Adjustable threshold-voltage in all-inkjet-printed organic thin film transistor using double-layer dielectric structures

• A double-layer dielectric organic thin film transistor, OTFT, is implemented.
• The threshold voltage of OTFT can be configured by the double dielectric structure.
• The composition of the dielectric determines the threshold voltage shift.
• The characteristics of OTFTs can be adjusted by double dielectric structures.

An all-inkjet-printed organic thin film transistor (OTFT) with a double-layer dielectric structure is proposed and implemented in this study. By using the double-layer structure with different dielectric materials (i.e., polyvinylphenol with poly(vinylidene fluoride-co-hexafluoropropylene)), the threshold-voltage of OTFT can be adjusted. The threshold-voltage shift can be controlled by changing the composition of dielectric layers. That is, an enhancement-mode OTFT can be converted to a depletion-mode OTFT by selectively printing additional dielectric layers to form a high-k/low-k double-layer structure. The printed OTFT has a carrier mobility of 5.0 × 10− 3 cm2/V-s. The threshold-voltages of the OTFTs ranged between − 13 V and 10 V. This study demonstrates an additional design parameter for organic electronics manufactured using inkjet printing technology.