A Low-Noise PINP Diode Made of CH ₃ NH ₃ PbBr _2.5 Cl _0.5 Perovskite Single Crystals for High-Energy Proton Spectroscopy

Halide perovskite single crystals are promising materials for radiation detection. However, their long-term operational stability under a high bias, particularly for methylammonium (MA)-based compositions, remains a challenge. Herein, we fabricate a structure of p-type/intrinsic/n-type/p-type diode (PINP diode) made of MAPbBr 2.5 Cl 0.5 single crystals that significantly enhances stability. Compared to a conventional Au/intrinsic/Au structure, the dark current density of the PINP diode is markedly reduced from 698.2 nA cm –2 to 86.6 nA cm –2 under the bias of 200 V. In the proton-counting mode, the noise level is only 487 ± 50 electrons at 150 V bias. Thanks to the low noise and long-term stability, this MAPbBr 2.5 Cl 0.5 -based PINP diode achieves proton-counting detection for 60 MeV and 20 MeV protons. This work provides a viable strategy for developing stable perovskite single-crystal detectors capable of high-energy proton detection.