Electric Field-Induced Giant Strain and Photoluminescence-Enhancement Effect in Rare-Earth Modified Lead-Free Piezoelectric Ceramics

In this work, an electric field-induced giant strain response and excellent photoluminescence-enhancement effect was obtained in a rare-earth ion modified lead-free piezoelectric system. Pr³⁺-modified 0.93­(Bi_0.5Na_0.5)­TiO₃-0.07BaTiO₃ ceramics were designed and fabricated by a conventional fabrication process. The ferroelectric, dielectric, piezoelectric, and photoluminescence performances were systematically studied, and a schematic phase diagram was constructed. It was found the Pr³⁺ substitution induced a transition from ferroelectric a long-range order structure to a relaxor pseudocubic phase with short-range coherence structure. Around a critical composition of 0.8 mol % Pr³⁺, a giant reversible strain of ∼0.43% with a normalized strain <i>S</i>_max/<i>E</i>_max of up to 770 pm/V was obtained at ∼5 kV/mm. Furthermore, the <i>in situ</i> electric field enhanced the photoluminescence intensity by ∼40% in the proposed system. These findings have great potential for actuator and multifunctional device applications, which may also open up a range of new applications