Substituent-Induced Aggregated State Electrochemiluminescence of Tetraphenylethene Derivatives

The development of highly active, eco-friendly, and structurely fine-tunable organic luminophores is currently desirable for electrochemiluminescence (ECL). Tetraphenylethene (TPE) derivatives are the most representative aggregation-induced emission characteristic (AIEgens). In contrast, their aggregation-induced ECLs have not been detail studied. Herein, we report the bright cathodic aggregated state ECL of TPE derivatives by a coreactant approach. In this system, the substituents profoundly affect ECL emissions by changing the relative intensities of R and B band intensity ratios in their UV–vis spectra as well as the HOMO and LUMO energies. It was discovered that electron-withdrawing nitro-substituted TPE-(NO2)4 with a smaller LUMO/HOMO band gap and stronger R band featured the strongest ECL emissions and became the best luminophore for the highly efficient detection of iodide (I–) in the aqueous phase. This work not only reveals the influence of R and B bands in TPE derivative UV–vis spectra on their optical properties but also constructs a novel aggregation-induced ECL sensing.