Tuning the properties of ZnxS1-x nanoparticles by controlling reaction conditions

Abstract

In this work, a modified synthesis method was deployed to obtain nanocrystalline zinc sulfide from zinc acetate. By utilizing the hydrothermal and sol gel method, the influence of: reaction time, solvent and temperature control were used to tune the properties of zinc sulfide. Our results showed that ZnS(B) (which was obtained by sol gel in water + hydrothermal) typified formation of increased sulfur vacancies while an increase in reaction time resulted in decreased sulfur vacancies. The introduction of chemical defects in ZnS(A) (which was obtained by sol gel in methanol + KOH) resulted in lower crystallite size. We observed that crystallinity improved with increased reaction time and utilization of water as solvent improved the crystallinity of the material as confirmed in ZnS(C) and ZnS(B). Furthermore, our result showed that reaction time influenced dislocation density of the material to a greater extent than type of solvent used. The crystallite size estimated by Scherer formula was in the range 1.35 nm – 18.64 nm while the band gap energy of the ZnS samples were calculated in the range 3.8 eV- 4.6 eV. Utilizing these novel syntheses methods can stimulate new directions in synthesizing ZnS crystals with options of choosing appropriate method for specific applications depending on properties to be traded off.