Nanosecond exciton recombination dynamics in colloidal CdSe quantum dots under ambient conditions

In solution, CdSe quantum dot exciton recombination is composed of an intrinsic band edge exciton decay and a photoinduced charged exciton, which produces the observation of biexponential decay dynamics. The nearly identical radiative lifetimes of both intrinsic and extrinsic decays scale with the cube of the size, and the nonradiative rate for the intrinsic decay follows the energy gap law, while the charged exciton exhibits strong lattice perturbations arising from Frölich coupling to optical phonons. The charged exciton, which arises from recombination in a particle that has a photo-induced trapped carrier has a temporally resolved Stark shift of ∼20 meV.