High photostrictive efficiency of Mg <sub>3</sub> V <sub>2</sub> O <sub>8</sub> ceramics under visible light illumination
Muzaffar Ahmad Boda, Chen Chen, Xiang He, Lu Wang, Zhiguo Yi
Abstract
Abstract The materials showing significant photostrictive effect under visible light are of great interest for the development of advanced micro‐optomechanical systems (MOMS). Till date, ferroelectrics have remained the most widely investigated materials for photostriction, but due to wide bandgap their efficiency remains poor in visible light. Herein, magnesium orthovandate (Mg 3 V 2 O 8 ) ceramics, showing a bandgap of 2.43 eV, is demonstrated for significant photostrictive efficiency ( η ) under visible light. In the illumination of laser 655 nm, it shows η = 1.5 × 10 −11 m 3 /W, the highest efficiency ever reported for any ceramic under visible light, and under laser405 nm, shows η = 1.0 × 10 −11 m 3 /W, the efficiency higher than most of the reported materials in similar illumination conditions. The in situ X‐ray diffraction patterns collected under external laser illumination in conjunction with power dependent Raman spectroscopy indicates that the photostriction of Mg 3 V 2 O 8 ceramics is attributed to light induced distortion of its VO 4 tetrahedrons and MgO 6 octahedrons. Whilst, comparative analysis of Raman modes identified experimentally and modes calculated by density functional theory reveals that the light‐triggered electron–phonon resonating interactions and light‐induced phase transition are the most likely origin of large polyhedral distortions and hence higher value of η at specific light intensity of lasers 655 and 405 nm, respectively. These results show considerable advantage of Mg 3 V 2 O 8 ceramics for MOMS and other light‐driven applications.