Photosensitized generation of singlet oxygen in porous silicon studied by simultaneous measurements of luminescence of nanocrystals and oxygen molecules

✍ Scribed by Gongalsky, M. B.; Kharin, A. Yu.; Zagorodskikh, S. A.; Osminkina, L. A.; Timoshenko, V. Yu.

• Book ID: 115503544
• Publisher: American Institute of Physics
• Year: 2011
• Tongue: English
• Weight: 526 KB
• Volume: 110
• Category: Article
• ISSN: 0021-8979
• DOI: 10.1063/1.3586044

✦ Synopsis

Photosensitization of singlet oxygen generation in porous silicon (PSi) was investigated by simultaneous measurements of the photoluminescence (PL) of silicon nanocrystals (nc-Si) and the infrared emission of the 1Δ-state of oxygen molecules at 1270 nm (0.98 eV) at room temperature. Photodegradation of the nc-Si PL properties was found to correlate with the efficiency of singlet oxygen generation. The quantum efficiency of singlet oxygen generation in PSi was estimated to be about 1%, while the lifetime of singlet oxygen was about fifteen ms. The kinetics of nc-Si PL intensity under cw excitation undergoes a power law dependence with the exponent dependent on the photon energy of luminescence. The experimental results are explained with a model of photodegradation controlled by the diffusion of singlet oxygen molecules in a disordered structure of porous silicon.