2003/03/26 by E. V. Tsiper, Z. G. Soos · 2 citations
Chemistry · Engineering · Materials Science · Physics and Astronomy · #Conducting polymers and applications #Electrochemical Analysis and Applications #Organic Electronics and Photovoltaics #cond-mat
paper · pdf · doi:10.1103/physrevb.68.085301
10 revtex pages, 6 PS figures embedded
arxiv created 2003/03/26 · openalex publication_date 2003/08/07 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
Electronic polarization is evaluated in pentacene crystals and in thin films on a metallic substrate using a self-consistent method for computing charge redistribution in nonoverlapping molecules. The optical dielectric constant and its principal axes are reported for a neutral crystal. The polarization energies P+ and P_\ensuremath- of a cation and anion at infinite separation are found for both molecules in the crystal's unit cell in the bulk, at the surface, and at the organic-metal interface of a film of N molecular layers. We find that a single pentacene layer with herring-bone packing provides a screening environment approaching the bulk. The polarization contribution to the transport gap P=P++P_\ensuremath-, which is 2.01 eV in the bulk, decreases and increases by only \ensuremath∼10% at surfaces and interfaces, respectively. We also compute the polarization energy of charge-transfer states with fixed separation between anion and cation, and compare to electroabsorption data and to submolecular calculations. Electronic polarization of \ensuremath∼1eV per charge has a major role for transport in organic molecular systems with limited overlap.