Controllable Preparation And Luminescence Properties Of Rare Earth-Doped SiO₂ Microspheres

In recent years,with the development of modern medicine,molecular biology,materials science and application of advanced fluorescence detection technology and instruments,fluorescence labeling has become a common analysis method.Rear earth doped silica microspheres have been widely used in fluorescent tags materials because of their good stability,good bio-compatibility and high luminous intensity.The controllable of the aspects such as morphology,size and luminous performance are beneficial to improve the applicability and efficiency of fluorescence silica microspheres.In this work,on the basis of exploring the influence of different reaction conditions on the size and distribution of pure silica microspheres by the sol-gel method,three kinds of core-shell structure fluorescent microspheres were prepared with the chemical structures of SiO2:Re3+,SiO2@SiO2:ReX3Y and ReX3Y@SiO2(Re =rear earth,X represents the first ligand Y represents the second ligand).And we had detailed ananalyze the synthesis,and the control of the morphlogy,size of the fluorescent microspheres.Then preliminary discussed the application of fluorescent labeling in silicone rubber of the three kinds of fluorescent microspheres.The main work is as follows:(1)The pure silica microspheres were prepared by sol-gel method,then the influence on the size,the spherical degree and size distribution of the microspheres caused by different concentration of tetraethyl orthosilicate(TEOS),ammonia,temperature and volume proportion of solvent were explored in this part.Then the best reaction condition of small size or good monodispersity microspheres was explored by an orthogonal test.And the pure silica microspheres controllable particle sizes were obtained in a sol seeded method.The rear earth ions doped fluorescent microspheres SiO2:Re3+were synthesized by a midified sol seeded way.The experimental results show that SiO2:Re3+ microspheres had obvious rough structure surface,uniform particle size,good monodispersity and sphericity.The particle size of the fluorescent microspheres was controllable within the scope of 85-510 nm.Finally through the control of reaction conditions on the types and amount of doping rare earth ions,theluminescence property of the microspheres fluorescent microspheres was controllable and the best rare earth doping concentration should be 5mol%.(2)The fluorescent microspheres SiO2@SiO2:Eu(DBM)3phen which have a typical core-shell structure with silica microspheres as the core and mesoporous silica doped with rare earth complexes as the shell were prepared by a modified sol seeded method.The results showed that the fluorescent microspheres have good sphericity and monodispersity,uniform particle size and smooth surface.The surface of the microspheres is a layer of mesoporous silica with the pore size of 2.9 nm.The particle size of the fluorescent microspheres was controllable within the scope of 77-595 nm.The products show the obvious characteristic of the Eu3+ emission peak,and the fluorescence intensity increases with increasing of concentration of Re conplexes with a Concentration quenching of 7mol%.The core-shell structure fluorescent microspheres Eu(DBM)3phen@SiO2 with the rare earth complexes as the core and silica as the shell were also obtained by a modified sol seeded method,The results showed that of the microspheres have uniformity particle size,smooth surface,good monodispersity and spherical degree,the particle size of the fluorescent microspheres was controllable within the scope of 77-595 nm.And the fluorescent microspheres show the obvious characteristic of the Eu3+ emission peak.The number of silicon hydroxyl and the luminous intensity were compared with each other for the three types of microspheres,the results show that there is not much difference of the number of silicon hydroxyl between all of these fluorescent microspheres and the pure silica microspheres.Indicating that surface activity the microspheres affects little by the incorporation of rear earth,and SiO2@SiO2:Eu(DBM)3phen microspheres show the highest luminous intensity.(3)Finally,the Fluorescent functional silicone rubber was otained by a polymer processing by the filling of Eu(DBM)3phen@SiO2,SiO2@Si O2:Eu(DBM)3phe SiO2:Eu3+ microspheres as the filler,and the dispersion of the fluorescent microspheres have been analyzed by Laser scanning confocal microscope.The results show that the visualization rate of SiO2:Eu3+microspheres is 26.7%,he visualization rate of SiO2@SiO2:Eu(DBM)3phen microspheres is 93.2% and Eu(DBM)3phen@SiO2,microspheres is 93.2%.And the the aggregate size distribution ofSiO2@SiO2:Eu(DBM)3phen microspheres was focus on 1-6 μm.