Air-stable π-conjugated amorphous copolymer field-effect transistors with high mobility of 0.3 cm²/Vs

We have fabricated organic bottom-contact top-gate field-effect transistors with an indenofluorene-phenanthrene co-polymer semiconductor, exhibiting ON/OFF ratio of 10(7) and uncommonly high mobility for an amorphous conjugated polymer of up to 0.3 cm(2)/Vs. Lack of crystallinity in this material is indicated by atomic force microscopy, grazing incidence wide angle X-ray scattering, and differential scanning calorimetry data. Nevertheless, fitting transistor data to the Gaussian disorder model gives low energetic disorder of sigma = 48 meV and high prefactor mobility mu(0) = 0.67 cm(2)/Vs. The measured transistor mobility is also exceptionally stable in ambient conditions, decreasing only by approximately 15% over two months. (C) 2012 American Institute of Physics