Dielectric optimization for inkjet-printed TIPS-pentacene organic thin-film transistors

Abstract

We have fabricated inkjet-printed 6,13-bis(triisopropylsilylethynyl) (TIPS) pentacene thin-film transistor by optimizing a cross-linked poly-4-vinylphenol (PVP) dielectric on glass substrate. The quality and integrity of the polymer dielectric has been studied for different weight percent of PVP and the poly(melamine-co-formaldehyde) as a cross-linking agent (CLA) in propylene glycol methyl ether acetate (PGMEA), so as to minimize the dielectric leakage current. The dielectric constant is measured for different weight percent of the solution through capacitance measurements of metal-insulator-metal structures. The typical dielectric leakage current density ranges between 10-9 to 10-7 Ampere/mm2 for various weight percent and the dielectric capacitance ranges from 6 nF/cm2 to 21 nF/cm2. The electrical characteristics of the OTFT exhibits the saturation field effect mobility 2 × 10-3 cm2/V-s, the current ON/OFF ratio of ~102, a threshold voltage of 1.52 Volt.