Scintillation properties of (Ph₄P)₂ZnX₄ (X = Cl, Br)

We fabricated (Ph4P)(2)ZnCl4 and (Ph4P)(2)ZnBr4 crystals (Ph4P: tetraphenylphosphonium) with zero-dimensional structures via solvent evaporation and evaluated their optical and scintillation properties. Fluorescence and phosphorescence peaks derived from Ph4P+ cations appeared at 345 and 510 nm, respectively, for both crystals, while an emission originating from self-trapped excitons was also detected for (Ph4P)(2)ZnBr4. In the scintillation spectra, both samples exhibited a phosphorescence peak, while a weak fluorescence peak was also observed for (Ph4P)(2)ZnCl4. In addition, the scintillation light yield (LY) was determined by pulse-height spectra with 1 mu s shaping time. A pulse-height peak was observed from (Ph4P)(2)ZnCl4, and the scintillation LY was about 670 photons/5.5 MeV-alpha, which was higher than that of a ZnO single crystal.