Low-voltage indium-zinc-oxide thin film transistors gated by solution-processed chitosan-based proton conductors

We fabricated indium-zinc-oxide (IZO) thin film transistors (TFT) gated by chitosan (CS) on ITO/glass substrate. Chitosan is demonstrated to be a new kind of solution-processed organic polymer electrolyte, which has nice film-forming characteristic. The chitosan thin film shows a large specific gate capacitance of 8.06 μF/cm² due to the mobile-ions induced electric-double-layer effect. These devices exhibited a good performance with a small subthreshold swing of 0.3 V/dec, a large on-off current ratio of ~10⁶, a high field-effect mobility of 1.24 cm²V^-1 s^-1 and a low operate voltage of 2 V. The solution-processed chitosan-based TFTs may have many potential applications for large-area, mechanically flexible, lightweight, and inexpensive electronic logic circuits.