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

Autor: Fujii, Minoru, Nishimura, Naoki, Fumon, Hirokazu, Hayashi, Shinji, Kovalev, Dmitry, Goller, Bernhard, Diener, Joachim
Předmět:
Zdroj: Journal of Applied Physics; 12/15/2006, Vol. 100 Issue 12, p124302, 5p, 1 Diagram, 4 Graphs
Abstrakt: 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. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index