High-performance organic transistors based on solution-processed rubrene crystals directly grown on a polymeric dielectric

High-quality rubrene crystals were directly grown on a polymeric gate dielectric-coated ITO/glass substrate by a simple solution process. Organic field-effect transistors were fabricated based on these rubrene crystals, and their electrical performance was investigated. Atomic force micrographs of the rubrene crystal reveal that its surface has a conventional terrace structure, confirming the well-ordered rubrene molecules. The organic transistor with the rubrene crystal shows the highest charge carrier hole mobility of 3.74 cm2/V·s that can be attributed to the strong π-π overlap between the adjacent rubrene molecules. The device shows a stable static and dynamic electrical stress response under ambient conditions. For evaluating the applicability of the transistor in a logic circuit, a simple load-type inverter is fabricated by combining the rubrene transistor and a 10 MΩ load-resistor, to achieve a clear dynamic switching response up to 100 Hz.