Quasi-Phase Diagrams at Air/Oil Interfaces and Bulk Oil Phases for Crystallization of Small-Molecular Semiconductors by Adjusting Gibbs Adsorption
Quasi-Phase Diagrams at Air/Oil Interfaces and Bulk Oil Phases for Crystallization of Small-Molecular Semiconductors by Adjusting Gibbs Adsorption
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DOI：
10.1021/acs.langmuir.7b01603
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发表时间：
2017-09-12
期刊：
影响因子：
3.9
通讯作者：
Kunitake, Masashi
中科院分区：
文献类型：
--
作者：
Watanabe, Satoshi;Ohta, Takahisa;Kunitake, Masashi
两个小分子半导体的结晶的温度和浓度的依赖关系，澄清通过构建准相图在空气/油界面和散装油相。采用含四个烷基链的四元噻吩衍生物（QQT（CN）-4）和含两个烷基链的噻吩并苯衍生物（C8-BTBT）分别在1，1，2，2-四氯乙烷（TCE）和邻二氯苯中进行催化反应。通过光学显微镜观察，测定了分子在密闭玻璃毛细管中缓慢冷却和缓慢加热过程中的表观晶体成核温度（Tn）和溶解温度（Td）。Tn和Td分别被认为是成核和晶体生长临界温度的估计值。QQT（CN）-4和C8-BTBT在空气/油界面的Tn值高于在油相中的Tn值，而在空气/油界面的Td值与在油相中的Td值基本相同。这些吉布斯吸附现象归因于烷基链部分的疏溶剂效应。Tn和Td之间的温度范围对应于基于抑制成核的理想晶体生长的合适的过冷条件。在水/油和油/玻璃界面的Tn值没有移动相比，那些的体相，表明吸附没有发生在亲水界面。在空气/油界面和亲水界面分别实现了半导体晶体生长的成核促进和抑制。
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-n) and dissolution temperature (T-d) of the molecules were determined based on optical microscopy examination in closed glass capillaries and open dishes during slow cooling and heating processes, respectively. Tn and Td were considered estimates of the critical temperatures for nuclear formation and crystal growth, respectively. The Tn values of QQT(CN)-4 and C8-BTBT at the air/oil interfaces were higher than those in the bulk oil phases, whereas the Td 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 Tn and Td corresponds to suitable supercooling conditions for ideal crystal growth based on the suppression of nucleation. The Tn 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.