Roy, Sutapa and Ganguli, Dibyendu (1992) Optical-properties of Ni-2+-doped silica and silicate gel monoliths. Journal of Non-Crystalline Solids, 151 (3). pp. 203-208. ISSN 0022-3093

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Abstract

Divalent nickel (0.20-0.41 mol/l) was introduced in silica and potassium silicate gel monoliths prepared via sols obtained from tetraethoxysilane and metal salts under various water/alkoxide mole ratio and final pH conditions. The UV-visible spectra of the gels dried at 60-degrees-C showed the presence of Ni2+ in octahedral coordination in all cases. However, when the doped silica gels were heated to 150-250-degrees-C the spectra showed changes similar to those attributed to the transformation of octahedral nickel to tetrahedral nickel in alkali borate glasses. In doped potassium silicate gels heated to 500-800-degrees-C, the generation of tetrahedral nickel was confirmed by the transitions observed in the spectra. Colours of the doped silica gels showed shifts from the green to the yellow region, with increasing heat-treatment temperature. For the potassium silicate gels, however, the dominant wavelength was in the red or violet region depending on the basicity of the system.

Item Type:	Article
Subjects:	Engineering Materials
Divisions:	Sol Gel
Depositing User:	Bidhan Chaudhuri
Date Deposited:	28 Nov 2013 08:15
Last Modified:	28 Feb 2016 16:12
URI:	http://cgcri.csircentral.net/id/eprint/2348

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