Unlocking High-Performance Electrochemiluminescence in Supramolecular Coordination Frameworks via π-Bridge...

Aggregation-induced electrochemiluminescence (AIECL) is a promising strategy for enhancing electrochemiluminescence (ECL) efficiency by minimizing energy loss of excited-state ECL emitters. However, rational design of high-efficiency AIECL emitters is hindered by limited mechanistic understanding and an unclear structure-performance relationship. To address this, four supramolecular coordination frameworks (SCFs) with varying π-bridge structures are synthesized using pyridine-functionalized tetraphenylethene (TPE) as the ligand and Pt(II) as the coordination center. Electrochemical and electron paramagnetic resonance analyses revealed that the TPE-SCFs generated excited-state species and singlet oxygen (¹O₂) and collectively enhanced cathodic ECL. Meanwhile, π-bridge engineering activated electron distribution and delocalization of the highest occupied molecular orbital within TPE, narrowing the energy gap by 0.82 eV, facilitating charge transfer and ultimately enhancing ECL, as evidenced by density functional theory calculation. Particularly, aggregation of the TPE-SCFs promotes self-catalytic heterocleavage of K₂S₂O₈, boosting SO₄ ^●- generation and accelerating the formation of excited-state TPE-SCFs and ¹O₂, leading to strong ECL emission. This study unveils a dual enhancement mechanism: π-bridge-mediated intramolecular charge transfer process synergizing with aggregation-driven self-catalytic radical amplification, offering valuable insights for rational design of high-performance AIECL materials suitable for diverse applications.