title: Bragg stack-functionalized counter electrode for solid-state dye-sensitized solar cells.
abstract: A highly reflective counter electrode is prepared through the deposition of alternating layers of organized mesoporous TiO(2) (om-TiO(2)) and colloidal SiO(2) (col-SiO(2)) nanoparticles. We present the effects of introducing this counter electrode into dye-sensitized solar cells (DSSCs) for maximizing light harvesting properties. The om-TiO(2) layers with a high refractive index are prepared by using an atomic transfer radical polymerization and a sol-gel process, in which a polyvinyl chloride-g-poly(oxyethylene) methacrylate graft copolymer is used as a structure-directing agent. The col-SiO(2) layers with a low refractive index are prepared by spin-coating commercially available silica nanoparticles. The properties of the Bragg stack (BS)-functionalized counter electrode in DSSCs are analyzed by using a variety of techniques, including spectroscopic ellipsometry, SEM, UV/Vis spectroscopy, incident photon-to-electron conversion efficiency, electrochemical impedance spectroscopy, and intensity modulated photocurrent/voltage spectroscopy measurements, to understand the critical factors contributing to the cell performance. When incorporated into DSSCs that are used in conjunction with a polymerized ionic liquid as the solid electrolyte, the energy conversion efficiency of this solid-state DSSC (ssDSSC) approaches 6.6 %, which is one of the highest of the reported N719 dye-based ssDSSCs. Detailed optical and electrochemical analyses of the device performance show that this assembly yields enhanced light harvesting without the negative effects of charge recombination or electrolyte penetration, which thus, presents new possibilities for effective light management.
authors.affiliation: Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, South Korea.
authors.forename: Jung Tae
authors.initials: JT
authors.lastname: Park
authors.forename: Jacob H
authors.initials: JH
authors.lastname: Prosser
authors.forename: Dong Jun
authors.initials: DJ
authors.lastname: Kim
authors.forename: Jong Hak
authors.initials: JH
authors.lastname: Kim
authors.forename: Daeyeon
authors.initials: D
authors.lastname: Lee
mesh_terms: D004396:Coloring Agents / Q000737:chemistry; D011211:Electric Power Supplies; D004566:Electrodes; D053758:Nanoparticles / Q000737:chemistry*; D009942:Organometallic Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry*; D012993:Solar Energy; D013861:Thiocyanates / Q000737:chemistry; D014025:Titanium / Q000737:chemistry*
chemical_list: D004396:Coloring Agents; D009942:Organometallic Compounds; D013861:Thiocyanates; C506095:bis(2,2'-bipyridyl-4,4'-dicarboxylate)ruthenium(II) bis(tetrabutylammonium) bis(thiocyanate); C009495:titanium dioxide; D012822:Silicon Dioxide; D014025:Titanium