The spatial extension and binding energy of excitons in semiconducting conjugated polymers are still the subject of a great debate. We address this problem through first-principles calculations (within DFT-LDA, plane-waves and ab-initio pseudopotentials), which allow to include electron-hole correlation effects in a fully three-dimensional approach through the density-matrix formalism. We show results for the correlated optical spectrum and the exciton wavefunctions of single-chain poly(para)phenylene-vinylene (PPV), that support the picture of a strongly bound anisotropic exciton localized over similar to 4-5 monomers.
Ab-initio study of Coulomb-correlated optical properties in conjugated polymers / Ruini, Alice; F., Rossi; U., Hohenester; Molinari, Elisa; R., Capaz; M. J., Caldas. - In: SYNTHETIC METALS. - ISSN 0379-6779. - STAMPA. - 119:(2001), pp. 257-258. [10.1016/S0379-6779(00)01016-X]