Nano Lett., 7 (12), 3827 -3831, 2007. 10.1021/nl072487g S1530-6984(07)02487-3
Web Release Date: November 7, 2007

Copyright © 2007 American Chemical Society

Uncovering Forbidden Optical Transitions in PbSe Nanocrystals

Jeffrey J. Peterson, Libai Huang, Christophe Delerue, Guy Allan, and Todd D. Krauss*

Department of Chemistry, University of Rochester, Rochester, NY, and Institut d'Electronique, de Microélectronique et de Nanotechnologie (UMR CNRS 8520), Département ISEN, Lille Cedex, France

Received September 28, 2007

Revised October 26, 2007

Abstract:

The 1Sh,e-1Pe,h exciton transition energy of PbSe nanocrystals was determined via two-photon photoluminescence excitation spectroscopy and was found to be in good agreement with predictions from a tight-binding calculation. The two-photon excitation peak occurs at energies very close to a strong feature in the one-photon absorption spectrum and suggests that it should be assigned as a formally forbidden S-P transition. Leading explanations for the unusual strength of the forbidden transition are discussed.

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