Photoinduced generation of radical ions in α-sexithyenil

Abstract

The cw photoinduced absorption technique has been applied to α-sexithyenil (T 6) molecules both in vacuum evaporated films and KBr pellets. We observed new IR active vibrations as well as new electronic transitions at low energy. We assigned these structures to charged species separated on different molecular layers and trapped to defects. The narrow line shape of the photoinduced features is indicative of the molecular solid character of T 6 thin films and it provides an upper limit for the charge symmetry breaking of 0.04 eV. A comparison with the longer chain polymer (polythyophene) is discussed.