Surface‐enhanced Raman scattering of carbazole‐based covalent triazine framework

Abstract A kind of carbazole‐based covalent triazine framework (CTF‐Cz) has been synthesized from a carbazole derivative. The porous polymer can efficiently adsorb probe molecules due to the strong intermolecular interactions caused by the polar triazine moiety. CTF‐Cz directly serves as the surface‐enhanced Raman scattering substrate without any post proceeding techniques. The enhancement factor of CTF‐Cz is ~10 5 for detecting rhodamine 6G (R6G). The lowest unoccupied molecular orbital energy level of CTF‐Cz (−3.93 eV) is much lower than that of R6G, which is in favor of the charge transfer from R6G to CTF‐Cz for illumination under a 532 nm laser, which is proved by time resolved photoluminescence spectra. The efficient charge transfer induced by the strong intermolecular π–π interactions and large molecular‐orbital delocalization contribute to the enhanced Raman signals of R6G on CTF‐Cz.