β-ray irradiation effects on silica nanoparticles

12th Europhysical Conference on Defects in Insulating Materials

材料科学;物理学

Alessi, A.^1 ; Agnello, S.^1 ; Buscarino, G.^1 ; Boizot, B.^2 ; Cannas, M.^1 ; Gelardi, F.M.^1

Department of Physics and Chemistry, University of Palermo, Via Archirafi 36, Palermo

I- 90123, Italy^1

Laboratoire des Solides Irradiés, UMR 7642 CEA-CNRS-Ecole Polytechnique, Ecole Polytechnique, Palaiseau Cedex

91128, France^2

关键词: Defects induced;    Electron paramagnetic resonances (EPR);    Irradiation effect;    Nanoparticles sizes;    Particles sizes;    Peroxy radicals;    Shell models;    Specific surface;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/80/1/012011/pdf
DOI  :  10.1088/1757-899X/80/1/012011

学科分类：材料科学（综合）

来源: IOP

【 摘 要 】

By electron paramagnetic resonance (EPR) measurements, we examine the amplitude of the signal typically due to a combination of NBOHC (Non Bridging Hole Center) and POR (Peroxy Radical) defects induced by β-ray irradiation (from 1.2 to 1200 MGy) in silica nanoparticles with diameter ranging from 7 to 20 nm. Our data indicate that the signal line-shapes recorded at different doses is quite independent from the particles sizes and from the dose. Furthermore, for each considered nanoparticles size, the concentration of defects is also almost constant with respect to dose, and it does not change significantly if measured after 2 or 9 months from the irradiation. By contrast, we observed that the concentration of NBOHC+POR decreases on increasing the specific surface, indicating that the content of the defects depends on the nanoparticles size. Such dependence can be explained by a shell model in which the detected defects are located in the inner part of the nanoparticles.