液晶性有機半導体材料の有機トランジスタへの展開

抄録

Liquid crystals can be used as a quality organic semiconductor material, because their intrinsic charge carrier transport is electronic. They show high solubility in organic solvents and easy control of molecular orientation, which helps to fabricate uniform films with good surface morphology. We have developed a novel liquid crystalline organic-semiconductor, 2-decyl-7-phenyl-benzothienobenzothiophene (Ph-BTBT-10), which exhibits highly ordered liquid crystal phase of Smectic E (SmE) phase, from 142℃ to 210℃. Uniform and flat polycrystalline thin films can be easily fabricated by spin-coating technique at a liquid crystalline temperature and cooling down to room temperature. The bottom-gate top-contact type field effect transistors (FETs) with the polycrystalline thin films exhibited high FET mobility of 16.6 cm²/Vs in the average of 12 devices and 22.4 cm²/Vs in the maximum. The FETs exhibited thermal durability up to 200℃ thanks to solid-like nature of the SmE phase.