Mesoporous silica molecular sieves, which consisted of a mixture of microtubules and hexagonal prisms, were prepared by using an hydrothermal self-organizing method under acidic conditions. The nanostructure of the silica was characterized by means of scanning electron microscopy and transmission electron microscopy. The composition of the sample was analyzed by using infra-red, Raman, and energy-dispersed X-ray techniques. The photoluminescence spectrum contained a broad emission band, at 400 to 800nm, which consisted of 2 broad emission sub-bands; one at 477nm and the other at 512nm. The visible luminescence which appeared in calcined samples was attributed to the presence of appreciable amounts of 2-fold coordinated Si centres, Si20.

Photoluminescence of Mesoporous Silica Molecular Sieves. Y.Zhang, F.Phillipp, G.W.Meng, L.D.Zhang, C.H.Ye: Journal of Applied Physics, 2000, 88[4], 2169-71