Two-Dimensional Dion-Jacobson Perovskite (NH 3 C 4 H 8 NH 3 )CsPb 2 Br 7 with High X-ray Sensitivity and Peak Discrimination of α-Particles.

Two-dimensional (2D) halide perovskites have attracted extensive interest because of their excellent optoelectronic properties, structural diversity, and promising stability. Herein, we grow a novel 2D Dion-Jacobson halide perovskite, (BDA)CsPb 2 Br 7 (BDA = 1,4-butanediamine, NH 3 C 4 H 8 NH 3 2+ ), which exhibits a large bandgap (∼2.76 eV), high resistivity (∼4.35 × 10 10 Ω·cm), and considerable switching ratio (>700), indicating great potential for radiation detection. Both experimental and calculated results demonstrate that (BDA)CsPb 2 Br 7 has a significantly improved mobility compared to those of Ruddlesden-Popper perovskites (BA) 2 CsPb 2 Br 7 and (i-BA) 2 CsPb 2 Br 7 , which is attributed to the shorter interlayer distance leading to the enhanced orbital interactions. The resulting (BDA)CsPb 2 Br 7 detector along the out-of-plane direction achieves a high X-ray sensitivity of 725.5 μC·Gy -1 ·cm -2 . Another fascinating attribute is that the detector exhibits good peak discrimination with an energy resolution of ∼37% when illuminated by the 241 Am@5.48 MeV α-particles under a negative bias of 260 V. These results provide a broad prospect for 2D Dion-Jacobson perovskites for future radiation detection applications.