화학공학소재연구정보센터
Molecular Crystals and Liquid Crystals, Vol.519, 179-186, 2010
An Amorphous Polythiophene as a Binder Material for Organic Thin-Film Transistor Channel Applications
Blending of crystalline low molecular-weight organic semiconductors, e. g., 6,13-bis (triisopropylsilylethynyl) pentacene (TIPS-Pentacene), and binder polymers has recently been known to be an effective way to achieve high performance organic thin-film transistors (OTFTs). However, only limited number of examples has been reported as binder materials for OTFT applications, e. g., poly(triarylamine), poly(a-methylstyrene), and etc. In this work, an amorphous polythiophene derivative, poly(3-(2-ethylhexyl) thiophene) (P3EHT), was prepared by introducing 2-ethylhexyl group as a side-chain to the polythiophene. The P3EHT was synthesized by Grignard metathesis (GRIM) polymerization to give a molecular weight (Mn) of 4,100 (PDI=3.4), and it was readily soluble in common organic solvents, such as chloroform, tetrahydrofuran, toluene, and etc. An amorphous nature of the P3EHT was confirmed from differential scanning calorimetry (DSC) and ultraviolet-visible spectroscopy results. A mobility of 2.5 x 10 (4) cm(2)/Vs, an on/off ratio of 0.57 x 10(3) and a threshold voltage of 1.6 V have been obtained with OTFTs using a P3EHT/TIPS-Pentacene blend.