Excited state characterization of a polymeric indigo

摘要: A comprehensive investigation of the solution photophysics a 5,5′-methylene-bridged polymeric indigo, statistical copolymer consisting indigo and N-acetylindigo units, was performed in organic solvents at room temperature further compared with indigo. complete spectral photophysical characterization based on photoacoustic calorimetry, steady-state time-resolved fluorescence data undertaken. quantum yield 0.00037 an intersystem crossing singlet-to-triplet 0.006 (close to value for indigo) were obtained, leading 0.9936 S1 S0 internal conversion (IC) yield. Spectral characteristics similar obtained with, however, special signature: it (mainly) decays single exponentially (in contrast found decay bi-exponentially), time 40–50 ps even more efficient IC deactivation channel, related energy migration within energetic ladder polymer chromophoric segments. The photochemistry this polymer, namely degradation under light excitation, also investigated photoreaction (ϕR) DMF be 0.003, which is lower than previously determined same solvent (ϕR = 0.0078). overall indicate that although have close finger-print, former stable suggested due additional intramolecular transfer process (within different units) polymer.