Size Control and Photoluminescence Enhancement of Mn2+-doped ZnS Nanoparticles Synthesized by AOT- Reverse Micelle Modified by Compressed CO2

Uniform Mn2+-doped ZnS nanoparticles with reduced surface defects and improved optical properties have been synthesized in a system of AOT-reverse micelle modified by compressed CO2 conditioned at relatively low pressures of 20-60 bars, at constant temperature of 40 oC and H2O/AOT ratio of 7. The results showed that ZnS:Mn2+ nanoparticles were crystallized in a zinc blende structure without any impurity. The calculated particles size of all samples ranged from 2 – 3nm and the band gap energy values ranged from 4.6 - 5.1eV. It was found that the synthesized ZnS:Mn2+ nanoparticles have the highest photoluminiscence (PL) intensity ratio of 32.2 at 60bar. The increase in PL intensity ratio indicated an increase in homogeneity in nanoparticle growth with a decrease in surface defects, which resulted in effective surface modification.