Construction And Magnetism-photoluminescence Bifunctionality Of One-dimensional Nanomaterials Based On Gadolinium Compounds

Gd³⁺ions take on the great magnetic moment due to possessing seven unpaired 4f electrons,therefore,Gd³⁺-based compounds are ideal paramagnetic materials.Rare earth luminescent materials of based on gadolinium compounds hosts have a wide range of applications in optical imaging,nanoprobes,biological labels and magnetic resonance imaging.Nowadays,some kinds of Gd³⁺-based compounds powders were successfully prepared,but there are only a few reports on the synthesis of one-dimentional nanomaterials.In recent years,a variety of one-dimensional nanomaterials have been successfully prepared by using electrospinning technology.Compared with other experimental methods,the advantages of electrospinning include simple operation procedure,wide applications and high cost-effectiveness.Therefore,study on rare earth doped Gd³⁺-based compounds one-dimensional nanomaterials synthesized by electrospinning technique is an important research subject.In the dissertation,the original composite nanofibers or nanobelts were synthesized by electrospinning,and then these composite nanofibers or nanobelts were calcined at high temperature to obtain Gd₂O₃:Dy³⁺,Eu³⁺nanofibers,Gd₂O₃:Yb³⁺,Tm³⁺nanofibers and nanobelts,Gd₂O₃:Yb³⁺,Ho³⁺nanofibers and nanobelts,Gd₂O₃:Tb³⁺,Eu³⁺nanofibers.For the first time,Gd₂O₂S:Dy³⁺,Eu³⁺nanofibers,GdOCl:Yb³⁺,Tm³⁺nanofibers and nanobelts,GdOCl:Yb³⁺,Ho³⁺nanofibers and nanobelts,GdOBr:Tb³⁺,Eu³⁺nanofibers were successfully synthesized via dual-boat sulfurization,double-crucible chlorination and dual-boat bromination techniques.The products were characterized by XRD,SEM,PL and magnetometer.The results indicate that Gd₂O₂S:Dy³⁺,Eu³⁺nanofibers are pure hexagonal system with space group of P3^-m1,GdOCl:Yb³⁺,Tm³⁺and GdOCl:Yb³⁺,Ho³⁺nanostructures are pure tetragonal structure with space group of P4/nmm,and GdOCl:Tb³⁺,Eu³⁺nanofibers are pure tetragonal system with space group of P4/nmm.The mean diameter and width of nanofibers and nanobelts are about 100-300 nm and 1-3?m respectively.PL spectra show that Gd₂O₂S:Dy³⁺,Eu³⁺nanofibers achieve multicolor emissions and energy transfer by changing the content of Dy³⁺or Eu³⁺under the 272 nm ultraviolet excitation.Upon respective 980 nm and 357 nm excitation,GdOCl:Yb³⁺,Tm³⁺nanofibers obtain up-conversion and down-conversion dual mode luminescence.At 980 nm and 455 nm respectively,GdOCl:Yb³⁺,Ho³⁺nanofibers also achieve dual mode luminescence.GdOBr:Tb³⁺,Eu³⁺nanofibers acquire multicolor emitting and energy transfer by modulating the ratios of Tb³⁺and Eu³⁺.Rare earth doped Gd³⁺-based compounds one-dimensional nanomaterials not only have excellent luminescent properties,but also have paramagnetic performances.In this work,some meaningful results have been obtained,which lays some foundations for further research of luminescence and magnetism of other Gd³⁺-based compounds one-dimensional nanomaterials.