Investigation of Structural, Optical and Electrical Properties of Lead-Free K0.5Na0.5NbO3 Ceramics Synthesized by Sol–Gel Reaction Route

In this paper, polycrystalline lead-free K0.5Na0.5NbO3 (KNN) ceramics were manufactured by a sol–gel reaction route. The effect of calcination temperature on optical, photoluminescence and electrical parameters has been studied. The optical parameters were investigated by using reflectance spectroscopy of ceramics which revealed a red shift in the wavelength with a rise in calcination temperature. The photoluminescence spectrum has an emission band in the UV–visible region at room temperature. Phase determination of KNN ceramics was analyzed by using an x-ray diffractometer. The microstructure and surface morphology of the KNN ceramic were studied by field emission scanning electron microscopy. I–V characteristics have been studied which revealed an ohmic conduction mechanism at higher applied electric voltages. The dependence of dielectric constant, AC conductivity and impedance plots on frequency have been studied at room temperature. The cole–cole plots have a linear curve, which disclosed that KNN ceramics have good insulating properties at room temperature.