Solution-processed organic field-effect transistors using directed assembled carbon nanotubes and 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT).

Achieving low-cost fabrication of organic field-effect transistors (OFETs) has long been pursued in the semiconductor industry. Solution-based process allows the fabrication of OFETs cost-effective because of its merit of vacuum-free and room temperature operation. Here, we show a facile and scalable fabrication of solution-processed OFETs using carbon nanotube (CNT) as source/drain electrodes and 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) as semiconducting layer on silicon as well as on flexible and transparent polyethylene terephthalate (PET) substrates. The CNT electrodes and the C8-BTBT film are fabricated using a dip coating-based directed assembly process, and two dip coating parameters, the pulling speed and the solution concentration, are carefully chosen so that the thickness of the C8-BTBT film is close to that of the CNT electrodes. The fabricated OFET devices show typical p-channel behavior. Low-cost, ease of processing, wafer level scalability and good compatibility with various substrates make the fabrication process presented in this paper well suited for next-generation electronics and sensors.