Paper TF-ThA11
Field-Effect Mobility Enhancement of Organic Thin Film Transistors on Flexible Substrates with Organosilanes-based Surface Modification

Thursday, October 23, 2008, 5:20 pm, Room 302

In Organic Thin Film Transistors (OTFTs), the performance is profoundly affected by organic semiconductor crystal formation or organic structure ordering. As it is known, the ability of conjugated molecules to transport charge due to the π-orbital overlap of neighboring molecules provides their semiconducting and conducting properties. The self-assembling or ordering of these molecules enhances this π-orbital overlap and is the key to improvements in carrier mobility. Since the semiconductor materials are deposited on dielectric layer, the surface chemical and mechanical properties of dielectric materials do affect the alignment and the crystal formation of semiconductor. For industrial applications requiring large area coverage, structural flexibility, and low cost, such as printed electronics, each layer is printed on the flexible plastic substrate, so that the dielectric materials have to be printable. In this work, poly(4-vinyl phenol-co-methyl methacrylate) (PVP-PMMA) was used as dielectric cross-linked at 200ºC by mixing with p- Tolyltrimethoxysilane (TTMS) on polyimide substrate, and Aluminum deposited on the polyimide as gate. The carbon ink could be printed on the cross-linked PVP-PMMA to form source and drain. Solution processed bis(triisopropylsilylethynyl) (TIPS) pentacene was deposited either by drop casting or rod coating and the field effect carrier mobility of 10^-3 ~10^-5 cm²/V•s were obtained. The resulting structures and systems were also characterized with differential scanning calorimetry and atomic force microscopy.