Rapid Exfoliation of Layered Covalent Triazine-based Frameworks into N-Doped Quantum Dots for Selective Detection of Hg2+ Ions
Metal-free carbon quantum dots (CQDs) have attracted great interests, but rapid preparation of doped CQDs with tunable optical properties is still an urgent task. Herein, we reports that the covalent organic frameworks (covalent triazine-based frameworks, CTF-1) with a layered structure can be rapidly exfoliated and cut into N-doped CQDs. The cutting mechanism involves triazine hydrolysis and the bond-broken between triazine and benzene ring. Experiments and density functional theory (DFT) calculations confirm that the fluorescence of the obtained CQDs mainly originates from the intrinsic states emission induced by localized π–π* transition, despite the contribution of the defect state emission. Due to its unique chemical structural, the CQDs could be further utilized as an efficient PL probe for detecting Hg2+. This study may open up new avenues for developing new kinds of CQDs using covalent organic frameworks as the starting materials.