上海科技大学知识管理系统

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 x 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 & horbar;Br & horbar;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.