Deep insights into the Cu- and W-doped Na0.5Bi0.5TiO3 solid solution: A study focusing on optical, dielectric and electrical properties

Abstract

Na0.5Bi0.5TiO3 ceramic is among the most promising dielectric materials for several advanced electronic devices due its exceptional features. However, its high oxygen ionic conductivity and wide band-gap energy limit its use for commercial applications. Here, a new Lead-free solid solution 0.995(Na0.5Bi0.5TiO3)-0.005(BiCu0.75W0.25O3), abbreviated 0.995NBT-0.005BCW, was investigated to enhance the electrical and optical performance of NBT ceramic. 0.995NBT-0.005BCW was successfully elaborated by the solid-state technique. The structural, optical, dielectric and electric properties were investigated systematically. The incorporation of BCW into NBT improved the long-range order of the structure, facilitated the poling process, enhanced the electrical properties of the pure NBT and led to the local lattice distortion, generating new electronic levels inside the NBT bandgap. The calculated band gap value ∼3 eV suggests its suitability in power electronic devices. The variation of dielectric constant and dielectric loss with temperature (370–800 K) at different frequencies (100–106 Hz) showed diffused phase transition. The study of dc-conductivity suggests that the substitution of Cu2+ for Ti4+ would formCuTi″, which transforms Cu2+ to Cu+. Our compound is a novel material with interesting properties and offers exciting possibilities for engineering and manufacturing applications.