Enhanced piezoelectricity and photoluminescence in Dy-modified 0.94(Bi1−x Dy x )0.5Na0.5TiO3–0.06BaTiO3 lead-free multifunctional ceramics

Abstract

Lead-free 0.94(Bi1−xDyx)0.5Na0.5TiO3–0.06BaTiO3 ceramics were prepared by an ordinary sintering method and their piezoelectric and photoluminescent properties were studied. All the ceramics possess a pure perovskite structure with the coexistence of the rhombohedral and tetragonal phase. The partial substitution of Dy3+ for Bi3+ enhanced effectively the piezoelectricity of the materials. The optimum piezoelectricity is obtained at x = 0.025, giving d33 = 190 pC/N and kP = 37.2 %, respectively. After the addition of Dy3+, excellent photoluminescence of the ceramics is induced. The Dy-doped ceramics exhibit strong emissions at ~478 nm (blue) and ~575 nm (yellow), corresponding to 4F9/2 → 6H15/2 and 4F9/2 → 6H13/2 of Dy3+ transitions, respectively. The optimum photoluminescence of the ceramics is reached at x = 0.025. The ceramics with the doping of 2.5 mol% Dy3+ exhibit simultaneously good piezoelectricity, strong ferroelectricity and excellent photoluminescence, suggesting a promising application in the electro-optic devices.