Luminescence and scintillation properties of Cs3BiCl6 crystals

The optical and scintillation properties of Cs3BiCl6 single crystals were characterized, and absorption properties were investigated for thin films. The thin films showed two absorption bands at ∼220 nm and 330 nm; these bands can be attributed to the 1A1g → 1T1u and 1A1g → 3T1u transitions of Bi3+ ions, respectively. A luminescence band was observed at ∼390 nm in the photoluminescence spectra; this band can be attributed to the 3T1u → 1A1g transition of Bi3+ ions. In the X-ray-induced radioluminescence spectrum, in addition to the luminescence band at 390 nm, another band was observed at 600-700 nm; this band was tentatively attributed to the radiative recombination of self-trapped excitons. The decay-time constants of photoluminescence and scintillation decay were of the order of nanoseconds. The scintillation light yield was 800 photons/MeV. The results indicate that Cs3BiCl6 has a fast scintillation decay and a relatively poor light yield.