Highly Dielectric and Photo-patternable Gate Insulators for Organic Field-effect Transistors

Abstract

A highly dielectric and photo-patternable polymer material has been developed as a gate insulating layer in organic field-effect transistors (OFETs). The partially cyanomethylated poly(vinyl phenol) (PVPCM) was synthesized as a highly dielectric polymer matrix. The photosensitive PVPCM (PS-PVPCM) consisting of PVPCM (72 wt%), 4,4’-methylenebis[2,6-bis(hydroxymethyl)phenol] (25 wt%) as a cross-linker, and Irgacure PAG-103 (3 wt%) as a photoacid generator showed a good patterning performance such as high resolution of 6 μm, high sensitivity of 15.5 mJ/cm2, and good contrast of 3.3 when i-line lithography was employed. PVPCM and PS-PVPCM exhibited high dielectric constants (PVPCM = 4.51 and PS-PVPCM = 4.29). The OFET performance using poly(3-hexylthiophene) as a polymeric semiconductor and PS-PVPCM as a gate insulator showed the excellent charge mobility of 0.102 cm2/Vs and on/off ratio of 1.1 × 106.