A method for temperature sensing based on non-thermal coupling energy levels

Abstract

The present invention discloses a method for temperature sensing based on non-thermal coupling energy levels, comprising: using an excitation wavelength of 354 nm to test the temperature-dependent emission spectrum data of a luminescent material; integrating the emission peaks at the emission center wavelengths corresponding to the two non-thermal coupling energy levels in the temperature-dependent emission spectrum to obtain the emission integral intensity; and determining the emission integral intensity based on the Tm in the YNbO4 sample. 3+ and Dy 3+ The dependence of the luminescence properties of ions on temperature is used to establish a model for the dependence of the fluorescence intensity ratio (FIR) on temperature. The luminescent material is placed at a test temperature and excited with a 354nm laser. The emission spectrum is obtained and the fluorescence intensity ratio (FIR) is calculated. Substituting this into the model, the measured ambient temperature can be calculated. This invention utilizes dual ion non-thermal coupling energy levels for temperature sensing and establishes a model for the dependence of the FIR on temperature. This improves the accuracy and sensitivity of temperature sensing and exhibits good thermal stability.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature sensing, and in particular to a method for temperature sensing based on non-thermal coupling energy levels. Background Art

[0002] Accurate temperature measurement plays a vital role in many areas of production and life, such as aviation and defense, electronics and electrical equipment, and transportation and operational engineering. Currently, temperature sensors have evolved from contact-based sensors such as glass thermometers and bimetallic thermometers to non-contact sensors such as infrared thermal imagers and fluorescence temperature sensors. This has not only broadened the application range of thermometers but also improved the accuracy of temperature measurements. While the measurement range of traditional contact thermometers continues to expand, their use is significantly limited in environments such as strong acids and bases, strong electromagnetic interference, or vacuum environments where oxygen deficiency makes operation difficult. Therefore, non-contact temperature sensors have gradually gained popularity. In recent years, optical-based non-contact temperature detection has rapidly become a hot research topic due to its advantages such as fast response, minimal impact on the measurement environment, and applicability to temperature measurement in confined spaces.

[0003] The non-contact detection modes based on optical properties mainly include: detection mode based on fluorescence peak position, spectral line width, detection mode based on fluorescence intensity ratio and detection mode based on fluorescence lifetime. Among them, one of the most commonly used methods is the fluorescence intensity ratio technology based on the two thermally coupled energy levels of rare earth ions. So far, many studies have focused on temperature sensing using the thermally coupled energy levels of a single rare earth ion, such as Er 3+ : 4 S 3 / 2 / 2 H 11 / 2 , Nd 3+ : 4 F 7 / 2 / 4 F 5 / 2 , Ho 3+ : 5 F3 / 3 K8, Dy 3+ : 4 I 15 / 2 / 4 F 9 / 2 However, the luminescence performance and thermal stability of single rare earth ion doped luminescent materials have certain limitations. When the thermal stability of the luminescent material is low, the luminescence intensity of the material decreases significantly with increasing temperature, thus affecting the material's temperature measurement range and temperature sensing sensitivity.

[0004] Currently, non-thermal coupled energy level pairs are gradually showing superior performance in optical temperature sensing applications. However, researchers have not only studied non-thermal coupled energy level pairs but also lack a corresponding theoretical basis for the application of the model. Therefore, it is of great significance to establish a method for temperature sensing using non-thermal coupled energy levels of dual ions. Summary of the Invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present invention is to provide a method for temperature sensing based on non-thermal coupling energy levels, which utilizes dual ion non-thermal coupling energy levels for temperature sensing, can improve the accuracy and sensing sensitivity of temperature sensing, and has better thermal stability.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A method for temperature sensing based on non-thermal coupling energy levels comprises the following steps:

[0008] The luminescent material YNbO4:xmol%Dy was tested at an excitation wavelength of 354nm in the temperature range of 293-573K at intervals of 30K. 3+ , y mol% Tm 3+ Temperature-dependent emission spectroscopy data;

[0009] Integrate the emission peak at the emission center wavelength corresponding to the two non-thermal coupling energy levels in the variable temperature emission spectrum, and calculate the emission integrated area of ​​the emission peak at the emission center wavelength at different temperatures, which is the emission integrated intensity;

[0010] According to the Tm 3+ and Dy 3+ The dependence of the luminescence characteristics of ions on temperature is used to establish a model for the dependence of the fluorescence intensity ratio FIR on temperature;

[0011] The luminescent material YNbO4:x mol% Dy 3+ , y mol% Tm 3+ Place it at the temperature to be measured, use a 354nm laser for excitation, obtain the emission spectrum and then calculate the fluorescence intensity ratio FIR. Substitute it into the model to calculate the ambient temperature to be measured.

[0012] Preferably, the luminescent material YNbO4:x mol% Dy 3+ , y mol% Tm 3+ YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ .

[0013] Preferably, the preparation method of the luminescent material is:

[0014] According to the stoichiometric ratio of each element in the luminescent material, Y2O3, Nb2O5, Dy2O3 and Tm2O3 raw materials are weighed respectively;

[0015] The weighed raw materials were fully ground in an agate mortar for 30 min until they were evenly mixed;

[0016] The obtained powder was placed in a muffle furnace and calcined at 1300° C. for 4 h, and then naturally cooled to room temperature. The obtained material was then ground to obtain the luminescent material YNbO4:3.0 mol% Dy 3+ , 2.0 mol% Tm 3+ .

[0017] Preferably, the emission center wavelengths corresponding to the two non-thermal coupling energy levels in the variable temperature emission spectrum are 456 nm and 487 nm.

[0018] Preferably, the emission center wavelength is 456 nm, and the emission peak corresponds to Dy 3+ : 4 I 15 / 2 → 6 H 15 / 2 and Tm 3+ : 1 D2→ 3 The transition of F4; the emission center wavelength is 487nm, and the emission peak corresponds to Dy 3+ : 4 F 9 / 2 → 6 H 15 / 2 The transition.

[0019] Preferably, the Tm 3+ and Dy 3+ The dependence of the luminescence characteristics of ions on temperature refers to the 3+ ion 4 I 15 / 2 → 6 H 15 / 2 and 4 F 9 / 2 → 6 H 15 / 2 The transition fluorescence intensity ratio satisfies the Boltzmann distribution relationship, Tm 3+ ion 1 D2→ 3 F4 and Dy 3+ ion 4 F 9 / 2 → 6 H 15 / 2 The luminous intensity changes with temperature and all satisfy the Arrhenius model.

[0020] Preferably, the model of the dependence between the fluorescence intensity ratio FIR and temperature is expressed by the formula:

[0021]

[0022] Among them, I, k, ΔE1, ΔE2, ΔE2 ’ Represent the emission integrated intensity, Boltzmann constant, energy level difference, Tm 3+ ions and Dy 3+ The activation energy in each thermal quenching process, A2, B, B ’ , Z is a constant.

[0023] Compared with the prior art, the present invention has the following advantages:

[0024] The temperature sensing method provided by the present invention is a Dy 3+ and Tm 3+ The method of temperature sensing by dual ion non-thermal coupling energy level. 3+ and Dy 3+ The dependence between the luminescence characteristics of ions and temperature, and the establishment of a model for the dependence between the fluorescence intensity ratio and temperature, provide new ideas for the study of temperature sensing using non-thermal coupling energy level pairs between two ions, which has important guiding significance.

[0025] The temperature sensing method provided by the present invention adopts Dy 3+ and Tm 3+ The dual-ion non-thermal coupling energy level performs temperature sensing, which has better thermal stability than single-ion doped luminescent materials, so that when the temperature to be measured increases, Dy 3+ and Tm 3+ The luminous intensity of the co-doped luminescent material remains relatively good, thereby reducing calculation errors and improving temperature measurement accuracy and temperature sensing sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 YNbO4:3.0mol%Dy prepared in Example 1 of the present invention 3+ , 2.0 mol% Tm 3+ XRD diffraction patterns of co-doped luminescent materials.

[0027] Figure 2 YNbO4:3.0mol%Dy under 354nm excitation 3+ , 2.0 mol% Tm 3+ Variable temperature emission spectrum between 293-573K.

[0028] Figure 3The dependence of the emission integrated intensity of the 456nm and 487nm transitions on temperature.

[0029] Figure 4 YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ Luminescent material FIR 456 / 487 and the temperature dependence of sensitivity. DETAILED DESCRIPTION

[0030] The embodiment of the present invention provides a method for temperature sensing based on non-thermal coupling energy level, comprising the following steps:

[0031] The luminescent material YNbO4:xmol%Dy was tested at 30K intervals within the temperature range of 293-573K using 354nm as the excitation wavelength. 3+ , 2.0 mol% Tm 3+ Temperature-dependent emission spectroscopy data;

[0032] Integrate the emission peak at the emission center wavelength corresponding to the two non-thermal coupling energy levels in the variable temperature emission spectrum, and calculate the emission integrated area of ​​the emission peak at the emission center wavelength at different temperatures, which is the emission integrated intensity;

[0033] According to the Tm 3+ and Dy 3+ The dependence of ion luminescence characteristics on temperature is used to establish a model for the dependence of fluorescence intensity ratio FIR on temperature.

[0034] The luminescent material YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ Place it at the temperature to be measured, use a 354nm laser for excitation, obtain the emission spectrum and then calculate the fluorescence intensity ratio FIR. Substitute it into the model to calculate the ambient temperature to be measured.

[0035] Example 1

[0036] Luminescent material YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ Preparation

[0037] According to YNbO4:3.0mol%Dy 3+ ,2.0mol%Tm 3+The raw materials of Y2O3, Nb2O5, Dy2O3 and Tm2O3 were weighed in the stoichiometric ratio of each element. The weighed raw materials were thoroughly ground in an agate mortar for 30 minutes until they were mixed evenly. The resulting powder was placed in a muffle furnace, the temperature was set to 1300℃, the calcination time was set to 4 hours, and the temperature was naturally cooled to room temperature after calcination. The resulting material was ground to obtain the YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ Co-doped luminescent materials.

[0038] The prepared YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ The co-doped luminescent materials were characterized by XRD, and the results were as follows Figure 1 As shown in the figure, it can be seen that all diffraction peaks can correspond well to the standard card diffraction peaks of YNbO4.

[0039] Example 2

[0040] YNbO4:3.0mol%Dy prepared in Example 1 3+ , 2.0 mol% Tm 3+ Study on temperature sensing properties of co-doped luminescent materials, including:

[0041] YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ The sample was placed in a heatable sample cell and excited at 354 nm. The sample was heated (293 K - 573 K) and the emission spectrum was tested every 30 K. The results are as follows: Figure 2 shown.

[0042] The emission integrated areas of the emission peaks at different temperatures at 456 nm and 487 nm were calculated, which were 6026, 5794, 5752, 5758, 6101, 6157, 6206, 5691, 5940, 6003 a.u. and 17571, 16688, 16014, 15543, 15493, 14670, 14140, 12009, 11695, 11500 a.u., respectively. The results are as follows Figure 3 As shown. Figure 3 It can be seen that within the 425-525nm band, as the temperature increases, Dy 3+ The luminous intensity of the blue light emission (487nm) of the ions gradually weakens; while the luminous intensity of the higher energy light at around 456nm does not change much with increasing temperature.

[0043] By considering the Tm 3+ and Dy3+ The dependence of ion luminescence properties on temperature establishes the fluorescence intensity ratio FIR 456 / 487 Model for the temperature dependence:

[0044]

[0045] I, k, ΔE1, ΔE2, ΔE2 ’ Represent the emission integrated intensity, Boltzmann constant, energy level difference, Tm 3+ ions and Dy 3+ The activation energy in each thermal quenching process, A2, B, B ’ , Z is a constant.

[0046] Using formula (1) Figure 3 The solid data points in the figure are fitted, and the results are as follows Figure 4 The solid line shows the fluorescence intensity ratio formula obtained by fitting:

[0047] Thus, in the specific measurement, YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ The sample is placed at the test temperature and excited by a 354nm laser. After obtaining the emission spectrum, the fluorescence intensity ratio FIR is calculated. 456 / 487 , and put it into formula (1) to get the ambient temperature to be measured.

[0048] In addition, the temperature sensing sensitivity of the material can be obtained by taking the derivative of the temperature T according to formula (1), which is expressed as:

[0049]

[0050] Will Figure 4 A2, B, B in ’ , Z, ΔE1 / k, ΔE2 / k, ΔE2 ’ Substituting / k into formula (2) we can get YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ The relationship curve between the temperature sensing sensitivity function S and T of the luminescent material is as follows: Figure 4 As shown by the dotted line in the figure, it can be seen that the temperature sensing sensitivity of the material reaches a maximum of about 0.0094K at a temperature of 573K. -1 .

[0051] It can be seen that the present invention studies the use of non-thermal coupling energy levels between two ions for temperature sensing and establishes a fitting model. 3+ and Tm 3+The dual-ion non-thermal coupling energy level performs temperature sensing, which has better thermal stability than single-ion doped luminescent materials, so that when the temperature to be measured increases, Dy 3+ and Tm 3+ The luminous intensity of the co-doped luminescent material remains relatively good, thereby reducing calculation errors and improving temperature measurement accuracy and temperature sensing sensitivity.

[0052] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for temperature sensing based on non-thermal coupling energy levels, characterized in that: The following steps are included: The luminescent material YNbO4:xmol%Dy was tested at an excitation wavelength of 354nm in the temperature range of 293-573K at intervals of 30K. 3+ , y mol% Tm 3+ Temperature-dependent emission spectroscopy data; Integrate the emission peak at the emission center wavelength corresponding to the two non-thermal coupling energy levels in the variable temperature emission spectrum, and calculate the emission integrated area of ​​the emission peak at the emission center wavelength at different temperatures, which is the emission integrated intensity; According to the Tm 3+ and Dy 3+ The dependence of the luminescence characteristics of ions on temperature is used to establish a model for the dependence of the fluorescence intensity ratio FIR on temperature; The luminescent material YNbO4:x mol% Dy 3+ , y mol% Tm 3+ Place it at the temperature to be measured, use a 354nm laser for excitation, obtain the emission spectrum and calculate the fluorescence intensity ratio FIR. Substitute it into the model to calculate the ambient temperature to be measured; The emission center wavelengths corresponding to the two non-thermal coupling energy levels in the variable temperature emission spectrum are 456 nm and 487 nm; The Tm 3+ and Dy 3+ The dependence of the luminescence characteristics of ions on temperature refers to the 3+ ion 4 I 15 / 2 → 6 H 15 / 2 and 4 F 9 / 2 → 6 H 15 / 2 The transition fluorescence intensity ratio satisfies the Boltzmann distribution relationship, Tm 3+ ion 1 D2→ 3 F4 and Dy 3+ ion 4 F 9 / 2 → 6 H 15 / 2 The changes of luminous intensity with temperature all satisfy the Arrhenius model; The model of the dependence of the fluorescence intensity ratio FIR on temperature is expressed by the formula: Among them, I, k, ΔE1, ΔE2, ΔE2 ’ Represent the emission integrated intensity, Boltzmann constant, energy level difference, Tm 3+ ions and Dy 3+ The activation energy in each thermal quenching process, A2, B, B ’ , Z is a constant.

2. The method for temperature sensing based on non-thermal coupling energy level according to claim 1, characterized in that: The luminescent material YNbO4:x mol% Dy 3+ , y mol% Tm 3+ YNbO4:3.0mol%Dy 3+ , 2.0 mol% Tm 3+ .

3. The method for temperature sensing based on non-thermal coupling energy level according to claim 1 or 2, characterized in that: The preparation method of the luminescent material is: According to the stoichiometric ratio of each element in the luminescent material, Y2O3, Nb2O5, Dy2O3 and Tm2O3 raw materials are weighed respectively; The weighed raw materials were fully ground in an agate mortar for 30 min until they were evenly mixed; The obtained powder was placed in a muffle furnace and calcined at 1300° C. for 4 h, and then naturally cooled to room temperature. The obtained material was then ground to obtain the luminescent material YNbO4:3.0 mol% Dy 3+ , 2.0 mol% Tm 3+ .

4. The method for temperature sensing based on non-thermal coupling energy level according to claim 1, characterized in that: The emission center wavelength is 456nm, and the emission peak corresponds to Dy 3+ : 4 I 15 / 2 → 6 H 15 / 2 and Tm 3+ : 1 D2→ 3 The transition of F4; the emission center wavelength is 487nm, and the emission peak corresponds to Dy 3+ : 4 F 9 / 2 → 6 H 15 / 2 The transition.

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