Novel Photophysical Properties of Fullerene Doped Conducting Polymers
Аннотация
Abstract Photoluminescence in conducting polymer with non-degenerated ground state (NDGS CP) such as polythiophene derivatives, poly(p-phenylene vinylene) derivatives and polyfluorene derivatives is quenched remarkably upon doping by fullerenes such as C60 and C70. On the other hand photoconductivity in NDGS CP and also in conducting polymer with degenerated ground state (DGS CP) such as polyacetylene derivatives is enhanced remarkably upon fullerene doping at the excitation of the wavelengths of the inter-band transition in conducting polymer and allowed and forbidden optical transitions in fullerene. Remarkable polarity effect is observed in the spectral response of enhanced photoconductivity. Conducting polymer/C60 layer interface exhibits also unique junction characteristics demonstrating sizable photovoltaic effect due to charges photoseparation at the interface. These unique characteristics are discussed in terms of photo-induced charge transfer between conducting polymers and fullerenes, taking into account the roles of photoexcited self-trapped excitations: exciton-polarons, polarons and charged solitons in polymer main chains and belt-like polaron in C60 spherical molecule.