Influence of calcination temperature on sol–gel synthesized single-phase bismuth titanate for high dielectric capacitor applications

Abstract

Abstract An inexpensive sol–gel combustion method using citric acid as fuel has been used to synthesize bismuth titanate, Bi4Ti3O12 nanopowders. Thermogravimetric analysis proved that a calcination temperature of 900 °C is sufficient for the preparation of single-phase bismuth titanate. X-ray diffraction and Fourier transform infrared spectroscopy are used to examine the influence of calcination temperature on the structural growth of the Bi4Ti3O12 nanopowder. The average crystallite size estimated by using the Scherrer method and the Williamson–Hall method was found to increase with calcination temperature. Photoluminescence behavior as a function of calcination temperature was observed at two different excitation wavelengths of 300 nm and 420 nm. The morphology of the particles analyzed using images obtained from field emission scanning electron microscopy displayed irregular, random sized, and spherical-shaped structures. The stoichiometry and purity of the nanopowder are confirmed by energy-dispersive spectroscopy. The broadband dielectric results established the highest dielectric constant (∊r = 450) for a frequency of 100 Hz achieved with a potential capacitance of 138 pF m−2. This establishes Bi4Ti3O12 as a promising dielectric material for achieving high energy density capacitors for the next-generation passive devices.