Electronic Properties of ZnO Nanoparticles Synthesized by Sol-gel Method: A LDA+U Calculation and Experimental Study

ZnO nanoparticles were prepared by sol-gel storage method to determine the optimum growth time. The precursor was zinc acetate dihydrate and methanol used as solvent. NaOH act as additive that changes the initial sol pH. The stabilize growth of ZnO nanoparticles was recorded after 12 hours aging time. Structural characterization revealed a single phase of ZnO with hexagonal wurtzite structure. Absorption spectra showed the synthesized ZnO nanoparticles exhibit an optical absorption in visible region. In addition, a systematic computational method within density functional theory frame work was used to elucidate the electronic properties of the synthesized ZnO nanoparticles. Calculations were performed using local-density approximation corrected by Hubbard U method. Hubbard U allowed the alteration of electronic state energy of Zn and O which improved the calculation. The calculated energy band gap demonstrates a value close to experimental data.