Abstract—
The reaction center (RC) of Rhodospirillum rubrum SI, which was prepared by ultrafiltration, showed one peak in molecular‐sieve HPLC, but it showed two peaks in diethylaminoethyl (DEAE) ion‐exchange HPLC; they were named as RC‐α and RC‐β in the order of elution, Nonequilibrated isoelectric electrophoresis, together with DEAE ion‐exchange HPLC, showed that RC‐β is electronically more negative than RC‐α. Oxidation of RC‐β by addition of ferricyanide caused its transformation into RC‐α, while reduction of RC‐α by adding ascorbate and subsequent illumination caused its transformation into RC‐β. Resonance Raman spectroscopy of the RC at liquid nitrogen temperature detected the all‐trans and the 15‐cis isomers in a ratio of 1:1, but HPLC analyses of the carotenoid extracted from the RC before and after the Raman measurements detected the pair of isomers in a ratio of 1:6. Thus, the 15‐cis to all‐trans isomerization takes place during irradiation at liquid nitrogen temperature, while the reverse isomerization takes place in the dark. The isolated RC‐α and RC‐β exhibited the bleaching of the 868 nm band, and contained the H, M and L subunits and 1.2‐1.4 molecules of ubiquinone‐10 per RC. Each RC slowly equilibrated in the dark toward a mixture of RC‐α and RC‐β. Generation of the all‐trans isomer in the light was found not in RC‐α but in RC‐β.
A series circuit of bulk hetero-junction (BHJ) organic thin-film solar cells (OSCs) is investigated for electrolyzing water to gaseous hydrogen and oxygen. The BHJ OSCs applied consist of poly(3-hexylthiophene) as a donor and [6,6]-phenyl C61 butyric acid methyl ester as an acceptor. A series circuit of six such OSC units has an open circuit voltage (V(oc)) of 3.4 V, which is enough to electrolyze water. The short circuit current (J(sc)), fill factor (FF), and energy conversion efficiency (η) are independent of the number of unit cells. A maximum electric power of 8.86 mW cm(-2) is obtained at the voltage of 2.35 V. By combining a water electrolysis cell with the series circuit solar cells, the electrolyzing current and voltage obtained are 1.09 mA and 2.3 V under a simulated solar light irradiation (100 mW cm(-2), AM1.5G), and in one hour 0.65 mL hydrogen is generated.
Series circuit of six organic thin-film solar cells (OSCs) consisting of poly(3-hexyl thiophene) and PCBM has been fabricated in order to electrolyze water into hydrogen and oxygen gases. The open circuit voltage increases linearly with the number of unit cells and becomes 2.9 V at the six unit cells. On the other hand, the short circuit current, the fill factor and the energy conversion efficiency are almost constant, independent of the number of unit cells. The series circuit of six OSCs was combined with the water electrolysis cell with two platinum electrodes. Hydrogen and oxygen gases were generated at each platinum electrodes of the electrolysis cell under illumination. The operating current and voltage was determined to be 1.3 mA=cm 2 and 2.6 V, respectively.
Series circuit of organic thin-film solar cells (OSCs), which are bulk hetero-junction (BHJ) solar cell composed of poly(3-hexylthiophene) (P3HT) as a donor and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) as an acceptor, has been investigated for electrolyzing water to hydrogen and oxygen gases. The cell performance parameters of OSC, such as the annealing time, P3HT/PCBM film thickness and the conductivity of PEDOT/PSS film were optimized. The series circuit of 6 unit OSCs shows the open circuit voltage (Voc) of 3.48 V, which is enough for electrolyzing water. By combination of water electrolysis cell using carbon supported Pt nanoparticles cathode and Ni anode, and the series circuit solar cells, the electrolyzing current and voltage are obtained to be 2.7 mA/cm2 and 2.2V, respectively under the simulated solar light irradiation. Hydrogen is generated to 0.5 mL after an hour irradiation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.