric field resulting from sub-50-femtosecond charge separation across the PbSe-TiO2 interface excited coherent vibrations of the TiO2 surface atoms, whose motions could be followed in real time. Copyright Science 2010 by the American Association for the Advancement of Science; all rights reserved.

Original languageEnglish (US)
Pages (from-to)1543-1547
Number of pages5
JournalScience
Volume328
Issue number5985
DOIs
StatePublished - Jun 18 2010

ASJC Scopus subject areas

  • General

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