Electrical performance of flexible OTFTs based on slot-die printed dielectric films with different thicknesses

Abstract

Abstract The use of large area, low-cost solution processes for OTFT fabrication constitutes a highly challenging yet promising field, considering the great amount of applications based on OTFTs. In this study, a roll-to-roll compatible technique- slot-die printing- is used in order to fabricate the OTFT Poly(4-vinylphenol) (PVP) dielectric film onto a 90x15 cm2 PET/IMI substrate. Via slot-die printing, different dielectric film thicknesses were achieved by altering the printing parameters in order to study various electrical characteristics in the OTFTs’ performance, such as the effect in capacitance values and leakage currents. 6,13-bis(triisopropylsilylethinyl) (TIPS) – Pentacene was used as a semiconducting layer and was airbrushed onto the PVP layer. The dielectric film thickness was investigated via Spectroscopic Ellipsometry, resulting in a thickness range of 310-460 nm. The fabricated devices exhibited a fluctuation in their average mobilities with respect to the thickness variation, reaching the highest value of 0.3 cm2/Vs in the case of the thickest dielectric film. Leakage currents were also investigated, reaching values of 10-5 10-6 A.