Location of charge transfer states in α-sexithienyl determined by the electroabsorption technique

Absorption and electroabsorption measurements were carried out at 300 and 4 K on evaporated thin films of α-sexithienyl, which is a chemically well-defined prototype of conjugated polymers (i.e. polythiophene). The results allowed for the determination of the energy for the optical charge pairs formation in this material. The polarizabilities of the excited Frenkel exciton states have also been estimated. The singlet exciton binding energy is in the order of 0.4 eV.