OPTICAL STUDIES OF CHEMICAL DOPING ACHIEVED BY ION-IMPLANTATION IN POLY(P-PHENYLENE VINYLENE)

Measurements of the optical properties of thin films of poly(p-phenyle ne vinylene) (PPV) implanted with caesium, xenon and iodine at a low e nergy (30 keV) are reported. Optical absorption shows evidence for gra phitization at high fluences, independent of the ion type. In contrast , for samples implanted with caesium and with iodine, the optical abso rption due to charge accumulation in the PPV layer, formed within a fi eld-effect device, shows infrared absorption characteristics of a chem ically doped polymer which are associated with charged bipolarons. Pho toluminescence is quenched as a result of ion implantation. We model t his in terms of exciton migration over a characteristic distance of 10 -15 nm to quenching centres introduced by the implantation.