Al Salman, A.Tortschanoff, A.van der Zwan, G.van Mourik, F.Chergui, M.2006-02-272006-02-272006-02-27200910.1016/j.chemphys.2008.10.042https://infoscience.epfl.ch/handle/20.500.14299/225847WOS:000263851800013We report on photoluminescence decay measurements of CdSe nanoparticles over several decades of intensities and times, and as a function of size and temp. A model is proposed for the multi-exponential decay kinetics, and their temp. dependence, in which a major role is played by the now well established presence of a large ground-state dipole moment in CdSe nano crystals. By two-photon excitation within the bandgap region we show that there is a link between the ground-state dipole moment and the excited-state decay. The stochastic nature of the magnitude of the dipole moment results in a complex temp. dependence. Contrary to studies that ascribe non-radiative decay processes to surface states/traps, the mechanism we propose considers the intrinsic states described within the effective mass approxn. models for the spectroscopy of the bandgap. Surface effects are mediated by the ground-state dipole moments that they constitute, which in turn perturb the intrinsic states.Cadmium selenideNanoparticlesElectron-hole recombinationNanosecond kineticsDipole momentsPermanent Dipole-MomentQuantum DotsRadiative DecayDark-ExcitonMonodisperseLuminescenceDependenceOrigintext::journal::journal article::research article