Aggregation‐Induced Resonance Energy Transfer in Polymer Dots to Boost Electrochemiluminescence Performance for Bioimaging of Glycan on Cells

To break through the bottleneck of electrochemiluminescence (ECL) efficiency (Φ_ECL), this study pioneers an aggregation-induced resonance energy transfer (ARET) mechanism for simultaneously boosting the exciton utilization efficiency and photoluminescence quantum yield of ECL emitters. This mechanism is achieved by synergistically integrating aggregation-induced emission (AIE), resonance energy transfer (RET), and thermally activated delayed fluorescence (TADF) within triethylamine-conjugated polymers featuring an AIE-active fluorene derivative as energy donor and a typical TADF molecule (DMAC-TRZ) as acceptor. Spectroscopic and theoretical analyses confirm that the polymers exhibit efficient RET, unique ARET behavior, and intrinsic TADF property with an ultralow singlet-triplet energy gap. The optimal coreactant-containing polymer dots yield self-enhanced ECL with an Φ_ECL of 92.6%, significantly outperforming those of the equimolar [Ru(bpy)₃]² ⁺ and state-of-the-art organic nanomaterials. Leveraging the small size, low ECL potential of +0.96 V, high Φ_ECL, and minimal cytotoxicity of the polymer dots, a hydrazide-functionalized ECL probe is developed for sensitive ECL imaging of cell surface glycans, offering improved signal-to-background ratio over fluorescence-based methods. The proposed ARET mechanism provides a transformative paradigm for designing efficient ECL nanoemitters and bioimaging protocols.