Solution-processable mixed-anion cluster chalcohalide Rb₆Re₆S₈I₈ in a light-emitting diode

Rhenium chalcohalide cluster compounds are a photoluminescent family of mixed-anion chalcohalide cluster materials. Here we report the new material Rb₆Re₆S₈I₈, which crystallizes in the cubic space group Fm[Formula: see text]m and contains isolated [Re₆S₈I₆]^4- clusters. Rb₆Re₆S₈I₈ has a band gap of 2.06(5) eV and an ionization energy of 5.51(3) eV, and exhibits broad photoluminescence (PL) ranging from 1.01 eV to 2.12 eV. The room-temperature PL exhibits a PL quantum yield of 42.7% and a PL lifetime of 77 μs (99 μs at 77 K). Rb₆Re₆S₈I₈ is found to be soluble in multiple polar solvents including N,N-dimethylformamide, which enables solution processing of the material into films with thickness under 150 nm. Light-emitting diodes based on films of Rb₆Re₆S₈I₈ were fabricated, demonstrating the potential for this family of materials in optoelectronic devices.