Multi-stimuli-responsive aggregation-induced emission copper iodide cluster

Stimuli-responsive luminescent materials have attracted significant attention in the development of smart photoactive materials for both fundamental research and technological applications. In this work, a new copper iodide cluster (1) with aggregation-induced emission (AIE) characteristic, was obtained combining Cu₄I₄ core with rhodamine B derivative ligand. 1 has reversible and distinct multi-stimuli-responsive luminescence for external temperature, volatile organic compound, and mechanical force. Significantly, 1 exhibited unusual large blue shift (84 nm) after being ground, which originated from the change of inter-molecular interactions. Moreover, 1 exhibits high oxygen quenching efficiency for 82.2% at 1 bar. Mechanistic studies showed that the multi-stimuli-responsive luminescence properties of 1 can be attributed to the regulation of cluster-centered luminescence process, metal-to-ligand charge transfer process, halide-to-metal charge transfer luminescence process and aggregation-induced barrier to oxygen process. This work not only reports an AIE copper iodide cluster, but also provides a new strategy to develop multi-stimuli-responsive luminescence materials.