Improvement of Characteristics of Organic Thin-Film Transistor with Anodized Gate Insulator by an Electrolyte Solution and Low-Voltage Driving of Liquid Crystal by Organic Thin-Film Transistors

The characteristics of pentacene-based organic thin-film transistors (OTFTs) on plastic substrates with anodized gate insulators using different electrolyte solutions were investigated. The characteristics were significantly improved by using ammonium borate as the solution. The results show a good current-saturation characteristic, field-effect mobility of 0.51 cm ²/Vs and a current on/off ratio of 10⁵ at a low drain voltage of 3V. To investigate the reason for the improvements, the structural and electrical characteristics of OTFTs and insulators were examined using various methods such as X-ray diffraction, atomic force microscope, capacitance-voltage measurement and secondary ion mass spectroscopy. From the results of these experiments, it was found that the orientation of pentacene was improved and the concentration of impurities in the insulator decreased in the case of ammonium borate. We also examined low-voltage driving of liquid crystal devices by the OTFT, targeting its application for flexible displays. Improvement of characteristics by the solution was also confirmed in the driving.