Self-Enhanced Luminophore with an Intrinsically Integrated "Energy Ladder" and CdIn2S4-Enabled Coreactant Activation for Electrochemiluminescence Sensing.

In recent years, electrochemiluminescence (ECL) has attracted widespread attention in bioanalysis and clinical diagnostics. However, improving its luminescence efficiency remains a key challenge. In this work, an efficient ECL system was constructed by synergistically regulating the energy utilization of the luminophore and the activation of the coreactant. A lanthanide-based coordination framework luminophore, Gd/Tb-DPA/DHTA, was designed, in which an intrinsically integrated "energy ladder" enables efficient energy transfer and utilization between the ligands and lanthanide ions. Meanwhile, the introduced Gd3+ endowed the luminophore with catalytic activity toward S2O82-, thereby coupling the internal energy-transfer process with coreactant activation and giving rise to self-enhanced ECL behavior. In addition, S-vacancy-containing CdIn2S4 was introduced as a coreactant activation unit to promote the adsorption and activation of S2O82- and accelerate the generation of SO4•- reactive species, thereby further enhancing the ECL performance. Based on this design, a sandwich-type ECL biosensor was constructed for the detection of carcinoembryonic antigen (CEA). The sensor exhibited a good linear relationship in the range from 100 fg mL-1 to 100 ng mL-1, with a detection limit as low as 43.5 fg mL-1, demonstrating excellent analytical performance. This work provides a new design strategy for constructing high-performance ECL sensing platforms through the synergistic integration of energy transfer regulation and defect engineering.