Fabrication of Sm2+-doped macroporous aluminosilicate glasses with high alumina content

Abstract Macroporous Al 2 O 3 –SiO 2 glasses doped with Sm 2+ have been prepared from a sol–gel system containing aluminum sec -butoxide, tetramethoxysilane, samarium chloride hexahydrate, poly(ethylene oxide), nitric acid, and water. Monolithic gels having interconnected macropores and skeletons are formed by inducing the phase separation parallel to the gelation. The use of aluminum sec -butoxide preheated at 80 °C as the starting material enables the incorporation of Al 3+ into the gel skeleton up to 20 mol% in cation ratio. The maximum amount of Al 3+ , i.e., 20 mol%, is twice as large as that reported in our previous study, where aluminum sec -butoxide was diluted with sec -butanol prior to the hydrolysis. Heat-treatment of Sm 3+ -doped 20AlO 3/2 · 80SiO 2 macroporous glass under the reducing atmosphere converts Sm 3+ to Sm 2+ , which is confirmed by the appearance of intense emission peaks attributed to 4f–4f transitions of Sm 2+ .