Air-stable operation of organic field-effect transistors on plastic films using organic/metallic hybrid passivation layers

We investigated the stability of organic field-effect transistors (FETs) under ambient conditions. By employing organic/ metallic hybrid passivation layers, we improved the electric stability of organic FETs in air. Pentacene FETs were fabricated on plastic films and encapsulated in organic/ metallic hybrid passivation layers. These FETs exhibited a high mobility of 0.6 cm(2) V-1 s(-1) and an on/off ratio greater than 10(6). When the devices were stored in air for two months, the change in mobility was less than 2%. When continuous source-drain and gate voltages of -40 V were applied to the FETs for 10 days in air, the change in saturation current was less than 5%. We performed bending and heating tests in air. The FETs retained their functionality after being bent with a bending radius of less than I mm, and exhibited no changes in the performance after being subjected to a number of heat cycles up to 160 degrees C. The organic/ metallic hybrid passivation layer is also effective in reducing air degradation of n-type organic FETs.