Solution-based silk fibroin dielectric in n-type C60 organic field-effect transistors: Mobility enhancement by the pentacene interlayer

A pentacene interlayer of 2 nm thick is inserted between fullerene (C-60) and the solution-based silk fibroin dielectric in C-60 organic field-effect transistors (OFETs). The pentacene interlayer assists to improve crystal quality of the C-60 layer, leading to the increase of field-effect mobility (mu(FE)) from 0.014 to 1 cm(2) V-1 s(-1) in vacuum. The mu(FE) value of the C-60 OFET is further enhanced to 10 cm(2) V-1 s(-1) when the OFET is exposed to air in a relative humidity of 55%. Generation of mobile and immobile charged ions in solution-based silk fibroin in air ambient is proposed. (C) 2013 AIP Publishing LLC.