Department of Applied Chemistry and Biochemistry, Kumamoto University , 2-39-1 Kurokami, Chuou-ku, Kumamoto, Japan 860-8555.
Graduate School of Natural Science and Technology, Okayama University , Tsushimanaka 3-1-1, Kita-ku, Okayama City, Okayama, Japan 700-8530.
Langmuir. 2017 Sep 12;33(36):8906-8913. doi: 10.1021/acs.langmuir.7b01603. Epub 2017 Aug 29.
The temperature and concentration dependencies of the crystallization of two small-molecular semiconductors were clarified by constructing quasi-phase diagrams at air/oil interfaces and in bulk oil phases. A quinoidal quaterthiophene derivative with four alkyl chains (QQT(CN)4) in 1,1,2,2-tetrachroloethane (TCE) and a thienoacene derivative with two alkyl chains (C8-BTBT) in o-dichlorobenzene were used. The apparent crystal nucleation temperature (T) and dissolution temperature (T) of the molecules were determined based on optical microscopy examination in closed glass capillaries and open dishes during slow cooling and heating processes, respectively. T and T were considered estimates of the critical temperatures for nuclear formation and crystal growth, respectively. The T values of QQT(CN)4 and C8-BTBT at the air/oil interfaces were higher than those in the bulk oil phases, whereas the T values at the air/oil interfaces were almost the same as those in the bulk oil phases. These Gibbs adsorption phenomena were attributed to the solvophobic effect of the alkyl chain moieties. The temperature range between T and T corresponds to suitable supercooling conditions for ideal crystal growth based on the suppression of nucleation. The T values at the water/oil and oil/glass interfaces did not shift compared with those of the bulk phases, indicating that adsorption did not occur at the hydrophilic interfaces. Promotion and inhibition of nuclear formation for crystal growth of the semiconductors were achieved at the air/oil and hydrophilic interfaces, respectively.
通过在空气/油界面和本体油相中构建准相图，阐明了两种小分子半导体的结晶的温度和浓度依赖性。使用了具有四个烷基链的醌式四噻吩衍生物（QQT（CN）4）在 1,1,2,2-四氯乙烷（TCE）和具有两个烷基链的噻吩并[3,2-b]噻吩衍生物（C8-BTBT）在邻二氯苯中。通过在封闭玻璃毛细管和开放盘中进行的光学显微镜检查，分别在缓慢冷却和加热过程中确定了分子的表观晶核形成温度（T）和解溶温度（T）。T 和 T 被认为分别是核形成和晶体生长的临界温度的估计值。在空气/油界面处，QQT（CN）4 和 C8-BTBT 的 T 值高于本体油相中的 T 值，而在空气/油界面处的 T 值几乎与本体油相中的 T 值相同。这些吉布斯吸附现象归因于烷基链部分的疏油效应。T 和 T 之间的温度范围对应于理想晶体生长的合适过冷条件，因为可以抑制成核。与本体相相比，水/油和油/玻璃界面处的 T 值没有变化，这表明亲水性界面没有发生吸附。半导体的成核促进和抑制分别在空气/油和亲水界面上实现了晶体生长。
