High performance organic transistors on cheap, commercial substrates

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, 400 nF cm −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 >10 5 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. (Some figures in this article are in colour only in the electronic version)