Author/Authors :
Ehrenfreund، نويسنده , , E. and Cravino، نويسنده , , Pamela A. and Neugebauer، نويسنده , , H. and Sariciftci، نويسنده , , N.S. and Luzzati، نويسنده , , S. and Catellani، نويسنده , , M.، نويسنده ,
Abstract :
Using the photon energy induced blue shift of the resonant Raman scattering frequencies in inhomogeneous films (‘RRS dispersion’), we extract the energy of the lowest even parity state of π-conjugated polymers. We show that in the small band gap (≈1.1 eV) poly(dithienothiophenes), the experimentally observed unusually large RRS dispersion yields for the lowest even parity state (2Ag) an energy, which is in the vicinity of the optically allowed state (1Bu).
