Study On The Photoluminescence And Photochromic Properties Of Europium-doped Silicate Materials

Inorganic photochromic materials as a kind of optical data storage,optical sensing,security encryption,and other characteristics of functional materials because of its high stability,fast response,good repeatability,large storage density,received extensive attention,but the reports of inorganic photochromic material system are very few.Inorganic photochromic materials with excellent color-changing properties and color rendering index are rare,which also limits their further application.Recently,there are some reports on innovative applications that combine photochromic and long afterglow characteristics in the field of anti-counterfeiting and encryption.Therefore,BaMgSiO₄with obvious pink coloration effect and afterglow property is selected as the matrix to prepare multiple groups of Eu doped ceramic materials in air and weak reducing atmosphere.The effects of doping concentration change and ion co-doping on the photoluminescence,photochromic and afterglow properties were discussed in detail.A series of experiments enriched inorganic photochromic material system,providing more references for its application in optical data storage,innovative anti-counterfeiting encryption and other aspects.The effect of the doping concentration of Eu ions on the photoluminescence and photochromism of BaMgSiO₄(BMS)ceramics was studied.The samples were prepared by high-temperature solid-phase method in a weakly reducing atmosphere of 5%H₂ and 95%N₂.The sample with x=0.06mol has a quantum yield as high as 25.01%.After being irradiated with a 405nm laser,the samples showed a color change from light green to pink and their photoluminescence(PL)emission was significantly reduced.The quenching degree(?R_t)for the sample with x=0.02mol reached 61.03%.According to the diffuse reflectance spectrum after light irradiation,the more significant absorption peak(above90%)located at 520 nm is the direct cause of the above phenomenon.Furthermore,on the basis of the above-mentioned BMS:0.01Eu system,the optical properties are further explored by doping 0.01 mol of Y,La,Ce et al.rare earth elements.These results show that the samples co-doped with Y and La have higher PL intensity,and their quantum yields are 13.17%and 12.45%,respectively,while the two samples co-doped with Ce and Gd have lower PL peak intensities and quantum yields.They are 6.75%and 7.42%,respectively.The?R_t value is around 46%,wherein the co-doped Yb has a maximum value of 48.72%,and the co-doped La has a minimum value of 41.02%,and the color changes from light yellow to pink.In addition,the designed SrMgSiO₄:0.03Eu/0.12Dy sample has a bright blue afterglow phenomenon,and it has a visually visible blue afterglow for 15 minutes after irradiated for 30s under the condition of a 365nm ultraviolet laser.