Research On Preparation And Luminescence Enhancement Of Ag-Er³⁺ Co-doped ZrO₂ Translucent Ceramics

Rare earth luminescent materials are widely applied in many fields such as lighting,display and monitoring due to their strong absorption capacity,high conversion rate,wide emission spectrum and stable performance.However,due to the effect of“temperature quenching”and“concentration quenching”,it is difficult to present high luminescence intensity.Hence,it is very important to find an effective method to improve the luminescence efficiency of rare earth luminescent materials.For now,there has been a lot of progress in the study of rare earth doped transparent ceramics,but there is little research on the luminescence enhancement.This paper focuses on the luminescence enhancement of ZrO₂ translucent ceramics,hoping to fill the gap in this direction.In this paper,the factors influencing the synthesis of silver nanoparticles and 6Y-ZrO₂ ceramic powder were studied in detail,and the effects of silver nanoparticles on the luminescence properties of 6Y-ZrO₂:Er³⁺translucent ceramics were discussed.The details of our research are as follows:1.Silver nanoparticles were prepared by sodium citrate reduction method.The effects of PVP,Ag NO₃,sodium citrate concentration and boiling time on the size and morphology of silver nanoparticles were investigated.The results showed that low PVP concentration greatly slowed down the Ag⁰ production rate,slowed down the nucleation of silver nanoparticles,resulting in secondary nucleation,and finally resulted in serious agglomeration of the synthesized samples.When PVP concentration was 0.001 g/m L,the synthesis of silver nanoparticles was the most favorable.When the concentration of Ag NO₃ solution is 0.02 mol/L,the quality of silver nanoparticles prepared is the best,while when the concentration of Ag NO₃ solution is too high,silver particles will agglomerate and abnormal growth.The change of sodium citrate concentration has little influence on the synthesis of silver nanoparticles.With the increase of sodium citrate concentration,the size of the reaction product will start to decrease,and the optimal concentration is 0.12 mol/L.The boiling time has a great influence on the size of silver nanoparticles.When the boiling time is 0 min,the reaction is incomplete and there are a large number of silver particles that are not completely grown after nucleation.When the boiling time is 30 min,the synthesized silver nanoparticles have uniform size and good shape.2.6Y-ZrO2 powder was prepared by coprecipitation method,and the influence of the conditions on the synthesis of 6Y-ZrO₂ ceramic powder was explored by changing the titration method,speed and the PH value of the solution.The results show that the ceramic powder prepared by reverse titration method shows better dispersion after calcination at 1100℃.The particle size of the powder is more uniform,the boundary between the particles is clear,and hard agglomeration does not appear.In the titration process,the reaction solution should be added drop by drop.The p H value of solution affects the particle size of ceramic powder.With the p H increasing from 7,the particle size of ceramic powder decreases.The best transmittance of ceramics is 31%at 688 nm and 74%at 1476 nm when p H=7 and sintered at 1500℃.3.The synthesized nano-silver powder was mixed with Er doped 6Y-ZrO₂,which was vacuum sintered at 1500℃for 2h.The 100 nm Ag NPs were detected by SEM and EDS at the grain boundary of the ceramic grain.The transmittance of ceramics decreases with the increase of Ag doping concentration.For the ceramics without Ag,the transmittance is about 67%at 1250 nm and 42%at 753 nm.Under 980 nm excitation,the co-doping of Ag improved the 524,561,1527,and 2815 nm emission intensities by an enhancement factor of～4.6,3.5,3.4,and 1.1,respectively,due to the modification of the local crystal field via Ag atoms and the SPR effect from Ag NPs.Using the FIR technique,the optical thermometric behaviors were investigated based on the TCLs of²H_11/2 and ⁴S_3/2.The maximal S_r of 6Y-ZrO₂:1 mol%Er³⁺,0.67μmol%Ag translucent ceramic was 1.12%K^-1,slightly higher than that of the Ag-free sample(1.10%K^-1).