One-Volt, Solution-Processed Organic Transistors with Self-Assembled Monolayer-Ta(2)O(5) Gate Dielectrics

Low-voltage, solution-processed organic thin-film transistors (OTFTs) have tremendous potential to be key components in low-cost, flexible and large-area electronics. However, for these devices to operate at low voltage, robust and high capacitance gate dielectrics are urgently needed. Herein, the fabrication of OTFTs that operate at 1 V is reported. These devices comprise a solution-processed, self-assembled monolayer (SAM) modified tantalum pentoxide (Ta(2)O(5)) as the gate dielectric. The morphology and dielectric properties of the anodized Ta(2)O(5) films with and without n-octadecyltrichlorosilane (OTS) SAM treatment have been studied. The thickness of the Ta(2)O(5) film was optimized by varying the anodization voltage. The results show that organic TFTs gated with OTS-modified tantalum pentoxide anodized at 3 V (d ~7 nm) exhibit the best performance. The devices operate at 1 V with a saturation field-effect mobility larger than 0.2 cm(2) V(−1) s(−1), threshold voltage −0.55 V, subthreshold swing 120 mV/dec, and current on/off ratio in excess of 5 × 10(3). As a result, the demonstrated OTFTs display a promising performance for applications in low-voltage, portable electronics.