Synthesis and Characterization of Liquid Crystal Molecule Based on Thieno [3,2-b] Thiophene for the Applications in Organic Field-Effect Transistors

• Main Authors: Su, Yi-Jen, 蘇怡禎
• Other Authors: Hsu, Chain-Shu
• Format: Others
• Language: zh-TW
• Published: 2014
• Online Access: http://ndltd.ncl.edu.tw/handle/83m5v5

碩士 === 國立交通大學 === 應用化學系碩博士班 === 103 === In this study, we synthesized a planar liquid crystal based on thieno [3,2-b] thiophene which added a phenyl and a thiophene unit to extend conjugated length (C12-PTTT) . In addition, two alkoxy groups were added to aromatic ring to gain additional liquid crystal phase and increase solubility. The obtained C12-PTTT compound was used to fabricate organic field effect transistor (OFET) devices. For the OFET device with self-assembled monolayers, its mobility increases from 6.14 × 10-4 cm2V-1s-1 to 2.44 × 10-3 cm2V-1s-1. Besides the traditional spin coating process, two methods were used to enhance the mobility of OFET device. The first method was applying a rubbed polyimide on the top of SiO2 layer. For this method, the mobility of its OFET device is enhanced to reach 1.88 × 10-2 cm2V-1s-1. The other method was using polydimethylsiloxane (PDMS) mode to fabricate microchannel on the top of SiO2 layer. The mobility of the OFET device based on C12-PTTT is further enhanced to reach 3.51 × 10-2 cm2V-1s-1 which is highest value for the OFET devices based on C12-PTTT. We also used microchannel method to fabricate a OFET device using another anthracenedithiophene-based liquid crystal compounds, i.e.,12PADT. It’s mobility reach the highest value of 1.31 cm2V-1s-1 which is much higher than that (2.77 × 10-2 cm2V-1s-1) of its traditional OFET device fabricated by spin coating process.