Exploring the possibilities of lead-free 0.98NaNbO3-0.02BiSmKZrO3 for electrical and optical applications using solid-state method

Abstract

A new lead-free ceramic materials 0.98NaNbO3 - 0.02 (Bi(1-x)Smx)0.5K0·5ZrO3, are developed with varying levels of x (mole) (x = 0.01, 0.02, 0.03, and 0.04). The conventional sintering process involves adjusting the ratio of the constituent elements to optimize the material's properties. This results enhanced electrical conductivity and improved optical properties. Our findings show that the material exhibits an orthorhombic phase at x (mole) levels between 0.01 and 0.04. The FESEM and TEM analysis provided detailed information about the surface morphology and internal structure of the NaNbO3 ceramic materials. Additionally, the UV–Vis absorption spectra indicated that the band-gap range of 3.3 eV (± 0.04) (at x = 0.01–0.04) makes these materials suitable for various optoelectronic applications Furthermore, the luminescence behaviors of Sm3+ doped NaNbO3 materials were found to be influenced by the co-doping of Bi3+. Additionally, the dielectric constant (εr) and dielectric loss (tan δ) measurements indicated that the material undergoes two phase transitions from antiferroelectric to paraelectric within a temperature range of 120–250 °C. The investigation also compared the material's electric features, such as piezoelectricity and ferroelectricity, with its leakage current. The results showed that the co-doping of Bi3+ not only influenced the luminescence behaviors but also had an impact on the material's electrical properties. The synthesized proposed system 0.98 NaNbO3 - 0.02BiSmKZrO3 material also demonstrates excellent optical properties, with a high color purity of 80–81 % at x-0.02 under a 407 nm excitation wavelength. Additionally, the estimated color coordinates of the material fall within the reddish-orange domain, further enhancing its visual appeal.