Mapping of the Photoinduced Electron Traps in TiO2 by Picosecond X‐ray Absorption Spectroscopy

• DOI: 10.1002/anie.201310522
• Publication Date: 2014-05-12T12:57:39Z
• Authors: M. Hannelore Ritt...; Chris J. Milne; Jochen Rittmann; Marco Reinhard; Thomas J. Penfold; Majed Chergui
• Keywords: Picosecond; Photoexcitation; Absorption edge; Nanosecond; Titanium Dioxide

Abstract Titanium dioxide (TiO 2 ) is the most popular material for applications in solar‐energy conversion and photocatalysis, both of which rely on creation, transport, trapping charges (holes electrons). The nature lifetime electron traps at room temperature have so far not been elucidated. Herein, we use picosecond X‐ray absorption spectroscopy Ti K‐edge Ru L 3 ‐edge to address this issue photoexcited bare N719‐dye‐sensitized anatase amorphous TiO nanoparticles. Our results show that 100 ps after photoexcitation, electrons are trapped deep defect‐rich surface shell case , whereas they inside bulk . In dye‐sensitized or outer surface. Only two were identified all cases, with lifetimes range nanoseconds tens nanoseconds.