Effect of Precursor Concentration on Optical, Grain Sizes and Structural Properties of Green Synthesized Zinc Oxide Nanoparticles

Abstract

Researchers are increasingly interested in zinc oxide (ZnO) nanoparticles for optoelectronic applications because of their wide band gap (~3.37 eV), large exciton binding energy (~60 meV) at room temperature, non-toxicity, environmental friendliness, and transparency over the visible light spectrum. In this study, ZnO nanoparticles were synthesized using a green method: zinc acetate served as the precursor, and Jatropha leaf extract as both reducing and capping agent; the reaction was carried out in Chemistry Advanced Research Laboratory SHESTCO using distilled water while the pH of the reaction was adjusted to 11.6 via dropwise addition of 1 M sodium hydroxide. The resulting nanoparticles were characterized using UV-Vis spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectrometry (EDX). UV-Vis spectra showed absorption peaks between 372 and 400 nm, corresponding to band gaps of about 3.11 to 3.34 eV. XRD data estimated the average nanoparticle size of three nanoparticles to be in the range of ~16.62 to ~21.11 nm. EDX revealed that the nanoparticles contained approximately 78.32% zinc and 12.78% oxygen by composition signals, while SEM images showed that the particles are agglomerated in morphology.