title: Hetero-type dual photoanodes for unbiased solar water splitting with extended light harvesting.
abstract: Metal oxide semiconductors are promising photoelectrode materials for solar water splitting due to their robustness in aqueous solutions and low cost. Yet, their solar-to-hydrogen conversion efficiencies are still not high enough for practical applications. Here we present a strategy to enhance the efficiency of metal oxides, hetero-type dual photoelectrodes, in which two photoanodes of different bandgaps are connected in parallel for extended light harvesting. Thus, a photoelectrochemical device made of modified BiVO4and α-Fe2O3as dual photoanodes utilizes visible light up to 610 nm for water splitting, and shows stable photocurrents of 7.0±0.2 mA cm-2at 1.23 VRHEunder 1 sun irradiation. A tandem cell composed with the dual photoanodes-silicon solar cell demonstrates unbiased water splitting efficiency of 7.7%. These results and concept represent a significant step forward en route to the goal of >10% efficiency required for practical solar hydrogen production.
authors.affiliation: School of Environmental Science &Engineering, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, South Korea.
authors.forename: Jin Hyun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels, Hahn-Meitner-Platz 1, Berlin 14109, Germany.|School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea.
authors.forename: Ji-Wook
authors.initials: JW
authors.lastname: Jang
authors.affiliation: Advanced Center for Energy, Korea Institute of Energy Research (KIER), Ulsan 44919, South Korea.
authors.forename: Yim Hyun
authors.initials: YH
authors.lastname: Jo
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels, Hahn-Meitner-Platz 1, Berlin 14109, Germany.
authors.forename: Fatwa F
authors.initials: FF
authors.lastname: Abdi
authors.affiliation: School of Environmental Science &Engineering, Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH), Pohang 790-784, South Korea.
authors.forename: Young Hye
authors.initials: YH
authors.lastname: Lee
authors.affiliation: Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Institute for Solar Fuels, Hahn-Meitner-Platz 1, Berlin 14109, Germany.
authors.forename: Roel
authors.initials: R
authors.lastname: van de Krol
authors.affiliation: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919, South Korea.
authors.forename: Jae Sung
authors.initials: JS
authors.lastname: Lee