Large-area patterning of a solution-processable organic semiconductor to reduce parasitic leakage and off currents in thin-film transistors

We describe two techniques for patterning spin-cast thin films of a solution-processable organic semiconductor, triethylsilylethylnyl anthradithiophene (TES ADT), to eliminate parasitic leakage currents and to lower off currents in thin-film transistors. One technique utilizes UV light in the presence of solvent vapors to simultaneously define the active channel and to crystallize TES ADT. The second technique selectively removes TES ADT from the nonchannel regions of the thin-film transistors through direct contact with a poly(dimethylsiloxane) stamp. Both patterning techniques yield thin-film transistors with high charge-carrier mobility (0.1 cm2 V s), low off currents (10-10 - 10-11 A), and minimal parasitic leakage.