Heterostructure CaF 2 @CsPbX 3 Nanoscintillators with Enhanced Stability and Brightness for High-Resolution X-ray Imaging

film exhibits significantly improved X-ray-excited optical luminescence, environmental stability, and suppressed self-absorption, along with superior high-resolution imaging. This work establishes fluoride incorporation as a general strategy to unlock the full potential of perovskite scintillators for next-generation optoelectronics and imaging.