The protonation effects on one- and two-photon absorption properties of an octupolar molecule TA with 1,3,5-triazine core and pyrrole electron-donating end-groups have been studied at hybrid density functional theory ...The protonation effects on one- and two-photon absorption properties of an octupolar molecule TA with 1,3,5-triazine core and pyrrole electron-donating end-groups have been studied at hybrid density functional theory level. A computational scheme is developed to simulate a proton attached to an atom. The numerical results show that large changes in both one- and two-photon absorption properties are observed when the compound is transformed from neutral to threefold protonated states. When the compound is protonated, more charge transfer states appear and the absorption band has a red-shift. Furthermore, the two-photon absorption cross-section is largely enhanced. The theoretical calculations demonstrate the protonation effect on promoting the intramolecular charge transfer strength. The results present qualitative agreement with the experimental observations. A two-photon absorption switch with the compound TA based on the protonation effect is proposed.展开更多
Two tribranched chromophores,1,3,5-triazine as electron deficient core,9,9-dimethylfluorene asπ-conjugated bridge, diphenylamino（4a） and naphthylamino（4b） as electron-donating end-groups,were successfully prepare...Two tribranched chromophores,1,3,5-triazine as electron deficient core,9,9-dimethylfluorene asπ-conjugated bridge, diphenylamino（4a） and naphthylamino（4b） as electron-donating end-groups,were successfully prepared via Buchwald-Hartwig coupling reaction.Their linear photophysical and two-photon absorption（TPA） properties were investigated by absorption, fluorescence and nonlinear transmission method,respectively.The absorption cut-offs of the chromophores are below 550 nm and both chromophores have strong fluorescence emission.The compound 4a（206.3 GM） exhibits larger TPA cross-section than 4b （57.8 GM） in the femtosecond regime at 800 nm.展开更多
文摘The protonation effects on one- and two-photon absorption properties of an octupolar molecule TA with 1,3,5-triazine core and pyrrole electron-donating end-groups have been studied at hybrid density functional theory level. A computational scheme is developed to simulate a proton attached to an atom. The numerical results show that large changes in both one- and two-photon absorption properties are observed when the compound is transformed from neutral to threefold protonated states. When the compound is protonated, more charge transfer states appear and the absorption band has a red-shift. Furthermore, the two-photon absorption cross-section is largely enhanced. The theoretical calculations demonstrate the protonation effect on promoting the intramolecular charge transfer strength. The results present qualitative agreement with the experimental observations. A two-photon absorption switch with the compound TA based on the protonation effect is proposed.
基金supported financially by National Natural Science Foundation of China(Nos.20774039 and 20872061)the National Basic Research(No.2007CB925103)
文摘Two tribranched chromophores,1,3,5-triazine as electron deficient core,9,9-dimethylfluorene asπ-conjugated bridge, diphenylamino（4a） and naphthylamino（4b） as electron-donating end-groups,were successfully prepared via Buchwald-Hartwig coupling reaction.Their linear photophysical and two-photon absorption（TPA） properties were investigated by absorption, fluorescence and nonlinear transmission method,respectively.The absorption cut-offs of the chromophores are below 550 nm and both chromophores have strong fluorescence emission.The compound 4a（206.3 GM） exhibits larger TPA cross-section than 4b （57.8 GM） in the femtosecond regime at 800 nm.
