Highly luminescent surface-passivated ZnS:Mn nanoparticles by a simple one-step synthesis

Highly luminescent surface-passivated ZnS:Mn nanoparticles were synthesized straightforwardly by a simple liquid-solid-solution method. Compared to the pristine Mn-doped zinc sulfide nanocrystals (quantum efficiency: similar to 19%), the Li-added ZnS:Mn exhibited significantly enhanced luminescence properties (quantum efficiency: similar to 43%). The surface passivation was investigated by x-ray photoelectron spectroscopy, transmission electron microscopy, and by the change in the radiative/nonradiative recombination rates. The photoluminescence enhancement is due to the formation of an effective passivation layer induced by lithium, and consequent suppression of the nonradiative recombination transitions. (C) 2008 American Institute of Physics. [DOI: 10.1063/1.3007980].