title: Carbon nanotube/graphene nanocomposite as efficient counter electrodes in dye-sensitized solar cells.
abstract: We demonstrated  the replacement of the Pt catalyst normally used in the counter electrode of a dye-sensitized solar cell (DSSC) by a nanocomposite of dry spun carbon multi-walled nanotube (MWNT) sheets with graphene flakes (Gr-F). The effectiveness of this counter electrode on the reduction of the triiodide in the iodide/triiodide redox (I(-)/I(3)(-)) redox reaction was studied in parallel with the use of the dry spun carbon MWNT sheets alone and graphene flakes used independent of each other. This nanocomposite deposited onto fluorinated tin-oxide-coated glass showed improved catalytic behavior and power conversion efficiency (7.55%) beyond the use of the MWNTs alone (6.62%) or graphene alone (4.65%) for the triiodide reduction reaction in DSSC. We also compare the use of the carbon MWNT/Gr-F composite counter electrode with a DSSC using the standard Pt counter electrode (8.8%). The details of increased performance of graphene/MWNT composite electrodes as studied are discussed in terms of increased catalytic activity permitted by sharp atomic edges that arise from the structure of graphene flakes or the defect sites in the carbon MWNT and increased electrical conductivity between the carbon MWNT bundles by the graphene flakes.
authors.affiliation: Alan G MacDiarmid Nanotech Institute, University of Texas at Dallas, Richardson, TX 75080-3021, USA.
authors.forename: Josef
authors.initials: J
authors.lastname: Velten
authors.forename: Attila J
authors.initials: AJ
authors.lastname: Mozer
authors.forename: Dan
authors.initials: D
authors.lastname: Li
authors.forename: David
authors.initials: D
authors.lastname: Officer
authors.forename: Gordon
authors.initials: G
authors.lastname: Wallace
authors.forename: Ray
authors.initials: R
authors.lastname: Baughman
authors.forename: Anvar
authors.initials: A
authors.lastname: Zakhidov
mesh_terms: D004396:Coloring Agents / Q000737:chemistry*; D011211:Electric Power Supplies; D004566:Electrodes; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006108:Graphite / Q000737:chemistry*; D008422:Materials Testing; D036103:Nanotechnology / Q000295:instrumentation*; D037742:Nanotubes, Carbon / Q000737:chemistry* / Q000648:ultrastructure; D012993:Solar Energy
chemical_list: D004396:Coloring Agents; D037742:Nanotubes, Carbon; D006108:Graphite