Study On The Synthesis And Fluorescence Properties Of Rare Earths Doped Fluorides Nanoparticles

Pseudo-ternary phase diagrams in quaternary microemulsions systems of cetyltrimethyl ammonium bromide (CTAB), n-butanol, n-octane and water (or salt solution) were presented. The structure of microemulsions systems were analysed from pseudo-ternary phase diagrams. Variation of the electrical conductivity with the water (or salt solution) content was observed, which supported the phase behavior of microemulsions systems.Nanoparticles of KMgF₃, KMgF₃:Eu and KMgF₃:Ce were prepared from the quaternary microemulsions of CTAB, n-butanol, n-octane and water based on the pseudo-ternary phase diagrams. IR showed the impurities in the samples. The X-ray diffraction (XRD) patterns were indexed to a pure KMgF₃ cubic phase. Environment scanning electron microscopy (ESEM) images showed spherical KMgF₃, KMgF₃:Eu and KMgF₃:Ce nanoparticles were about 20²5 nm in diameter. KMgF₃:Ce,Yb, KMgF₃:Er, KMgF₃:Pr, KMgF₃:Dy, KMgF₃:Tm and BaYF₅:Eu were prepared from the microemulsions system. The reason why KCaF₃, LiGdF₄, LiYF₄, BaY₂F₈ nanoparticles can't be prepared were explored.The emission of KMgF₃:Eu²⁺ nanoparticles peaked at 360 nm. The excitation band was observed at 250 nm, blue shifted respectively about 62 nm and 80 nm comparing with KMgF₃:Eu²⁺ multicrystal powders and single crystal. Fluorescence properties of KMgF₃:Ce and other Re-doped fluorides nanoparticles were discussed. The emission band of KMgF₃:Ce nanoparticles peaked at 330 nm, the excitation band was observed at about 260 nm. The emission band of KMgF₃: Ce,Yb nanoparticles also peaked at 330 nm. the excitation band was observed at about 244 nm. But its intensity was decreased with increasing the content of Yb. The emission of Yb²⁺ in KMgF₃: Ce,Yb nanoparticles was located at about 475nm.The synthesis of KMgF₃: Eu nanoparticles/PMMA composite materials was primarily studied. The difference of emission and excitation between KMgF₃:Eu nanoparticles/PMMA composite materials and KMgF₃:Eu nanoparticles was discovered by the fluorescence spectra.