Stokes Shift Engineered Mn:CdZnS/ZnS Nanocrystals as Reabsorption‐Free Nanoscintillators in High Loading Polymer Composites

Plastic scintillators are gaining attention as alternatives to inorganic scintillator crystals owing to their low fabrication cost, customable shape/size, and substantially lighter weight that make them suitable for various radiation detection technologies. These include scintillation panels for national security and industrial monitoring, radiation screens for medical diagnostics, and calorimeters for high energy physics. Because of their low density, plastic scintillators are typically doped with high atomic number (Z) sensitizers that enhance the interaction probability with ionizing radiation and excite molecular emitters. Although effective, such a two-component design suffers from incomplete sensitization, intrinsically limited efficiency due to multiple radiative steps with non-unity quantum yield, detrimental phase segregation effects and the fragility of organic emitters to ionizing radiation. In this work, an alternative single-component scheme is proposed based on high-Z reabsorption-free CdZnS/ZnS semiconductor nanocrystals (NCs) doped with manganese embedded in a polyvinyltoluene (PVT) waveguide. Optical-grade nanocomposites free from optical reabsorption of the scintillation light and with performance comparable to commercial products are obtained through a post-synthesis resurfacing procedure that maximizes the compatibility between the NCs and PVT and preserves their optical properties upon curing.