[23a-E206-1~10] 12.4 Organic light-emitting devices and organic transistors

△ [23a-E206-1] Mixing-Induced Orientational Ordering and Thermal Analysis of Phase Competitions
in Liquid-Crystalline Semiconductor, PE-BTBT-C_n

〇(M2)Kiyoshi Nikaido¹, Satoru Inoue¹, Toshiki Higashino², Reiji Kumai³, Satoshi Matsuoka¹, Shunto Arai¹, Tatsuo Hasegawa¹ (1.U. Tokyo, 2.AIST, 3.KEK IMSS)

Keywords:liquid crystal, phase transition, organic transistor

PE-BTBT-C_n is an organic semiconductor which exhibits the characteristic competition between the liquid crystal phase and the ordered crystal phase depending on the alkyl chain length n. In particular, the molecule with n = 6 exhibits a unique orientational disorder within the herringbone layer in a solid state, which can be regarded as a frozen state of the liquid crystal phase. We have reported that the structural ordering and the enhancement in the carrier mobility can be induced by mixing a small amount of longer-alkylated molecules (n ≥ 8). In this report, we discuss the unique growth mechanism of the order / disorder phases through the solution process, based on the results of the detailed thermal analyses on the mixtures.