Coupling Intracompound Charge Transfer and Cluster‐Centered Excited States in Cu(I) Halide Hybrids for Efficient White Light Emission

0D hybrid organic-inorganic metal halides have attracted significant interest due to their unique optoelectronic properties, but attainment of efficient and stable white light emission (WLE) in such compounds remains a challenge. Here, efficient WLE via a molecular design that couples intracompound charge transfer and cluster-centered excited states in 0D halide hybrids is demonstrated. Two Cu(I) halide hybrids, K(18-crown-6)Cu2Br3 and Na-4(18-crown-6)(5)In2Cu4Br14 center dot 8H(2)O, are synthesized wherein luminescent [Cu4Br6](2-) clusters are isolated from each other and surrounded by 18-crown-6 coordinated alkali metal cations. In the case of K(18-crown-6)Cu2Br3, [Cu4Br6](2-) clusters are only partially isolated, leading to strong orange emission with a photoluminescence quantum yield (PLQY) of 53% under UV excitation. Strikingly, to a larger extent of isolation as that, in Na-4(18-crown-6)(5)In2Cu4Br14 center dot 8H(2)O as a result of the incorporation of nonemissive [InBr4](-) clusters, intense white light emission with a PLQY of 97% is achieved. The dual cluster-centered states, coupled with a mixed metal-to-ligand and halide-to-ligand charge transfer state, are responsible for this bright white luminescence. This work provides new design principles for expanding the materials library for single-component, solid-state WLE.