Ultraflexible organic field-effect transistors embedded at a neutral strain position

We fabricated ultraflexible pentacene field-effect transistors (FETs) with a mobility of 0.5 cm(2)/V s and an on/off ratio of 10(5), which are functional at the bending radius less than 1 mm. The transistors are manufactured on a 13-mu m-thick polyimide film and covered by a 13-mu m-thick poly-chloro-para-xylylene encapsulation layer so that transistors can be embedded at a neutral position. This sandwiched structure can drastically suppress strain-induced changes in transistor characteristics. Furthermore, the FETs show no significant change after bending cycles of 60 000 times on inward and outward bending stresses. (C) 2005 American Institute of Physics.