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Dynamics of photosensitized formation of singlet oxygen by porous silicon in aqueous solution

Authors :
Dmitry Kovalev
Naoki Nishimura
Bernhard Goller
Shinji Hayashi
Joachim Diener
Minoru Fujii
Hirokazu Fumon
Source :
Journal of Applied Physics. 100:124302
Publication Year :
2006
Publisher :
AIP Publishing, 2006.

Abstract

Generation of singlet oxygen due to energy transfer from photoexcited silicon nanocrystals in D2O is demonstrated. It is shown that the singlet oxygen generation efficiency, i.e., the intensity of near-infrared emission from singlet oxygen gradually decreases when Si nanocrystals are continuously irradiated in O2-saturated D2O. The mechanism of the photodegradation of the photosensitizing efficiency is studied using photoluminescence and infrared absorption techniques. Experimental results suggest that the interaction of photogenerated singlet oxygen with the hydrogen-terminated surface of silicon nanocrystals results in photo-oxidation of silicon nanocrystals, and the surface oxides reduce the photosensitizing efficiency. It is also demonstrated that photo-oxidation of porous silicon in O2-saturated water results in a strong enhancement of the photoluminescence quantum yield of porous Si.

Details

ISSN :
10897550 and 00218979
Volume :
100
Database :
OpenAIRE
Journal :
Journal of Applied Physics
Accession number :
edsair.doi...........6483b450d19b4aba38eb444d5f41a9e1