Controllable Synthesis And Properties Of Rare Earth Ions Doped Bismuth Silicate Luminescent Materials

In recent years,inorganic solid luminescent materials have been widely used in lighting,information displays,and medical diagnosis due to their stable structure and easy availability of raw materials.Among them,rare earth luminescent materials exhibit some advantages in comparison with other luminescent materials due to their special electronic layer structure,which lays a foundation for the production of efficient luminescent materials.Therefore,it has become a research hotspot for exploring new materials with low phonon energy,high quantum efficiency,and high physicochemical stability as luminescent host.In this paper,a series of bismuth silicate(Bi₄Si₃O₁₂)luminescent materials have been prepared by sol-gel method and electrostatic spinning method.The main contents are as follows:The novel bismuth silicate Bi₄Si₃O₁₂:Yb³⁺/Ln³⁺?Ln=Er,Tm,Ho?up-conversion?UC?phosphors have been synthesized via a simple sol-gel approach with sodium citrate as complexing agent and water as solvent.Under NIR light excitation,the Yb³⁺/Er³⁺,Yb³⁺/Tm³⁺,and Yb³⁺/Ho³⁺-doped Bi₄Si₃O₁₂2 samples exhibit intense green,blue,and red emissions,respectively.The light-emitting diode?LED?devices have been fabricated by coating the as-synthesized phosphors into 940 nm NIR chips.The as-obtained LED devices can emit visible multicolor emissions under an injection current,which indicates that Bi₄Si₃O₁₂:Yb³⁺/Ln³⁺?Ln=Er,Tm,and Ho?UC luminescent materials may be potentially applied in solid state lighting.A series of down-conversion?DC?lanthanide activator ions?Ln=Sm,Dy,Eu?doped bismuth silicate Bi₄Si₃O₁₂2 phosphors have been synthesized by a sol-gel route.The Bi₄Si₃O₁₂host exhibits intense green-blue emission which are due to the existence of Bi³⁺ions.The as-synthesized Bi₄Si₃O₁₂:Ln³⁺phosphors show both the intrinsic broad band luminescence of Bi₄Si₃O₁₂2 host and the characteristic sharp peak emissions of Ln³⁺ions,which can generate the tunable multicolor emissions in a single-phase phosphor by adjusting the Ln³⁺doping concentrations.By integrating the Bi₄Si₃O₁₂:Ln³⁺phosphors into a 280 nm UV LED chip,all the fabricated WLED devices can exhibit bright white light emission,which provides direct evidence that the as-synthesized BSO:Ln³⁺?Ln=Sm,Dy,and Eu?single-phase white-emitting phosphors have great potential for WLEDs and optoelectronic devices.A series of novel one-dimensional bismuth silicate(Bi₄Si₃O₁₂)fibers have been synthesized via electrospinning method followed by a subsequent annealing process for the first time.During the synthesis process,the mass ratio of PVP/PEO additives plays a crucial role for the formation of the uniform and well-dispersed fibrous precursors.Due to the good crystallinity,uniform fibrous morphology,and eminent DC and UC luminescence properties,the as-synthesized Ln³⁺doped Bi₄Si₃O₁₂2 fibers may find potential applications in fields of optoelectronic devices and solid state lightening.