Abstract
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 (μ FE ) from 0.014 to 1 cm 2 V -1 s -1 in vacuum. The μ 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. © 2013 AIP Publishing LLC.