Abstract

An investigation of the structural, electrical, optical, and gas sensing properties of K0.5Na0.5NbO3-based ceramic powders has been conducted at ambient temperature. Molten salt synthesis was used to synthesize lithium (Li)doped K0.5Na0.5NbO3 ceramic powders. The composition of the material K0.5, Na0.5_ x Lix NbO3 at x = 0.05 and 0.1 was synthesized, characterized by X-Ray diffraction (XRD), field scanning electron microscopy (FESEM) with energy-dispersive spectroscopy (EDS), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) analytical methods. Phase analysis showed an orthorhombic crystal structure with an amm2 space group and crystallite sizes were determined from Scherrer ' s average model, Monshi-Scherrer's model, W-H plots. Optical studies revealed band gaps grow with the increase in doping concentration. Raman spectra displayed a shift in Raman peaks towards higher wavenumbers at 280 cm_ 1, corresponding to changes in Li-O bond distances around 860 cm_ 1. A semicircle behavior shows higher conductivity and supports perfect Debye-type behavior. M ' approaches 0 at low frequency and high temperature, indicating electrode and/or ionic polarization. The M '' peak's frequency shift indicates conductivity relaxation in the origin above 460 degrees C in K0.5Na0.45Li0.05NbO3 and 320 degrees C in K0.5Na0.4Li0.1NbO3. P-E hysteresis loop of K0.5Na0.5NbO3, as previously reported, poled samples may have favorable Pr, Ec, and Ps values for K0.5Na0.45Li0.05NbO3 and K0.5Na0.4Li0.1NbO3. The K0.5Na0.45Li0.05NbO3, ceramic powder exhibits a rapid sensing response for all gas concentrations attributed to the oxygen deficiency. In comparison with pure K0.5Na0.5NbO3 (KNN), Li-substituted ceramic powders, K0.5Na0.45Li0.05NbO3 and K0.5Na0.4Li0.1NbO3 showed better response to ammonia (NH3) gas sensing. Molten salt routine is a promising method for the synthesis of highly active Limodified ceramic powders and can be used for advanced NH3 gas sensing devices, and electrical applications.