Temperature dependence of the multiple fluorescence of 9,9′-dianthrylmethanol Original Research Article

Temperature- and solvent polarity-dependent fluorescence spectra and decay curves of 9,9′-dianthrylmethanol are analysed using global analysis. The spectra can be decomposed into three contributions which are assigned to an anthracene-type, an excimer and a charge transfer (CT) species. The latter shows significant red-shifts with increasing solvent polarity and gains in relative importance upon lowering the temperature. It reaches a maximum at 200 K in n-butyronitrile where the excimer component is already negligible. These findings are interpreted with the possibility of small-overlap and large-overlap molecular conformations. In addition to these three emitting states, at least two quenching channels (photoproduct and intramolecular exciplex) have to be taken into account.