Structure of exciplexes: solvent and temperature dependences of charge transfer character.

The influence of temperature on the efficiency of fluorescence of the encounter complex (A- ...D+)* in intermolecular electron transfer starting from neutral precursors has been studied. In contrast to what is generally assumed, fluorescence emission of the exciplexes is found to be thermally activated. The systems studied here consist of N,N-dimethylaniline (DMA), and tributylamine (TBA) as electron donors and anthracene (An) as electron acceptor. This study has proved that the two exciplexes behave differently with temperature.