High Performance Organic Field-Effect Transistors Using cyanoethyl Pullulan (CEP) High- k Polymer Cross-linked with Trimethylolpropane Triglycidyl Ether (TTE) at Low Temperatures

Abstract

Low-voltage operable organic field-effect transistors (OFETs) were fabricated using a low-temperature curable high-k polymer cyanoethyl pullulan (CEP) as a gate insulator with trimethylolpropane triglycidyl ether (TTE) as a crosslinking agent. With this crosslinking agent, the gate insulators showed low leakage current and a high dielectric constant of 14.8-16, and most importantly, could be cured at low temperatures around 100 degrees C, which is compatible with most plastic substrates for future plastic electronics. The favorable semiconductor-dielectric interface was obtained due to the surface alignment of well-packed pentacene domains, which enabled excellent transistor performance, with one of the highest mobilities around 6 cm(2) V-1 s(-1), an on/off current ratio (I-on/I-off) similar to 10(5), and a steep subthreshold (SS) similar to 0.095 V dec(-1). The high mobility was found to be closely correlated with the surface C equivalent to N dipole density rather than other possibilities, such as dielectric roughness and surface energy. The initial growth of the semiconductors was also studied and correlated with the affecting variables.