title: Urchin-like nanowire array: a strategy for high-performance ZnO-based electrode utilized in photoelectrochemistry.
abstract: The electrodes in photoelectrochemical cells responsible for the generation of hydrogen and oxygen by water splitting have been intensively studied because of their high photon-to-electron conversion efficiency. The morphology of nanostructures with these high-efficiency electrodes was systematically compared with the morphology of ZnO structures with vertically aligned nanorod arrays (NA), hollow hemisphere arrays (HA), urchin-like (UL) nanorod arrays, and thin films (TF). The UV-vis light absorption, photoresponse (current-voltage characteristics in the dark and under light), and photoelectrochemistry of the electrodes were measured. The highest photon-to-electron conversion efficiency of 65% at a specific UV wavelength for an electrode with a ZnO UL structure was derived from the UL morphology of high light-trapping efficiency and carrier collection efficiency. The UL morphology also produced a photon-to-electron conversion efficiency of 4.5% under a solar simulator by CdS-sensitization of the ZnO UL electrode. The value was the highest observed thus far among the ZnO-based electrodes. We demonstrated that photoresponse measurement is a practical and simple technique for the estimation of the photon-to-electron conversion efficiency of an electrode.
authors.affiliation: Department of Materials Science and Engineering, Chungnam National University, Daejeon, 305-764, Rep. of Korea.
authors.forename: Hoang Nhat
authors.initials: HN
authors.lastname: Hieu
authors.forename: Nguyen Quoc
authors.initials: NQ
authors.lastname: Dung
authors.forename: Jimin
authors.initials: J
authors.lastname: Kim
authors.forename: Dojin
authors.initials: D
authors.lastname: Kim
mesh_terms: D004566:Electrodes; D006859:Hydrogen / Q000737:chemistry; D008027:Light; D053770:Nanowires / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D012993:Solar Energy; D014867:Water / Q000737:chemistry; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D014867:Water; D006859:Hydrogen; D010100:Oxygen; D015034:Zinc Oxide