Dye capped semiconductor nanoclusters. Role of back electron transfer in the photosensitization of SnO{sub 2} nanocrystallites with cresyl violet aggregates
- Univ. of Notre Dame, IN (United States)
Adsorption of a cationic dye, cresyl violet, on SnO{sub 2} and SiO{sub 2} nanoclusters and nanocrystalline thin films results in the formation of H-aggregates. These dyes are photochemically and electrochemically active and extend the photoresponse of large bandgap semiconductors such as SnO{sub 2}. Photocurrent generation in dye capped nanocrystalline films of SnO{sub 2} has been demonstrated with visible light excitation. A photon-to-photocurrent generation efficiency around 1% has been observed at 510 nm. Back electron transfer between the photoinjected electron and the oxidized sensitizer plays an important role in controlling the efficiency of net electron transfer. Transient absorption and microwave absorption measurements of the dye aggregate capped SnO{sub 2} films suggest that the back electron transfer is multiexponential and most is completed within a few hundred nanoseconds. The activation energy of the back electron transfer process is very low (nearly 1.7 kJ/mol). 68 refs., 10 figs.
- OSTI ID:
- 535435
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Journal Name: Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical Journal Issue: 14 Vol. 101; ISSN 1089-5647; ISSN JPCBFK
- Country of Publication:
- United States
- Language:
- English
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