High-performance organic thin-film transistors with polymer-blended small-molecular semiconductor films, fabricated using a pre-metered coating process

Abstract

We herein present results obtained from our study of flat and uniform polymer-blended small-molecular semiconductor thin films. These films were produced for organic thin film transistors (OTFTs), using a simple pre-metered horizontal dipping process. The organic semiconductor thin films were composed of a small molecular 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-PEN) composite blended with a polymer binder of poly(α-methylstyrene) (PaMS). We show that the pre-metered solution-coating process allowed the critical control of the thickness of the TIPS-PEN:PaMS film; extremely thin films could be produced using the downstream meniscus of the solution at high speeds (of the order of a few metres per minute). The fabricated TIPS-PEN:PaMS OTFTs exhibited a maximum field-effect mobility of 0.22 cm² V⁻¹ s⁻¹, and on/off ratios of over 10⁵, that were consistently superior to those of conventional spin-cast devices. These results demonstrate that horizontal dip-coated TIPS-PEN:PaMS films show considerable promise for the production of reliable, reproducible, high-performance OTFTs.