Roll-Printed Organic Thin-Film Transistor Using Patterned Poly(dimethylsiloxane) (PDMS) Stamp

Abstract

The roll-printed gate, source, and drain electrodes of organic thin-film transistors (OTFTs) were fabricated by gravure printing or gravure-offset printing using patterned poly(dimethylsiloxane) (PDMS) stamp with various channel lengths and low-resistance silver (Ag) pastes on flexible 150 x 150 mm2 plastic substrates. Bottom-contact roll-printed OTFTs used polyvinylphenol (PVP) as polymeric dielectric and bis(triisopropyl-silylethynyl) pentacene (TIPS-pentacene) as organic semiconductor; they were formed by spin coating or ink-jetting. Depending on the choice of roll-printing method, the printed OTFTs obtained had a field-effect mobility of between 0.08 and 0.1 cm2/Vs, an on/off current ratio of between 10(4) and 10(5), and a subthreshold slope of between 1.96 and 2.32 V/decade. The roll-printing using patterned PDMS stamp and soluble processes made it possible to fabricate a printed OTFT with a channel length of between 12 to 74 microm on a plastic substrate; this was not previously possible using traditional printing techniques. The proposed fabrication process was 20 steps shorted than conventional fabrication techniques.