Synthesis and characterization of Eu-doped cadmium selenide nanocrystals

Substitution of Cd(II) sites by Eu ions in 5.0 nm 0.25 nm CdSe, Cd1-xEuxSe (x = 0-0.374), can be achieved by modification of a lyothermal, single source precursor method. The Eu guest ion occupies a tetrahedral lattice site as a Eu(III) defect ion based on analysis of the XPS and XAS data. XRD and XAS measurements show a linear contraction of the lattice parameters for increasing Eu(III) concentration consistent with statistical substitution at both core and surface sites in the lattice by a random ion displacement mechanism. On the basis of a Vegard's law analysis, the Eu(III) ion is substituted in the tetrahedral cationic lattice site without formation of vacancies or phase segregation of the Eu ion in the lattice.