Photoinduced electron transfer from pi-conjugated polymers onto Buckminsterfullerene, fulleroids and methanofullerenes

We present near-steady-state photoinduced absorption (PIA), photoluminescence, and light-induced electron spin resonance (LESR) studies on photoinduced electron transfer reactions from poly(bis-2,5-epi-cholestanoxy-1,4-phenylene vinylene) (BeCHA-PPV) as a donor to Buckminsterfullerene (C60) and a number of functionalized fullerenes as acceptors. We show that functionalized fullerenes with a solubilizing side chain linked to C60 in a [5,6] (fulleroid) or [6,6] (methanofullerene) fashion, are efficient electron acceptors towards BeCHA-PPV, as evidenced from changes in the PIA, the efficient quenching of the photoluminescence, and the LESR spectra of BeCHA-PPV cation and fullerene anion radicals. The increased miscibility of the functionalized fullerenes with the conjugated polymer as compared to C60, can be important for the preparation of future electrooptic devices, based on the photoinduced charge separation.