Colloidal ZnSe nanocrystals are coated with a ZnS shell and are investigated by means of time-resolved photoluminescence spectroscopy. These nanocrystals are stable against photooxidation and have photoluminescence quantum efficiencies around 15% even months after the synthesis. Recombination processes are investigated as a function of the excitation intensity and the emission energy. Nonlinear processes such as Auger recombination dominate in the early times after the photogeneration of electron-hole pairs. The lifetime of single exciton states is shorter in smaller ZnSe dots than in larger ones, in accordance with theoretical predictions and as previously observed on similar systems.
Exciton relaxation processes in colloidal core/shell ZnSe/ZnS nanocrystals
Lomascolo M;Leo G;
2003
Abstract
Colloidal ZnSe nanocrystals are coated with a ZnS shell and are investigated by means of time-resolved photoluminescence spectroscopy. These nanocrystals are stable against photooxidation and have photoluminescence quantum efficiencies around 15% even months after the synthesis. Recombination processes are investigated as a function of the excitation intensity and the emission energy. Nonlinear processes such as Auger recombination dominate in the early times after the photogeneration of electron-hole pairs. The lifetime of single exciton states is shorter in smaller ZnSe dots than in larger ones, in accordance with theoretical predictions and as previously observed on similar systems.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
