The blue-light emission enhancement mechanism of Eu2+ in Eu, Dy: SiO2 matrix

Abstract A Eu, Dy co-doped SiO 2 matrix xerogel with blue emission was prepared by the sol–gel method. Strong blue emission located between 425 nm and 525 nm with a peak at 486 nm is observed under UV laser excitation at room temperature, which is related to a 4f → 5d energy transition of Eu 2+ . Such techniques as FT-IR and TGA–DSC were used to measure the microstructure of the luminescent materials. The influence of Dy 3+ ions on the luminescent property of Eu 2+ was investigated. The emission intensity of Eu, Dy-codoped samples is stronger than that of Eu doped samples. The emission enhancement mechanism relating to Eu 2+ is attributed to an energy transfer involving Dy 3+ → Eu 2+ . Using energy transition theory, we speculate that the mechanism may be one of the resonance transfers via multi-polar interactions, and present a possible energy transfer model. The Eu 2+ blue emission intensity reaches the maximum when the Dy 3+ concentration is 0.1 mol%. When the concentration of Dy 3+ is 0.3 mol%, a fluorescence quenching appears which might be related to the overlap part of Eu 2+ excitation and emission levels, and also suggests the existence of Eu 2+ → Eu 2+ energy transfer.