Synthesis and photoluminescence properties of zinc sulfide nanoparticles doped with copper using effective surfactants

Zinc sulfide (ZnS), various concentrations of Cu2+ (0.25%–1.25%)-doped ZnS and ZnS:Cu2+ nanoparticles capped with various surfactants have been successfully synthesized by a chemical precipitation method in ambient air at 80 ˚C. The synthesized particles were characterized by UV–visible absorption (UV–vis), X-ray diffraction (XRD), transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) and photoluminescence (PL) spectroscopy. The absorption peaks of the synthesized nanoparticles were noticeably blue-shifted from the bulk material. The XRD analysis confirmed the formation of a cubic phase for all samples. The average size of the particles ranged from 3.2 to 5.3 nm. The TEM analysis showed that the particles were highly monodispersed and spherical in shape. Particles with increased Cu2+ concentrations had a red shift in their PL emission spectra. Enhanced PL emissions were observed for surfactant-capped particles. The experimental results indicate that, as expected, the PL spectrum confirms the presence of Cu2+ ions in the ZnS nanoparticles.

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► Very small (<6 nm) ZnS:Cu2+ nanoparticles were synthesized by chemical precipitation method.
► An optimum Cu2+-doping concentration of 0.5% was selected by PL study.
► Highly monodispersed ZnS:Cu2+ nanoparticles capped with surfactants were synthesized.
► The PL intensity was improved by the effective surfactants, especially by TOPO.
► A red shift was observed by incorporated the Cu ions.