Effect of precursor molar ratio of [S-2-]/[Zn2+] on particle size and photoluminescence of ZnS : Mn2+ nanocrystals

摘要

We investigate the influence of precursor molar ratio of [S2-]/[Zn2+] on particle size and photoluminescence (PL) of ZnS:Mn2+ nanocrystals. By changing the [S2-]/[Zn2+] ratio from 0.6 (Zn-rich) to 2.0 (S-rich), the particle size increases from nearly 2.7 nm to about 4.0 nm. The increase in the ratio of [S2-]/[Zn2+] causes a decrease of PL emission intensity of ZnS host while a distinct increase of Mn2+ emission. The maximum intensity for the luminescence of Mn2+ emission is observed at the ratio of [S2-]/[Zn2+] approximate to 1.5. The possible mechanism for the results is discussed by filling of S2- vacancies and the increase of Mn2+ ions incorporated into ZnS lattices.