Synthesis, structural and optical characterization of nanocrystalline ZnS:Cu embedded in silica matrix

The synthesis of Cu doped ZnS nanoparticles inside the pore of an inorganic silica gel matrix is presented. The synthesized nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). X-ray diffraction pattern reveals the crystalline wurtzite phase of ZnS. The existence of silica gel in modeling morphologies of the nanoparticles was characterized using Fourier transform infrared (FTIR) spectrometer. Thickness of the silica shell was also calculated. UV- absorption spectrum shows the appearance of an absorption peak at 273 nm which confirms the blue shift as compared to that of bulk ZnS. The photoluminescence (PL) emission spectrum of the sample showed a broad band in the range 465–510 nm due to the transition from the conduction band edge of ZnS nanocrystals to the acceptor like t2 state of Cu.

► ZnS:Cu nanoparticles were prepared in silica gel matrix. ► Thickness of the silica shell was calculated. ► The particle size can be calculated as a function of peak absorbance wavelength. ► Optical studied revealed blue shifting of band gap. ► PL spectrum shows a broad band between 465 nm - 530 nm.