以萘为π-中心的双芪类衍生物双光子上转换荧光性能研究

Study on Two-Photon Induced Fluorescence of Newly Synthesized Chromophore BECVN and BMABN

研究了2个新的双光子上转换荧光分子-1,4-双-(9-乙基咔唑基)萘(简称为BECVN)和1,4- 双-(4’-N,N-二甲氨基苯乙烯基)萘(简称为BMABN)的单光子、双光子光谱性质。在-375 nm Xe灯 光源激发下,两样品的DMF溶液发出很强的蓝、绿色荧光(峰位492-541 nm),视感效果非常明显。 BMABN分子的线性吸收／发射光谱的峰位与BECVN分子相比,均发生红移;相对荧光量子产率(φf)比 BECVN降低了7．4倍。在飞秒钛宝石激光器泵浦下(760 nm),两样品的DMF溶液发出强的双光子上转换 荧光发射,峰位与单光子荧光峰位相比发生红移(500-556 nm)。BMABN的双光子荧光强度和双光子吸收 截面分别是BECVN的3倍和30．4倍。

One-photon fluorescence（OPF） and two-photon fluorescence （TPF） of two chromophores 1,4-bis（9-ethyl-vinyl carbazole） naphthalene （abbreviated as BECVN） and 1,4-bis（4-N, N-methylamino styryl） naphthalene （abbreviated as BMABN） were resported. Strong emission at 492-541 nm and at 500-556 nm, respectively, were obtained under the excitation of -370 nm （Xe lamp） and of 730-800 nm femto-second laser pulses, respectively. Although the relative fluorescence quantum yield （ Фf ） of BECVN is as high as 7.4 times that of BMABN, the latter possesses higher TPF intensity and larger two-photon absorption （TPA） cross-section, suggesting that BMABN containing naphthalene as n-center end-capped with N, N-methylamino styryl group exhibits more effective two-photon process. Lippert equation showed that the difference of dipole momnet （△μge） between the ground state and the excited state for BECVN is nearly twice that for BMABN, conforming to that the △μge value is not the key for the enhancement of two-photon absorption cross-section.