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

## TL;DR

Researchers improved the light-emitting efficiency of carbon nitrides by using molecular capacitors, enabling better detection of environmental pollutants like nitrite ions.

## Contribution

A spatiotemporal coordination strategy using molecular capacitors to boost electrochemiluminescence efficiency in carbon nitrides.

## Key findings

- Molecular capacitors enhance ECL efficiency by up to 100 times in carbon nitrides.
- The new method allows for a 3600-fold lower detection limit for nitrite ions.
- The detection linear range is improved by three orders of magnitude.

## 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)3Cl2/K2S2O8 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.

Molecular capacitors are modified on carbon nitrides (CN) to dynamically regulate electron capture and accumulation in the defect states under different potentials. As a result, the electrochemiluminescence (ECL) efficiency increases by up to 100 times, owing to a new spatiotemporal coordination mechanism. It enables visual ECL testing of nitrite contaminants with significantly improved sensitivity and linear detection range.