title: Reactive ballistic deposition of alpha-Fe2O3 thin films for photoelectrochemical water oxidation.
abstract: We report the preparation of alpha-Fe2O3 electrodes using a technique known as reactive ballistic deposition in which iron metal is evaporatively deposited in an oxygen ambient for photoelectrochemical (PEC) water oxidation. By manipulating synthesis parameters such as deposition angle, film thickness, and annealing temperature, we find that it is possible to optimize the structural and morphological properties of such films in order to improve their PEC efficiency. Incident photon to current conversion efficiencies (IPCE) are used to calculate an AM1.5 photocurrent of 0.55 mA/cm(2) for optimized films with an IPCE reaching 10% at 420 nm in 1 M KOH at +0.5 V versus Ag/AgCl. We also note that the commonly observed low photoactivity of extremely thin hematite films on fluorine-doped tin oxide substrates may be improved by modification of annealing conditions in some cases.
authors.affiliation: Department of Chemical Engineering, Texas Materials Institute, Center for Nano- and Molecular Science, The University of Texas at Austin, 1 University Station C0400, Austin, Texas 78712, USA.
authors.forename: Nathan T
authors.initials: NT
authors.lastname: Hahn
authors.forename: Heechang
authors.initials: H
authors.lastname: Ye
authors.forename: David W
authors.initials: DW
authors.lastname: Flaherty
authors.forename: Allen J
authors.initials: AJ
authors.lastname: Bard
authors.forename: C Buddie
authors.initials: CB
authors.lastname: Mullins
mesh_terms: D017097:Electric Impedance; D004563:Electrochemistry; D005290:Ferric Compounds / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D055668:Photochemical Processes; D013696:Temperature; D014867:Water / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D005290:Ferric Compounds; D014867:Water; C000499:ferric oxide