Structural, optical and photoluminescence properties of K0.5Na0.5NbO3 ceramics synthesized by sol–gel reaction method

A polycrystalline KNN precursor solution has been prepared by using sodium acetate, potassium acetate and niobium pentaethoxide as initial chemical reagents using sol–gel method. The pure phase XRD pattern of KNN powder calcined at 750 °C was achieved and SEM clear that fine and homogeneous powder was formed. Raman spectroscopy analysis was done to study the extent of crystallization and Raman scattering mode during temperature variation in the sample which is good in this sample. The values of optical band gap energies are 3.27 eV and 3.17 eV for KNN-850 and KNN-1050, respectively. This revealed that optical band gap energy decreases with increase in sintering temperature due to increase in crystallite size and formation of intermediate energy levels. PL spectra have an emission band in UV/visible region, which explore their application fields of electro-optics devices. I–V characteristics showed that KNN samples have linear ohmic and SCLC conduction mechanisms at higher applied electric voltages.