Detection of bright trion states using the fine structure emission of single CdSe/ZnS colloidal quantum dots.

Fernée, Mark J; Littleton, Bradley N; Rubinsztein-Dunlop, Halina · ACS Nano · 2009

basic_science · Level V

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Abstract

We report direct observation of the lowest two states of the band-edge exciton fine structure in the photoluminescence from single CdSe/ZnS core/shell nanocrystals at cryogenic temperatures. The temperature dependence of this spectral fingerprint reveals exciton spin relaxation rates as low as 10 micros(-1). The fine structure is also dependent on the nanocrystal charge state facilitating the identification of a bright negatively charged trion state with a quantum yield comparable to that of neutral emission.