Solution processed OTFTs for OLED backplanes: development of high performance short channel length devices

Abstract

ABSTRACT High performance short channel OTFTs with field effect mobilities greater than 1cm 2 V -1 s -1 have been developed for OLED driver applications incorporating soluble crystalline semiconductor materials. We highlight the impact of contact resistance on the mobility in these devices and show by functionalising both the source and drain contacts and channel regions in a top gate bottom contact device architecture that the mobility can be significantly improved. Our approach also includes the optimisation of solvent selection from which the semiconductor material is deposited in order to enhance crystalline domain formation. Keywords: Organic transistor, OLED, high mobility, TIPS Pe ntacene, contact resistance , crystalline semiconductor 1. INTRODUCTION Organic thin film transistors (OTFTs) are a promising alte rnative candidate to silicon based devices in active matrix backplanes for a wide range of display technologies due to their solution processing properties, potential for lower cost of production and flexibility in device design. For a semiconductor material to be considered as a candidate for driving a display medium, particularly a current driven technology such as organic light emitting diode (OLED), field effect mobilities greater than 0.5 cm