Progress of Flexible Printed Organic Electronics

Abstract

Flexible and printed organic electronics technology has garnered increasing attention and resources in research and development because of its potential use in low-cost, environmentally friendly electronic devices. We successfully fabricated pseudo-CMOS inverters using p-type organic thin-film transistor (OTFT) devices and NAND logic gates. The inverters exhibited ideal characteristics at low operating voltages and high gains. Using our newly developed n-type organic semiconductor (OSC) material (TU-3) and a commonly used p-type OSC material (diF-TES-ADT), we successfully demonstrated a CMOS inverter that employed a stacked TFT device construction. Based on this CMOS inverter design, an operational amplifier, ring oscillators, and D-flip flop circuits were also fabricated. To realize very short-channel OTFT devices and higher-performance integrated circuits, we employed the reverse-offset printing method to form narrow channel lengths of less than 10μm, which resulted in good electrical characteristics. Pressure sensors based on ferroelectric polymer (PVDF-TrFE) materials are excellent at detecting vital signs in the human body. We previously succeeded in precisely detecting pulse waves with a wearable patch-type sensor, which was fabricated on a plastic film substrate using printing methods. Our goal was to develop a smart sensor device that can be connected wirelessly to the Internet and that combines printed integrated circuits and one or more sensors. More recently, we developed flexible hybrid electronic (FHE) devices that use silicon-based LSI die for signal processing and wireless communication circuits and that are integrated onto a flexible plastic film substrate.