title: Single-nanowire photoelectrochemistry.
abstract: Photoelectrochemistry is one of several promising approaches for the realization of efficient solar-to-fuel conversion. Recent work has shown that photoelectrodes made of semiconductor nano-/microwire arrays can have better photoelectrochemical performance than their planar counterparts because of their unique properties, such as high surface area. Although considerable research effort has focused on studying wire arrays, the inhomogeneity in the geometry, doping, defects and catalyst loading present in such arrays can obscure the link between these properties and the photoelectrochemical performance of the wires, and correlating performance with the specific properties of individual wires is difficult because of ensemble averaging. Here, we show that a single-nanowire-based photoelectrode platform can be used to reliably probe the current-voltage (I-V) characteristics of individual nanowires. We find that the photovoltage output of ensemble array samples can be limited by poorly performing individual wires, which highlights the importance of improving nanowire homogeneity within an array. Furthermore, the platform allows the flux of photogenerated electrons to be quantified as a function of the lengths and diameters of individual nanowires, and we find that the flux over the entire nanowire surface (7-30 electrons nm(-2) s(-1)) is significantly reduced as compared with that of a planar analogue (∼1,200 electrons nm(-2) s(-1)). Such characterization of the photogenerated carrier flux at the semiconductor/electrolyte interface is essential for designing nanowire photoelectrodes that match the activity of their loaded electrocatalysts.
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Yude
authors.initials: Y
authors.lastname: Su
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Chong
authors.identifier: 0000-0001-5546-3852
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Brittman
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Jinyao
authors.initials: J
authors.lastname: Tang
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Anthony
authors.initials: A
authors.lastname: Fu
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
authors.forename: Nikolay
authors.initials: N
authors.lastname: Kornienko
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.
authors.forename: Qiao
authors.initials: Q
authors.lastname: Kong
authors.affiliation: Department of Chemistry, University of California, Berkeley, California 94720, USA.|Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.|Department of Materials Science and Engineering, University of California, Berkeley, California 94720, USA.|Kavli Energy Nanosciences Institute, Berkeley, California 94720, USA.
authors.forename: Peidong
authors.initials: P
authors.lastname: Yang