VALENCE-BAND OFFSET IN POLYMERIC CHAINS - THE POLYTHIOPHENE POLYPARAPHENYLENE INTERFACE/

The valence band offset Delta E(v) at the interface between polythioph ene and polyparaphenylene is derived from electronic structure calcula tions within the local-density approximation to the density functional theory. We use both the macroscopic electrostatic potential, and the core levels as reference energies to compute the alignment of the vale nce band maxima of the two polymers at the interface. When the spacing between polymeric chains in a simple orthorhombic lattice is large en ough, we obtain Delta E(v) = 0.75 +/- 0.05 eV, giving roughly equal va lence and conduction band offsets. For smaller separations we find a s mall but sizable (approximate to 0.15 eV) increase of Delta E(v). Copy right (C) 1996 Published by Elsevier Science Ltd.