Influence of Ordering in Porous TiO2 Layers on Electron Diffusion

• Published in: The journal of physical chemistry. B Vol. 110; no. 33; pp. 16165 - 16168
• Main Authors: Tirosh, Shay, Dittrich, Thomas, Ofir, Ashi, Grinis, Larisa, Zaban, Arie
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 24.08.2006
• ISSN: 1520-6106; 1520-5207
• DOI: 10.1021/jp063595e

Layers of porous TiO2 fabricated by electrophoretic deposition at different temperatures with subsequent sintering in air were investigated by transient photocurrent measurements in aqueous electrolyte. The effective diffusion coefficient of excess electrons changed between 1.6 × 10-5 and 1.4 × 10-4 cm2/s depending strongly on the solution temperature during the TiO2 layer deposition. Characterization, in terms of average degree of preferred orientation, shows that low deposition temperature results in orientation of the nanocrystals forming the porous film. Consequently, the increase of effective diffusion coefficient is attributed to a higher degree of ordering in the nanoporous TiO2 layer.