title: Formation of a CdO layer on CdS/ZnO nanorod arrays to enhance their photoelectrochemical performance.
abstract: The performance and photocatalytic activity of the well-known CdS/ZnO nanorod array system were improved significantly by the layer-by-layer heterojunction structure fabrication of a transparent conductive oxide (TCO) CdO layer on the CdS/ZnO nanorods. Accordingly, a CdO layer with a thickness of approximately 5-10 nm can be formed that surrounds the CdS/ZnO nanorod arrays after annealing at 500 °C under air. At an external potential of 0.0 V vs. Ag/AgCl, the CdO/CdS/ZnO nanorod array electrodes exhibit an increased incident photon to conversion efficiency, which is significantly higher than that of the CdS/ZnO nanorod array electrodes. The high charge separation between the electrons and holes at the interfaces of the heterojunction structure results from the specific band energy structure of the photoanode materials, and the unique high conductivity of the CdO layer is attributed to the suppression of electron-hole recombination; this suppression enhances the photocurrent density of the CdO/CdS/ZnO nanorod arrays. The photoresponse of the electrodes in an electrolytic solution without sacrificial agents indicated that the CdO layer also has the ability to suppress the well-known photocorrosive behavior of CdS/ZnO nanorods.
authors.affiliation: Korea Center for Artificial Photosynthesis, Department of Chemistry, Sogang University, Seoul (Korea), Fax: (+82) 2-701-0967.
authors.forename: Thanh Khue
authors.initials: TK
authors.lastname: Van
authors.forename: Long Quoc
authors.initials: LQ
authors.lastname: Pham
authors.forename: Do Yoon
authors.initials: DY
authors.lastname: Kim
authors.forename: Jin You
authors.initials: JY
authors.lastname: Zheng
authors.forename: Dokyoung
authors.initials: D
authors.lastname: Kim
authors.forename: Amol U
authors.initials: AU
authors.lastname: Pawar
authors.forename: Young Soo
authors.initials: YS
authors.lastname: Kang
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D055664:Electrochemical Techniques; D008855:Microscopy, Electron, Scanning; D043942:Nanotubes; D010087:Oxides / Q000737:chemistry*; D055668:Photochemical Processes; D013440:Sulfides / Q000737:chemistry*; D014961:X-Ray Diffraction; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D010087:Oxides; D013440:Sulfides; C034939:cadmium sulfide; C029663:cadmium oxide; D015034:Zinc Oxide
keywords: cadmium; electrochemistry; nanostructures; photochemistry; zinc