N-channel organic field-effect transistors containing carbonyl-bridged bithiazole derivative fabricated using polyfluorene derivatives as solution-processed buffer layers

The effects of adding solution-processed polyfluorene derivatives as buffer layers between the polymer insulator and active layer of n-channel organic field-effect transistors (OFETs) containing a carbonyl-bridged bithiazole derivative were investigated. The surface free energy was modified by the polyfluorene derivatives. A poly(9,9-dioctylfluorene) (F8) buffer layer, which has a hydrophobic nature, a low surface free energy, and consists almost entirely of a dispersion component, improved the growth morphology of the OFET active layer. An OFET with an F8 buffer layer exhibited n-channel characteristics, and an electron field-effect mobility of 0.025 cm2 V−1 s−1.