Light emitting mechanisms in an alternated fluorene EDOT copolymer—A theoretical and photophysical study

The synthesis and photophysical characterization of a PPV type copolymer containing a fluorene derivative alternated with ethylenedioxythiophene units, poly[2,5-(3,4-ethylenedioxythiophene)-alt-(9,9'-dihexil-2,7-fluorene)] (LaPPS32) are presented and discussed. The photophysical studies along with theoretical simulation demonstrated that the main factor responsible for the polymer behavior is the progressive conformational twisting upon addition of each repeating unit to the polymer chain, together with intra- and intermolecular energy transfer processes. The main electroluminescence parameters are also discussed in connection with the photophysical behavior. - Highlights: ► Synthesis and photophysical properties of an alternated PPV type are described. ► Repeating units were fluorene and ethylenedioxythiophene. ► A twisted conformation upon the addition of each repeating unit was shown theoretically. ► Photo-physical data demonstrated the formation of an ICT state. ► Time resolved measurements indicated intra- or intermolecular energy transfer processes