Regulation Of Luminescence Properties Of Fluoride Doped With Rare Earth Ions

In recent years,trivalent rare earth ion(Re³⁺)-doped fluoride has become a hotspot in luminescent materials due to its excellent optical properties and good chemical stability.Among them,Er³⁺,Ho³⁺,and Tm³⁺doped fluorides are even more popular as luminescent materials,this is because they have rich energy level structures.Not only can emit ultraviolet and visible up-conversion fluorescence,but also can emit near-infrared and mid-infrared fluorescence upon excitation of 980 nm laser diode.Among them,up-converted fluorescence shows great application potential in the fields of biological imaging,photodynamic therapy,anti-counterfeiting technology and solar cells,while infrared radiation has broad applications in optical communication,remote sensing technology,radar and optical waveguide amplifier prospect.For the current rare earth ion-doped fluoride luminescent materials,the luminous efficiency is generally low,the band is few,and the color is not rich enough.In this paper,K₂YF₅?K₂YbF₅?and KZnF₃ doped with rare earth ions(Er³⁺,Ho³⁺,Tm³⁺)are used as research objects.By co-doping other ions as a medium for energy transfer,the population of rare earth ions at the luminous energy level is effectively controlled and obtained efficient visible up-conversion fluorescence and near-infrared radiation,and a detailed study of the corresponding luminescence mechanism.The main research contents and results of this paper are as follows:?1?K₂YF₅ crystallites co-doped with Re³⁺/Yb³⁺and Re³⁺/Yb³⁺/Nd³⁺?Re=Er,Ho,Tm?were prepared by solvothermal method.Using 980 nm laser as the excitation light source,effective visible up-conversion fluorescence was achieved in K₂YF₅:Re³⁺/Yb³⁺crystallites,the effect of Yb³⁺concentration on the up-conversion luminescence properties was systematically studied,and the luminescence mechanism was discussed in detail;Using 980 nm and 800 nm lasers as excitation sources,effective up-conversion fluorescence was achieved in K₂YF₅:Re³⁺/Yb³⁺/Nd³⁺crystallites,the effect of Nd³⁺concentration on the up-conversion luminescence properties was studied,and its luminescence mechanism was investigated in detail.?2?By doping Ce³⁺into K₂YbF₅:Ho³⁺and K₂YF₅:Er³⁺/Yb³⁺crystallites,effective up-conversion fluorescence and near infrared radiation were obtained.The results show that Ce³⁺doping can not only control the color of the up-converted fluorescence,but also effectively enhance the near-infrared radiation.Compared to the sample without Ce³⁺doping,the infrared radiation of 2?m in 16%Ce³⁺K₂YbF₅:Ho³⁺crystallites is increased 4.5 times,in 4%Ce³⁺doped K₂YF₅:Yb³⁺/Er³⁺crystallites,the 1.5?m infrared radiation is increased by 4 times,the reason for the enhancement is due to the effective energy cross-relaxation between Ho³⁺,Er³⁺and Ce³⁺.?3?The perovskite structure KZnF₃ nanocrystals co-doped with Er³⁺/Yb³⁺/Mn²⁺and Ho³⁺/Yb³⁺/Mn²⁺were synthesized by solvothermal method.Under the excitation of 980 nm laser,the effect of Mn²⁺concentration on the luminescence properties of Er³⁺and Ho³⁺was systematically studied.Compared with the case where Mn²⁺is not doped,the up-converted red light of Er³⁺and Ho³⁺is enhanced by 11 times and 22times in the sample with 20%doping concentration of Mn²⁺,respectively,and the color of light emission is almost pure red light.The reason is attributed to the efficient energy transfer of Er³⁺or Ho³⁺by Mn²⁺-Yb³⁺dimer.