Fully inkjet-printed short-channel organic thin-film transistors and inverter arrays on flexible substrates

Abstract

We report fully inkjet-printed organic thin-film transistors (OTFTs) and inverters with an average channel length of 9 μm and minimized overlap capacitance between gate and source/drain (S/D) electrodes on a flexible plastic substrate. Metal-organic precursor-type silver ink, poly(4-vinylphenol), and 6, 13-bis (triisopropylsilylethynyl)pentacene were used to form the gate and S/D electrodes, the gate dielectric, and the active semiconductor layer, respectively. Well-defined S/D electrodes with narrow width and spacing can be realized by introducing a separate printing process and interdigitated structure with a cartridge that can eject a 1 picoliter volume of ink droplets without any assistant surface treatments or structures. Fully inkjet-printed short channel OTFT arrays presenting an average mobility of 0.065 cm2 V−1 s−1 and on/off ratio of 4 × 103 and inverter arrays exhibiting a voltage gain of 5.5 at a VDD of −30 V and good frequency response were demonstrated.