Role of annealing temperature on electrical and optical properties of ZnO nanoparticles for renewable energy applications

Hexagonal wurtzite ZnO nanoparticles prepared by sol–gel technique followed by thermal treatment at different temperatures. The structural properties showed that the ZnO nanoparticles exhibit hexagonal wurtzite structure. The dielectric constant, loss tangent and ac conductivity were studied as a function of frequency and annealing temperature. All the dielectric parameters show dispersion and decrease with increase in annealing temperature. The optical band gap of our samples varied between 3.34 and 3.21 eV with increasing annealing temperature. The obtained results reveal that the as synthesized samples are promising for potential applications in the renewable energy devices.