D. Oelkrug et al., ELECTRONIC DEACTIVATION IN SINGLE CHAINS, NANO-AGGREGATES AND ULTRATHIN FILMS OF CONJUGATED OLIGOMERS, Synthetic metals, 76(1-3), 1996, pp. 249-253
Fluorescence spectra, quantum yields Phi(F), decay curves, and fluores
cence anisotropies of oligothiophenes and oligophenylenevinylenes with
varying chain lengths are determined in the dissolved state, in nano-
aggregates acid in ultrathin films. Phi(F) decreases in the series mon
omer > aggregate approximate to disordered film > oriented film by fou
r 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 th
e increasing density of luminescence centers.