Beneficial effects of Bi/Co co-doping on the structural, optical, dielectric, and electrical properties of Ba1-xBixTi1-xCoxO3 perovskite ceramics

In this study, Bi/Co co-doped BaTiO3 perovskites, with excellent visible light absorption properties, were synthesized using the solid-state reaction method. The impact of the co-doping on the structural, optical, and electrical properties, along with the photocatalytic behavior, was investigated. X-ray diffraction and Raman spectroscopy confirm that all compositions exhibit a typical ABO3-type perovskite structure with high crystallinity. Rietveld refinement revealed the existence of a structural transition sequence from P4mm tetragonal to P4/mmm tetragonal, and ultimately to Pm3m cubic, as the BiCoO3 content increases. Analysis of the UV-vis curves revealed an enhancement of the visible light absorption of BaTiO3 and decreased its band gap energy from 3.12 eV to 1.23 eV, with the incorporation of Bi and Co dopants. which allows them to be promising and interesting materials for photocatalysis under visible light. In addition, a reduction of the dielectric permittivity and an increase in dielectric loss, while simultaneously enhancing the electrical conductivity of BaTiO3 were obtained. Furthermore, Impedance analysis indicated that both the grain (G) and grain boundary (GB) significantly contribute to the overall electrical conduction with the semiconductor behavior for all synthesized perovskites. Moreover, the conduction mechanism was elucidated based on the activation energy of the conductivity, revealing that it occurs via the hopping process along ionized oxygen vacancies.