title: Enabling unassisted solar water splitting by iron oxide and silicon.
abstract: Photoelectrochemical (PEC) water splitting promises a solution to the problem of large-scale solar energy storage. However, its development has been impeded by the poor performance of photoanodes, particularly in their capability for photovoltage generation. Many examples employing photovoltaic modules to correct the deficiency for unassisted solar water splitting have been reported to-date. Here we show that, by using the prototypical photoanode material of haematite as a study tool, structural disorders on or near the surfaces are important causes of the low photovoltages. We develop a facile re-growth strategy to reduce surface disorders and as a consequence, a turn-on voltage of 0.45 V (versus reversible hydrogen electrode) is achieved. This result permits us to construct a photoelectrochemical device with a haematite photoanode and Si photocathode to split water at an overall efficiency of 0.91%, with NiFeOx and TiO2/Pt overlayers, respectively.
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Ji-Wook
authors.initials: JW
authors.lastname: Jang
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Chun
authors.initials: C
authors.lastname: Du
authors.affiliation: 1] Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA [2] National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China.
authors.forename: Yifan
authors.initials: Y
authors.lastname: Ye
authors.affiliation: Department of Electrical Engineering and Computer Sciences and the Joint Center for Artificial Synthesis, University of California, Berkeley, California 94720, USA.
authors.forename: Yongjing
authors.initials: Y
authors.lastname: Lin
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Xiahui
authors.initials: X
authors.lastname: Yao
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: James
authors.initials: J
authors.lastname: Thorne
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Erik
authors.initials: E
authors.lastname: Liu
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: McMahon
authors.affiliation: National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029, China.
authors.forename: Junfa
authors.initials: J
authors.lastname: Zhu
authors.affiliation: Department of Electrical Engineering and Computer Sciences and the Joint Center for Artificial Synthesis, University of California, Berkeley, California 94720, USA.
authors.forename: Ali
authors.initials: A
authors.lastname: Javey
authors.affiliation: Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Jinghua
authors.initials: J
authors.lastname: Guo
authors.affiliation: Department of Chemistry, Merkert Chemistry Center, Boston College, 2609 Beacon St, Chestnut Hill, Massachusetts 02467, USA.
authors.forename: Dunwei
authors.initials: D
authors.lastname: Wang