Flexible complementary inverter with low-temperature processable polymeric gate dielectric on a plastic substrate

We report low-temperature processability of poly(4-vinylphenol) based gate dielectric by investigating the effect of composition and processing temperature on the thermal, mechanical and electrical characteristics of the gate dielectric. We found that the processing temperature of the gate dielectric could be reduced up to 70 °C by optimizing the composition of the gate dielectric solution. Based on this finding, we have fabricated a flexible organic complementary inverter by integrating n- and p-type organic thin-film transistors (OTFTs) with the low-temperature processable gate dielectric on a plastic substrate. Pentacene and F16CuPc were used as p-type and n-type semiconductor, respectively. The inverter shows that the swing range of Vout is same as VDD, which ensures “zero” static power consumption in digital circuits. The logic threshold of the inverter with G5 gate dielectric cured at 70 °C is 21.0 V and the maximum voltage gain (∂Vout/∂Vin) of 8.1 is obtained at Vin = 21.0 V. In addition, we have discussed in more detail the characteristics of the OTFTs and the complementary inverter with respect to the process condition of the gate dielectric.