Improved photostability of organic thin film transistors with tantalum oxide/poly(4-vinylphenol) double gate insulators

In this letter, the authors investigated the photostability of pentacene organic thin film transistors (OTFTs) with Ta2O5 gate insulators. Under illumination, the threshold voltage shift of the Ta2O5-based OTFTs reached 5.51V. The obvious photoinstability was attributed to the electron trapping ability of the Ta2O5 film. To solve this problem, poly(4-vinylphenol) (PVP), a type of polymer with low trap density and high photostability was used to modify Ta2O5. It was found that OTFTs with Ta2O5∕PVP double gate insulators showed improved performance, and the voltage shift after illumination was greatly reduced to 0.04V.