Highly Efficient Aggregation-induced Electrochemiluminescence Performance of Covalent Organic Frameworks with Electron-rich Conjugated Structures.

Abstract

Since aggregation-induced electrochemiluminescence (AIECL) luminophore overcomes the restriction of aggregation-caused quenching in solid luminescent materials, AIECL luminophore has become a promising material in the field of electrochemiluminescence (ECL) engineering. However, the lack of ECL emitters with high AIECL performance limits its wide application. Herein, imine-linked covalent organic frameworks (COFs) with C4 symmetrical tetraphenyl ethylene and C2 symmetrical five-membered heteroaromatic monomers are designed as ECL emitter in aqueous media. Significantly, the ECL intensity of COFs with terthienyl units (TTA-TAPE) is 206 times that of COFs with furan units in the presence of tri-n-propylamine (TPrA), which is the result of enhancing ECL signals by increasing the thiophene units and π-π conjugation of COFs. Furthermore, the ECL mechanism of these COFs is vested in the bandgap model. Thus, the study provides a strategy for designing highly efficient ECL-active COFs emitters with excellent AIECL efficiency.