3D Digital Holography Investigations of Giant Photostriction Effect in MAPbBr₃ Perovskite Single Crystals

The photoinduced physics always is a critical but controversial question for the new optoelectronic materials of halide perovskites. A high‐quality MAPbBr 3 single crystal is grown and the lattice expansion induced by variable power X‐ray irradiation is investigated.A photoinduced deformation measurement system utilizing the off‐axis holography technique is developed and constructed to measure and illuminate the global photo‐induced deformation of MAPbBr 3 . Under a 473 nm laser with a power of 50 mW, MAPbBr 3 exhibits an average maximum relative deformation of 1.27 × 10 −3 , demonstrating its remarkable photosensitivity and robust geometric response capabilities. Digital holography reveals photostriction as a localized phenomenon, reflecting the localization effect of the photogenerated carriers. The energetic and spatial transitions of those photogenerated carriers weaken the interatomic forces and in turn straighten the Pb─Br─Pb frameworks, expanding the lattice. This geometric change and the corresponding electronic impact are verified by Raman spectra, photoluminescence measurements, and first‐principle calculations. The methods and results are significant for future research on light‐induced phenomena in perovskites and other solid materials.