Photochemistry on surfaces. Intermolecular energy electron transfer processes between excited Ru(bpy){sub 3}{sup 2+} and H-aggregates of cresyl violet on SiO{sub 2} and SnO{sub 2} colloids
- Univ. of Notre Dame, IN (United States)
Cresyl violet, a cationic dye (CV{sup +}), forms H-aggregates on the negatively charged SiO{sub 2} and SnO{sub 2} colloids. These aggregates exhibit broad absorbance around 520 nm. By coadsorbing a sensitizer, Ru(bpy){sub 3}{sup 2+}, we are able to characterize the triplet excited state and reduced form of dye-aggregates on the colloidal SiO{sub 2} and SnO{sub 2} suspensions. On SiO{sub 2} surfaces, the excited state quenching of Ru(bpy){sub 3}{sup 2+} by dye-aggregates proceeds via an energy transfer mechanism. Picosecond laser flash photolysis experiments indicate that such a surface-promoted energy transfer is completed within 20 ps. On the other hand dye-aggregates adsorbed onto SnO{sub 2} colloids undergo photosensitized reduction since the excited sensitizer, Ru(bpy){sub 3} {sup 2+}, is efficiently quenched by the semiconductor support. The role of support material in promoting energy and electron transfer processes is described. 87 refs., 11 figs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 171507
- Journal Information:
- Journal of Physical Chemistry, Journal Name: Journal of Physical Chemistry Journal Issue: 45 Vol. 99; ISSN JPCHAX; ISSN 0022-3654
- Country of Publication:
- United States
- Language:
- English
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