Hydrothermal and Mechanosynthesis of Mixed-Cation Double Perovskite Scintillators for Radiation Detection

This article details work performed on the synthesis and characterization of an inorganic mixed-cation double halide perovskite, Cs₂Ag_.6Na_.4In_.85Bi_.15Cl₆ (CANIBIC). Single crystals have been created via a hydrothermal reaction, milled into a powder, and pressed into pellets, while nanocrystals have been directly synthesized via mechanosynthesis. A computational model is constructed to predict the X-ray diffraction pattern of CANIBIC; this model aligns very well with the X-ray diffraction pattern measured for CANIBIC crystal powder. This model can therefore be developed in the future as a tool to predict lattice parameters and crystal structures of other novel double-halide perovskites. Photoluminescence spectra obtained from each format show broad emission centered at 630 nm, as is typical for self-trapped exciton emission; self-trapped exciton emission is also confirmed by investigating photoluminescence intensity as a function of laser power. Nanocomposites are produced via the loading of nanocrystals of CANIBIC into PMMA. Although nanocomposite disks consisting of a small proportion of CANIBIC nanocrystals in PMMA have a smaller mass attenuation coefficient than a pressed pellet of CANIBIC, these disks have comparatively bright radioluminescence due to their optical transparency. These nanocomposite disks are therefore a particularly useful format for the practical use of the CANIBIC scintillator.