A facile and simple fabrication of Zn-doped α-Fe₂O₃ thin films as a photocathode for solar hydrogen generation was proposed in this report. Transparent Zn-doped α-Fe₂O₃ films were prepared by a deposition-annealing (DA) process using nontoxic iron(III) chloride as the Fe precursor and zinc chloride as a acceptor dopant, followed by annealing at 550 °C in air. In terms of the structural examination of as-grown samples, X-ray diffraction analysis demonstrated an increase in the lattice parameters of Zn incorporated in Fe₂O₃ by substituting Fe in the host lattice. No second phase was determined, indicating no phase separation in the ternary materials. Energy dispersive spectroscopy results demonstrated that Zn, Fe, and O elements existed in the deposits. Furthermore, impedance measurements show that the Zn-dopant serves as an hole acceptor and increases the acceptor concentration by increasing concentration of zinc precursor. Significantly, the photoelectrochemical measurements exhibited remarkable cathodic current, corresponding to the reduction reaction of hydrogen. Finally, the optimum photocurrent can be achieved by controlled variation of the Fe and Zni precursor concentration, annealing conditions, and the number of DA cycles. According to our investigation, the understandings of morphology effect on PEC activity give the blueprint for materials design in the application of solar hydrogen.

Date Published: 7 October 2014
PDF: 7 pages
Proc. SPIE 9176, Solar Hydrogen and Nanotechnology IX, 91760N (7 October 2014); doi: 10.1117/12.2060703

Published in SPIE Proceedings Vol. 9176:
Solar Hydrogen and Nanotechnology IX
Sanjay Mathur, Editor(s)