Highly transparent thin-film transistors using wide-bandgap organic semiconductors and multilayer transparent electrodes

Highly transparent organic thin-film transistors operable at low voltages were demonstrated using a wide-bandgap organic semiconductor for channel layers, metal-based multilayers for transparent source/drain (S/D) electrodes, and an ultrathin fluoropolymer for gate dielectric layers. The devices optimized for high transparency based on characteristic-matrix formalism exhibited transmittances over 85% for the channel region and over 70% for the S/D region in almost the entire visible range. The validity of the multilayer S/D contact and the ultrathin fluoropolymer dielectrics on indium tin oxide (ITO) gate electrodes for favourable electrical characteristics were also verified. The resultant transparent thin-film transistors showed a typical p-channel operation switchable under 2 V with ca. 0.72 cm2/V s mobility.