H 2 O effect on the stability of organic thin-film field-effect transistors

Degradation of organic thin-film field-effect transistors (OTFTs) with pentacene as the active material has been studied. It was found that the field-effect mobility of the device decreased by 30% and the on/off current ratio decreased to one fifth after the OTFTs had been stored in atmosphere for 500 h. Through surface morphology analysis by atomic force microscopy and absorption analysis by infrared spectroscopy, it was found that the adsorption of ${\mathrm{H}}_2\mathrm{O}$ on the pentacene layer was the main reason for the degradation. Remarkable improvement in the device performance was achieved by device encapsulation with UV curable resin.