title: Epitaxial Bi2 FeCrO6 Multiferroic Thin Film as a New Visible Light Absorbing Photocathode Material.
abstract: Ferroelectric materials have been studied increasingly for solar energy conversion technologies due to the efficient charge separation driven by the polarization induced internal electric field. However, their insufficient conversion efficiency is still a major challenge. Here, a photocathode material of epitaxial double perovskite Bi(2) FeCrO(6) multiferroic thin film is reported with a suitable conduction band position and small bandgap (1.9-2.1 eV), for visible-light-driven reduction of water to hydrogen. Photoelectrochemical measurements show that the highest photocurrent density up to -1.02 mA cm(-2) at a potential of -0.97 V versus reversible hydrogen electrode is obtained in p-type Bi(2) FeCrO(6) thin film photocathode grown on SrTiO(3) substrate under AM 1.5G simulated sunlight. In addition, a twofold enhancement of photocurrent density is obtained after negatively poling the Bi(2) FeCrO(6) thin film, as a result of modulation of the band structure by suitable control of the internal electric field gradient originating from the ferroelectric polarization in the Bi(2) FeCrO(6) films. The findings validate the use of multiferroic Bi(2) FeCrO(6) thin films as photocathode materials, and also prove that the manipulation of internal fields through polarization in ferroelectric materials is a promising strategy for the design of improved photoelectrodes and smart devices for solar energy conversion.
authors.affiliation: Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada.
authors.forename: Shun
authors.initials: S
authors.lastname: Li
authors.affiliation: Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, H3A 0E9, Canada.
authors.forename: Bandar
authors.initials: B
authors.lastname: AlOtaibi
authors.affiliation: Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada.
authors.forename: Wei
authors.initials: W
authors.lastname: Huang
authors.affiliation: Department of Electrical and Computer Engineering, McGill University, 3480 University Street, Montreal, Quebec, H3A 0E9, Canada.
authors.forename: Zetian
authors.initials: Z
authors.lastname: Mi
authors.affiliation: PhotoGreen Laboratory, Dipartimento di Chimica, Universita di Pavia, Via Taramelli 12, Pavia, 27100, Italy.
authors.forename: Nick
authors.initials: N
authors.lastname: Serpone
authors.affiliation: Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada.|NAST Center & Department of Chemical Science and Technology, University of Rome Tor Vergata, Via della Ricerca Scientifica 1, 00133, Rome, Italy.
authors.forename: Riad
authors.initials: R
authors.lastname: Nechache
authors.affiliation: Institut National de la Recherche Scientifique (INRS), Centre Énergie, Matériaux et Télécommunications, 1650 Boulevard Lionel-Boulet, Varennes, Québec, J3X 1S2, Canada.|Centre for Self-Assembled Chemical Structures, McGill University, 801 Sherbrooke Street West Montreal, Quebec, H3A 2K6, Canada.
authors.forename: Federico
authors.initials: F
authors.lastname: Rosei
keywords: cationic ordering; ferroelectrics; perovskites; photocathodes; pulsed laser deposition; solar water splitting