Controllable Synthesis And Luminescence Properties Of Rare Earth Ions Doped Lutetium Oxide And Lutetium Vanadate

As a special functional material,rare earth luminescence materials can be widely used in lighting,displays,biology and medical fields due to their unique properties of optical,electric and magnetic.As we known,the properties of materials can be influenced by their structure,and nano/micro-materials have attracted great interest because of their smaller size,good dispersion and uniform granularity.So the preparation of nano/micro-size rare earth luminescence materials with excellent properties was the hotspot of research in recent years.In some degree,the host materials will influence the property of luminescence materials.Thus,choosing appropriate host materials was the key of preparing rare earth luminescence materials with excellent luminescence property.Rare earth oxides and lanthanide orthovanadates are the excellent host materials due to their good physical and chemical properties.Additionally,the charge transfer band?CTB?of rare earth oxides and the characteristic absorption of VO₄3-in lanthanide orthovanadates can also increase the luminescence intensity of rare earth ions.So,preparing nano/micro-structure rare earth oxides and lanthanide orthovanadates with uniform morphology and good dispersion were the tremendous challenge,and the synthesis of multi-colors emitting phosphors from single component was also the hotspot of research.In this paper,a series of morphology controlled nano/micro-size lutetium oxide and lutetium orthovanadates have been synthesized by simple and eco-environment method,the multicolor emitting properties have also been investigated.The main work as following:1.Cauliflower-like microstructural Lu2?C4H4O6?3·6H2O precursor with the size about 2 ?m has been successfully synthesized by precipitation method using tartaric acid as precipitant,water and ethanol as solvent.Then,uniform cauliflower-like Lu₂O₃ microspheres with size of that was 1 ?m can be obtained after calcination at 800 oC.Additionally,the formation mechanism of cauliflower-like structure was investigated in detail.Moreover,the morphologies of the precursor were controlled by adjusting the ratio of ethanol to water,and the reason of that was investigated.Furthermore,the dependence of luminescence performance on morphology(nano-flake and micro-cauliflower Lu2?C4H4O6?3·6H2O:Eu³⁺,Lu₂O₃:Eu³⁺)has been discussed in detail.They all exhibited the characteristic transitions of Eu³⁺,and the luminescence intensity of micro-cauliflower Lu2?C4H4O6?3·6H2O:Eu³⁺,Lu₂O₃:Eu³⁺ were more stronger.At last,the luminescence properties of cauliflower-like Lu2?C4H4O6?3·6H2O:Tb³⁺ and Lu₂O₃:Tb³⁺ microcrystals were investigated.Both of that all exhibited strong green emission corresponding to the 5D4-7FJ transitions of the Tb³⁺ ions under UV light excitation.2.3D-hierachical microspherical LuVO₄ with the diameter about 2 ?m were successfully synthesized by a solvothermal process with tartaric acid as template,and microspheres were consist of nanosheets.The influences of the amount of tartaric acid,the pH value,the reaction time and temperature on the morphologies of samples have been investigated.The possible formation mechanism of multi-morphologies?nanoparticles,nanosheets,nanodisks,sub-microflakes,nanoquadrangles,microspheres,and bulks?was proposed.In Dy-Eu co-doped LuVO₄ microspheres,the energy transfer mechanism from Dy³⁺ to Eu³⁺ was investigated.Furthermore,the multicolor?yellow-green,orange,red light?emitting can be realized by energy transfer process.Under 275 nm light irradiation,the luminescence properties of LuVO₄:Tm³⁺,Dy³⁺,Lu VO₄:Dy³⁺,Eu³⁺ and Lu VO₄:Tm³⁺,Dy³⁺,Eu³⁺ samples were investigated in detail.All characteristic transitions of doped ions can be observed in emission spectra of samples.Thus,the colorful emitting can be obtained by giving abundant blue,blue-green,yellow-green,orange,red,especially white-light-emission.