Harnessing Self‐Sensitized Scintillation by Supramolecular Engineering of CsPbBr ₃ Nanocrystals in Dense Mesoporous Template Nanospheres

Abstract Perovskite‐based nanoscintillators, such as CsPbBr 3 nanocrystals (NCs), are emerging as promising candidates for ionizing radiation detection, thanks to their high emission efficiency, rapid response, and facile synthesis. However, their nanoscale dimensions — smaller than the mean free path of secondary carriers — and relatively low emitter density per unit volume, limited by their high molecular weight and reabsorption losses, restrict efficient secondary carrier conversion and hamper their practical deployment. In this work, a strategy is introduced to enhance scintillation performance by organizing NCs into densely packed domains within porous SiO 2 mesospheres (MSNs). This engineered architecture achieves up to a 40‐fold increase in radioluminescence intensity compared to colloidal NCs, driven by improved retention and conversion of secondary charges, as corroborated by electron release measurements. This approach offers a promising pathway toward developing next‐generation nanoscintillators with enhanced performance, with potential applications in high‐energy physics, medical imaging, and space technologies.