Ferroelectrics with a perovskite structure, exhibiting strong coupling between photons, carriers, and phonons, have been demonstrated to show a strong photostrictive response. Limited by the optical bandgap, most of the reported ferroelectric perovskites respond only to UV light or weakly respond to visible light below 550 nm. Herein, the photostrictive performance of CaCu3Ti4O12 (CCTO) ceramics, with a low bandgap of ∼1.5 eV (ideal for solar spectrum absorption), is comprehensively investigated. Although the compound presents no ferroelectricity, in general, a giant photostriction of ∼10−3 with a large photostrictive efficiency of ∼10−11 m3/W in CCTO ceramics is observed by applying purple (405 nm), green (520 nm), and red (655 nm) laser illumination. Evidenced by the XRD peak shifts under external laser illumination and the phonon mode shifts via the power-dependent Raman spectrum, the light-induced non-thermal deformation in CCTO is attributed to the enhanced stretching of O–Ti–O chains and the distortions of TiO6 octahedrons. The excellent and uniform photostrictive performance of CCTO ceramics in the visible-light region makes them potential candidates for practical applications in next-generation photo-driven electromechanical devices.

中文翻译：

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CaCu3Ti4O12 陶瓷在可见光照射下的巨大光致伸缩

具有钙钛矿结构的铁电体在光子、载流子和声子之间表现出强耦合，已被证明显示出强烈的光致伸缩响应。受光学带隙的限制，大多数报道的铁电钙钛矿仅对紫外光有反应或对 550 nm 以下的可见光反应较弱。在此，全面研究了具有约 1.5 eV 低带隙（太阳光谱吸收的理想选择）的 CaCu3Ti4O12 (CCTO) 陶瓷的光致伸缩性能。尽管该化合物不表现出铁电性，但通常通过施加紫色（405 nm）、绿色（520 nm）、和红色 (655 nm) 激光照明。通过外部激光照射下的 XRD 峰位移和通过功率相关的拉曼光谱的声子模式位移证明，CCTO 中的光诱导非热变形归因于 O-Ti-O 链的增强拉伸和TiO6 八面体。CCTO陶瓷在可见光区优异且均匀的光致伸缩性能使其成为下一代光驱动机电设备实际应用的潜在候选者。