Fabrication of highly crystalline covalent organic framework(COF)films with tunable thickness and good substrate adaptability remains a substantial challenge.Here,we have developed an effective approach for fabricatin...Fabrication of highly crystalline covalent organic framework(COF)films with tunable thickness and good substrate adaptability remains a substantial challenge.Here,we have developed an effective approach for fabricating crystalline COF films based on elaborately designed bifunctional A_(2)B_(2) monomers.Typically,amorphous drop-casted monomer[e.g.,1,4-bis(4-formylphenyl)-2,5-bis((4-aminophenyl)ethynyl))benzene(BFBAEB)]films were directly transformed into corresponding highly crystalline BFBAEB-COF film upon in situ vapor-assisted self-polycondensation in high yields(93-97%).The thickness of the BFBAEB-COF film could be modulated readily by varying the monomer concentration.These crystalline COF films could be grown on various substrates,including silicon,indium-doped tin oxide(ITO),glass,and gold.Moreover,such an in situ film-tofilm transformation approach has been demonstrated as versatile and applicable to different A2B2 monomers.This work provides a novel pathway toward homogeneous and highly crystalline COF films,representing a key step forward to explore the application of COFs.展开更多
基金financially supported by the National Key Research and Development Program of China(grant no.2017YFA0207500)the Natural Science Foundation of China(grant no.51973153).
文摘Fabrication of highly crystalline covalent organic framework(COF)films with tunable thickness and good substrate adaptability remains a substantial challenge.Here,we have developed an effective approach for fabricating crystalline COF films based on elaborately designed bifunctional A_(2)B_(2) monomers.Typically,amorphous drop-casted monomer[e.g.,1,4-bis(4-formylphenyl)-2,5-bis((4-aminophenyl)ethynyl))benzene(BFBAEB)]films were directly transformed into corresponding highly crystalline BFBAEB-COF film upon in situ vapor-assisted self-polycondensation in high yields(93-97%).The thickness of the BFBAEB-COF film could be modulated readily by varying the monomer concentration.These crystalline COF films could be grown on various substrates,including silicon,indium-doped tin oxide(ITO),glass,and gold.Moreover,such an in situ film-tofilm transformation approach has been demonstrated as versatile and applicable to different A2B2 monomers.This work provides a novel pathway toward homogeneous and highly crystalline COF films,representing a key step forward to explore the application of COFs.
