Supramolecular Confinement Endows Carbon Dots with Room-Temperature Phosphorescence for Efficient Electrochemiluminescence Detection

Electrochemiluminescence (ECL), a light-emitting phenomenon triggered by electrochemical reactions, faces intrinsic limitations due to the low quantum efficiency of singlet excitons and the susceptibility of triplet excitons to nonradiative decay and oxygen quenching. To address these challenges, this study pioneers a triplet exciton-based ECL sensing platform by encapsulating carbon dots (CDs) within a hydrogen-bonded organic framework (HOFs), forming a host-guest composite (CDs@HOFs). The rigid HOF matrix suppresses nonradiative transitions and oxygen quenching, extending triplet exciton lifetimes to 652.94 ms while enhancing phosphorescence efficiency through host-guest energy transfer. Characterizations confirmed the confinement of CDs within HOFs and hydrogen-bond-mediated interactions. Under K2S2O8 coreaction, the CDs@HOFs-modified electrode exhibited prolonged ECL decay (0.6 s) and high stability. Leveraging the prolonged triplet exciton, the sensor demonstrated selective ECL enhancement toward erythromycin (EM) with a detection limit of 0.74 nM (linear range: 1.0 × 10-8-1.0 × 10-5 mol·L-1), outperforming conventional spectroscopic methods. This work not only overcomes the singlet exciton efficiency bottleneck but also establishes a paradigm for exploiting triplet excitons in ECL sensing, offering potential for microenvironment-responsive biosensing and real-time monitoring.