作者:Chandrasekaran Suryanarayanan、Ezhakudiyan Ravindran、Soundaram Jeevarathinam Ananthakrishnan、Narayanasastri Somanathan、Asit Baran Mandal
DOI:10.1039/c2jm30550j
日期:——
Herein, the relationship between supramolecularly self-assembled microstructures and the chemical structures of photoluminescent molecules is discussed. A series of non-amphiphilic molecules with different length alkyl chains (4–14), central mesogenic groups, and chemical linkers were designed and synthesized. Intricate analysis shows that the supramolecular assembly varies with change in torsion angle of the thiophene linking group on elongation of the alkyl chain. Small angle X-ray scattering measurement shows long range molecular interaction for lower alkyl chain length, AFM reveals circular domains for octyl and decyl alkyl group polymers. UV-Visible and photoluminescence studies in solution and thin-film show that the J-aggregate patterns for the circular domain of the polymer backbone has a major effect on the polymer absorbance, and produces a larger shift for the photoluminescence signals at higher wavelengths. Excitation polarisation studies show a change in molecular ordering in various colour regions with change in aggregation by means of maximum dichroic ratio for the circular domain assembly. Charge carrier mobility and cyclic voltammetry studies show higher mobility and reduced band gap for these circular domain polymers. Dynamic light scattering studies of octyl alkyl chain polymers show a bimodal distribution, which shows the apparent nature of anisotropy in solution.
本文讨论了超分子自组装微结构与光致发光分子化学结构之间的关系。研究人员设计并合成了一系列具有不同长度烷基链(4-14)、中心介原基团和化学连接体的非两亲分子。复杂的分析表明,烷基链伸长时,噻吩连接基团的扭转角发生变化,超分子组装也随之变化。小角 X 射线散射测量显示,烷基链长度较低时,分子间的相互作用范围较长;原子力显微镜显示,辛基和癸基烷基聚合物具有圆形结构域。溶液和薄膜中的紫外可见光和光致发光研究表明,聚合物骨架环形结构域的 J-聚合模式对聚合物的吸光度有重大影响,并在较高波长下产生较大的光致发光信号偏移。激发偏振研究表明,随着环形结构域组装的最大二色性比率发生变化,不同颜色区域的分子有序性也发生了变化。电荷载流子迁移率和循环伏安法研究表明,这些环状结构域聚合物的迁移率更高,带隙更小。辛基烷基链聚合物的动态光散射研究显示出一种双峰分布,这表明了溶液中各向异性的明显性质。