Ink-jet-printed organic-inorganic hybrid dielectrics for organic thin-film transistors

Using a thermally crosslinkable organosiloxane-based organic-inorganic hybrid material, we formulated a functional ink suitable for ink-jet printing of dielectric thin films. Ink solvent chemistry plays an important role in producing a uniform dielectric layer. In particular, the hydrodynamic motion of the solvents is controlled during the drying period. We used a higher-boiling-point solvent in order both to prevent a nozzle from clogging and to suppress convective flow. We also incorporated a lower-boiling-point solvent of high surface tension for diminishing the outward Marangoni flow. We successfully applied the printed hybrid dielectric layer with smooth surface morphology to the gate dielectric layer for organic thin-film transistors and analyzed the electrical performance of the transistor based on the ink-jet-printed dielectric layer, comparing with that of the transistor based on the spin-coated dielectric layer.