Electronic deactivation in single chains, nano-aggregates and ultrathin films of conjugated oligomers

摘要

Fluorescence spectra, quantum yields PHI_F, decay curves, and fluorescence anisotropies of oligothiophenes and oligophenylenevinylenes with varying chain lengths are determined in the dissolved state, in nano-aggregates and in ultrathin films, PHI_F decreases in the series monomer >aggregate approx approx disordered film > oriented film by four powers of ten, whereas the average decay times remain unchanged. The orientational relaxation time is 35 ps in condensed oligothiophenes. the strong increase of PHI_F with disorder is mainly attributed to the increasing density of luminescence centers.