LOCATION OF CHARGE-TRANSFER STATES IN ALPHA-SEXITHIENYL DETERMINED BYTHE ELECTROABSORPTION TECHNIQUE

Absorption and electroabsorption measurements were carried out at 300 and 4 K on evaporated thin films of alpha-sexithienyl, which is a chem ically well-defined prototype of conjugated polymers (i.e. polythiophe ne). The results allowed for the determination of the energy for the o ptical charge pairs formation in this material. The polarizabilities o f the excited Frenkel exciton states have also been estimated. The sin glet exciton binding energy is in the order of 0.4 eV.