Effect of solvent on the microstructure and optical band gap of ZnO nanoparticles

Abstract

ZnO nanoparticles have been synthesized by chemical route using different solvents. X-ray diffraction characterization of the samples indicated ZnO nanoparticles crystallize in wurtzite phase with for all the samples is ~ 1.6. Though all the samples exhibit same crystal structure, the microstructure of ZnO nanoparticles is influenced with solvent. The ZnO nanoparticles have been synthesized using ethanol as solvent has smaller crystallite size than that obtained for ZnO nanoparticles synthesized using propanol and ethylene glycol as solvent. In accordance with crystallite size variation, the lowest and highest specific surface area has been calculated for ZnO nanoparticles synthesized using propanol and ethanol as solvent, respectively. Stress analysis using lattice parameter indicated that the crystallites of all ZnO samples experience compressive stress and the magnitude of the stress is nearly twice for ZnO nanoparticles synthesized with ethanol than that obtained for ZnO nanoparticles synthesized using ethylene glycol as solvent. UV-visible characterization of these samples indicated that the bang gap of ZnO nanoparticles is not affected much with the solvent. The refractive index and electron polarizability for all samples have been determined from the optical band gap of corresponding samples.