Cryogenic Scintillation Performance of Cs₄PbI₆ Perovskite Single Crystals

All-inorganic Cs₄PbI₆ single crystals (SCs) is emerging scintillators for radiation detection. In this study, we report on the X-ray scintillation properties of Cs₄PbI₆ SCs at the temperature range of 50-290 K. The temperature-dependent radioluminescence (RL) spectrum and decay time were investigated. It was found that the RL spectra show very pronounced temperature-dependent changes in the overall shape. The RL intensity increases with a decrease in the temperature under X-ray excitation. The emission bands at 318, 360, and 554 nm are attributed to the near-band-edge emission in Cs₄PbI₆ SCs, the ³P₁ → ¹S₀ transition of the Pb²⁺ ion, and the emission of δ-CsPbI₃ aggregates dispersed in the Cs₄PbI₆ SC matrix, respectively. With decreasing temperature, the fast and slow decay times tend to slow down and are estimated to be 46.0 ns (33.22%) and 820 ns (66.78%) at 50 K, which are far superior to that of the common cryogenic scintillator. These cryogenic scintillation characteristics of Cs₄PbI₆ SCs demonstrate its potential for cryogenic detection.