Effect of Li+ concentration on the structural and optical properties of chemically synthesized ZnS nanoparticles
Abduelwhab B. Alwany, Ali Alnakhlani, G. M. Youssef, Mohammed A. Algradee, Belqees Hassan
Abstract
ZnS nanoparticles (NPs) with different concentrations of Li-doping (0, 2.5, 4.5, 6.5, and 10.5 %) were synthesized by the co-precipitation method. Crystalline structure, surface morphologies, and optical properties were studied in detail. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) confirmed the cubic phase of un-doped and Li doped-ZnS NPs. Scanning electron microscopy (SEM) and HRTEM images showed that un-doped and Li-doped ZnS NPs contain agglomerated particles, and agglomeration is increased by increasing Li-doping. Different vibration modes are observed in a Fourier transform infrared spectrophotometer (FTIR) analysis. Defects are observed in the photoluminescence spectra (PL) of un-doped and Li-doped ZnS NPs, and a dominant green-orange transition is observed. Absorption studies using UV–vis spectroscopy reveal a quantum confinement effect for un-doped and Li- doped ZnS NPs. The direct band gap energy (Egp) increased with increasing Li concentration in the range of 3.728–3.875 eV.