title: Use of highly-ordered TiO(2) nanotube arrays in dye-sensitized solar cells.
abstract: We describe the use of highly ordered transparent TiO(2) nanotube arrays in dye-sensitized solar cells (DSCs). Highly ordered nanotube arrays of 46-nm pore diameter, 17-nm wall thickness, and 360-nm length were grown perpendicular to a fluorine-doped tin oxide-coated glass substrate by anodic oxidation of a titanium thin film. After crystallization by an oxygen anneal, the nanotube arrays are treated with TiCl(4) to enhance the photogenerated current and then integrated into the DSC structure using a commercially available ruthenium-based dye. Although the negative electrode is only 360-nm-thick, under AM 1.5 illumination the generated photocurrent is 7.87 mA/cm(2), with a photocurrent efficiency of 2.9%. Voltage-decay measurements indicate that the highly ordered TiO(2) nanotube arrays, in comparison to nanoparticulate systems, have superior electron lifetimes and provide excellent pathways for electron percolation. Our results indicate that remarkable photoconversion efficiencies may be obtained, possibly to the ideal limit of approximately 31% for a single photosystem scheme, with an increase of the nanotube-array length to several micrometers.
authors.affiliation: Department of Electrical Engineering and Department of Material Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA.
authors.forename: Gopal K
authors.initials: GK
authors.lastname: Mor
authors.forename: Karthik
authors.initials: K
authors.lastname: Shankar
authors.forename: Maggie
authors.initials: M
authors.lastname: Paulose
authors.forename: Oomman K
authors.initials: OK
authors.lastname: Varghese
authors.forename: Craig A
authors.initials: CA
authors.lastname: Grimes
mesh_terms: D002152:Calorimetry, Differential Scanning; D004396:Coloring Agents / Q000737:chemistry* / Q000528:radiation effects; D003460:Crystallization; D004566:Electrodes; D008567:Membranes, Artificial; D036103:Nanotechnology / Q000379:methods*; D043942:Nanotubes / Q000737:chemistry* / Q000528:radiation effects; D010100:Oxygen / Q000737:chemistry; D010316:Particle Size; D010777:Photochemistry; D012428:Ruthenium / Q000737:chemistry; D012680:Sensitivity and Specificity; D013499:Surface Properties; D013997:Time Factors; D014025:Titanium / Q000737:chemistry* / Q000528:radiation effects
chemical_list: D004396:Coloring Agents; D008567:Membranes, Artificial; C009495:titanium dioxide; D012428:Ruthenium; D014025:Titanium; D010100:Oxygen