All-inorganic CsPbCl \(_3\) perovskite is a promising material for high-performance radiation detection owing to its extraordinary photoelectric properties and chemical stability. The critical challenge in developing wide-bandgap CsPbCl \(_3\) perovskite lies in the quantitative assessment of its charge transport properties, which regulate its performance optimization. Herein, we report the first spectroscopic \(\upalpha\) particles using CsPbCl \(_3\) detectors with asymmetric contact. CsPbCl \(_3\) single crystals ( \(\upphi\) 15 mm \(\times\) 50 mm) were successfully grown using the Bridgman melt method and subsequently fabricated into Schottky-type Bi/CsPbCl \(_3\) /Au detectors. Owing to its high electrical resistivity of 1.25 \(\times\) 10 \(^9\) \(\Omega\) \(\cdot\) cm, the CsPbCl \(_3\) detector demonstrated a low dark current density ( \(\sim\) 870 nA/cm \(^2\) ) and stable performance. The CsPbCl \(_3\) detector was also capable of resolving both the \(\upalpha\) particle (5.5 MeV) and \(\upgamma\) -ray (59.5 keV) peaks from the \(^{241}\) Am radioactive isotope. Furthermore, the carrier transport properties of CsPbCl \(_3\) were evaluated quantitatively by the time-of-flight technology using \(^{241}\) Am \(\upalpha\) particle response, revealing the hole and electron mobilities as \(\sim\) 11.12 and \(\sim\) 12.92 cm \(^2\) \(\cdot\) V \(^{-1}\) \(\cdot\) s \(^{-1}\) , respectively. Meanwhile, the hole and electron mobility–lifetime products were obtained as \(\sim\) 1.72 \(\times\) 10 \(^{-4}\) and \(\sim\) 1.04 \(\times\) 10 \(^{-4}\) cm \(^2\) \(\cdot\) V \(^{-1}\) , respectively. The planar CsPbCl \(_3\) detector achieved an excellent energy resolution of \(\sim\) 14.9% at 122 keV under \(\upgamma\) -ray exposure, which is the highest energy resolution reported to date for CsPbCl \(_3\) detectors. This study highlights the considerable potential of inorganic perovskite detectors for radiation detection and provides a practical approach for the future development of perovskite materials.
