Self-luminescent cyano-vinylene-linked covalent organic framework boosts coreactant-free electrochemiluminescence for...

Exogenous coreactants required in conventional electrochemiluminescence (ECL) systems inevitably bring about toxicity, poor signal reproducibility and unstable luminescence output, severely restricting the biological compatibility and practical application of ECL sensors. Herein, we designed a novel self-luminescent cyano-vinylene-linked covalent organic framework (CV-COF) via Knoevenagel polycondensation using 1,3,6,8-tetrakis(p-formylphenyl) pyrene (Py) and 2,2'-([2,2'-bipyridine]-5,5'-diyl) diacetonitrile (Bpda) as building monomers. Its π-conjugated skeleton and electron-deficient units boost intramolecular charge transfer to generate coreactant-free ECL without extra oxidants/reductants or dissolved oxygen. Leveraging this self-luminescent CV-COF, a highly sensitive and selective ECL sensing platform was constructed for iodide ion detection, achieving a low detection limit of 83.8 nM, and could also quantitatively detect iodixanol with an LOD of 74.47 nM. This work pioneers the design of self-luminescent cyano-vinylene COFs as coreactant-free ECL emitters, establishes a universal molecular engineering strategy for constructing intrinsic self-enhanced ECL COF materials, and broadens the application prospect of COF-based ECL sensors in environmental pollutant monitoring.