Enhanced Aggregation-Induced Electrochemiluminescence Enabled by Tuned Molecular Rigidity and Rotatability for Highly Sensitive Detection of Lithium Ions

Aggregation-induced emission electrochemiluminescence (AIE-ECL) has emerged as a promising strategy for aqueous-phase detection and sensing by overcoming aggregation-caused quenching (ACQ) and poor water solubility. However, the relatively low ECL efficiency of existing systems limits broader applications due to the intrinsic molecular rotatability of ECL emitters. In this work, we designed and synthesized a heptagonal diimide-based luminophore, DMAC-BPI, which exhibits outstanding ECL efficiency due to its well-balanced rigidity and rotatability. This AIE-ECL system demonstrated an ultrahighly sensitive and selective response toward lithium ions (Li⁺) in salt-lake environments, with a detection limit as low as 5.7 μM. This study not only addresses the challenge of insufficient AIE-ECL efficiency at the molecular design level but also provides a highly efficient strategy for detecting the strategic resource Li⁺ in salt lakes.