CdS deposited polycarbonate membranes were made by a very simple way: separation of a Lucite cell into two compartments by two pieces of Teflon sheets which were tightly inserted into the slot of the cell. The membrane was placed between holes of the Teflon sheets. The cadmium nitrate aqueous solution were poured into one compartment, and sodium sulfide aqueous solution to the other chamber, were introduced simultaneously. The CdS precipitates formed in situ blocked the tiny holes of the membrane. On illumination, about 150 mV photovoltage (V_(op)) and 0.5 μAcm~(-2) photocurrent (I_(sc)) could be produced, one side of the membrane acted as photoanode and the other side photocathode. By means of coprecipitating CdS and FeS (the ratio of FeS to CdS in the mixture wasabout 1 : 1000) onto the membrane, the maximum V_(op) and I_(sc) of the membrane could reach 500 mV and 3.0 μAcm~(-2), respectively. CdS_xSe_(1-x) mixture deposited membrane has also been tested and found to have both the advantages ofhigh photovoltage (over 400 mV) and od stability after modification. The essential aspect of the system, modelled after the photosynthetic thylakoid membrane, contains an asymmetrical, ultrathin semiconductor polycrystallites membrane separating two aqueous solutions.
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