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.