LAUSR

Abstract In this work, Zn1-xHgxS EDTA-capped nanocrystals (x = 0.00–0.75) were synthesized via a co-precipitation route. The effect of Hg substitution was investigated by details on the structural and optical characteristics of the synthesized particles using X-ray diffraction, transmission electron microscopy, Fourier transform infrared, UV–Vis and photoluminescence spectroscopies. It was revealed that the nanoparticles are single-phased and well-dispersed with diameters of about 2–4 nm. The results show that their cubic zinc blende lattice constant and direct band gap energy increase while the particle size decreases somehow with Hg substitution. The effect of Hg-doping is also observed as the weakening of the blue photoluminescence band around 430 nm ascribed to the defect states in ZnS matrix, and the emerging of a red excitonic emission at 640 nm. It was found that the size effect dominates the influence of the chemical composition in governing the band gap energy, and is a key factor in controlling the efficiency of the photoluminescence emissions in ZnS:Hg nanoparticles.