Fabrication and Light‐Driven Displacement of Ferroelectric Freestanding Epitaxial Sheets of Lead Lanthanum Zirconate Titanate

The development of peeling techniques for highly oriented and crystalline ferroelectric sheets is crucial for various applications. Recently, a remarkable light-induced displacement is demonstrated in BaTiO₃ freestanding sheets. However, their displacement is still limited. In this study, lead lanthanum zirconate titanate (PLZT) freestanding sheets are fabricated using a water-soluble Sr₃Al₂O₆ sacrificial layer. The resulting 5 mm × 2 mm sheets are entirely crack-free and exhibit epitaxial c-axis orientation with room-temperature ferroelectricity and a remanent polarization of 20 µC cm^-2. In a cantilevered configuration, the sheets display repeatable displacement under UV light, driven by the ferroelectric photovoltaic and converse piezoelectric effects, facilitated by a ferroelectric PLZT layer and an AlO_x glass protective layer. Notably, the displacement-to-length ratio reaches 3.5% under UV light at a power density of 32 mW cm^-2-much larger than that of BaTiO₃ sheets (0.9%). Furthermore, stable resonant actuation is achieved by synchronizing the UV modulation frequency with the mechanical resonance of the PLZT sheets, enabling phase-locked operation. Under these conditions, the actuator exhibits excellent durability, maintaining consistent displacement over 300 million cycles. These results demonstrate the superior performance of PLZT for light-driven actuator applications and mark a significant step toward high-efficiency, light-responsive functional devices.