Ultrafast Superradiant Scintillation from Isolated Weakly Confined Perovskite Nanocrystals.

Abstract

Efficiency and emission rate are two traditionally conflicting parameters in radiation detection, and achieving their simultaneous maximization can significantly advance ultrafast time-of-flight (ToF) technologies. In this study, it is demonstrated that this goal is attainable by harnessing the giant oscillator strength (GOS) inherent to weakly confined perovskite nanocrystals, which enables superradiant scintillation under mildly cryogenic conditions that align seamlessly with ToF technologies. It is shown that the radiative acceleration due to GOS encompasses both single and multiple exciton dynamics arising from ionizing interactions, further enhanced by suppressed non-radiative losses and Auger recombination at 80 K. The outcome is ultrafast scintillation with 420 ps lifetime and light yield of ≈10 000 photons/MeV for diluted NC solutions, all without non-radiative losses. Temperature-dependent light-guiding experiments on test-bed nanocomposite scintillators finally indicate that the light-transport capability remains unaffected by the accumulation of band-edge oscillator strength due to GOS. These findings suggest a promising pathway toward developing ultrafast nanotechnological scintillators with optimized light output and timing performance.