Effect of Electrical Poling on the Structural, Dielectric, and Photoluminescence Properties of Eu³⁺ Substituted Eco-Friendly Ferroelectric Material Na_0.5Bi_0.5TiO₃

Abstract

In this work, the effect of electric field on structural, photoluminescence, dielectric, and piezo/ferroelectric properties of 2.5 mole % Eu3+substituted sodium bismuth titanate (Na0.5Bi0.475Eu0.025TiO3 abbreviated as NBT-Eu) ferroelectric material has been investigated. Rietveld refinement on the X-ray diffraction patterns of poled and unpoled ceramics suggested lower monoclinic symmetry (Cc) with 93.64% as major phase fraction and higher orthorhombic symmetry (Pbnm) with 6.36% as minor phase fraction. For the poled composition, the monoclinic (Cc) phase fraction decreased to 83.53%, and the orthorhombic (Pbnm) phase fraction increased to 16.47%. Improved ferroelectric and piezoelectric characteristics in comparison to pure NBT were found in Eu3+ substituted NBT. Moreover, the substitution with Eu3+ enabled observation of photoluminescence (PL) emission in the visible region under an excitation wavelength of 532 nm for electrically poled and unpoled ceramics, thereby enabling additional functionality for this material along with ferroelectric and dielectric properties. Intensities of PL emissions were tuned by the application of electric poling of the ceramic, which generates the possibility of using these materials in optoelectronics device applications.