Perovskite Nanocrystal-Based Scintillators: Synthesis Routes, Matrix Engineering, and Performance Optimization for Radiation Detection.

Abstract

Semiconductor nanocrystals with a perovskite crystal structure, both fully inorganic and hybrid, have found broad application as scintillation materials over the past decade, owing to their high absorption capability, fast response time, tunable optical properties, and radiation hardness achievable through compositional and matrix engineering, as demonstrated in a large number of recent works. At the same time, scintillating materials based on perovskite nanocrystals (PNCs) are not devoid of drawbacks. These fall into two groups: intrinsic limitations-such as self-reabsorption of the emitted light caused by a small Stokes shift, and a soft ionic lattice with labile surface ligands that renders PNCs sensitive to humidity, heat, and ionizing radiation-and limitations introduced during composite fabrication, such as aggregation at the PNC loadings needed for sufficient X-ray absorption, poor compatibility between the ligand shell and the host matrix, light scattering, and matrix-induced degradation. These limitations constrain scintillator performance-particularly the light yield achievable without additional material engineering-and necessitate the development of new synthesis strategies and material architectures. The characteristics of PNC-based scintillators are determined both by the PNC synthesis route-in situ growth directly within the host material, or the use of pre-synthesized PNCs subsequently incorporated into a supporting matrix-and by compositional and functional modification strategies such as PNC doping, surface ligand engineering, or coupling of PNCs with an energy donor, acceptor, or plasmonic component. In this review, we examine how PNC chemical composition, surface ligands, synthesis route, and other fabrication strategies jointly determine the performance of the final functional scintillator, in terms of light yield, radiation detection limit, radio- and photoluminescence decay time, stability under ionizing radiation and environmental factors, optical transparency, and spatial resolution. We discuss the most problematic issues associated with these composite nanomaterials and highlight the most promising strategies for developing highly efficient, long-lasting scintillators for applications in medical imaging, radiotherapy, forensics, and quality control.