Star-shaped molecules containing both azo chromophores and carbazole units as a new type of photoresponsive amorphous material
作者:Jianjun Yin、Gang Ye、Xiaogong Wang
DOI:10.1039/c3tc30536h
日期:——
We synthesized a series of star-shaped molecules containing both azo chromophores and carbazole units (nCz-AZ-X), where n is the number of carbazole units (n = 3 and 6) and X represents cyano (CN) and nitro (NT) as the electron-withdrawing groups on the azobenzenes. The azo compounds existed as amorphous solids at room temperature with glass transition temperatures (Tg) of 89, 86, 74 and 73 °C for 3Cz-AZ-CN, 3CZ-AZ-NT, 6Cz-AZ-CN and 6Cz-AZ-NT, respectively. Thin solid films of the azo molecular glasses were obtained by spin-coating. The formation of the photoinduced self-structured surface patterns was investigated by irradiating the solid thin films of the azo molecular glasses with a uniform laser beam (532 nm, 200 mW cm−2) at normal incidence. The formation of surface-relief-gratings (SRGs) was studied by exposing the thin films to an interference pattern of the laser beams (532 nm, 80 mW cm−2). The formation of both the self-structured surface patterns and SRGs showed a close correlation with the electron-withdrawing groups of the azo chromophores and the content of the carbazole units in the molecules. The development of these new star-shaped molecules can add a new member to the category of azo molecular glasses and lead to a deeper understanding of the photoinduced effects and their correlation with molecular structures.
我们合成了一系列含有偶氮色素和咔唑单元的星形分子(nCz-AZ-X),其中 n 是咔唑单元的数量(n = 3 和 6),X 表示作为电子吸引基团的氰基(CN)和硝基(NT)在偶氮苯上。这些偶氮化合物在室温下以无定形固体存在,玻璃转变温度(Tg)分别为 89、86、74 和 73 °C,针对 3Cz-AZ-CN、3Cz-AZ-NT、6Cz-AZ-CN 和 6Cz-AZ-NT。通过旋涂法获得了偶氮分子玻璃的薄固体膜。通过用均匀激光束(532 nm,200 mW cm−2)在法向入射下照射偶氮分子玻璃的固体薄膜,研究了光诱导自结构表面图案的形成。通过将薄膜暴露于激光束的干涉图案(532 nm,80 mW cm−2),研究了表面光栅(SRGs)的形成。这些自结构表面图案和 SRGs 的形成与偶氮色素的电子吸引基团以及分子中咔唑单元的含量密切相关。这些新型星形分子的开发可以为偶氮分子玻璃类别增添新成员,并有助于更深入地理解光诱导效应及其与分子结构之间的关系。