Li Wei-Shi, Yamamoto Yohei, Fukushima Takanori, Saeki Akinori, Seki Shu, Tagawa Seiichi, Masunaga Hiroyasu, Sasaki Sono, Takata Masaki, Aida Takuzo
ERATO-SORST Nanospace Project, Japan Science and Technology Agency (JST), National Museum of Emerging Science and Innovation, 2-41 Aomi, Koto-ku, Tokyo 135-0064, Japan.
J Am Chem Soc. 2008 Jul 16;130(28):8886-7. doi: 10.1021/ja802757w. Epub 2008 Jun 18.
For tailoring solution-processable optoelectronic thin films, a rational strategy with amphiphilic molecular design is proposed. A donor-acceptor dyad consisting of an oligothiophene and C60, when modified with a hydrophilic wedge on one side and a paraffinic wedge on the other (1Amphi), forms over a wide temperature range a photoconducting smectic A liquid crystal having bicontinuous arrays of densely packed donor and acceptor units. In contrast, when modified with only paraffinic wedges (1Lipo), the dyad forms a smectic A liquid crystalline mesophase, which however is poorly conductive. As indicated by an absorption spectral feature along with a synchrotron radiation small-angle X-ray scattering profile, 1Lipo in the lamellar structure does not adopt a uniform head/tail orientation. Such defective donor and acceptor arrays likely contain a large number of trapping sites, leading to short-lived charge carriers, as observed by a flash photolysis time-resolved microwave conductivity study.
为了定制可溶液加工的光电薄膜，提出了一种基于两亲分子设计的合理策略。由低聚噻吩和C60组成的供体-受体二元体系，当一侧用亲水性楔块修饰而另一侧用链烷烃楔块修饰时（1Amphi），在很宽的温度范围内形成具有密集堆积的供体和受体单元的双连续阵列的光导近晶A液晶。相比之下，当仅用链烷烃楔块修饰时（1Lipo），该二元体系形成近晶A液晶中间相，但其导电性很差。如吸收光谱特征以及同步辐射小角X射线散射轮廓所示，层状结构中的1Lipo没有采用均匀的头/尾取向。这种有缺陷的供体和受体阵列可能包含大量的俘获位点，导致电荷载流子寿命短，这在闪光光解时间分辨微波电导率研究中得到了观察。
