High performance organic transistors on cheap, commercial substrates

Abstract

We present here our latest results on high quality gate insulators for organic electronics. Ultra-thin films of n-octadecyltrichlorosilane-treated, anodized aluminium (Al) grown onto flexible, Al-sputtered polyester substrates combine low cost and manufacture under ambient conditions with excellent performance characteristics (negligible leakage and hysteresis, 400nFcm -2 capacitance). With pentacene as organic semiconductor, we present organic transistors with inverse subthreshold slope of approximately 200 mV dec-1, threshold of the order of -2 V and > 105 on/off ratio. The subthreshold behaviour is significantly better than for transistors with pentacene deposited onto a gate insulator optimized for high mobility. Above the threshold, the higher capacitance compensates for the somewhat lower mobility. Crucially, the cheap, sputtered Al-on-polyester films resulted in transistors that were as good as transistors fabricated on the same substrate with evaporated Al.