Silver nanocrystals in silica by sol-gel processing

• Published in: Journal of non-crystalline solids Vol. 194; no. 3; pp. 225 - 234
• Main Authors: De, G., Licciulli, A., Massaro, C., Tapfer, L., Catalano, M., Battaglin, G., Meneghini, C., Mazzoldi, P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01-02-1996; Elsevier
• Subjects: Chemistry; Colloidal gels. Colloidal sols; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Fourier transformation; Transition metal Compounds; Glass; Temperature effect; X ray spectrometry; Alcohol; Organic silane; Experimental study; Sol gel transition; X ray diffraction; Nitric acid; Aggregation; Characterization; Infrared spectrometry; Rutherford backscattering; Transmission electron microscopy; Doped compound; Preparation; Noble metal; Photoelectron spectrometry; Silica gel; Aqueous solution; Silver Nitrates; Nanocrystal
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/0022-3093(91)00511-F

Silver nanocrystal doped silica films were prepared by the sol-gel process. The sol was prepared from 1:0.12:12:0.2:6:7 molar ratios of Si(OC
2H
5)
4:AgNO
3:H
2O:HNO
3:C
3
nH
7OH:C
4
iH
9OH. The glassy, highly transparent film with high dopant concentration (silver/silicon atomic ratio = 0.12) was successfully prepared by the dip-coating method. After drying in air at 60°C for 30 min, samples were heat-treated, in air, at 300, 350, 400, 450, 500 and 550°C using 30–100 min soaking periods for each step in a cumulative heating procedure. Measurements on the films were made by ultraviolet-visible and infrared spectroscopy, X-ray photoelectron spectroscopy, Rutherford backscattering spectrometry and transmission electron microscopy. Mechanisms of silver colloid formation in the densified silica matrix with respect to the thermal treatment are discussed. To understand the formation of silver nanocrystals from the silver silicate network, the corresponding doped bulk gel samples were analyzed by X-ray diffraction and differential scanning calorimetry.