Metal sodium nanoparticles in fluorophosphate glasses

• Published in: Journal of alloys and compounds 2015-07, Vol.637, p.545-551
• Main Authors: Kolobkova, E., Nikonorov, N.
• Format: Article
• Language: English
• Subjects: Alloys; Compressing; Fluorine; Glass; Heating; Metal nanoparticles; Nanoparticles; Plasmons; Sodium; Surface plasmon resonance
• ISSN: 0925-8388; 1873-4669
• DOI: 10.1016/j.jallcom.2015.02.148

•4–6nm sized sodium nanoparticles are formed in fluorophosphate glasses by heat treatment in the glass transition region.•The variation of the heating temperature and time as well as the compression load provides the adjustment of nanoparticle shape from spherical to ellipsoidal with different ratios between the axes as indicated by the appearance of two well resolved peaks in the surface plasmon resonance spectra of the studied samples.•An increase in the heat treatment time leads to the chemical damping. Metallic sodium nanoparticles with the sizes 4–6nm are synthesized for the first time in bulk of fluorine phosphate glass by the high-temperature synthesis under reducing conditions with the subsequent additional heating. The obtained nanoparticles manifest themselves by the absorption band in the region 400–450nm determined by the surface plasmon resonance. The effect of additional compression of the melt in the course of cooling as well as the subsequent heating conditions on the characteristics of plasmon resonance band intrinsic to sodium nanoparticles was studied. The glasses subjected to high compression in the course of cooling in combination with the subsequent heating near Tg are featured with two peaks in the surface plasmon resonance band indicating the symmetry distortion in the nanoparticles due to the transition from spherical to ellipsoidal shape. The increase of additional heating temperature is found to provide spherical nanoparticles. The increase of additional heating time resulted in (i) the “red” (longer wave) shift of the surface plasmon resonance band, (ii) a certain decrease in the band intensity, and (iii) broadening of the band probably determined by the chemical damping due to the formation of new surface states at the nanoparticle/matrix interface.