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Author Nasr, C. ♦ Liu, D. ♦ Kamat, P. V. ♦ Hotchandani, S.
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword MATERIALS SCIENCE ♦ CHEMISTRY ♦ RHODAMINES ♦ PHOTOCHEMICAL REACTIONS ♦ PHOTOSENSITIVITY ♦ SEMICONDUCTOR MATERIALS ♦ DYES ♦ EXCITED STATES ♦ SILICA ♦ TIN OXIDES ♦ COLLOIDS ♦ ELECTRON TRANSFER
Abstract SiO{sub 2} and SnO{sub 2} colloids are capped with a cationic dye, rhodamine 6G, by electrostatic interaction. The close packing of these dye molecules on the negatively charged SiO{sub 2} and SnO{sub 2} colloid results in the formation of H-aggregates. These aggregates are nonfluorescent but can inject electrons from the excited state into SnO{sub 2} colloids. The photophysical and photochemical properties of rhodamine-6G-aggregate on SiO{sub 2} and SnO{sub 2} colloids have been investigated using picosecond laser flash photolysis. Charge injection from the excited dye aggregate into SnO{sub 2} nanocrystallites occurs with a rate constant of 5.5 x 10{sup 9} s{sup -1}. The application of these dye aggregates in extending the photoresponse of nanocrystalline SnO{sup 2} film has been demonstrated by constructing a photoelectrochemical cell. A maximum incident photon-to-photocurrent efficiency of nearly 1% was observed for the photosensitized current generation. Fast reverse electron transfer between the injected electron and the cation radical of the dye aggregate is a limiting factor in maximizing the incident photon-to-photocurrent efficiency (IPCE). 65 refs., 11 figs.
ISSN 00223654
Educational Use Research
Learning Resource Type Article
Publisher Date 1996-06-27
Publisher Place United States
Journal Journal of Physical Chemistry
Volume Number 100
Issue Number 26


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