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A novel fabrication route for core/sheath heterostructure CdS/TiO(2) nanotube arrays is proposed using ac electrodeposition for application in photoelectrochemical cells. The morphologies of the CdS/TiO(2) electrodes, which were prepared by electrochemically depositing CdS directly into anodic titanium nanotubes from an electrolyte containing Cd(2+) and S in dimethyl sulfoxide, were characterized by a field emission scanning electron microscope (FESEM). The deposited material was found to be in a hexagonal CdS structure by x-ray diffraction (XRD). The synthesized CdS/TiO(2) electrodes showed much higher photocurrent density in the visible wavelength region than pure TiO(2) nanotube arrays. We demonstrate that ac deposition voltage and time can control the CdS/TiO(2) composite architecture, which is crucial in determining the overall efficiency of the water-splitting reaction. The maximum photocurrent density was obtained with the core/sheath heterostructure CdS/TiO(2) nanotube arrays, which were fabricated by deposition of CdS at 5 V for 30 min with 2.5 microm tube length.

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A stable aqueous electrolyte solution containing Cu2+ and SCN− was prepared by adding triethanolamine (TEA, N(CH2CH2OH)3) to chelate with Cu(II) cations. The electrolyte solutions were basic, with pH values in the range of 8.5–9, and could be used in the electrodeposition of CuSCN as a hole‐conducting layer on a ZnO substrate and as an electron‐conducting layer for nanocrystal photovoltaic cells because it could prevent the ZnO layer from acidic etching. CuSCN films were potentiostatically deposited on indium tin oxide glass substrates through the aqueous solutions, and the deposition potential for the sole CuSCN phase layer was determined by a linear sweep voltammetry measurement. The influence of applied potentials, electrolyte components, and deposition temperatures on the stoichiometry, phase, and particle morphology of the CuSCN films was investigated by X‐ray photoelectron spectra, X‐ray diffraction, and a field‐emission scanning electron microscope. The results showed that the morphology of the dense CuSCN films was trigonal pyramid and the stoichiometric portions of SCN/Cu were excess of SCN. The current–voltage (I–V) characteristic of the junction between electrodeposited CuSCN and ZnO nanostructured layer displayed p‐type semiconductor characteristics of CuSCN. The transmittance measurements detected high transmittance (≥87%) in the visible wavelength range, and the direct transition band gap calculated was 3.88 eV.

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