Host-matrix gels were prepared by hydrolysis of TEOS with the addition of
cadmium nitrate, formamide as DCCA (drying control chemical additive) and
submitted to a preselected dose of high power ultrasound. The impregnation
of the dry “sonogel” with KSeCN solution under vacuum conditions promoted
the formation of the CdSe nanocrystals and enhanced the mechanical
properties of the matrix. A transparent red xerogel was obtained and
characterized by optical spectroscopy, TEM and SAXS measurements. The
results support a structural model of a porous matrix containing CdSe
nanocrystals exhibiting a bimodal size distribution that depends on the Se
content of the impregnating solutions. The blue shift of the optical
absorption bands reveal the quantum-size confinement effects of CdSe
nanocrystals.