Micro-Nanometer Rare Earth Borate Phosphors By In-situ Sol-gel Construction Of Hybrid Precursors

In this paper,we firstly put forward a novel optimized synthesis of rare earth silicates luminescence micron-nanometer materials through in-situ sol-gel route:We select rare earth coordination polymers as the precursors of corresponding rare earth rare earth silicates for their infinite chain-like polymeric structure similar to organic polymer template.Organic polymer was used as dispersing medium template and the polybasic hybrid polymeric precursors were assembled with other functional components such as PEG,PVA for the precursor of network.After heat-treatment of the resulting muticomponent hybrid precursors,the rare earth borate phophors were achieved.Most of the the particles exhibit good crystal morphology and the size of the particles is in the range of micrometer or sub-micrometer.The three-dimensional sizes of crystalline grain are rather thick to afford high powder,it needs to refer that the crystalline powder and the micrometer dimension for these powders with high strength would be very useful for the application to obtain high efficient phosphors because these macro crystalline materials can result in the high luminescent intensities which can avoid the traps formation of excess surface area for nanometer phosphors.We have already successfully synthesized three series of luminescence materials:LnBO₃:RE,Ln=Y,Gd;RE=Eu³⁺,Tb³⁺;Ln₃BO₆:RE,Ln=La,Y,Gd; RE=Eu³⁺,Tb³⁺,Dy³⁺;LnAl₃(BO₃)₄:RE,Ln=La,Y,Gd;RE=Eu³⁺,Tb³⁺.We have firstly achieved novel unexpected morphological structure just like coral in the silicate oxyapatites luminescence nanophosphor.There are also exhibit some novel morphological structures of microrod of LnAl₃(BO₃)₄:RE,Ln=La,Y,Gd;RE =Eu³⁺,Tb³⁺,Dy³⁺with huntite structure.The photoluminescent properties of materials doped with Tb³⁺has been studied as a function of Th³⁺doping concentration.Cross-relaxation process between identical Tb³⁺ions results in the quenching of the ⁵D₃ emission for high concentration sample.The photoluminescent properties of samples doped with Eu³⁺has been studied as a function of Eu³⁺doping concentration.Cross-relaxation process between Eu³⁺ions results in the quenching of the ⁵D₁ emission for high concentration sample.As for the system of LnAl₃(BO₃)₄: Dy³⁺,Ln=La,Y,Gd,we find that the intensity ratio of yellow-to blue(Y/B)of Dy³⁺ was significantly influenced by the x value,which is that with the x value increasing, the Y/B intensity ratio increased and then decreased,and through the adjustment on treatment and dopant,white emition could be achieved.