Fabrication of ambipolar organic field-effect transistors(OFETs) is essential for the achievement of an organic complementary logic circuit.Ambipolar transports in OFETs with heterojunction structures are realized.We select pentacene as a P-type material and N,N'-bis(4-trifluoromethylben-zyl)perylene-3,4,9,10-tetracarboxylic diimide(PTCDI-TFB) as a n-type material in the active layer of the OFETs.The field-effect transistor shows highly airstable ambipolar characteristics with a field-effect hole mobility of 0.18 cm 2 /(V·s) and field-effect electron mobility of 0.031 cm 2 /(V·s).Furthermore the mobility only slightly decreases after being exposed to air and remains stable even for exposure to air for more than 60 days.The high electron affinity of PTCDI-TFB and the octadecyltrichlorosilane(OTS) self-assembly monolayer between the SiO 2 gate dielectric and the organic active layer result in the observed air-stable characteristics of OFETs with high mobility.The results demonstrate that using the OTS as a modified gate insulator layer and using high electron affinity semiconductor materials are two effective methods to fabricate OFETs with air-stable characteristics and high mobility.
