Adjusting valence state of europium in sintered porous glass by adding of aluminum and yttrium

We report on valence state adjusting of europium in porous glass by co-doping with aluminum or yttrium into porous glass. The influence of Al³⁺ and Y³⁺ on the emission intensity of Eu³⁺ and Eu²⁺ in sintered high-silica porous glass has been investigated. It is found that the emission intensity of Eu³⁺ can be increased by adding of Y³⁺ and Al³⁺, and the emission intensity of Eu²⁺ can be decreased by adding of Y³⁺ and increased by Al³⁺. At the same time, the emission peak position of Eu²⁺ can also be changed by adding of Al³⁺ or Y³⁺. It is suggested that the adjusting of valence state and the peak position shift is relative to the optical basicity of glasses or crystal field strength around REs.