Dissociation of sexithiophene on Al(1 1 1) surface

The growth of sexithiophene ultra-thin films on an atomically clean Al(1 1 1) surface has been investigated by angle-resolved ultraviolet photoemission spectroscopy. Although sexithiophene on Al(1 1 1) represents a weakly interacting system, sexithiophene molecules were found to dissociate even below room temperature, presumably via reactive sites. The mechanism is distinctly different to that claimed on the reverse system, i.e. aluminum evaporated on thiophene oligomers films, where isolated aluminum atoms were reported to covalently bond to thiophene rings and thus dramatically affect the molecule geometry and the conjugation. The effect of the insertion of an ultra-thin separator film of sexiphenyl, on the dissociation of sexithiophene was also examined.