双光子吸收材料二苯乙烯衍生物的合成及光谱性质

设计、合成并用红外光谱、1H NMR、元素分析表征了三种用于双光子吸收材料的二苯乙烯衍生物，4,4′-双(二苯氨基-反式-苯乙烯基)联苯(BPSBP)，4,4′-双(二乙氨基-反式-苯乙烯基)联苯(BESBP)和4,4′-双(9-咔唑基-反式-苯乙烯基)联苯(BCSBP)。实验结果表明三者最强的单光子吸收出现在350～400 nm之间，且单光子吸收和荧光光谱中表现出明显的溶剂化显色效应，揭示了分子内对称电荷转移的本质，双光子荧光光谱则揭示了单光子和双光子吸收具有相同的发射机理。利用双光子上转换荧光法测试发现，三种双光子吸收材料在800 nm飞秒激光的激发下具有较大的吸收截面，分别为892，617和483 GM，这表明在双光子领域有潜在的应用价值。

Synthesis and Spectral Properties of Stilbene Derivatives as Two-Photon Absorption Materials

Three stilbene derivatives with good coplanarity and enhanced charge delocalization in the conjugated molecular system, 4,4′-bis(diphenylamino-trans-styryl)biphenyl (BPSBP), 4,4′-bis(diethylamino-trans-styryl)biphenyl (BESBP) and 4,4′-bis(9-carbazyl-trans-styryl)-biphenyl (BCSBP), were designed, synthesized and characterized by infra-red spectroscopy, hydrogen nuclear magnetic resonance and elemental analysis. Experimental results reveal that the strongest one-photon absorption peaks appear between 350 and 400 nm, which is the energy region of two near infrared photons. The obvious solvatochromism was observed in five different polar solvents and the corresponding one-photon absorption and fluorescence emission spectra validate the character of intramolecular symmetric charge transfer. Two-photon fluorescence spectra show that both one- and two-photon processes share the same emission mechanism although they have different excitation processes and selection rules. The quadratic dependence of fluorescence intensity on excitation intensity indicates a real two-photon absorption process. The two-photon absorption cross section was measured via two-photon induced upconversion fluorescence method. The large values of two-photon absorption cross section, 892 GM, 617 GM and 483 GM for BPSBP, BESBP and BCSBP respectively, were obtained at 800 nm wavelength from a femtosecond laser source, which means potential applications in two-photon absorption fields.