Enhanced Performance of CsPbBr ₃ Radiation Detectors by Surface Passivation and Transient Current Analysis

Metal halide perovskites have emerged as promising materials for radiation detection due to their outstanding optoelectronic properties. However, practical applications are often limited by surface defects and carrier recombination, which result in delayed charge carrier transit and reduced charge collection efficiency. Here, this study reports the successful fabrication and enhancement of CsPbBr 3 single‐crystal (SC) detectors specifically optimized for photon‐counting radiation detection. High‐quality CsPbBr 3 SCs are grown using a space‐confined inverse temperature crystallization method. Detectors fabricated with an asymmetric Au/CsPbBr 3 /Ga structure are successfully detected 5.48 MeV α ‐particle spectrum from a 241 Am source in photon‐counting mode. Surface passivation with phenylethylammonium iodide markedly enhances device performance by forming a 2D perovskite layer, significantly increasing the μ ‐ τ product and improving energy resolution (ER) from 25.6% to 13.2%. Employing transient current analysis allows direct visualization of accelerated charge transport and effective suppression of deep‐level defects by surface passivation. Additionally, a simple pulse discrimination algorithm effectively excludes events with low charge collection efficiency, further improving ER without the need for material modification. These findings provide important insights for optimizing perovskite‐based radiation detectors.