Luminescence and photosensitization properties of ensembles of silicon nanocrystals in terms of an exciton migration model
- Russian Research Center Kurchatov Institute (Russian Federation)
The relaxation processes that occur in ensembles of coupled silicon nanocrystals are described by a quantitative model that takes into account the energy transfer between them during exciton migration. This model is used to study the formation of singlet oxygen during the photoexcitation of silicon nanocrystals in porous silicon layers under various external conditions. It is experimentally found that, upon fine milling of as-deposited porous silicon films, the photoluminescence decay time increases despite an increase in the concentration of point defects. The photosensitized activity of ensembles of silicon nanocrystals degrades monotonically during their photostimulated oxidation. These experimental results agree completely with the conclusions of the model and are explained by a decrease in the number of exciton migration ways between nanocrystals when the granule size of a porous silicon powder decreases and by an increase in the efficiency of nonradiative recombination during the photostimulated oxidation of the nanocrystals. Our data indicate that nanocrystalline silicon is a promising material for the methods of nontoxic photodynamic therapy of oncological diseases.
- OSTI ID:
- 21443345
- Journal Information:
- Journal of Experimental and Theoretical Physics, Journal Name: Journal of Experimental and Theoretical Physics Journal Issue: 5 Vol. 111; ISSN 1063-7761
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
77 NANOSCIENCE AND NANOTECHNOLOGY
CHEMICAL REACTIONS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
CRYSTALS
ELEMENTS
EMISSION
ENERGY TRANSFER
EXCITONS
FILMS
LAYERS
LUMINESCENCE
MACHINING
MATERIALS
MILLING
NANOSTRUCTURES
NONMETALS
OXIDATION
OXYGEN
PHOTOLUMINESCENCE
PHOTON EMISSION
POINT DEFECTS
POROUS MATERIALS
POWDERS
QUASI PARTICLES
RECOMBINATION
RELAXATION
SEMIMETALS
SILICON