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Uncovering forbidden optical transitions in PbSe nanocrystals
Jeffrey J Peterson1, Libai Huang, Christophe Delerue
1Department of Chemistry, University of Rochester, Rochester, NY, USA.
Abstract:
The 1S(h,e)-1P(e,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.
