Sodium fluoride-assisted modulation of anodized TiO2 nanotube for dye-sensitized solar cells application

Authors

Attila J. Mozer, University of WollongongFollow
Gordon G. Wallace, University of WollongongFollow
Yun Hau Ng, ARC Centre of Excellence for Functional NanomateriFollow
Jung-Ho Yun, ARC Centre of Excellence for Functional NanomateriFollow
Changhui Ye, Key Laboratory of Materials Physics, Institute ofFollow
Rose AmalFollow

RIS ID

47390

Publication Details

Yun, J., Ng, Y., Ye, C., Mozer, A. J., Wallace, G. G. and Amal, R. (2011). Sodium fluoride-assisted modulation of anodized TiO2 nanotube for dye-sensitized solar cells application. ACS Applied Materials and Interfaces, 3 (5), 1585-1593.

Abstract

This work reports the use of sodium fluoride (inethylene glycol electrolyte) as the replacement of hydrofluoricacid and ammonium fluoride to fabricate long and perpendicu-larly well-aligned TiO2 nanotube (TNT) (up to 21 ¿m) usinganodization. Anodizing duration, applied voltage and electro-lyte composition influenced the geometry and surface morphol-ogies of TNT. The growth mechanism of TNT is interpreted byanalyzing the current transient profile and the total chargedensity generated during anodization. The system with lowwater content (2 wt %) yielded a membrane-like mesoporousTiO2 film, whereas high anodizing voltage (70 V) resulted in theunstable film of TNT arrays. An optimized condition using 5 wt %water content and 60 V of anodizing voltage gave a stable array of nanotube with controllable length and pore diameter. Upon photoexcitation, TNTs synthesized under this condition exhibited a slower charge recombination rate as nanotube length increased. When made into cis-diisothiocyanato-bis(2,2-bipyridyl-4,4-dicarboxylato) ruthenium(II) bis (tetrabutyl-ammonium)(N719) dye- sensitized solar cells, good device efficiency at 3.33 % based on the optimized TNT arrays was achieved with longer electron time compared with most mesoporous TiO2 films.