Enhanced Structural Stability and Pressure‐Induced Photoconductivity in Two‐Dimensional Hybrid Perovskite (C6H5CH2NH3)2CuBr4

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 CuBr4 perovskites under compression up to 30 GPa, without obvious volume collapse or structural amorphization, by inserting organic C6H5CH2NH3 (PMA) groups between layers. The band gap value of (PMA)2CuBr4 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. The enhanced structural stability and pressure‐induced photoconductivity in two‐dimensional Cu−Br perovskites by inserting organic C6H5CH2NH3 groups between layers is reported. No obvious volume collapse and amorphization of the perovskite‐like structure is observed under compression up to 30 GPa. The pressure‐induced photoconductivity behavior ranging from 10 to 40 GPa enables the further development for photovoltaic devices under extreme conditions.