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

ABSTRACT 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.