Luminescence Properties And Temperature Sensing Behavior Of Rare Earth Doped Oxide

Rare earth-doped up-conversion luminescent materials are a physical process with anti-Stokes law,which can convert long-wavelength light into short-wavelength light,and convert low-energy radiation into high-energy radiation.Rare earth-doped up-conversion luminescent materials have the advantages of non-contact,fast response to light and temperature,strong resistance to electromagnetic interference,and high spatial resolution of temperature measurement.They have broad prospects in the field of optical temperature measurement.In recent years,there have been many applications of up-conversion luminescent materials based on rare earth doping,such as biological imaging,solar cells,optical sensing,and temperature measurement.Among the rare-earth-doped up-conversion luminescent materials,the oxide-based matrix has received more attention in practical applications due to its good stability and ease of synthesis.In this paper,the Er³⁺-Yb³⁺co-doped oxide up-conversion phosphor was prepared by high-temperature solid-phase method,and its luminescence characteristics,pump power relationship,energy level transport mechanism and temperature sensing characteristics were studied.The main content and results are as follows:(1)A series of rare earth-doped Lu₂O₃,In₂O₃,(Lu_0.5In_0.5)₂O₃ up-conversion phosphors were successfully prepared by high-temperature solid-phase method.The intensity of green light and red light emitted by(Lu_0.5In_0.5)₂O₃ is much greater than that of Lu₂O₃ and In₂O₃.Therefore,we used(Lu_0.5In_0.5)₂O₃ as the matrix to analyze the influence of a series of different ions on the crystal structure and coordination environment of(Lu_0.5In_0.5)₂O₃.Changing the concentration of Er³⁺and Yb³⁺in the sample respectively has an effect on the luminous intensity of the sample,and the addition of Zn²⁺has a more obvious effect on the luminous intensity of the sample.In a series of doped samples,according to the experimental data,the optimal doping concentration selected is Er³⁺=0.03,Yb³⁺=0.14,Zn²⁺=0.08.The pump power dependence proves that all samples emit light in a two-photon process.In the temperature sensing characteristics,FIR=4.82×exp(-905.85/T)is obtained according to the fluorescence intensity ratio technique,the degree of fit is 99.36%,and the maximum relative sensitivity is 0.0030K^-1.After adding Zn²⁺,the fluorescence intensity ratio FIR=7.77×exp(-850.01/T),the degree of fit increased to 99.67%,and the maximum relative sensitivity increased to 0.0050K^-1.(2)Based on the successful synthesis of a series of rare earth doped(Lu_0.5In_0.5)₂O₃up-conversion phosphors.We used(Y_0.5In_0.5)₂O₃ as the matrix and analyzed the effects of different doping of ions on the structure and morphology of(Y_0.5In_0.5)₂O₃ through XRD and SEM.In the experiment,the optimal concentration is Er³⁺=0.05 mol,Yb³⁺=0.14 mol,and it is determined that the emission of all samples is a two-photon process.The temperature sensing characteristics of the sample are explored.According to the experimental analysis,FIR=6.03×exp(-1038.61/T)is obtained.It is calculated that the absolute sensitivity reaches the maximum value of 0.00316 K^-1.(3)For the Er³⁺-Yb³⁺co-doped(Y_0.5In_0.5)₂O₃ up-conversion luminescent material,we improved the luminous intensity and temperature sensing properties of the sample by adding Mg²⁺.XRD showed that the added Mg²⁺completely entered the main matrix.In terms of luminescence,the intensity of green light and red light emitted by the sample after introducing Mg²⁺was increased by 12 times and 8 times.Mainly due to the entry of other metal ions,the symmetry of the local crystal field of the matrix is changed,and the 4f electric dipole parity prohibition inside the ion is broken.In terms of temperature sensing,the fluorescence intensity ratio of the sample after the addition of Mg²⁺is FIR=8.3×exp(-1089.88/T),and the maximum sensitivity is increased to 0.0039 K^-1,all of which indicate that the matrix can be improved after doping with Mg²⁺.(4)For the Er³⁺-Yb³⁺co-doped Sc₂(WO₄)₃ material,through XRD characterization,it was determined that the sample was pure phase without impurities,and Er³⁺and Yb³⁺would preferentially replace Sc³⁺and enter the main matrix.The crystal structure of the sample was analyzed.,Belongs to the structure of orthorhombic crystal system.Under the 980 nm near-infrared laser,the sample emits strong green light and weak red light,showing strong green light visible to the naked eye.The temperature sensing characteristics of the two thermal coupling energy levels of the sample Er³⁺in the range of 303?573 K are also studied.At 393 K,the absolute sensitivity of the sample reaches the maximum 0.0068 K^-1.Compared with other phosphor materials,the sensitivity of Sc₂(WO₄)₃:Er³⁺-Yb³⁺is at a higher level,and it has a better prospect in actual temperature measurement.