An all-inorganic Li-doped Cs3Cu2I5 single crystal for dual gamma ray and neutron detection applications

Abstract

Recently, the all-inorganic metal halide Cs₃Cu₂I₅ has attracted extensive attention because of its potential use in X-ray and gamma ray detection. Herein, a high-quality and efficient Li⁺-doped Cs₃Cu₂I₅ single crystal with good air stability was grown and utilized for dual gamma ray and neutron detection for the first time. X-ray diffraction, X-ray photoelectron spectroscopy, inductively coupled plasma optical emission spectrometry, and nuclear magnetic resonance were employed to prove that Li⁺ was successfully introduced into Cs₃Cu₂I₅, and the lattice sites of Li⁺ were investigated. The photoluminescence quantum efficiency of the Cs₃Cu₂I₅ crystal was improved from 83.4% to 88.6% via Li⁺ doping. The photoluminescence and X-ray results showed that the emission peak of Cs₃Cu₂I₅:Li was located at 445 nm and was ascribed to the self-trapped exciton emission. The light yield and energy resolution of the Cs₃Cu₂I₅ crystal were significantly improved under ¹³⁷Cs irradiation after Li⁺ doping. The effects of the Li⁺ doping on the performance were also investigated. In particular, the Cs₃Cu₂I₅:Li crystal achieved an excellent figure-of-merit of 2.25, which showed its significant potential for dual gamma-ray and neutron detection applications.