• Analytical Science and Technology
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• v.9 no.1
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• pp.62-71
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• 1996

The enhancement of the solar energy conversion efficiency into the electrical energy by the dye sensitization with a photoelectrochemical cell was studied. The magnitude of the rose bengal sensitized photocurrent containing the supersensitizer, thiourea was five times greater than that in the absence of thiourea. It was observed, however, that the long time span of irradiation causes the decrease in the photocurrent. Spectroscopic analysis of the dye solution showed that the dye molecule was photobleached and the insoluble aggregate which settles down in the solution, was formed as a result of the possible photocatalytic reaction and the disappearance of dye from the solution was the cause of the decreased photocurrent in the sensitization run.

• Analytical Science and Technology
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• v.9 no.1
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• pp.72-77
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• 1996

In the process of solar energy conversion into electrical energy using the photoelectrochemical cell containing the sensitizer, rose bengal and supersensitizer. $I^-$, the photocurrent is stabilized and durable. But the long time span of irradiation causes the decrease of photocurrent monotonically. Spectroscopic and electrochemical analyses of rose bengal solution containing $I^-$ revealed that the decrease of concentration of rose bengal was attributed to the reaction of rose bengal in the dark with $I_2$ formed as a result of the possible photocatalytic reaction of rose bengal with $I^-$.

• Analytical Science and Technology
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• v.11 no.1
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• pp.20-28
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• 1998

Fluorimetric and absorption spectroscopic studies were performed to elucidate the photocurrent decay with time in the conversion process of solar energy into electrical energy using a photoelectrochemical cell containing rose bengal as a sensitizer, and allylthiourea as a supersensitizer. Spectra of dye solution before and after irradiation revealed a new photocatalytic dimerization reaction between sensitizer and supersensitizer. It was also found that the geometrical arrangement of the transition dipoles is oblique in the dimer of dye molecules.

• Analytical Science and Technology
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• v.11 no.1
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• pp.13-19
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• 1998

In the dye sensitization for the solar energy conversion with a photoelectrochemical cell containing allylthiourea, the time profile of the sensitized photocurrent showed a rise and fall with the irradiation time. The dye solution before and after irradiation was analyzed by means of spectroscopic methods. A new precipitation reaction between sensitizer and supersensitizer and photobleaching of the dye appeared to be involved in the decreased photocurrent.