AVS 57th International Symposium & Exhibition
    Energy Frontiers Topical Conference Thursday Sessions
       Session EN+NS-ThM

Paper EN+NS-ThM11
Device Characteristics of Dye Sensitized Solar Cells Based on Evaporated TiO2 Nanowire Photoanodes

Thursday, October 21, 2010, 11:20 am, Room Mesilla

Session: Nanostructures for Energy Conversion & Storage II
Presenter: S.M. Pursel, The Pennsylvania State University
Authors: S.M. Pursel, The Pennsylvania State University
S.H.A. Lee, The Pennsylvania State University
T.E. Mallouk, The Pennsylvania State University
M.W. Horn, The Pennsylvania State University
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Dye sensitized solar cells (DSSCs) continue to be the subject of intensive research because of their potential low cost with efficiencies near 11%. In this talk, we report on engineered one-dimensional TiO2 nanowire photoanodes as an alternative to the standard colloidal based photoanodes currently used in most DSSC’s. By using one dimensional nanowire photoanodes, there is potential to speed up electron collection thereby permitting the use of faster acting redox couples in future electrolytes. The nanowire photoanodes are made by evaporation of TiO2 at an oblique deposition angle. Dense arrays of nanowires, of any thickness, can be deposited with an orientation normal to the front contact. Deposition methods that enable growth of nanowires with a consistent diameter (~30 nm) and interwire spacing (~5-10 nm) have been developed for use with DSSCs, unlike most sputtered wires. Optically uniform films have been deposited over 7 cm diameter substrates. These arrays are improvements over past lithographically or hydrothermally deposited nanowires in terms of dye loading, which in our case match or improve upon the dye loading of standard colloidal based photoanodes. Dye loading data, obtained through spectroscopic measurements of desorbed dye, is presented along with SEM images of the various architectures of nanowire arrays. Devices are constructed using ruthenium based N719 dye, I-/I3- based electrolyte, and Pt coated FTO counter electrodes and temporary sealing. Performance data is obtained under AM 1.5G or D simulated solar illumination. Electron transport data is obtained through electrochemical impedance spectroscopy (EIS) and open circuit voltage decay (OCVD). Data is analyzed using published theoretical models to quantify transport properties.