A study of α- and β-phase poly(9,9-dioctylfluorene) by electroabsorption spectroscopy

The excited-state structure of β-phase poly(9,9-dioctylfluorene) (F8) is investigated by means of optical absorption and electroabsorption spectroscopies in order to reveal the effect of β-phase formation on the excited-state structure in F8. The excited-state structure of β-phase F8 consists of six essential states, where two new Bu states are formed on the four essential states of α-phase F8. The two additional Bu states result from the energy splitting of the Bu states of α-phase F8, caused by intermolecular interaction in β-phase F8.