Development of organometallic single-crystal scintillators with CuI clusters and 18-crown-6 ether–alkali metal complexes

Abstract

Organometallic single-crystal scintillators with CuI clusters and 18-crown-6 ether ((CH₂CH₂O)₆)–alkali metal complexes – (18-crown-6)₃Cs₂Cu₂I₄ (CCI), (18-crown-6)₂Rb₂(CH₃COCH₃)Cu₄I₆ (RCI), (18-crown-6)KCuI₂ (KCI), (18-crown-6)₂Na₂(H₂O)₃Cu₄I₆ (NCI), and (18-crown-6)₂Li_1.35Na_0.65(H₂O)₂Cu₄I₆ (LCI) – were synthesized via the slow evaporation method. Their photoluminescence (PL) and scintillation properties were systematically evaluated. In both PL and scintillation spectra, broad emission bands were observed at 450–550 nm for CCI and KCI, and at 500–600 nm for RCI, NCI, and LCI. Among the prepared samples, NCI exhibited the highest PL quantum yield (99%). The afterglow level of NCI at 20 ms after X-ray exposure (3 ppm) was comparable to that of the commercial scintillator (CdWO₄, 5 ppm) in the same evaluation manner. Among all the samples, NCI exhibited the highest scintillation light yield of 59 000 photons per MeV under ¹³⁷Cs γ-ray irradiation.