Poly(3-alkylthiophenes) (P3ATs)因為其可溶液製程、可靈活調整的化學結構以及其優秀的電洞傳輸性能而被廣泛地運用於各種有機電子元件，在這些聚噻吩衍生物中又以poly(3-hexylthiophene) (P3HT)最具有代表性且被深入地研究，許多研究都指出立體規則度(regioregularity , R.R.)與分子量對於高分子堆疊及排列有很大的影響力，而這對於載子傳輸是很重要的。但是相對的較少有人研究R.R.及分子量對於其它具有側鏈官能基的P3ATs的影響，而完整且系統性的研究是需要的。 此外，將一硫元素加入烷基側鏈基已經被證明可以有效的對高R.R.的P3HT及其衍生物的固態結構進行微調。這裡我們合成並分析了poly(3-alkylthio-thiophene) (P3ATTs)這一系列的高分子半導體包括poly(3-hexylthiothiophene) (P3HTT) (P3HTT)、poly(3-decylthiothiophene) (P3DTT)與poly(3-(2-ethyl)hexylthiothiophene) (P3EHTT)，並且探討了R.R.與分子量對於P3HTT的影響。透過將硫烷基測鏈取代烷基測鏈，π-π堆疊的距離從原本P3HT的3.88 Å縮近至P3HTT 的3.76 Å，而π-π堆疊的距離與主鏈的排列的方向性是決定元件效能的兩個最關鍵性的因素，因此溶液剪切力塗佈法被選擇用來製備高方向性高分子薄膜並應用於有機場效應電晶體，於P3HTT與P3DTT的電洞遷移率分別達到1.48×10-2 cm2 V-1 s-1與7.67×10-3 cm2 V-1 s-1。 ;Poly(3-alkylthiophenes) (P3ATs) have been used broadly in organic electronic application by virtue of its solution processability, tunable chemical structure and high hole mobility. Among these polythiophene derivatives, poly(3-hexylthiophene) (P3HT) is most representative and well-studied, and many studies revealed polymer regioregularity (R.R.) and molecular weight have an influence on molecular packing and ordering of polymers, which is important to charge transfer. However, there is less research about the effects of regioregularity or molecular weight on other P3ATs with functionalized sidechain, and the systematic research is needed. Furthermore, alkyl sidechain substituent with a sulfur atom has been proven to enable fine tuning of the solid-state organization of the corresponding regioregular P3HT analogues. In this paper, we present the synthesis and characterization of a series of poly(3-alkylthiothiophene) (P3ATT)-based polymer semiconductors including poly(3-hexylthiothiophene) (P3HTT)、poly(3-decyl-thiothiophene) (P3DTT) and poly(3-(2-ethyl)hexylthiothiophene) (P3EHTT). P3HTT with various R.R. and molecular weights were also discussed. In this case, the π-π stacking distance successfully decreased from 3.88 Å to 3.76 Å by substituting hexyl sidechain by thiohexyl sidechain. Since both π-π interaction and backbone alignment are significant factors affecting charge transport behavior, unidirectional solution shearing method was applied to fabricate oriented polymer thin film for organic field effect transistor, reaching the mobility to 1.48×10-2 cm2 V-1 s-1 and 7.67×10-3 cm2 V-1 s-1 for P3HTT and P3DTT, respectively.
