Temperature-Dependent Exciton Recombination Dynamics of CdTe Nanocrystals

Exciton recombination dynamics of zinc-blende CdTe nanocrystals (NCs) have been investigated by using an ionic liquid as a cryogenic matrix. Size and temperature dependence of photoluminescence lifetimes of CdTe NCs were studied by time-resolved spectroscopy. The photoluminescence properties in a low-temperature range were characterized by a simple three-level model where populations of two emitting states in CdTe NCs are determined by Boltzmann distribution. Observation at low temperature suggests that the relaxation pathway is dependent on the population between two kinds of excited states of the CdTe NC generated by an electron-hole exchange interaction in the tightly confined particle-in-a-box system.