Luminescence quenching by inter-chain aggregates in substituted polythiophenes
Time-resolved photo luminescence spectra measured in solid films of two polythiophene derivatives with different chain packing allow to distinguish emission of intra-chain excitations from the luminescence of inter-chain aggregates. Aggregate luminescence is red shifted by about 0.1 eV relative to intra-chain emission and shows vibronic coupling to the C=C bond stretch with the Huang-Phys factor o