All-polymer thin film transistors fabricated by high-resolution ink-jet printing

All-polymer thin film transistors (TFTs) are fabricated by ink-jet printing for the first time. Source/drain electrodes are printed using a conducting polymer (PEDOT) solution on substrates with patterned wetting-and-dewetting regions. A channel length down to 5 mum has been achieved without short-circuits. The TFTs show a high mobility of 0.02 cm(2)/V .s and on/off ratio of more than 10(5). These characteristics are equal or better than reference devices with gold electrodes. The fabrication of printed inverters is also demonstated, in which components such as gate electrodes, interconnections, via-holes or resistors, are patterned with the ink-jet technique.