Boosting Electrochemiluminescence of Carbon Nitrides via Molecular Capacitor‐Mediated Spatiotemporal Electron Coordination

Abstract Carbon nitride (CN) enables non‐toxicity, low cost, high quantum efficiency, and tunable spectrum. Nevertheless, there co‐exists a timescale mismatch among kinetic steps of electrochemiluminescence (ECL) and a spatial competition of electrons between radiative recombination and interfacial redox reactions. Herein, a spatiotemporal coordination strategy is reported to enhance Φ _ECL of CN by molecular capacitor functionalization. Mechanism studies show the capacitor, consisting of N‐vacancies and −C≡N terminal groups, dynamically regulates electron capture and accumulation. Interestingly, the spatial confinement of accumulated electrons in molecular capacitors effectively enhances the radiative recombination probability. Meanwhile, the accumulated electrons construct a new pathway for fast electron transport, and the relaxation of the accumulated electrons coordinates the electron transfer in bulk CN and redox reactions at the electrode surface on the µs‐ms timescale, establishing temporal coordination across multiple time domains. As a result, the Φ _ECL of CN increases by up to 100 times, reaching 1480 times that of the standard Ru(bpy) ₃ Cl ₂ /K ₂ S ₂ O ₈ system. Accordingly, compared to pristine CN, the as‐developed ECL sensors using CN with molecular capacitor functionalization demonstrate significantly improved performance in the visual detection of nitrite ions (a typical environmental pollutant), for example, a 3600 fold lower detection limit and a 3‐order of magnitude broader detection linear range.