中文摘要：

随着双光子显微技术的发展,获得性质优良的双光子荧光染料成为研究热点.因此,通过密度泛函理论（DFT）对一系列D-π-A-π-D型1,4-二（4＇-N,N-二苯胺基苯乙烯基）苯（DPA-DSB）衍生物平衡几何结构、电子结构、单双光子吸收以及荧光发射性质进行了理论研究,对其结构和光学性质的分析表明,对A,π结构元进行修饰或更换可有效地调节光谱;向分子片段A引入杂原子可有效提高双光子吸收截面;和乙烯基团相比,π桥为乙炔基,若对分子平面性改变不大,则导致分子双光子吸收截面值减小,若乙炔桥很大程度改善分子平面性,则导致分子的TPA截面增大.本研究旨在理解DPA-DSB衍生物分子结构与双光子性质间的关系,为设计合成新型双光子材料提供重要信息.

英文摘要：

With the development of two-photon microscopy, getting excellent two-photon fluorescence dyes become a hot topic. In this work, the equilibrium geometries, electronic structures, one-and two-photon absorption properties and the fluorescent emission properties for a series of D-π-A-π-D type 1,4-di（4＇-N,N-diphenylaminostyryl）benzene（DPA-DSB） derivatives were investigated by the density functional theory（DFT）. The results show that the one photon absorption wavelengths of this series of one-dimensional linear conjugated molecules are in the range 370~540 nm, fluorescence emission wavelengths are in the range 435~700 nm, provided the absorption of the UV to green light and the emission of the all visible range. The Stokes shifts are in the 47~270 nm range. Thus, these molecules provide broad color fluorophore options molecules for biological fluorescence imaging and fluorescence microscopy. The response function approach has been used to calculate the two-photon properties. Analysis of two-photon properties of these molecules suggests that these molecules two-photon absorption wavelengths are at 650~880 nm. The molecules 2, 4, 5, 6, 8 and 12, 14 have two-photon absorption in the infrared light range, which means these molecules can be used as alternative molecules to design the infrared medical material. These molecules have the fluorescence signal in the visible range and excellent two-photon characteristics; can be used as two-photon fluorescent probes biomarkers and alternative materials. Analyzing its structure and optical properties indicate that the modification or replacement of the electron-withdrawing group in the center of the molecule can effectively shift its electronic spectrum, the addition of N atom or S atom can significantly improve the two-photon absorption cross-section. For the acetylenyl moiety as π bridge, if the molecular plane did not change compared with ethylene bridge, it makes the two-photon absorption cross-section decreases; if acetylene bridge improved the planarity of