Synthesis And Fluorescence Properties Of Rare Earths Doped Fluorides And Nanocomposites Of Luminescence

In the dissertation, nanoparticles of YF₃:Eu, YF₃:Tb, YF₃:Ce and YF₃:Er were prepared from the quaternary microemulsions of CTAB, n-butanol, n-octance and water based .The X-ray diffraction (XRD) patterns were indexed to a pure YF₃ orthorhombic phase. Envrionment scanning electron microscopy (ESEM) images showed spherical YF₃:Eu,YF₃:Tb,YF₃:Ce and YF₃:Er nanoparticles which were about 13-40 nm in diameter.The emission of YF₃: Eu nanoparticles peaked at 592 nm attributed to Eu³⁺ 5D₀→⁷F₁ transition.The emission of YF₃:Tb nanoparticles peaked at 544 nm attributed to Tb^{3+ 5}D₄→⁷F₅ transition which is the green transition emission of ⁵D₄ level.The emission peak of YF₃:Ce nanoparticles located at 340 nm belong to luminesence of near ultraviolet.The emission of YF₃: Er peaked at 1547nm. There is red shift and up-conversion in YF₃:Er nanoparticles which emits red and green.The synthesis of YF₃:Eu/PMMA and YF₃:Tb/PMMA composite materials were primarily studied. Compared to YF₃:Eu and YF₃:Tb nanoparticles, the emission and excitation peaks do not change but the intensity weaken of YF₃:Eu and YF₃:Tb nanoparticles and PMMA composite materials by the fluorescent spectra.