Doping of nanoporous glasses by supercritical fluid impregnation of β-diketonate Cu

Abstract

EPR and optical spectra of Cu2+ impregnated into nanoporous glass by β-diketonate from a supercritical solution of CO2 were investigated. It is shown that the environment of Cu2+ is static even at room temperature due to large size of the molecules and the steric factors of the pores. EPR spectra typical of Cu2+ in tetragonally elongated octahedron of D4h symmetry are observed. The local environment is determined by elements of molecule β-DKCu. On the basis of the EPR data, the effect of heat treatment on the evolution of the state of Cu2+ centers after dissociation (at 250°C) of the β-DKCu molecule is found. It is shown that, after the dissociation of the β-DKCu molecule, only 10% Cu2+ contributes EPR spectra. They form complexes with fragments of β-DKCu and are characterized by new EPR parameters. The optical spectrum of Vycor glass annealed at 800oC indicates the potential formation of colloid nanoparticles of metallic Cu.