Effect of Zn2+ and Mn2+ introduction on the luminescent properties of colloidal ZnS:Mn2+ nanoparticles

We report the observation of photoluminescence (PL) enhancement and quenching for 580 nm emission following the variation of time decay patterns, induced by Zn2+ and Mn2+ introduction, respectively, in colloidal ZnS:Mn2+ nanoparticles (NPs). The activation and quenching processes are analyzed considering surface nonradiative relaxation based on the Langmuir isotherm and Poisson statistics, respectively. The PL enhancement is most likely related to the elimination of dangling bonds from the lone pairs on surface S2- anions. The results indicate that rich Zn2+ and poor Mn2+ in colloidal ZnS:Mn2+ NPs are the key to obtain highly efficient luminescence. (C) 2004 American Institute of Physics.