Preparation Of Tm³⁺(Ho³⁺) Doped Rare Earth Oxide Materials And Study Of White Light Up-conversion

In recent years,rare earth luminescent materials have received more and more attention from researchers in the field of lighting due to their outstanding advantages of energy saving,environmental protection and long service life.The application of rare earth luminescence in lighting is mainly divided into two aspects.First,the blue-violet photodiode is used as the pump,and the rare earth material is used as the red phosphor,which is mixed to obtain white light radiation;second,the rare earth up-conversion luminescence is used,and infrared light is used for pumping Through doping with reasonable design of rare earth ions,the three primary colors of red,green and blue are emitted,and then white light radiation is obtained.The rare earth up-conversion luminescence is used to obtain white light radiation,and the infrared LED can be used for pumping.The light emission range of white light can be adjusted by the doping change of rare earth ions,so this luminescent material has important research significance.There are two main points in the research of rare earth up-conversion white light emitting system,one is the choice of matrix,and the other is the choice of doping rare earth ions.Among the many substrates that can be used as rare earth luminescent materials,tungstate has become one of the key research objects of rare earth luminescent matrix materials due to its characteristics of good stability,high luminous efficiency,and low cost.Tm³⁺and Ho³⁺have blue violet light-emitting level??475 nm?,green light-emitting level??540 nm?and red light-emitting level??655 nm?respectively,which are considered to be doping ions in white light up conversion experiment of rare earth.Based on the above background,five groups of Re WO₄?Re WO₄ is Zn WO₄;Sr WO₄;Ba WO₄?:Yb³⁺,Tm³⁺,Ho³⁺phosphors were synthesized by high temperature solid-phase method,and the samples were characterized and measured.Based on the 980 nm Pump Power excitation,the up-conversion luminescence spectra of Rewo4:Yb³⁺,Tm³⁺,Ho³⁺samples were measured,and the data were processed and analyzed.Secondly,by calculating and summarizing the luminescent principle of rare earth samples,and calculating the tristimulus value to synthesize the chromatogram of each sample,it can be seen that Yb³⁺is used as the sensitizer in the material to improve the up conversion luminescent efficiency;in the visible light range,Tm³⁺provides strong blue violet light?peak position is about 475 nm?and weak red light,and the red light emitted by Tm³⁺can be ignored in this experiment Ho³⁺provides red?peak position is about 545 nm?and green luminescence?peak position is about 655 nm?.In addition,by comparing two samples of Sr WO₄ and Ba WO₄ with tetragonal crystals as the matrix,under the excitation of 980 nm pump light,the same excitation power and photomultiplier tube voltage,the magnitude relationship of white light radiation intensity is:I_Sr>I_Ba,The relationship between the ion radius is Sr²⁺<Ba²⁺,and the possible explanation is that for the strontium tungstate and barium tungstate,both of which have a tetragonal structure,the larger the ion radius,the smaller the luminous intensity of the sample.