Study on high performance organic field effect transistors based on highly ordered and orientation controllable organic semiconductors

Abstract

Organic field effect transistors (OFETs) based on organic semiconductors (OSCs) have been extensively studied in material science due to low temperature and low cost processes as well as mechanical flexibility, which can be facilitated to the next generation flexible, foldable, and stretchable electronics. For charge carrier mobility of transistors, there has been a need to exhibit high performance above $10 cm^2V^{-1}s^{-1}$ of common silicon-based inorganic semiconductors mobility to realize large area displays operation with high resolution as well as wireless communication with standard protocols. However, the electrical properties of OSCs are relatively low compared to them, which are obstacles for practical applications. To improve the charge carrier mobility of OFETs, the study from OSCs molecular ordering and orientation to domain size should be ideally combined. In this Ph. D. dissertation, we mainly discuss the high performance OFETs by optimizing and controlling OSCs ordering and orientation. To this end, we suggest the OSCs exhibiting liquid crystal (LC) properties for highly ordered and oriented structures to improve electrical properties. Additionally, highly ordered and oriented OSCs via a DNA template is proposed for sustainable and efficient organic devices. Finally, we demonstrate the system which can modulate molecular orientation of OSCs by tuning microchannel widths showing different optical and electrical properties.