Fast quenching of manganese emission in ZnS:Mn2+ nanoparticles

Abstract

The Monte Carlo method was used to calculate static dipole-dipole (Förster) quenching of manganese luminescence in nanoparticles of various sizes in the semi-magnetic semiconductor Zn0.99Mn0.01S. For the first time, the quenching is stated to play insignificant role in sub-nanosecond huge drop of the emission transient. Parameter values of Förster's quenching stage of luminescence transient – characteristic quenching distance, concentration of quenchers, average quenching rate, probability of quencher absence in a nanoparticle, quenching amplitude, etc. − were found from a comparison of calculations with experimental transients. The values are dependent on nanoparticle growth technology. Calculations show that luminescence efficiency increases with a decrease in actual size of nanoparticles, while probability of obtaining nanoparticles without quenchers asymptotically approaches unity at smaller size. The latter condition together with agglomeration absence and greater intrinsic time decay are the main conditions for higher efficiency of manganese luminescence in ZnS:Mn2+ nanoparticles. The analysis of previous researches and our experiments showed that the most fast transient component originated from ZnS host.