title: Highly efficient solar cells using TiO(2) nanotube arrays sensitized with a donor-antenna dye.
abstract: Donor antenna dyes provide an exciting route to improving the efficiency of dye sensitized solar cells owing to their high molar extinction coefficients and the effective spatial separation of charges in the charge-separated state, which decelerates the recombination of photogenerated charges. Vertically oriented TiO(2) nanotube arrays provide an optimal material architecture for photoelectrochemical devices because of their large internal surface area, lower recombination losses, and vectorial charge transport along the nanotube axis. In this study, the results obtained by sensitizing TiO(2) nanotube arrays with the donor antenna dye Ru-TPA-NCS are presented. Solar cells fabricated using an antenna dye-sensitized array of 14.4 microm long TiO(2) nanotubes on Ti foil subjected to AM 1.5 one sun illumination in the backside geometry exhibited an overall conversion efficiency of 6.1%. An efficiency of 4.1% was obtained in the frontside illumination geometry using a 1 microm long array of transparent TiO(2) nanotubes subjected to a TiCl(4) treatment and then sensitized with the Ru-TPA-NCS dye. Open circuit voltage decay measurements give insight into the recombination behavior in antenna-dye sensitized nanotube photoelectrodes, demonstrating outstanding properties likely due to a reduction in the influence of the surface traps and reduced electron transfer from TiO(2) to ions in solution.
authors.affiliation: Department of Electrical Engineering, Materials Research Institute, The Pennsylvania State University, University Park, PA 16802, USA.
authors.forename: Karthik
authors.initials: K
authors.lastname: Shankar
authors.forename: Jayasundera
authors.initials: J
authors.lastname: Bandara
authors.forename: Maggie
authors.initials: M
authors.lastname: Paulose
authors.forename: Helga
authors.initials: H
authors.lastname: Wietasch
authors.forename: Oomman K
authors.initials: OK
authors.lastname: Varghese
authors.forename: Gopal K
authors.initials: GK
authors.lastname: Mor
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: LaTempa
authors.forename: Mukundan
authors.initials: M
authors.lastname: Thelakkat
authors.forename: Craig A
authors.initials: CA
authors.lastname: Grimes
mesh_terms: D004396:Coloring Agents; D003460:Crystallization / Q000379:methods*; D011211:Electric Power Supplies; D004867:Equipment Design; D019544:Equipment Failure Analysis; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D036103:Nanotechnology / Q000295:instrumentation* / Q000379:methods; D043942:Nanotubes / Q000737:chemistry* / Q000528:radiation effects*; D010316:Particle Size; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects*
chemical_list: D004396:Coloring Agents; D046911:Macromolecular Substances; C009495:titanium dioxide; D014025:Titanium