Abstract
Time-resolved photoacoustic spectroscopy (TRPAS) has been employed to probe directly the trap state energetics of photogenerated electrons in nanocrystalline colloidal titanium dioxide dispersed in aqueous solution. Deconvolution of the photoacoustic signals obtained following bandgap excitation allowed for separation of components associated with conduction band electron trapping, trapped electron-hole recombination, and a slower recombination step. The results indicate that the lifetime of the electron-hole pair is on the order of 25 ns with about 60% of the trapped electrons recombining on this time scale. The electron trapping sites were determined to lie, on average, 0.8 eV below the conduction band edge.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 231-236 |
| Number of pages | 6 |
| Journal | Chemical Physics Letters |
| Volume | 330 |
| Issue number | 3-4 |
| DOIs | |
| State | Published - Nov 10 2000 |
Funding
We gratefully acknowledge Professor Kenneth Spears for loan of laser equipment. We thank the Office of Naval Research and the Institute for Environmental Catalysis at Northwestern University for financial support.
ASJC Scopus subject areas
- General Physics and Astronomy
- Physical and Theoretical Chemistry