Synergistic Coupling of Antenna Effect and Schottky Junction in Tb-Doped Covalent Organic Framework for Enhanced Electrochemiluminescence Sening of Isobutyryl Fentanyl

Rational design of both mechanistic pathways and material compositions is essential to advance COF-based electrochemiluminescence (ECL) systems. In this study, aggregation-induced emission covalent organic framework (AIE-COF) nanoprobes with excellent ECL performance were developed based on Tb³⁺-functionalized covalent organic framework (Tb@A-COF). The Tb@A-COF system demonstrates enhanced ECL performance through synergistic integration of three complementary mechanisms: (1) (4',4',4',4'-(1,2-ethenediylidene)tetrakis [1,1'-biphenyl]-4-carboxaldehyde (ETBC) ligands function as antenna-like sensitizers that amplify luminescence intensity by 14.62-fold via efficient energy transfer to Tb³⁺ centers; (2) the constructed silver nanowire-based (Ag NWs) Schottky junction effectively suppresses electrode passivation while improving signal stability through optimized interfacial charge transfer kinetics; (3) cobalt oxide nanosheets (CoOOH NSs) enable dynamic signal modulation via precisely regulated quenching effects on the ECL process. This multidimensional optimization strategy achieves coordinated enhancement of both emission intensity and system stability. The synergistic optimization strategy resulted in an ultrasensitive biosensor capable of detecting isobutyryl fentanyl (iBF) with an ultralow detection limit of 8.97 × 10^-16 g/L. This study establishes a multiple amplification strategy for rare-earth-COF composites in the field of ECL, which provides both a conceptual framework for improving the performance of ECL in crystalline frameworks and a new perspective for the development of efficient and stable ECL technology.