作者:Pim G. A. Janssen、Maarten Pouderoijen、Albert J. J. M. van Breemen、Peter T. Herwig、Guy Koeckelberghs、Andreea R. Popa-Merticaru、Stefan C. J. Meskers、Josué J. P. Valeton、E. W. Meijer、Albertus P. H. J. Schenning
DOI:10.1039/b608441a
日期:——
Nine different α,Ï-phenyl-endcapped bithiophenes were synthesised, and the effect of the different side chains on the liquid crystalline properties, alignment ability and charge carrier mobility have been studied. An increase in chain length leads to a decrease in the liquid crystallineâisotropic phase (clearing) transition temperature. Remarkably, introduction of an asymmetric carbon centre close to the Ï-conjugated segment resulted in the loss of the liquid crystalline phase. Alignment on rubbed polyimide was obtained for the liquid crystalline thiophene derivatives lacking heteroatoms in the side chain and for the chiral α,Ï-phenyl-endcapped bithiophene. Some bithiophenes showed bipolar charge transport in time-of-flight (TOF) measurements, with mobilities up to 3 à 10â3 cm2 Vâ1 sâ1 in the liquid crystalline state. Field effect transistors revealed mobility for holes up to 1 à 10â3 cm2 Vâ1 sâ1 (crystalline state). From the data set obtained, it can be concluded that the use of linear hydrocarbon chains as solubilising tails in these types of Ï-conjugated building blocks gives the best overall electronic performance.
合成了九种不同的α,ω-苯基封端双噻吩,并研究了不同侧链对液晶性质、排列能力和电荷载流子迁移率的影响。随着链长的增加,液晶-各向同性相(清亮点)转变温度下降。值得注意的是,在π共轭段附近引入不对称碳中心会导致液晶相的丧失。在摩擦聚酰亚胺上获得排列的液晶噻吩衍生物缺乏侧链中的杂原子,并且对于手性α,ω-苯基封端双噻吩也是如此。一些双噻吩在飞行时间(TOF)测量中显示出双极性电荷传输,液晶态下的迁移率高达3×10^-3 cm^2 V^-1 s^-1。场效应晶体管显示,晶体态下空穴的迁移率高达1×10^-3 cm^2 V^-1 s^-1。从获得的数据集可以得出结论,在这种类型的π共轭构建块中使用线性碳氢链作为增溶尾链可以获得最佳的整体电子性能。