Here, we report a significant improvement of the photoelectrochemical (PEC) properties of hematite (α-Fe2O3) to oxidize water by doping with manganese. Hematite nanorods were grown on a fluorine-treated tin oxide (FTO) substrate by a hydrothermal method in the presence on Mn. Systematic physical analyses were performed to investigate the presence of Mn in the samples. Fe2O3 nanorods with 5 mol % Mn treatment showed a photocurrent density of 1.6 mA cm(-2) (75% higher than that of pristine Fe2O3) at 1.23 V versus RHE and a plateau photocurrent density of 3.2 mA cm(-2) at 1.8 V versus RHE in a 1 M NaOH electrolyte solution (pH 13.6). We attribute the increase in the photocurrent density, and thus in the oxygen evolving capacity, to the increased donor density resulting from Mn doping of the Fe2O3 nanorods, as confirmed by Mott-Schottky measurement, as well as the suppression of electron-hole recombination and enhancement in hole transport, as detected by chronoamperometry measurements.

Lead-free double perovskite Cs2AgSbBr6 is synthesized to show a low indirect bandgap of 1.64 eV.

Controlling novel morphologies and developing effective doping strategies are two important tasks for advancing ZnO-based nanomaterials. We have grown vertically aligned Cu-doped ZnO nanonails and nanoneedles and observed a continuous evolution between various morphologies. Selecting source compositions and regulating vapor and gas pressures modify the Ehrlich-Schwoebel energy barrier for the surface diffusion and determine the morphologies. X-ray diffraction study indicates a decrease in the lattice parameter after the Cu doping. Photoluminescence measurements taken on both doped and undoped samples show that, in the Cu-doped ZnO nanostructures, the band-edge UV emission and the broad green emission are red-shifted by ∼7 and 20 nm, respectively. X-ray photoelectron spectroscopy study revealed a higher level of oxygen vacancies in nanoneedles, which was found to enhance the green emission. Room-temperature ferromagnetism was also observed in Cu-doped ZnO nanomaterials. On the basis of the strong correlations between structures and properties, we demonstrate that the morphologies and the optical and magnetic characteristics can be tailored to a large degree in transition-metal-doped ZnO nanostructures.