Development of High‑<i>k</i> Polymer Materials for Use as a Dielectric Layer in the Organic Thin-Film Transistors

In this article, we developed a series of novel high dielectric polymers based on 5-TPM-co-HEMA-co-GMA (TP) and 5-CTPM-co-HEMA-co-GMA (TP–CN) containing alkylated terphenyl and alkylated terphenyl with a cyano group, respectively. These organic insulating materials provide smooth surface topographies, lower leakage current densities (–7 A/cm2 at 2 MV/m), and small dielectric loss (3 to 105 Hz), which display excellent insulating properties. Simultaneously, two kinds of polymer films have higher dielectric constants of 6.8 and 8.6 than other dielectric constants reported in some literatures and most commercial organic dielectric materials. To investigate the potential of TP and TP–CN as gate dielectrics, we successfully prepared bottom-gate top-contact organic thin-film transistors, with para-hexaphenyl (p-6P) as the buffer layer and vanadyl phthalocyanine (VOPc) as the active layer, which yields a higher charge carrier mobility of 0.52 cm2 V–1 s–1 and on/off ratio > 104