Structural and optical properties of ZnO nanoparticles synthesized at different pH values

In this paper, the structural and optical properties of zinc oxide nanoparticles synthesized by hydrothermal method at different selected pH values ranging from 7 to 11 are presented. The synthesized nanoparticles are characterized for structural properties by X-ray diffractrometer and transmission electron microscope and the optical properties are carried out through UV–Visible spectrophotometers, photoluminescence and Raman spectroscopy. The X-ray diffractrometer pattern indicates the pure phase formation of ZnO and transmission electron microscope images show that the particle size varies from 63 to 23 nm for samples synthesized at different pH values ranging from 7 to 11, respectively. Raman and Photoluminescence spectrum also confirm the phase formation of ZnO. Moreover, the optical band gaps calculated through UV spectroscopy are found to be increases from 5.57 (±0.02) to 5.79 (±0.02) eV for samples synthesized at different pH values ranging from 7 to 11, respectively.

► The ZnO nanoparticles were synthesized by hydrothermal method at different pH values. ► The effects of pH values on structural and optical properties of ZnO were investigated. ► The reduction in particle size is observed by increasing the pH values. ► Increasing pH also shows the enhancement in optical band gap.