2D Bands and Electron-Phonon Interactions in Polyacene Plastic Transistors

We present a simple tight-binding model for the two-dimensional energy bands of polyacene field-effect transistors and for the coupling of these bands to lattice vibrations of their host molecular crystal. We argue that the strongest electron-phonon interactions in these systems originate from the dependence of intermolecule hopping amplitudes on collective molecular motion, and introduce a generalized Su-Schrieffer-Heeger model and is parameter-free once the band mass has been specified. We compute α²F(ω) as a function of two-dimensional hole density, and are able to explain the onset of superconductivity near 2D carrier density n_2D~10¹⁴ cm^-2, observed in recent experiments.