title: Ordered mesoporous tungsten suboxide counter electrode for highly efficient iodine-free electrolyte-based dye-sensitized solar cells.
abstract: A disulfide/thiolate (T(2)/T(-)) redox-couple electrolyte, which is a promising iodine-free electrolyte owing to its transparent and noncorrosive properties, requires alternative counter-electrode materials because conventional Pt shows poor catalytic activity in such an electrolyte. Herein, ordered mesoporous tungsten suboxide (m-WO(3-x)), synthesized by using KIT-6 silica as a hard template followed by a partial reduction, is used as a catalyst for a counter electrode in T(2)/T(-)-electrolyte-based dye-sensitized solar cells (DSCs). The mesoporous tungsten suboxide, which possesses interconnected pores of 4 and 20 nm, provides a large surface area and efficient electrolyte penetration into the m-WO(3-x) pores. In addition to the advantages conferred by the mesoporous structure, partial reduction of tungsten oxide creates oxygen vacancies that can function as active catalytic sites, which causes a high electrical conductivity because of intervalence charge transfer between the W(5+) and W(6+) ions. m-WO(3-x) shows a superior photovoltaic performance (79 % improvement in the power conversion efficiency) over Pt in the T(2)/T(-) electrolyte. The superior catalytic activity of m-WO(3-x) is investigated by using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS), and Tafel polarization curve analysis.
authors.affiliation: Department of Chemical Engineering, Pohang University of Science and Technology, Kyungbuk 790-784, Korea.
authors.forename: Inyoung
authors.initials: I
authors.lastname: Jeong
authors.forename: Changshin
authors.initials: C
authors.lastname: Jo
authors.forename: Arockiam
authors.initials: A
authors.lastname: Anthonysamy
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Kim
authors.forename: Eunae
authors.initials: E
authors.lastname: Kang
authors.forename: Jongkook
authors.initials: J
authors.lastname: Hwang
authors.forename: Easwaramoorthi
authors.initials: E
authors.lastname: Ramasamy
authors.forename: Shi-Woo
authors.initials: SW
authors.lastname: Rhee
authors.forename: Jin Kon
authors.initials: JK
authors.lastname: Kim
authors.forename: Kyoung-Su
authors.initials: KS
authors.lastname: Ha
authors.forename: Ki-Won
authors.initials: KW
authors.lastname: Jun
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Lee
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D011211:Electric Power Supplies; D004566:Electrodes; D010087:Oxides / Q000737:chemistry*; D010984:Platinum / Q000737:chemistry; D016062:Porosity; D012993:Solar Energy; D013438:Sulfhydryl Compounds / Q000737:chemistry*; D014414:Tungsten / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D004220:Disulfides; D010087:Oxides; D013438:Sulfhydryl Compounds; D010984:Platinum; C511604:tungsten oxide; D014414:Tungsten