Study On Preparation Of Eu³⁺Doped YVO₄,LaF₃ And NaYF₄ Luminescent Materials And Their Wide-spectrum Excitation And Luminescence Properties

Rare-earth and alkaline-earth doped YVO₄nanomaterials is a current research hotspots of luminescent materials recently due to their stable chemical properties and excellent properties.YVO₄,La F₃and Na YF₄which doped with rare earth are good luminescent materials with simple preparation method,regular and controllable morphology,stable physicochemical properties,and good thermal stability.However,these luminescent materials have a narrow excitation spectra,which is difficult to meet the requirements of luminescent materials properties.Therefore,it is a important research significance that studying the preparation,wide-spectrum excitation and luminescence properties of YVO₄,La F₃and Na YF₄host materials.In this work,we focused on YVO₄,La F₃,a-Na YF₄luminescent materials,which were doped by Eu³⁺,Ba²⁺,Bi³⁺?rare-earth and alkaline-earth ions?and organic hybridized by benzoic acid?BA?,2-thieneoformyl trifluoro acetone?TTA?.Sol-gel solvothermal/hydrothermal process and ion exchange process were used to prepare YVO₄:Eu³⁺/La F₃:Eu³⁺/a-Na YF₄:Eu³⁺-BA/TTA/BA+TTA nanocrystals.Combining luminescent materials and Methyl methacrylate?MMA?to prepare Poly Methyl methacrylate?PMMA?composite materials.The crystal structure,microscopic morphology,crystal size,transmittance,and luminescence properties of samples were analyzed and characterized by XRD,SEM,TEM,EDS,FTIR,PL and UV.The main research contents and results are as follows.The YVO₄:Eu³⁺,Ba²⁺,Bi³⁺powders and films were successfully prepared by the sol-gel method.The effects of annealing temperatures,concentration of Ternary dopant and films thickness on luminescence properties were investigated.It was found that Ba²⁺doped enhanced the luminescence intensity and the addition of Bi³⁺broadened the excitation spectra,the effect of YVO₄:5%Eu³⁺,5%Ba²⁺,0.5%Bi³⁺wide spectra excitation was especially obvious after annealing at 1100?,the excitation width was 1.39 times of YVO₄:5%Eu³⁺and the luminescence intensity was 1.97times of YVO₄:5%Eu³⁺.It was found that YVO₄:5%Eu³⁺,5%Ba²⁺,0.5%Bi³⁺with three layers film thickness had the highest luminescence intensity,which was 2.52 times of one layer and 3.02 times of five layers.The YVO₄:Eu³⁺nanocrystals were successfully prepared by hydrothermal method and ion exchange method,and using organic ligand BA/TTA/BA+TTA to hybridized YVO₄:Eu³⁺.The effects of Eu³⁺concentration and organic ligands on the luminescent properties were researched.It was found that the excitation width and luminescence intensity of YVO₄:15%Eu³⁺-BA/TTA/BA+TTA were significantly improved.The effect of YVO₄:15%Eu³⁺-TTA wide spectra excitation was especially obvious,which can cover the entire UV band,the excitation width was 1.55 times of YVO₄:15%Eu³⁺,the luminescence intensity was 2.11 times of YVO₄:15%Eu³⁺.The La F₃:Eu³⁺nanocrystals were successfully prepared by hydrothermal method,and using organic ligand BA/TTA/BA+TTA to hybridized La F₃:Eu³⁺.The effects of Eu³⁺concentration and organic ligands on the luminescent properties were researched.It was found that the excitation width and luminescence intensity of La F₃:Eu³⁺-BA/TTA/BA+TTA were significantly improved.The effect of La F₃:5%Eu³⁺-BA+TTA wide spectra excitation was especially obvious,which can cover the entire UV band,the excitation width was 13.91 times of La F₃:5%Eu³⁺,the effect of La F₃:5%Eu³⁺-BA excitation intensity is 1.52 times of La F₃:5%Eu³⁺.The ?-Na YF₄:Eu³⁺nanocrystals were prepared by solvothermal method and ion exchange method,and?-Na YF₄:Eu³⁺was hybridized by organic ligand BA/TTA/BA+TTA.The effects of Eu³⁺concentration and organic ligands on the luminescent properties were researched.It was found that the excitation width and luminescence intensity of?-Na YF₄15%Eu³⁺-TTA/BA+TTA were significantly improved,the excitation width was 1.30 times and 1.20 times of a-Na YF₄:15%Eu³⁺,the luminescence intensity was 4.55 times and 5.13 times of a-Na YF₄:15%Eu³⁺.Various luminescent materials could be uniformly dispersed in MMA,and the prepared PMMA composite materials exhibited strong absorption performance in the ultraviolet region.It was found that the composite materials of PMMA-La F₃:5%Eu³⁺/?-Na YF₄:15%Eu³⁺had a transmittance of less than 10%between the wavelength of 240?300nm and had a transmittance of more than 60%between the visible light,which provided a reference for widening the application range of composite materials.