This work provides new routes for developing efficient photoelectrodes for photoelectrochemical (PEC) water splitting using a low-cost electrophoretic film preparation method. A series of (Cu 2 Sn) x Zn 3(1−x) S 3 (0 ≤ x ≤ 0.75) quaternary nanocrystals (NCs) with tunable optical band gaps are synthesized. Morphologies including particles, rods, and wires are obtained by tuning the composition of the NCs. (Cu 2 Sn) 0.75 Zn 0.75 S 3 (Cu 2 ZnSnS 4 ) has a pure kesterite structure, but an increase in the Zn content results in a kesterite−wurtzite polytypism. (Cu 2 Sn) x Zn 3(1−x) S 3 films are fabricated from their colloidal solutions via electrophoretic deposition, and the PEC properties of these films with p-type character have been examined under water-splitting conditions. It is shown that the photocurrent varies as a function of film thickness as well as chemical composition. The produced (Cu 2 Sn) 0.45 Zn 1.65 S 3 (x = 0.45) film has the highest photocurrent, and the incident photon to current conversion efficiency is improved compared with previously reported results of Cu 2 ZnSnS 4 photocathodes.

Transparent photocatalytic surfaces are of ever increasing importance for many applications on self-cleaning windows and tiles in everyday applications. Here, we report the formation and photocatalytic testing of a quasi-transparent thin and nanoporous titania films deposited on glass plates. Sputtered Ti thin films were anodized in fluoride-ion-containing neutral electrolytes to form optically semitransparent nanoporous films, which transformed to be completely transparent after thermal annealing. The nanoporous films were studied at different stages, such as before and after anodization, as well as after thermal annealing using scanning electron microscopy (SEM), X-ray diffraction (XRD), and UV-vis and Raman spectroscopy. It was observed that anodization at 20 V of high-temperature deposited titanium films resulted in regular nanopore films with pore diameters of 30 nm. Structural investigations on the transparent nanopore arrays reveal the presence of anatase phase TiO(2) even after annealing at 500 °C, which was confirmed by XRD and Raman spectroscopy measurements. The solar-light induced photocatalytic decomposition of stearic acid and photoconductivity characteristics of these nanoporous thin films are also presented.