Nonclassical Hydrogen Bond-Based Efficient Solid-State Organic Emitters Enabled by a Synergistic Anion and Mechanical Bond Effect

Traditional fluorophores often face aggregation-caused quenching (ACQ), limiting their efficacy in high-concentration applications. We demonstrate that a combined effect of anion and mechanical bond can significantly increase fluorescence intensity, up to 14-fold, and a quantum yield of 97.0%. A large number of crystal analyses reveal that this enhancement is primarily driven by nonclassical hydrogen bonds, which stabilize the structure and restrict molecular motion. The versatility of this synergistic effect opens up new avenues for applications, including circularly polarized luminescence (CPL) facilitated by chiral anions and the development of a fluorescence switchable rotaxane shuttle-based stimuli-responsive material.