Photoelectrochemical properties of dye sensitized Zr-doped SrTiO3 electrodes

Abstract Zr-doped SrTiO3 was used as a photoanode in a three-electrode electrochemical cell. The three organic dyes Safranin, Fluorescein and Eriochrome black T were used as sensitizers in the cell. The results showed that applying the dyes in photoelectrochemical solar (PECS) cells increased the solar efficiency to 2–3 times its value without dyes. The efficiency reaches its maximum value when the dye concentration is sufficient to cover the surface of the semiconductor electrode with a continuous monolayer. Dye concentration higher than this value resulted in a decrease of the efficiency. Mott-Schottky plots gave a doping density of 1.34 × 1016cm−3 for the sample and a space charge width of 1.5–2.0 × 10−6cm (pH dependent). H2 was produced at zero bias in the presence of Safranin dye at a light intensity of 25mW/cm2 with an efficiency of about 39%. Both H2 and O2 were produced in the stiochiometric ratio. Cyclic voltammetry (c.v.) measurements showed two cathodic current peaks revealing two reduction processes at the semiconductor electrode.

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