Large-sized, room-temperature ultrafast scintillator single crystals are highly demanded for fast timing applications such as time of flight–positron emission tomography, high-speed medical imaging, and pulse heavy-ray detection. Sub-nanosecond scintillation was discovered in 16 mm sized CsPbCl3Brx single crystals in our previous research. In this work, the crystal size of CsPbCl3Br0.03 was enlarged to 2 inches (50.8 mm). Meanwhile, by precisely optimizing the vertical Bridgman growth process, we further increased the concentration of Br dopant to realize even faster scintillation decay. In this study, we conducted a series of tests on the grown crystals, including temperature-dependent photoluminescence tests, alpha particle excitation tests, X-ray imaging tests, etc. Via the strategy of the incorporation of Br2, Br dopant introduces highly efficient fast recombination centers in perovskite CsPbCl3Br0.03 crystals, resulting in an unprecedently fast scintillation decay time of 303 ps under 241Am α-particle excitation, which is significantly shorter than that of the pure CsPbCl3 and all other perovskites by at least two orders of magnitude. Benefiting from the excellent optical transparency and high crystalline quality of the CsPbCl3Br0.03 crystal, an X-ray spatial resolution of up to 20 lp/mm is achieved. These results further demonstrate the great potential of large-sized CsPbCl3Brx single crystals for fast timing applications.
Yang et al. (Wed,) studied this question.