Enhancement of Field-Effect Mobility By Controlling the Surface Potential of PVP Insulator in Pentacene-Based Thin Film Transistors

Abstract

In recent years, the surface potential at insulator/semiconductor interface has received considerable attention for improving the electrical performance of various electronic and optoelectronic device. Many studies of the effect of a surface potential at insulator/semiconductor interface have been carried out. Most of these studies have focused on achieving efficient hole or electron injection at the inorganic insulator (i.e., such as SiO2)/ semiconductor interface. But the surface potential effects at the polymer insulator/semiconductor interface of organic thin-film transistors have not been sufficiently studied. In this presentation, we focus in particular on the effects of varying the surface potential on the polymer insulator/semiconductor interface. We demonstrated a method of reducing the surface energy in a polymer insulator for use in high-performance OTFTs. The surface energy of a poly(4-vinyl phenol) insulator was reduced from 45 mJ/m2 to 32 mJ/m2 through treatment with UV/ozone and ODTS. These treatments facilitated the deposition of the pentacene film onto the ODTS-treated poly(4-vinyl phenol) insulator to prepare a single phase that showed better π-orbital overlap among the pentacene molecules. As a result, the field-effect mobility in the insulator increased by 209 %. These results demonstrated that adjusting the surface energy of a polymer insulator provided a suitable approach to enhancing the performances of OTFTs. Acknowledgments This study was supported by the R&D program of the Korea Research Council for Industrial Science and Technology of Republic of Korea (Grant 2015K000217/ 10052802/ KM3710/ NK186C/ SC1130/ MO5970/ NM8270).