Synthesis and photoluminescence properties of Mn2+ doped ZnS nano-crystals with surface passivation

Manganese(II) doped ZnS nano-particles were synthesized by a precipitation reaction from homogeneous solutions of zinc acetate and manganese acetate. The particles are sterically stabilized using methacrylic acid (MAA) and cetyltrimethylammonium bromide (CTAB). The nano-particles of 10–20 nm in diameter, each containing primary crystallites were obtained. The size of the particles estimated from X-ray diffraction studies was found to be between 2.4 nm and 3 nm. A five- and ten-fold increase in photoluminescence intensity has been observed from Mn2+ doped ZnS nano-particles after surface passivation by CTAB and MAA, respectively. The quantity of passivating agent used during preparation of nano-particles affects the photoluminescence property. The photoluminescence intensity increases with the increase of doping concentration of Mn2+ and a small red shift is observed in maxima.