The comprehensive study of hybrid dielectric layer adopted organic thin film transistors for low voltage operation

•A new class of low voltage driven organic thin film transistors (OTFTs) is realized.•We have adopted hybrid gate insulators composed of polymer buffer layer and oxygen-plasma reacted high-k metal oxides.•Our approach yields the commendable field-effect mobility (1.5 cm2/Vs) and a near zero threshold voltage.•The internal interaction between the polymer PVP layer and high-k metal oxide, generates an additional internal electric field. Organic electronics hold immense promise due to their flexibility, low-cost processing, and diverse applications. Despite tremendous progress, low-voltage operation has remained a significant hurdle, impacting device efficiency. Our investigation introduces a new class of low voltage driven pentacene transistors, featuring hybrid gate insulators composed of polymer buffer layer and oxygen-plasma reacted high-k metal oxides viz. AlOx, TiOx, and TaOx. We demonstrate that a combination of titanium dioxide (TiOx) as the high-k dielectric layer and poly vinyl phenol (PVP) as a buffer layer in organic thin-film transistors (OTFTs) achieves exceptional performance compared to aluminium oxide (AlOx) and tantalum oxide (TaOx). This innovative approach yields the notable field-effect mobility (1.5 cm2/Vs) and a commendable on/off ratio (3.4 × 104), surpassing devices fabricated with other high-k oxides. The success lies in the PVP’s ability to smooth surfaces and reduce interface defects, while TiOx’s superior dielectric constant fosters stronger gate control. These findings pave the way for the development of next-generation organic devices with significantly lower operating voltages, opening doors for energy-efficient and flexible electronics.