Marked Enhancement of Photoconductivity and Quenching of Luminescence in Poly(2,5-dialkoxy-p-phenylene vinylene) upon C60 Doping

Abstract
The absorption spectrum and electrical conductivity of poly(2,5-dioctyloxy-p-phenylene vinylene) (OO-PPV) are hardly influenced by doping of a small amount of C60, suggesting that C60 is not an effective dopant for OO-PPV. On the other hand, photoluminescence has been markedly quenched and photoconductivity has been enhanced by several orders of magnitude upon introduction of several mol% of C60, suggesting photo-induced charge transfer between OO-PPV and C60. These results are discussed in terms of relative electronic energy states of OO-PPV and C60. The photoexcited exciton-polaron (Ex-P) is speculated to migrate along 50∼100 monomer units of the polymer main chain in its lifetime and dissociate when encountered with C60.