Effect of Ce Doping on the Structural, Dielectric, Ferroelectric, and Optical Characteristics of Bi3LaTi3O12 Ceramic

Herein, cerium-modified bismuth lanthanum titanate (Bi3LaTi3-xCexO12) with composition x = 0, 0.1, 0.2, and 0.3, prepared using solid-state reaction route is reported. The initial phase from room temperature X-ray diffraction and Rietveld refinement analysis confirms the orthorhombic symmetry of the compound. Scanning electron micrograph shows an increase in grain size of the compounds from 0.61 to 0.80 mu m with cerium doping. Temperature-dependent dielectric study reveals diffused type of phase transition (DPT) around 257 degrees C for Bi3LaTi3O12. DPT becomes more evident with cerium substitution, and is distinctly observed for Bi3LaTi2.8Ce0.2O12. Complex impedance spectroscopic analysis indicates negative temperature coefficient of resistance behavior and non-Debye type of relaxation in the compound. The room temperature P-E hysteresis loop confirms the ferroelectric property in the studied compounds. Moreover, with cerium substitution, energy storage efficiency increases from 62.7% to 77.1%. UV-visible spectroscopic analysis of the compounds shows reduction in the energy bandgap from 3.02 to 2.87 eV (for direct transition) and from 2.88 to 1.37 eV (for indirect transition) with incorporation of cerium at Ti site. Consequently, high energy storage density and low optical bandgap energy observed indicate the material's amenity for energy harvesting and optoelectronic device applications.