Performance improvement of pentacene organic field-effect transistor through introducing polymer buffer layers

Pentacene organic field-effect transistors (OFETs) employing poly(methyl methacrylate) (PMMA), polystyrene and polyvinylidene fluoride as the electrode buffer layers by simple spray-coating fabrication process were systematically investigated. Significant performance enhancement of the OFETs was obtained. By analyzing the morphologies of pentacene films grown on gold electrodes and the electrical characteristics of these OFETs, the performance improvement was attributed to the uniform and hydrophobic properties of polymer surface, leading to a remarkable reduction of contact resistance at the pentacene/electrodes interface. Moreover, the results showed that the device employing PMMA as the electrode buffer layer exhibited the highest hole mobility of 0.59 cm(2)/Vs, which was almost five times of the control one. Such effect was ascribed to the optimal surface energy and appropriate dielectric constant of PMMA, which were favorable for the growth of pentacene crystal and responsible for the highest performance of OFET using PMMA as the electrode buffer layer.