Observation of photoinduced charge transfer in conducting polymer/fullerene composites using a high-bandgap polymer

We report photoinduced electron transfer in films of poly(3-decyloxy-1,4-phenylene) (DO-PPP) blended with C60, observed by infrared photoexcitation spectroscopy. The photoinduced IR-active vibrational (IRAV) structure and electronic subgap absorption features of the DO-PPP are greatly enhanced upon adding just two percent C60- The spectral signature of the C60 anion at 1.15 eV is clearly observed as a peak superimposed on the weak background between the midgap states of the polymer. The system is pumped at 2.41 eV, below the bandgap of the polymer, but within the visible absorption tails of both the polymer and of the C60.