Luminescence Quenching By Iron And Copper In Luminescence Materials Excited By Europium

Rare earth luminescence materials have been widely applied to every field of the national defence, space navigation, industry and agriculture due to their properties of high fluorescent efficiency, sharp emission lines, long emission lifetimes and steady nature in physics and chemistry. However, transition metal impurities such as iron and copper reduce the luminescence intensity or lose the luminescence thoroughly. Thus the effect of Fe²+. Fe³+and Cu²+ ions on the phosphors of alkaline earth aluminate excited by Eu²+ and rare earth complexes excited by Eu³+ is studied in the thesis. The thesis consists of the following parts:1. The preparation of the long afterglow phosphors SrAl₂O₄: Eu²+, Dy³+ and luminescence quenching by ironThe long afterglow phosphors SrAl₂O₄: Eu²+, Dy³+ with different iron content are prepared by nano-alumina coating process. The effect of crystal structure and luminescence properties of the phosphors by iron is investigated by XRD and luminescence spectra. It is found that crystal structure has no change, but the luminescence intensity is reduced. The luminescence intensity decreases with the increase of iron content. The causes are discussed.2. The synthesis of the Europium carboxylic acid complexes and luminescence quenching by ironThe complexes of Eu-Fe²+(Fe³+)-BA, Eu-Fe²+(Fe³+)-Phthate, Eu-Fe²+(Fe³+)-BA-Phen, and Eu-Fe²+(Fe³+)-EDTA are synthesized in liquid phase to study the relationship between iron content and the luminescence of the complexes. FT-IR and fluorescence spectra are investigated. The results show that Fe²+and Fe³+ ions have a strong quenching effect on the luminescence of the complexes. The luminescence intensity decreases with the increase of iron content. The causes are studied.3. Luminescence quenching by copper in Eu-BA complexThe complexes of Eu-Cu²+-BA are synthesized in liquid phase to study the relationship between copper content and the luminescence of the complex. FT-IR and fluorescence spectra are investigated. The results show that Cu²+ ion reduces the intensity of Eu-BA complex. The luminescence intensity decreases with the increase of copper content. The causes are discussed.