Enhanced photocurrent spectral response in low-bandgap polyfluorene and C70-derivative-based solar cells

Journal article, 2005

Plastic solar cells have been fabricated using a low-bandgap alternating copolymer of fluorene and a donor-acceptor-donor moiety (APFO-Green1), blended with 3'-(3,5-bis-trifluoromethylphenyl)-1'-(4-nitrophenyl)pyrazolino fullerene (BTPF70) as electron acceptor. The polymer shows optical absorption in two wavelength ranges, l < 500 nm and 600 < l < 1000 nm. The BTPF70 absorbs light at l < 700 nm. A broad photocurrent spectral response in the wavelength range 300 < l < 1000 nm is obtained in solar cells. A photocurrent d. of 3.4 mA cm-2, open-circuit voltage of 0.58 V, and power-conversion efficiency of 0.7% are achieved under illumination of AM1.5 (1000 W m-2) from a solar simulator. Synthesis of BTPF70 is presented. Photoluminescence quenching and electrochem. studies are used to discuss photoinduced charge transfer. [on SciFinder (R)]