Ultrafast femtosecond pressure modulation of structure and exciton kinetics in 2D halide perovskites for enhanced light response and stability

• Published in: Nature communications Vol. 12; no. 1; p. 4879
• Main Authors: Song, Chunpeng, Yang, Huanrui, Liu, Feng, Cheng, Gary J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group 12.08.2021; Nature Publishing Group UK; Nature Portfolio
• Subjects: Confinement; Crystal structure; Density functional theory; Dielectric strength; Dimensional stability; Excitons; Laser shock processing; Lasers; Light effects; Perovskites; Pressure; Reduction; Single crystals
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-25140-2

Abstract The carriers’ transportation between layers of two-dimensional (2D) perovskites is inhibited by dielectric confinement. Here, for the first time, we employ a femtosecond laser to introduce ultrafast shock pressure in the range of 0~15.45 GPa to reduce dielectric confinement by modulating the structure and exciton dynamics in a perovskite single crystal (PSCs), e.g. (F-PEA) 2 PbI 4 (4-fluorophenethylammonium, F-PEA). The density functional theory (DFT) simulation and experimental results show that the inorganic framework distortion results in a bandgap reduction. It was found that the exciton-optical phonon coupling and free excitons (FEs) binding energy are minimized at 2.75 GPa shock pressure due to a reduction in dielectric confinement. The stability testing under various harsh light and humid thermal conditions shows that femtosecond laser shocking improves the stability of (F-PEA)2PbI4 PSCs. Femtosecond laser shock processing provides a new approach for regulating the structure and enhancing halide perovskite properties.