Time-resolved optical study on the charge carrier dynamics in a TiO{sub 2}/AgI sandwich colloid

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Journal of Physical Chemistry

DOI:https://doi.org/10.1021/j100022a034· OSTI ID:68006

Fitzmaurice, D; Frei, H; Rabani, J ^[1]

---

1. Univ. of California, Berkeley, CA (United States)

Preparation of a sandwich colloid involving TiO{sub 2} and AgI (hexagonal) particles in alkaline aqueous solution is described. Time-resolved optical absorption experiments are reported that involve pulsed laser excitation at 355 nm (TiO{sub 2} bandgap) and at 410 nm (AgI bandgap). Charge carrier dynamics was probed directly by transient absorption measurements in the near-infrared and by reaction with methyl viologen (MV{sup 2+}). Reduction of MV{sup 2+} was observed to occur over a period of 100-200 {mu}s. MV{sup +} so produced reduced AgI to silver. By contrast, MV{sup 2+} reduction upon bandgap excitation of neat alkaline TiO{sub 2} colloid was complete within 1 {mu}s. These observations signal a prolonged electron-hole separation in the case of the AgI/TiO{sub 2} sol and indicate the formation of sandwich particles. 33 refs., 5 figs.

• Sponsoring Organization: USDOE
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 68006
• Journal Information: Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 22 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
66 PHYSICS
ABSORPTION SPECTRA
BIPYRIDINES
CHARGE CARRIERS
CHEMICAL PREPARATION
CHEMICAL REACTIONS
COLLOIDS
DYNAMICS
SILVER IODIDES
TITANIUM OXIDES