TY - JOUR
T1 - Efficient methano[70]fullerene/MDMO-PPV bulk heterojunction photovoltaic cells
AU - Wienk, M.M.
AU - Kroon, J.M.
AU - Verhees, W.J.H.
AU - Knol, J.
AU - Hummelen, J.C.
AU - Hal, van, P.A.
AU - Janssen, R.A.J.
PY - 2003
Y1 - 2003
N2 - The authors report on a bulk heterojunction photovoltaic cell in which an isomeric mixt. of C70 derivs. is used as an electron acceptor in combination with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-p-phenylenevinylene] (MDMO-PPV). [70]PCBM, in this case a mixt. of isomeric [6,6]-phenyl- C71- butyric acid Me esters, is the higher fullerene analog of [60]PCBM, and displays improved light absorption in the visible region. Consequently, when this material is used in a photovoltaic cell instead of [60]PCBM, 50 % higher current densities are obtained. The synthesis of [70]PCBM was performed and the monoadduct fraction was isolated from the higher adducts and unreacted C70 by column chromatog. 1H and 13C NMR were performed on the [70]PCBM, as was UV/VIS absorption in toluene soln. Spin-coated composite films were made with MDMO-PPV, and photoinduced absorption measurements give direct spectral evidence for photoinduced charge sepn., not only upon excitation of the polymer, but also after selective excitation of [70]PCBM at 630 nm. Time-resolved photoluminescence measurements ater excitation at 488 mn, obsd. at 570 nm indicate near quant. charge generation upon polymer excitation, but at 720 nm this quenching depends on the processing solvent, chlorobenzene, o-dichlorobenzene, vs. o-xylene. At. force microscopy reveals a difference in film roughness dependent upon spinning solvent. Photovoltaic cells were made by sandwiching the photoactive mixt., consisting of [70]PCBM and MDMO-PPV in a 4.6:1 (wt./wt.) ratio, between charge-selective electrodes of ITO/PEDOT:PSS (ITO: indium tin oxide; PEDOT: poly(3,4-ethylenedioxythiophene); PSS: poly(styrenesulfonate)) and LiF/Al. The external quantum efficiency (EQE) from a 12V, 50 W halogen lamp varied from a max. of 0.2 for chlorobenzene- processed films, to 0.68 for the o-dichlorobenzene- processed films, compared to 0.5 for equiv. films made with [60]PCBM. Photovoltage-photocurrent behavior were also measured. Overall power conversion efficiency was about 3.0%. [on SciFinder (R)]
AB - The authors report on a bulk heterojunction photovoltaic cell in which an isomeric mixt. of C70 derivs. is used as an electron acceptor in combination with poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-p-phenylenevinylene] (MDMO-PPV). [70]PCBM, in this case a mixt. of isomeric [6,6]-phenyl- C71- butyric acid Me esters, is the higher fullerene analog of [60]PCBM, and displays improved light absorption in the visible region. Consequently, when this material is used in a photovoltaic cell instead of [60]PCBM, 50 % higher current densities are obtained. The synthesis of [70]PCBM was performed and the monoadduct fraction was isolated from the higher adducts and unreacted C70 by column chromatog. 1H and 13C NMR were performed on the [70]PCBM, as was UV/VIS absorption in toluene soln. Spin-coated composite films were made with MDMO-PPV, and photoinduced absorption measurements give direct spectral evidence for photoinduced charge sepn., not only upon excitation of the polymer, but also after selective excitation of [70]PCBM at 630 nm. Time-resolved photoluminescence measurements ater excitation at 488 mn, obsd. at 570 nm indicate near quant. charge generation upon polymer excitation, but at 720 nm this quenching depends on the processing solvent, chlorobenzene, o-dichlorobenzene, vs. o-xylene. At. force microscopy reveals a difference in film roughness dependent upon spinning solvent. Photovoltaic cells were made by sandwiching the photoactive mixt., consisting of [70]PCBM and MDMO-PPV in a 4.6:1 (wt./wt.) ratio, between charge-selective electrodes of ITO/PEDOT:PSS (ITO: indium tin oxide; PEDOT: poly(3,4-ethylenedioxythiophene); PSS: poly(styrenesulfonate)) and LiF/Al. The external quantum efficiency (EQE) from a 12V, 50 W halogen lamp varied from a max. of 0.2 for chlorobenzene- processed films, to 0.68 for the o-dichlorobenzene- processed films, compared to 0.5 for equiv. films made with [60]PCBM. Photovoltage-photocurrent behavior were also measured. Overall power conversion efficiency was about 3.0%. [on SciFinder (R)]
U2 - 10.1002/anie.200351647
DO - 10.1002/anie.200351647
M3 - Article
C2 - 12888961
SN - 0570-0833
VL - 42
SP - 3371
EP - 3375
JO - Angewandte Chemie - International Edition
JF - Angewandte Chemie - International Edition
IS - 29
ER -
