We perform ab initio calculations of optical properties for a typical semiconductor conjugated polymer, poly-para-phenylenevinylene, in both isolated chain and crystalline packing. In order to obtain results for excitonic energies and real-space wave functions we explicitly include electron-hole interaction within the density-matrix formalism. We find that the details of crystalline arrangement crucially affect the optical properties, leading to a richer exciton structure and opening nonradiative decay channels. This has implications for the optical activity and optoelectronic applications of polymer films.

• Received 17 January 2002

DOI:https://doi.org/10.1103/PhysRevLett.88.206403