Effect of gate electrode conductivity on operation frequency of inkjet-printed complementary polymer ring oscillators

Abstract

We report the effect of the conductivity of the gate electrode on operation speeds in printed organic ring oscillators (RO). The highly conducting gate electrode leads to a superior oscillation frequency (as high as ~30kHz) for the printed ROs. Above the optimum thickness of the gate electrodes (~30nm), inkjet-printed p-type poly(3-hexylthiophene) (P3HT) and n-type poly([N,N-9-bis(2-octyldodecyl)naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-5,59-(2,29-bithiophene)) (P(NDI2OD-T2)) organic field-effect transistors showed reasonably high hole and electron mobilities of ~0.05cm2V−1s−1 and ~0.25cm2V−1s−1, respectively. Complementary inverters and ring oscillators based on these p- and n-type semiconductor transistors were constructed, where the inverters showed the inverting voltage, (Vinv) near the ideal switching points at 1/2 the drain voltage (VDD), high gain (~10), low static power consumptions, as well as high noise margin (~60% of 1/2VDD). Finally, printed P3HT complementary ring oscillators with a gate thickness over 30nm exhibited the highest oscillation frequency (~30kHz).