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Fabrication of nanoporous titania on glass and transparent conducting oxide substrates by anodization of titanium films

Published online by Cambridge University Press:  03 March 2011

Andrew J. Leenheer*
Affiliation:
National Renewable Energy Laboratory, Golden, Colorado 80401
Alexander Miedaner
Affiliation:
National Renewable Energy Laboratory, Golden, Colorado 80401
Calvin J. Curtis
Affiliation:
National Renewable Energy Laboratory, Golden, Colorado 80401
Maikel F.A.M. van Hest
Affiliation:
National Renewable Energy Laboratory, Golden, Colorado 80401
David S. Ginley
Affiliation:
National Renewable Energy Laboratory, Golden, Colorado 80401
*
a) Address all correspondence to this author. e-mail: andrew_leenheer@nrel.gov
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Abstract

Nanoporous titania (TiO2) or titania nanotubes could provide a continuous nanostructured electron-conducting anode for organic photovoltaics. In this work, nanoporous titania was formed by anodizing thin films of titanium on both glass and transparent conducting oxide (TCO) substrates. Titanium thin films (500–700 nm) were deposited by radio frequency (RF) magnetron sputtering. Films were anodized in acidic electrolytes containing small amounts of hydrofluoric acid (HF) at constant voltages ranging from 7 to 15 V. Scanning electron microscope (SEM) analysis revealed a nanoporous structure. Nanoporous titania structures were grown on glass in an electrolyte containing sulfuric acid, trisodium citrate, and potassium fluoride, with pore diameters around 50 nm. Analyzing the films at different anodization times, the stages of nanopore formation were elucidated. Additionally, nanoporous titania was formed on a TCO substrate by anodizing in an electrolyte containing acetic acid and hydrofluoric acid. While not completely transparent, the nanoporous titania is promising for use in organic photovoltaics.

Type
Articles
Copyright
Copyright © Materials Research Society 2007

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References

REFERENCES

1Diggle, J.W., Downie, T.C., and Goulding, C.W.: Anodic oxide films on aluminum. Chem. Rev. 69, 365 (1964).CrossRefGoogle Scholar
2Tang, H., Prasad, K., Sanjinès, R., Schmid, P.E., and Lévy, F.: Electrical and optical properties of TiO2 anatase thin films. J. Appl. Phys. 75, 2042 (1994).CrossRefGoogle Scholar
3Gratzel, M.: Dye-sensitized solar cells. J. Photochem. Photobiol. C: Photochem. Rev. 4, 145 (2003).CrossRefGoogle Scholar
4Varghese, O.K., Gong, D., Paulose, M., Ong, K.G., Dickey, E., and Grimes, C.A.: Extreme changes in the electrical resistance of titania nanotubes with hydrogen exposure. Adv. Mater. 15, 624 (2003).CrossRefGoogle Scholar
5Paulose, M., Mor, G.K., Varghese, O.K., Shankar, K., and Grimes, C.A.: Visible light photoelectrochemical and water-photoelectrolysis properties of titania nanotube arrays. J. Photochem. Photobiol. A: Chemistry. 178, 8 (2005).CrossRefGoogle Scholar
6Wu, J-M., Wu, W-T., and Shih, H.: Characterization of single-crystalline TiO2 nanowires grown by thermal evaporation. J. Electrochem. Soc. 152, G613 (2005).CrossRefGoogle Scholar
7Chu, S-Z., Inoue, S., Wada, K., Hishita, S., and Kurashima, K.: Self-organized nanoporous anodic titania films and ordered titania nanodots/nanorods on glass. Adv. Funct. Mater. 15, 1343 (2005).CrossRefGoogle Scholar
8Chu, S-Z., Wada, K., and Inoue, S.: An integrated array of TiO2-SiO2-TeO2 nanotubules on glass: Fabrication and structural characteristics. Adv. Mater. 14, 1752 (2002).3.0.CO;2-1>CrossRefGoogle Scholar
9Macak, J.M., Tsuchiya, H., and Schmuki, P.: High-aspect-ratio TiO2 nanotubes by anodization of titanium. Angew. Chem. Int. Ed. Engl. 44, 2100 (2005).CrossRefGoogle ScholarPubMed
10Gong, D., Grimes, C.A., Varghese, O.K., Hu, W., Singh, R.S., Chen, Z., and Dickey, E.: Titanium oxide nanotube arrays prepared by anodic oxidation. J. Mater. Res. 16, 3331 (2001).CrossRefGoogle Scholar
11Zhao, J., Wang, X., Chen, R., and Li, L.: Fabrication of titanium oxide nanotube arrays by anodic oxidation. Solid State Commun. 134, 705 (2005).CrossRefGoogle Scholar
12Varghese, O.K., Gong, D., Paulose, M., Grimes, C.A., and Dickey, E.: Crystallization and high-temperature structural stability of titanium oxide nanotube arrays. J. Mater. Res. 18, 156 (2003).CrossRefGoogle Scholar
13Cai, Q., Paulose, M., Varghese, O., and Grimes, C.A.: The effect of electrolyte composition on the fabrication of self-organized titanium oxide nanotube arrays by anodic oxidation. J. Mater. Res. 20, 230 (2005).CrossRefGoogle Scholar
14Delplancke, J-L. and Winand, R.: Galvanostatic anodization of titanium—I. Structures and compositions of the anodic films. Electrochim. Acta 33, 1539 (1988).CrossRefGoogle Scholar
15Choi, J., Wehrspohn, R.B., Lee, J., and Gösele, U.: Anodization of nanoimprinted titanium: A comparison with formation of porous alumina. Electrochim. Acta 49, 2645 (2004).CrossRefGoogle Scholar
16Mor, G.K., Varghese, O.K., Paulose, M., Ong, K.G., and Grimes, C.A.: Fabrication of hydrogen sensors with transparent titanium oxide nanotube-array thin films as sensing elements. Thin Solid Films 496, 42 (2005).CrossRefGoogle Scholar
17Mor, G.K., Shankar, K., Paulose, M., Varghese, O.K., and Grimes, C.A.: Use of highly-ordered TiO2 nanotube arrays in dye-sensitized solar cells. Nano Lett. 6, 215 (2006).CrossRefGoogle ScholarPubMed
18Paulose, M., Shankar, K., Varghese, O.K., Mor, G.K., Hardin, B., and Grimes, C.A.: Backside illuminated dye-sensitized solar cells based on titania nanotube array electrodes. Nanotechnology 17, 1446 (2006).CrossRefGoogle Scholar
19Mor, G.K., Varghese, O.K., Paulose, M., Mukherjee, N., and Grimes, C.A.: Fabrication of tapered, conical-shaped titania nanotubes. J. Mater. Res. 18, 2588 (2003).CrossRefGoogle Scholar
20Taveira, L.V., Macak, J.M., Sirotna, K., Dick, L.F.P., and Schmuki, P.: Voltage oscillations and morphology during the galvanostatic formation of self-organized TiO2 Nanotubes. J. Electrochem. Soc. 153, B137 (2006).CrossRefGoogle Scholar