Improving microstructured TiO 2 photoanodes for dye sensitized solar cells by simple surface treatment

Saquib Ahmed, Aurelien Du Pasquier, Tewodros Asefa, Dunbar P. Birnie

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)


TiCl 4 surface treatment studies of porous electrode structure of TiO 2 aggregates synthesized using an acidic precursor and CTAB as a templating agent are carried out in order to understand and improve upon recombination kinetics in the photonanode film matrix, together with enhancing the intrinsic light scattering. The key beneficial features of the photoanode included high surface roughness, necessary for superior dye adsorption, nanocrystallite aggregates leading to diffuse light scattering within the film matrix, and a hierarchical macro- and mesopore structure allowing good access of electrolyte to the dye, thereby assisting in dye regeneration (enhanced charge transfer). Pre-treatment of the TiO 2 electrodes reduced recombination at the fluorine-doped tin oxide (FTO)/electrolyte interface. The post-treatment study showed enhanced surface roughness through the deposition of a thin overlayer of amorphous TiO 2 on the film structure. This led to a notable improvement in both dye adsorption and inherent light scattering effects by the TiO 2 aggregates, resulting in enhanced energy harvesting. The thin TiO 2 overlayer also acted as a barrier in a core-shell configuration within the porous TiO 2 matrix, and thereby reduced recombination. This allowed the hierarchical macro- and mesoporosity of the film matrix to be utilized more effectively for enhanced charge transfer during dye regeneration. Post-treatment of the aggregated TiO 2 matrix resulted in a 36% enhancement in power conversion efficiency from 4.41% of untreated cells to 6.01%.

Original languageEnglish
Pages (from-to)879-887
Number of pages9
JournalAdvanced Energy Materials
Issue number5
Publication statusPublished - Oct 2011

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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