Size dependence of negative trion Auger recombination in photodoped CdSe nanocrystals.

Cohn, Alicia W; Rinehart, Jeffrey D; Schimpf, Alina M; Weaver, Amanda L; Gamelin, Daniel R · Nano Lett · 2014

basic_science · Level V

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Abstract

We report a systematic investigation of the size dependence of negative trion (T(-)) Auger recombination rates in free-standing colloidal CdSe nanocrystals. Colloidal n-type CdSe nanocrystals of various radii have been prepared photochemically, and their trion decay dynamics have been measured using time-resolved photoluminescence spectroscopy. Trion Auger time constants spanning 3 orders of magnitude are observed, ranging from 57 ps (radius R = 1.4 nm) to 2.2 ns (R = 3.2 nm). The data reveal a substantially stronger size dependence than found for bi- or multiexciton Auger recombination in CdSe or other semiconductor nanocrystals, scaling in proportion to R(4.3).