Large electrostrain and strong photoluminescence in rare-earth-modified (Na0.5Bi0.5)TiO3-based lead-free piezoelectric ceramics

Abstract

Rare-earth (RE)-doped ferroelectric materials have received much attention due to their good performance with combined excellent luminescence and electrical properties. In this work, we report multifunctional features with large electrostrain and strong photoluminescence in (Na0.5Bi0.5)TiO3-based lead-free piezoelectric ceramics. By introducing RE3+ (RE = Sm, Pr, Eu) ions as activators into the host material with the composition of (Bi0.5Na0.5)0.94Ba0.06Ti0.98(Fe0.5Nb0.5)0.02O3 (BNBT-FN), the ceramics gradually adopts a higher structural symmetry, leading to the destruction of the long-range ferroelectric order, which is conducive to the electrostrain response. When the RE3+ content is 0.6 mol.%, the ceramic samples exhibited large unipolar strains of 0.34–0.39% and high electrostrictive coefficients Q33 of 0.021–0.029 m4/C2 under an electric field of 80 kV/cm. Furthermore, due to the luminescence activity of the RE3+ ions, the samples exhibited strong red or reddish-orange emission and simultaneously showed good temperature sensing behavior. These results suggest that the RE3+-doped BNT-based materials have great application potential in multifunctional devices.