Lead-free Ce-doped perovskite scintillators with high figure of merit

Lead halide perovskite scintillators have recently received extensive research attention owing to their short fluorescence lifetimes, low detection limits, and ease of fabrication compared to traditional scintillators. The nontoxic cerium-doped lead-free perovskites with intrinsically efficient and short lifetime d–f transitions are a prospective replacement for the toxic Pb 2+ . Here, we demonstrated Ce-doped cesium lanthanide chloride perovskites (Cs 3 LnCl 6 , Ln = Gd, Y, Lu) synthesized through a facile solution method for the first time. These perovskites exhibit blue-violet emission, which arises from Ce 5d → 4f transitions. Among three types of Cs 3 LnCl 6 perovskites, Ce:Cs 3 LuCl 6 exhibited high photoluminescence quantum yield (PLQY) of 82% and a short excited-state lifetime of approximately 34 ns. When utilized as X-ray scintillators, Ce:Cs 3 LuCl 6 crystals display a high light yield of 8120 photons per MeV and a low detection limit of 36.8 nGy air s −1 . Importantly, the figure of merit (FoM), representing the ratio of light yield to decay time, reaches 239, which is the highest reported value for lead-free perovskite scintillators up to now. Additionally, the fabrication of perovskite/PMMA films was undertaken for practical demonstrations in X-ray imaging, resulting in the attainment of a resolution of up to 8.38 lp/mm. We anticipate that this work will inspire the utilization of Ce-doped Cs 3 LnCl 6 perovskites in ultrafast scintillation applications such as high-energy physics, nuclear reaction monitoring, and dynamic X-ray imaging.