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. A new mechanical synthesis model for sub 500 nm nanocrystals of the mixed-cation double perovskite Cs2Ag.6Na.4In.85Bi.15Cl6 is presented alongside to hydrothermally grown single crystals. The crystal structure, elemental composition, and scintillation properties of these materials are discussed alongside nanocomposites incorporating nanocrystals. These materials present a viable path for radiation detectors, as displayed by their responses to X-ray and gamma radiation.image