Giant Bulk Photostriction and Accurate Photomechanical Actuation in Hybrid Perovskites

It is well known that a material may be strained by mechanical, thermal, electric, magnetic, and light stimuli, and this effect has been extensively utilized in industries. However, the observed photostrictive effect usually occurs in the very thin surface layer and the photostriction of most bulk materials has been too small to be applied in a device until now. Here, a giant bulk photostriction is achieved, evidenced by the measured linear strain epsilon approximate to 0.72-0.43% for MAPbI(3) single crystal plates of 0.05-0.5 mm in thickness under the 532 nm illumination. More importantly, the MAPbI(3) single crystals also exhibit accurate photomechanical actuation functionality and the actuator can precisely adjust the displacement from hundreds of pm to tens of mu m or the angle of a hard mirror from approximate to 10(-6) to 0.2 degree. The present work not only unveils the huge bulk photostriction in lead halide perovskite single crystals but also demonstrates a wireless photomechanical actuator which is much simpler and smaller than conventional piezoelectric actuators.

Automated summary

This study demonstrates a significant bulk photostriction effect and accurate photomechanical actuation functionality in MAPbI(3) single crystals. The actuator allows precise adjustment of displacement and angle within a wide range.