Constructing polymorphic phase boundary for high-performance inorganic photostrictive materials.

Chen, Chen; Liu, Wenhao; Guo, Fengwu; He, Xiang; Wang, Lu; Boda, Muzaffar Ahmad; Wang, Xiao; Luo, Junwei et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

By converting light into mechanical strain, photostrictive materials are expected to define a revolutionary solution to the wireless micro-electromechanical devices. However, the photoinduced strain (photostriction) of most inorganic materials are unsatisfactory as compared to the electric-field-induced strain of ferro/piezoelectric materials. Here, we demonstrate the effective optimization of the photostriction of inorganic materials by constructing polymorphic phase boundary (PPB) in Pb<sub>3</sub>V<sub>2-x</sub>P<sub>x</sub>O<sub>8</sub> compounds. Large photostriction over 0.3% and excellent photostrictive efficiency in the level of 10<sup>-10</sup> m<sup>3</sup>/W are realized in Pb<sub>3</sub>V<sub>2-x</sub>P<sub>x</sub>O<sub>8</sub> compositions at the PPB region, which perform better than most of the existing inorganic photostrictive materials. Besides, photostriction over 0.1% (same level of piezoelectric strain) can be achieved with light intensity as low as 200 mW/cm<sup>2</sup>. We theoretically reveal that enhanced photostriction arises from photoinduced phase transition driven by Pb-O-V collinearity and V-V dimer formation, and P-doping can facilitate the transition, enabling large deformation at low photoexcitation. This work will accelerate the development of high-performance inorganic photostrictive materials and their applications for optomechanical devices.