Abstract
A large number of organic materials have to be deposited by thermal evaporation for the fabrication of organic field-effect transistors. In order to realize the low-cost and flexible electronic with various thin-film transistor application, the organic materials need to be deposited by solution processing for the fabrication of polymer field-effect transistors. In this thesis, the low cost and flexible device of field-effect transistors have been fabricated by spin coating. We not only fabricate and investigate the unipolar transport of the organic field-effect transistor on flexible substrates using solution processing, but also fabricate and investigate the bipolar transport of the organic field-effect transistor using solution processing by blending two organic materials. For the logic circuit application, we have demonstrated the complementary transistor circuits which comprised p-type and n-type transistor and utilized low-power consumption. Also, for the design of efficient organic integrated circuits, there is an urgent need for complementary technology, where both n-type and p-type transistor operation is realized in a single layer, while maintaining the attractiveness of easy solution processing. We demonstrate, by using solution-processed field-effect transistors, that hole transport and electron transport are both generic properties of organic semiconductors. Ambipolar field-effect transistor devices were fabricated through solution processing, mixtures of p-type and n-type semiconductors Poly (3-hexylthiophene) and fullerene providing balanced ambipolar characteristics with high hole and electron mobilities. Finally, we also implemented the low-voltage operation inverter though using the high-k metal oxides as gate insulators.