Low-Voltage Flexible Organic Electronics Based on High-Performance Sol–Gel Titanium Dioxide Dielectric

In this letter, we report that high-performance insulating films can be generated by judicious control over the microstructure of sol–gel-processed titanium dioxide (TiO₂) films, typically known as wide-bandgap semiconductors. The resultant device made of 23 nm-thick TiO₂ dielectric layer exhibits a low leakage current density of ∼1 × 10^–7 A cm^–2 at 2 V and a large areal capacitance of 560 nF cm^–2 with the corresponding dielectric constant of 27. Finally, low-voltage flexible organic thin-film transistors were successfully demonstrated by incorporating this versatile solution-processed oxide dielectric material into pentacene transistors on polyimide substrates