Research On The Improvement Of Luminescence Properties Of Bi³⁺,Sm³⁺ Excited By Near-ultraviolet

The new optical function materials doped with rare earth ions become a popular trend in today's research,because they have so many advantages.Such as rich energy level structure,long light emitting life,high stability of the matrix material,flexibility of selecting dopants and matrix materials.Therefore,rare earth materials are widely used in solar cells,laser materials,3D display technology and electroluminescence devices.Rare earth materials become a hot trend in todays'research.In the past of several decades,inorganic microcrystals doped with trivalent rare earths have also attracted extensive attention.It has been reflected in the application of luminescence,display devices and biochemical probes.For example,microcrystals doped with europium,cerium and other elements can show good luminescence properties in a suitable crystal field environment.These rare earths have widely application,but still have some problems,such as visible light reabsorption and inappropriate emission position.This will lead to the color distortion or imbalance,reduce the luminescence efficiency of white light emitting diodes(WLEDs).In this case,the microcrystals doped with bismuth ion has gradually attracted extensive attention,due to its characteristics of UV excitation and visible light emission.In application,the emission intensity of Bi³⁺ion needs to be improved.In this paper,under the ultraviolet light excitation,luminescence of Bi³⁺ion doped in Lu₂O₃/La₂O₃microcrystals and Bi³⁺/Sm³⁺ions co-doped in Y₃Al₅O₁₂microcrystals were researched.The innovations of the paper are as follows:A series of Bi³⁺/La³⁺ions doped Lu₂O₃microcrystals and a series of Bi³⁺/Lu³⁺ions doped La₂O₃have been prepared through urea-based precipitation method.The crystal structure,morphology and luminescence properties were researched in this paper.The results show that,in the Bi³⁺ion doped Lu₂O₃microcrystals,Bi³⁺ion(in Lu₂O₃C₂site)can transfer energy to Bi³⁺ion(in Lu₂O₃S₆site).We found that in Lu₂O₃:1 mol%Bi³⁺,0?5mol%La³⁺microcrystals,under the excitation of 372 nm and 337 nm(Bi³⁺ion)UV light,the emission peak intensities of Bi³⁺ion increase with the La³⁺ion concentration.The luminescence intensity of Bi³⁺ion is significantly increased about 3.1 times by doped with5mol%La³⁺.Similarly,in La₂O₃:1mol%Bi³⁺,0?5 mol%Lu³⁺microcrystals,under the excitation of 313 nm(Bi³⁺ion)UV light,the emission peak intensities of Bi³⁺ion increase with the Lu³⁺ion concentration.The luminescence intensity of Bi³⁺ion is significantly increased about 1.8 times by doped with 5mol%Lu³⁺.This is due to changing the symmetry of the crystal field around the Bi³⁺ions.Our paper provides a reference for the Bi³⁺and La³⁺/Lu³⁺doped other oxides.A series of Bi³⁺/Sm³⁺and Li⁺/Na⁺/K⁺ions co-doped Y₃Al₅O₁₂microcrystals were prepared by high temperature solid phase method.The luminescence performance,fluorescence lifetime and energy transfer process in Bi³⁺/Sm³⁺co-doped Y₃Al₅O₁₂microncrystals are studied.We found that in Y₃Al₅O₁₂:Bi³⁺/Sm³⁺microcrystals,under the excitation of 283 nm(Bi³⁺ion)UV light,the emission peak intensities of Bi³⁺ion decrease as increasing the concentrations of Sm³⁺ion.When the Sm³⁺ion concentration exceeded2.0 mol%,the luminescence intensity of Sm³⁺ion was decrease due to the concentration quenching.This proves that energy transfer processes maybe exist from Bi³⁺ion to Sm³⁺ion,so the luminescence intensity of Sm³⁺ion was enhanced.Meanwhile,the luminescence intensity of Bi³⁺/Sm³⁺ions co-doped Y₃Al₅O₁₂microcrystals was enhanced by doped Li⁺/Na⁺/K⁺ions.By increasing the doping concentration of Sm³⁺ion,the tunable emission of the microncrystal can be changed from blue to white.