Direct Printed Flexible Organic Thin-Film Transistors With Cross-Linked PVA-Carrageenan Gate Dielectric

There is an urgent need to develop and implement green materials in electronic systems to minimize the negative environmental impact of traditional electronic materials. In this letter, low-temperature cross-linked polyvinyl alcohol (PVA)-carrageenan (CAR) layer is presented as a green electronic gate dielectric for high-performance organic thin-film transistors (OTFT). A metal-free, flexible OTFT, direct printed on polyaniline films using poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) gel-based gate–source–drain layers, PVA-CAR gate dielectric, and 6,13-bis(triisopropylsilylethynyl)pentacene semiconductor, is tested and characterized compared with a more conventional organic gate dielectric polymethylmethacrylate. PVA-CAR metal–dielectric–metal capacitors showed excellent dielectric properties with an average absolute dielectric constant value of 22.36 and an absolute capacitance density value of 168 nF/cm
²
at 40 Hz under room temperature conditions. The PVA-CAR OTFT consistently demonstrated a low gate leakage current of 0.2–52.8 nA, a low device override voltage of VDS around -4V, and
on/off
current ratio of 10
⁵
–10
⁶
. The direct printed PVA-CAR OTFT has excellent transistor characteristics for low-temperature processed organic transistors and show promise for application in sensors and green flexible electronics.