Photoexcitations in poly(p-phenylenevinylene) aggregates

Photo-induced electronic excitations of poly(p-phenylenevinylene) (PPV) agg regates are simulated and characterized using a recently developed linear-s caling localized-density-matrix (LDM) method. The intra- and inter-chain co mponents of excitations are analyzed and quantified for different inter-cha in distances. The excitations for the absorption and luminescence in PPV fi lm and its derivatives are identified and are found analogous to those of H -aggregates. Their energy shifts upon aggregation are determined mainly by the inter-chain kinetic energy reduction and the Coulomb interaction of the electron-hole pair. It is concluded that the luminescence is caused by the intra-chain electron-hole pairs. (C) 2001 Elsevier Science B.V. All rights reserved.