Delayed fluorescence of InP:Mn/ZnS nanocrystals

The photoluminescence properties of ZnS-capped Mn-doped InP nanocrystals are shown to be determined by the high ratio of the radiative rate constants of the host and dopant emission, by the polydispersity-induced inhomogeneous broadening, and by the rapid establishment of thermal equilibrium in the distribution of the excitation between the energy levels of the quantum dot and the dopant ion. Because of the combination of these factors, the resulting photoluminescence includes the delayed host fluorescence and the quenched dopant phosphorescence, both having very broad lifetime distributions.