Photochromic Effect And Upconversion Temperature Sensing Performance Of Rare Earth Doped Bismuth Sodium Niobate Based Materials

In recent years,due to the advantages of rare-earth-doped oxides compared to fluoride or organic substrates,such as excellent environmental friendliness,excellent stability at high temperatures,and resistance to strong acid and strong alkali corrosion,rare-earth-doped oxides have pontential applications in temperature sensing,photochromism,two-dimensional optical storage,and photothermal diagnosis and treatment.At present,the conventional ways to improve the temperature sensing performance based on fluorescence intensity ratio technology mainly include as follows:replacing rare earth doped ions,changing different matrix materials or changing the structure of the matrix.Based on our previously reported results,the photochromic properties of rare-earth-doped oxide ceramics can significantly control the intensity of up-conversion luminescence.Due to the difference in the degree of response to the photochromic effect between the energy levels,there are also obvious differences in the regulation of the photochromic energy levels.Based on this,we tried to combine the photochromic effect of rare earth-doped oxides and the up-conversion luminescence,and control the luminescent intensity ratio to improve the temperature sensing performance using the photochromic effect.In this work,we construct a method to improve the temperature sensing performance using the photochromic effect,and explore the luminescnece regulation of the thermally coupled energy level and the non-thermally coupled energy level,the detailed contents include three parts,as follows.Er-doped M_0.5Bi_2.5Nb₂O₉(M=Li,Na,K)ceramics were used to explore the photochromism and temperature sensing characteristics.It is found that the photochromic effect can effectively improve the thermal stability and temperature sensing of thermally coupled energy level.(1)The luminescent switching contrast of NBN matrix is optimal;(2)Photochromism can improve the luminescen intensity ratio of NBN matrix,thus enhance the temperature sensing performance of NBN matrix.This study breaks through the traditional method of modifying different matrix materials or doping with different rare earth ions to modify temperature sensing.These results reveal that the photochromic reaction based on defect trapping effect plays an important role in modulating thermal stability and temperature sensing performance.This method has more potential research value and significance to further improve the temperature sensing performance.The up-conversion multicolor emission(548 nm,674 nm,809 nm)has been successfully achieved by doping NBN ceramics with rare earth ions of Yb/Tm/Er.By controlling the content of Yb ions,the luminescent intensity at different wavelengths can be regulated,and the adjustment of different energy levels by photochromism has obvious differences.The presence of defect energy level has an important impact on the thermal stability and temperature sensing characteristics by using the difference of photochromism on the regulation and control of luminescent intensity of each energy level.Photochromism can improve the temperature sensing performance of thermally coupled energy level and non-thermally coupled energy level,and the adjustment and control effect of non-thermally coupled energy level is more significant.Through detailed mechanism discussion,it was proved that Yb/Tm/Er co-doped NBN ceramics have potential application in the field of temperature sensing.The effect of photochromic reaction on photochromism and temperature sensing performance at low temperature was explored in NBN ceramics doped with Yb/Mo/Er by changing the content of Mo ions.It was found that with the increase of Mo³⁺doping,the concentration of Mo ions increased from 0 to 0.15,and the luminescent control ratio?R_talso gradually decreased from 95.97%to 74.02%.However,as the content of Mo³⁺increased,the temperature sensing performance gradually improved,and the absolute sensitivity increased from 0.00337K^-1(x=0)to 0.00729K^-1(x=0.15).