Temperature dependence of O2 singlet photoluminescence in silica nanoparticles.

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Bibliographic Details
Title: Temperature dependence of O2 singlet photoluminescence in silica nanoparticles.
Authors: Agnello, S.1 simonpietro.agnello@unipa.it, Vaccaro, L.1, Cannas, M.1, Kajihara, K.2
Source: Journal of Non-Crystalline Solids. Nov2013, Vol. 379, p220-223. 4p.
Subjects: Temperature effect, Oxygen, Photoluminescence, Silica nanoparticles, Thermal stability, Relaxation phenomena
Abstract: Abstract: The near infrared singlet emission and photoluminescence lifetime of O2 molecules embedded in silica nanoparticles are studied from room temperature down to 10K. The area of the photoluminescence band under infrared excitation decreases for temperature above 100K and the lifetime is shortened. These observations provide evidence of a thermally activated relaxation channel with activation energy of about 40meV. This relaxation mechanism adds to the already known temperature independent electronic-to-vibrational coupling involving high energy vibrational modes of the host matrix or its impurities. The thermally activated process is suggested to consist in the breakage of the O2 molecule weak bonds with walls of the matrix interstices with ensuing molecular motion and collisional exchange of energy. [Copyright &y& Elsevier]
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Database: Engineering Source
Description
Abstract:Abstract: The near infrared singlet emission and photoluminescence lifetime of O2 molecules embedded in silica nanoparticles are studied from room temperature down to 10K. The area of the photoluminescence band under infrared excitation decreases for temperature above 100K and the lifetime is shortened. These observations provide evidence of a thermally activated relaxation channel with activation energy of about 40meV. This relaxation mechanism adds to the already known temperature independent electronic-to-vibrational coupling involving high energy vibrational modes of the host matrix or its impurities. The thermally activated process is suggested to consist in the breakage of the O2 molecule weak bonds with walls of the matrix interstices with ensuing molecular motion and collisional exchange of energy. [Copyright &y& Elsevier]
ISSN:00223093
DOI:10.1016/j.jnoncrysol.2013.08.016