Enhanced Structural Stability and Pressure-Induced Photoconductivity in Two-Dimensional Hybrid Perovskite (C 6 H 5 CH 2 NH 3 ) 2 CuBr 4 .

The eco-friendly properties enable two-dimensional (2D) Cu-based perovskites as ideal candidates for next-generation optoelectronics, but practical application is limited by low photoelectric conversion efficiency because of poor carrier transport abilities. Here, we report enhanced structural stability of 2D CuBr 4 perovskites under compression up to 30 GPa, without obvious volume collapse or structural amorphization, by inserting organic C 6 H 5 CH 2 NH 3 (PMA) groups between layers. The band gap value of (PMA) 2 CuBr 4 can be effectively tuned from 1.8 to 1.47 eV by employing external pressures, leading to a broadened absorption range of 400-800 nm. Notably, we successfully detected photoconductivity of the photoresponse at pressures from 10 to 40 GPa; the maximum value of 5×10 -3  S cm -1 is observed at 28 GPa, indicating potential applications for high performance photovoltaic candidates under extreme conditions.