Preparation And Properties Of Rare-earth Doped Based Magnetic-fluorescent Nanocomposites

In recent years,magnetic nanoparticles and lanthanum rare earth fluorescent materials have been aroused a wide range of the researchers'interest because of their unique magnetic and fluorescent properties.However,with the development of biological science and technology,materials with single function have failed to meet the needs of experimental research.Therefore,the materials with both magnetic and fluorescent properties have attracted much attention.Bifunctional nanocomposites have been gradually applied in biomedical applications,which include magnetic-resonance imaging,biological labeling,and biochemical separation,because they possess both magnetic and fluorescent properties.In this paper,it is selected lanthanide rare earth-doped materials to be combined with magnetic Fe₃O₄ particles to achieve bifunctional properties,we employ the improvement of preparation,the co-doped with rare earth ions,the hollow structured Fe₃O₄ to obtain magnetic-fluorescent nanoparticles through the three aspects above,the magnetic-fluorescent nanocomposites were synthesized using homogeneous precipitation method,the phase constitution,microstructure,fluorescence properties and magnetic properties were analyzed by used a series of characterization methods,the specific content and conclusions are as follows:Firstly,the improvement of the preparationEu³⁺-doped gadolinium oxide luminescent shell was deposited on the magnetic Fe₃O₄ core bifunctional nanoparticles by homogeneous precipita-tion method.It researched the effect of solution p H value?p H=1.6,2.0,2.4,2.8,3.0,3.4?on the phase constitution,microstructure,particle size distribution and luminescence of the particles.The samples showed the spherical morphology,an average particle size of⁶0 nm;the fluorescence spectrum displayed emission characteristic peak of Eu³⁺;high saturation magnetization?Ms?of 1.29emu/g,coercivity Hc of 60Oe and a remanence Mr of 0.01emu/g,the solution p H value can effect the performance of the sample,the samples treated at the solution of p H=3.0,the phase constitution,microstructure,particle size distribution and luminescence of particles had arrived at the optimum.Secondly,the co-doped with rare-earth ionsThe Gd³⁺ion,Eu³⁺ion co-doped nanoparticles,Fe₃O₄@(Y_1-x-x Gd_x)₂O₃:Eu³⁺,were synthesized through homogeneous precipitation method.It researched the effect of the Gd³⁺ion concentration?x=0mol%,10mol%,20mol%,30mol%,40mol%?on the photoluminescence of the particles.The results showed that the Gd³⁺ion concentration was found at x=30mol%,the luminescence of particles arrived at the optimum.Under the optimum fluorescent properties condition,the particles showed a spherical shape and an average particle size of¹80 nm;the fluorescence spectrum displayed emission characteristic peak of Eu³⁺;a good saturation magnetization?Ms?of1.09 emu/g,a coercivity Hc of 20 Oe and a remanence Mr of 0.01 emu/g.Due to the Gd³⁺-Eu³⁺energy transfer,an optimized doping concentration of Gd³⁺was found at x=30mol%,leading to the luminescence intensity 2.7 times higher that than of the undoped sample.Thirdly,the hollow structured Fe₃O₄ particleHollow structured Fe₃O₄@Gd₂O₃:Eu³⁺nanoparticles with hollow Fe₃O₄as the core and the Gd₂O₃:Eu³⁺as the shell were synthesized through the homogeneous precipitation method.It researched the effect of hollow structure on the luminescence properties and magnetic properties of the particles.The particles showed the spherical morphology,an average particle sizeof¹400nm;thefluorescencespectrumdisplayedemission characteristic peak of Eu³⁺;high saturation magnetization?Ms?of 1.33 emu/g,coercivity Hc of 160 Oe and a remanence Mr of 0.05 emu/g.Particularly,at the same condition,the hollow structure nanoparticles exhibited the photoluminescence intensity 2.45 times higher than the solid structure samples,due to the hollow structure.In this paper,some new way on adjusting the solution p H value,rare earth ions co-doped,hollow structure Fe₃O₄ research are provided for improving the fluorescent intensity of nanoparticles.These ways can effectively improve the way of directly to bring low fluorescence performance defects,these establish a foundation for the subsequent application of nanoparticles,which will play a key role in promoting the development in the field of biological,medical and so on.