Photophysical characteristics of soluble oligo(p-phenylenevinylene)-fullerene dyad

The fact that C,, is a good acceptor has stimulated interest in covalently linked complexes, including polymers and oligomers. Photoinduced charge transfer in these systems has great potential for use in photovoltaic devices. In this study, an alternating conjugated oligomer of alkylated carbazole and dialkoxyl-substituted phenylene, with pendant C-60 moieties, (PPV-AFCAR) was prepared and characterized. The excited-state properties of PPV-AFCAR were investigated with steady-state spectroscopy and lifetime measurements. After photoexcitation, photoinduced energy transfer from the oligomer chain to the pendant moiety occurred in great proportion, but a charge-separation process did not. Whether the energy-transfer process was measurable or not depended on the system temperature. At 77 K, a quantum yield of more than 50% for energy transfer was found by the fitting of a linear combination of the excitation spectra of the precursor oligomer, the alternating conjugated oligomer of alkylated carbazole and dialkoxyl-substituted phenylene PPV-ACAR, and the absorption spectra of C-60. (C) 2001 John Wiley & Sons, Inc.