Synthesis and investigation on optoelectronic properties of mesogenic triphenylene–perylene dyads linked by ethynylphenyl bridges
Synthesis and investigation on optoelectronic properties of mesogenic triphenylene–perylene dyads linked by ethynylphenyl bridges
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乙炔基苯基桥介晶苯并菲-苝二元体的合成及光电性能研究
DOI：
10.1039/c7nj04328g
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发表时间：
--
影响因子：
3.3
通讯作者：
Zhiqun He
中科院分区：
文献类型：
--
作者：
Xiangfei Kong;Hongkang Gong;Peng Liu;Wei Yao;Zheng Liu;Guixia Wang;Shufen Zhang;Zhiqun He
制备了具有五（己氧基）苯并菲供体通过乙炔基苯基桥连接到二萘嵌苯单酰亚胺二己酯受体的酰亚胺氮原子的光化学电子给体-受体二联体，得到TP-n-PIE（n = 1、2和3）。通过13 C和1H核磁共振谱（NMR）、红外光谱（IR）、质谱（MS）和元素分析（EA）对其结构进行了表征。差示扫描量热法（DSC）的痕迹，偏光显微镜（POM）的纹理和X-射线衍射图证实，较短的乙炔基苯基桥促进了柱状六方液晶相的形成。芘单元的光吸收强度与桥长无关，而苯并菲单元的光吸收强度随桥长的增加而红移。二维和三维光致发光谱表明，刚性桥越短，荧光猝灭程度越大。根据二联体的能级结构，荧光猝灭归因于分子内光诱导电子转移过程。在这些过程中，得到了分子的电荷分离态TP+ stec-1-PIE− stec，并通过光电流响应曲线进一步证实。循环伏安法显示，虽然乙炔基苯基桥与苯并菲单元共轭连接，但当桥长变化时，最高占据分子轨道（HOMO）能级、最低未占据分子轨道（LUMO）能级和带隙几乎不变.这些结果与理论模型的结果一致。柱状液晶相的形成、大的摩尔消光系数和激发时电荷分离分子的有效形成，使这些二元体具有用作新型单组分光伏活性材料的前景。
Photochemical electron donor–acceptor dyads having a penta(hexyloxy)triphenylene donor attached to the imide nitrogen atom of a perylene monoimide dihexyl ester acceptor by an ethynylphenyl bridge were prepared to give TP-n-PIE (n = 1, 2 and 3). Their molecular structures were characterized by 13C and 1H nuclear magnetic resonance (NMR) spectroscopy, infrared spectroscopy (IR), mass spectroscopy (MS) and elemental analysis (EA). Differential scanning calorimetry (DSC) traces, polarizing optical microscopy (POM) textures and X-ray diffractograms confirmed that shorter ethynylphenyl bridges facilitated the formation of a columnar hexagonal liquid crystal phase. The intensity of light absorption of the perylene units was independent of the bridge lengths, while that of the triphenylene units was red-shifted with the increase of the bridge lengths. 2D and 3D photoluminescence emission showed that the fluorescence quenching degree of perylene units increased as the rigid bridges became shorter. According to the energy level structures of the dyads, fluorescence quenching was attributed to intramolecular photoinduced electron transfer processes. And in these processes the charge-separated state of the molecule, TP+˙-1-PIE−˙, further confirmed by the photocurrent response curve, was obtained. Cyclic voltammetry revealed that although the ethynylphenyl bridges were conjugatedly connected to the triphenylene units, the highest occupied molecular orbital (HOMO) energy levels, the lowest unoccupied molecular orbital (LUMO) energy levels and the band gaps of these dyads were nearly constant when the bridge lengths varied. And these results were in agreement with those of theoretical modelling. The formation of a columnar liquid crystal phase, the large molar extinction coefficient and efficient formation of charge-separated molecules when excited give these dyads the prospect of being used as a novel type of single-component photovoltaic active materials.