Direct-written polymer field-effect transistors operating at 20 MHz

Abstract

Printed polymer electronics has held for long the promise of revolutionizing technology by delivering distributed, flexible, lightweight and cost-effective applications for wearables, healthcare, diagnostic, automation and portable devices. While impressive progresses have been registered in terms of organic semiconductors mobility, field-effect transistors (FETs), the basic building block of any circuit, are still showing limited speed of operation, thus limiting their real applicability. So far, attempts with organic FETs to achieve the tens of MHz regime, a threshold for many applications comprising the driving of high resolution displays, have relied on the adoption of sophisticated lithographic techniques and/or complex architectures, undermining the whole concept. In this work we demonstrate polymer FETs which can operate up to 20 MHz and are fabricated by means only of scalable printing techniques and direct-writing methods with a completely mask-less procedure. This is achieved by combining a fs-laser process for the sintering of high resolution metal electrodes, thus easily achieving micron-scale channels with reduced parasitism down to 0.19 pF mm−1, and a large area coating technique of a high mobility polymer semiconductor, according to a simple and scalable process flow.

Accessing MHz Operation at 2 V with Field‐Effect Transistors Based on Printed Polymers on Plastic

“…[37] The same technique was also previously demonstrated to be compatible with plastic substrates for the fabrication of electrodes, [44,45] semi-transparent grids, [46] and transistors, [47][48][49] while it has not yet been adopted yet for high-frequency, printed electronics on plastic. We have previously adopted femtosecond-laser sintering for the realization of highresolution electrodes and high-frequency polymer transistors on glass.…”

Current Status and Opportunities of Organic Thin-Film Transistor Technologies

“…The record f T reported to date reaches the value of 27.7 MHz for a device based on C 60 with a channel length of 2 μm defined by photolithography [119]. Recently, OTFTs with f T of 20 MHz were fabricated by means only of scalable coating techniques and laser-based directwriting methods with a completely mask-less procedure [124]. A much higher throughput approach was demonstrated by Kang et al [126], who used highly scaled gravure printing to fabricate OTFTs with a fast printing speed of 1 m/s, despite a lower f T = 0.3 MHz.…”

Semiconducting Single‐Walled Carbon Nanotubes or Very Rigid Conjugated Polymers: A Comparison

“…[23,24,318] Related polymers with somewhat higher electron mobilities were only recently reported. [321] Clearly the advantage of semiconducting polymers for circuits lies more in their printability and low cost than in potential high-frequency applications. Figure 15 shows an example of a complementary inverter with printed DPPT-TT for the p-channel and P(NDI2ODT2) for the n-channel transistor.…”