Large-Scale Mechanochemical Synthesis of Cesium Lanthanide Chloride for Radioluminescence

Cesium lanthanide chloride (Cs₃LnCl₆), a recently developed class of lanthanide-based zero-dimensional metal halides, has garnered a significant amount of interest because of its potential applications in scintillators, light-emitting diodes, and photodetectors. Although cesium lanthanide chloride demonstrates exceptional scintillator properties, conventional synthesis methods involving solid-state and solution-phase techniques are complex and limited on the reaction scale. This study presents a facile mechanochemical synthesis method for producing Cs₃CeCl₆, Cs₃TbCl₆, and Cs₃EuCl₆ metal halides on a 5 g scale. These materials exhibit intense blue-violet, green, and red emissions upon ultraviolet excitation, with high photoluminescence quantum yields ranging from 54% to 93%. Furthermore, Cs₃CeCl₆, Cs₃TbCl₆, and Cs₃EuCl₆ metal halides exhibit intense radioluminescence spanning from the ultraviolet to the visible region. This research shows the potential of the scalable mechanochemical synthesis of lanthanide-based metal halides for the advancement of luminescent materials for scintillators.