Luminescence properties of chlorine and oxygen co-doped ZnS nanoparticles synthesized by a solid-state reaction

Cl− and O2− co-doped ZnS nanoparticles were synthesized using a low temperature solid-state reaction method. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and ultraviolet-visible spectroscopy were used to characterize their crystal structure, chemical state, diameter, surface states, and photoluminescence (PL) properties. The effects of Cl− and O2− doping concentration on the crystal structure, the crystallite size, and luminescence properties of ZnS nanoparticles were investigated. The results indicated that the ZnS:Cl, O nanoparticles had a cubic blende structure, and an average crystallite size of about 4.28-5.08 nm. It was found that the PL intensity of the Cl− and O2− co-doped ZnS nanoparticles remarkably increased with the increase of Cl− and O2− doping concentration. The emission intensity of the 7 mol% Cl− and 4 mol% O2− co-doped ZnS nanoparticles was about 4 (10) times stronger than the ZnS doped with Cl− (O2−) nanoparticles. Mechanism for the enhanced luminescence of Cl− and O2− co-doped ZnS nanoparticles was discussed. This work suggests that the low temperature solid-state reaction method can be used to synthesize Cl− and O2− co-doped ZnS nanoparticles with strong PL properties.