Sm ion / Tb ion luminescence-based ratio temperature sensing method

Abstract

The invention discloses a Sm ion / Tb ion luminescence-based ratio temperature sensing method, and belongs to the field of fluorescence temperature sensing. The invention aims to solve the problem that the traditional fluorescence intensity ratio temperature sensing technology cannot be applied to a higher-temperature area due to attenuation of two beams of fluorescence in the higher-temperature area caused by the existing fluorescence thermal quenching effect. The method comprises the following steps: 1, preparing a temperature-sensitive material; 2, determining a function relationship between the fluorescence intensity ratio A / B and the temperature; and 3, detecting the environment temperature. The invention is used for specific temperature sensing based on Sm ion / Tb ion luminescence.

Description

Technical Field

[0001] The invention belongs to the field of fluorescence temperature sensing. Background Art

[0002] The importance of temperature is self-evident, and it plays a key role in daily life, industrial production, crop growth and other scenarios. Among the many temperature measurement methods, the fluorescence temperature sensing method has unique application prospects due to its non-contact characteristics. Rare earth-doped luminescent materials have tunable luminescence bands and excitation strategies, so they are often used for fluorescence temperature detection. Among them, the fluorescence intensity ratio temperature sensing method is particularly eye-catching because of its strong anti-interference and detection portability. The core idea of ​​this method is to construct a functional relationship and a calibration curve between the ratio of two beams of fluorescence from the same luminescence center or different luminescence centers and the temperature, and to infer the temperature by actually measuring the ratio of the two beams of fluorescence.

[0003] Relative sensitivity is the core parameter of the fluorescence intensity ratio temperature sensing method. In order to pursue higher relative sensitivity, the following strategy is usually adopted: as the temperature increases, the intensity of one of the fluorescence beams increases monotonically, while the intensity of the other decreases monotonically. In this way, the intensities of the two fluorescence beams show opposite changes, so a higher relative sensitivity is usually obtained. However, this technology currently has defects: usually, fluorescence decreases with increasing temperature, that is, the so-called fluorescence quenching effect occurs. Therefore, although two fluorescence beams with different temperature responses can be found in a lower temperature range (such as near room temperature), in the higher temperature range (500K~800K), these two fluorescence beams will inevitably be severely quenched, so the relative sensitivity is not ideal, and the intensity quenching further leads to a poor signal-to-noise ratio. Summary of the invention

[0004] The present invention aims to solve the problem that the existing fluorescence thermal quenching effect causes both beams of fluorescence to attenuate in a higher temperature zone, thereby making the traditional fluorescence intensity ratio temperature sensing technology unable to be applied to a higher temperature zone, and further provides a ratio temperature sensing method based on Sm ion / Tb ion luminescence.

[0005] A ratiometric temperature sensing method based on Sm ion / Tb ion luminescence is carried out in the following steps:

[0006] 1. Preparation of temperature sensitive materials:

[0007] Preparation of Tb 3+ and Sm 3+ Doped CaWO4 to obtain temperature-sensitive materials;

[0008] 2. Determination of the functional relationship between the fluorescence intensity ratio A / B and temperature:

[0009] The temperature sensitive material is excited by laser with a wavelength of 405nm, and the emission spectrum of the temperature sensitive material at different calibration temperatures is recorded by a spectrometer; Tb 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+ The red fluorescence band at the central wavelength of the ion is located at 648nm and integrated, which is recorded as the fluorescence intensity B. The ratio of fluorescence intensity A to fluorescence intensity B is calculated, and a fluorescence intensity ratio A / B is obtained at each calibration temperature. After processing, a fitting curve is obtained, and the functional relationship between the fluorescence intensity ratio A / B and temperature is obtained according to the fitting curve:

[0010] A / B=-0.06173+4.91×10 -4 ×T-1.29×10 -6 ×T 2 +1.13×10 -9 ×T 3 , where T is the absolute temperature;

[0011] 3. Ambient temperature detection:

[0012] The temperature sensitive material is placed in the test environment, and then the temperature sensitive material is excited by a laser with a wavelength of 405nm. The emission spectrum of the temperature sensitive material is collected by a spectrometer, and Tb is recorded. 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+ The red light fluorescence band at the central wavelength of the ion is located at 648nm and is integrated; the ratio A / B of the fluorescence intensity A to the fluorescence intensity B is calculated, and the ratio A / B is substituted into the functional relationship obtained in step 2, and T is calculated as the ambient temperature, thus completing the ratio temperature sensing method based on Sm ion / Tb ion luminescence.

[0013] The beneficial effects of the present invention are:

[0014] The traditional fluorescence intensity ratio temperature sensing method cannot be applied to higher temperature range (500K~800K) because both the two fluorescence beams involved will experience severe thermal quenching. The present invention breaks this limitation and has the following advantages:

[0015] 1. Sm involved in the present invention 3+ The red light of the light only slightly decays with the increase of temperature, and can still maintain 80% of the room temperature even at 803K, which has a strong anti-thermal quenching effect; the Tb 3+ The green light of the sensor gradually increases with the temperature, up to 76 times. This ensures that the two beams of fluorescence have a good fluorescence signal-to-noise ratio. However, the two beams of fluorescence in the traditional fluorescence intensity ratio temperature measurement technology almost decay to zero at 803K, so it is not applicable.

[0016] 2. Tb involved in the present invention 3+ Green light and Sm 3+ The red light has different temperature response, Tb 3+ The green light at 545 nm of the ion increases rapidly with temperature, ensuring excellent relative sensitivity. 3+ Green light and Sm 3+ The intensity ratio of the red light can reflect the temperature change in time, which ensures good relative sensitivity. Together with the excellent signal-to-noise ratio, the Sm-based 3+ / Tb 3+ The temperature resolution of the luminescence ratio temperature sensing method is still better than 1K at 803K.

[0017] 3. The applicable temperature range of the present invention is 303K to 803K, and can be applied in a wider temperature range.

[0018] Instruction Manual

[0019] Figure 1 This is the XRD diffraction result of the temperature sensitive material prepared in step 1 of Example 1;

[0020] Figure 2 The emission spectrum of the temperature sensitive material prepared in step 1 of Example 1 in the range of 303K to 803K, with an excitation wavelength of 405nm and a temperature variation interval of 50K;

[0021] Figure 3 The variation rule of the intensity ratio of 545nm green light and 648nm red light of the temperature sensitive material prepared in step 1 of Example 1 in the range of 303K to 803K, with a temperature variation interval of 50K;

[0022] Figure 4 For Example 1 based on Sm 3+ / Tb 3+ The variation law of relative sensitivity of the luminescence ratio temperature sensing method in the range of 303K to 803K;

[0023] Figure 5 For Example 1 based on Sm 3+ / Tb 3+ Variation of temperature resolution of luminescence ratio temperature sensing method in the range of 303K to 803K. DETAILED DESCRIPTION

[0024] Specific implementation method 1: This implementation method is a ratio temperature sensing method based on Sm ion / Tb ion luminescence, which is carried out in the following steps:

[0025] 1. Preparation of temperature sensitive materials:

[0026] Preparation of Tb 3+ and Sm 3+ Doped CaWO4 to obtain temperature-sensitive materials;

[0027] 2. Determination of the functional relationship between the fluorescence intensity ratio A / B and temperature:

[0028] The temperature sensitive material is excited by laser with a wavelength of 405nm, and the emission spectrum of the temperature sensitive material at different calibration temperatures is recorded by a spectrometer; Tb 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+ The red fluorescence band at the central wavelength of the ion is located at 648nm and integrated, which is recorded as the fluorescence intensity B. The ratio of fluorescence intensity A to fluorescence intensity B is calculated, and a fluorescence intensity ratio A / B is obtained at each calibration temperature. After processing, a fitting curve is obtained, and the functional relationship between the fluorescence intensity ratio A / B and temperature is obtained according to the fitting curve:

[0029] A / B=-0.06173+4.91×10 -4 ×T-1.29×10 -6 ×T 2 +1.13×10 -9 ×T 3 , where T is the absolute temperature;

[0030] 3. Ambient temperature detection:

[0031] The temperature sensitive material is placed in the test environment, and then the temperature sensitive material is excited by a laser with a wavelength of 405nm. The emission spectrum of the temperature sensitive material is collected by a spectrometer, and Tb is recorded. 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+ The red light fluorescence band at the central wavelength of the ion is located at 648nm and is integrated; the ratio A / B of the fluorescence intensity A to the fluorescence intensity B is calculated, and the ratio A / B is substituted into the functional relationship obtained in step 2, and T is calculated as the ambient temperature, thus completing the ratio temperature sensing method based on Sm ion / Tb ion luminescence.

[0032] The beneficial effects of this embodiment are:

[0033] The traditional fluorescence intensity ratio temperature sensing method cannot be applied to higher temperature ranges (500K~800K) because both fluorescence beams involved will experience severe thermal quenching. This embodiment breaks this limitation and has the following advantages:

[0034] 1. Sm involved in this embodiment 3+The red light of the light source only slightly decays with the increase of temperature, and can still maintain 80% of the room temperature even at 803K, which has a strong anti-thermal quenching effect; the Tb 3+ The green light of the sensor gradually increases with the temperature, up to 76 times. This ensures that the two beams of fluorescence have a good fluorescence signal-to-noise ratio. However, the two beams of fluorescence in the traditional fluorescence intensity ratio temperature measurement technology almost decay to zero at 803K, so it is not applicable.

[0035] 2. Tb involved in this embodiment 3+ Green light and Sm 3+ The red light has different temperature response, Tb 3+ The green light at 545 nm of the ion increases rapidly with temperature, ensuring excellent relative sensitivity. 3+ Green light and Sm 3+ The intensity ratio of the red light can reflect the temperature change in time, which ensures good relative sensitivity. Together with the excellent signal-to-noise ratio, the Sm-based 3+ / Tb 3+ The temperature resolution of the luminescence ratio temperature sensing method is still better than 1K at 803K.

[0036] 3. The applicable temperature range of this embodiment is 303K to 803K, and it can be applied in a wider temperature range.

[0037] Specific implementation method 2: This implementation method is different from the specific implementation method 1 in that: Tb described in step 1 3+ and Sm 3+ Tb in doped CaWO4 3+ The molar percentage of ions is 10%; the Tb 3+ and Sm 3+ Sm in doped CaWO4 3+ The molar percentage of ions is 1.5%. Other aspects are the same as those of the first embodiment.

[0038] Specific implementation method three: This implementation method is different from specific implementation methods one or two in that: Tb described in step one 3+ and Sm 3+ The doped CaWO4 is prepared by a high temperature solid phase method. The rest is the same as the first or second specific implementation.

[0039] Specific implementation method 4: This implementation method is different from one of the specific implementation methods 1 to 3 in that: Tb described in step 1 3+ and Sm 3+ The doped CaWO4 is specifically prepared in the following steps:

[0040] 1. CaO, WO3, Sm2O3 and Tb4O7 are weighed as raw materials according to the stoichiometric ratio, and then the raw materials are put into an agate crucible and ground evenly to obtain a mixed material;

[0041] 2. The mixture is heated to 770K-780K at a heating rate of 4K / min-6K / min, and kept at 770K-780K for 0.5h-1.5h. Then, the mixture is heated to 1500K-1600K at a heating rate of 4K / min-6K / min, and kept at 1500K-1600K for 5h-10h to obtain Tb 3+ and Sm 3+ Doped CaWO4. Other aspects are the same as those of the first to third embodiments.

[0042] Specific implementation method 5: This implementation method is different from the specific implementation methods 1 to 4 in that: Tb in step 1 3+ and Sm 3+ The crystal phase of the doped CaWO4 is tetragonal. Other aspects are the same as those of the first to fourth embodiments.

[0043] Specific implementation example 6: This implementation example is different from specific implementation examples 1 to 5 in that the particle size of the temperature sensitive material in step 1 is 1 micron to 10 microns. The rest is the same as specific implementation examples 1 to 5.

[0044] Specific embodiment 7: This embodiment differs from specific embodiments 1 to 6 in that: in step 2, a temperature sensitive material is heated by a hot and cold stage to achieve different calibration temperatures, the range of different calibration temperatures is 303K to 803K, and the temperature interval between adjacent calibration temperatures is 50K. Other aspects are the same as specific embodiments 1 to 6.

[0045] Specific implementation eight: This implementation differs from specific implementations one to seven in that each calibration temperature in step two is kept warm for 3 minutes. The rest is the same as specific implementations one to seven.

[0046] Specific implementation method 9: This implementation method is different from specific implementation methods 1 to 8 in that: Tb in step 2 and step 3 3+ The green light at 545nm comes from Tb 3+ of 5 D4→ 7 F5 transition, Sm 3+ The red light at 648 nm comes from Sm 3+ of 4 G5 / 2→ 6 H 9 / 2 The rest is the same as the first to eighth embodiments.

[0047] Specific implementation example 10: This implementation example is different from specific implementation examples 1 to 9 in that the fitting curve is obtained after processing using the least squares method in step 2. The rest is the same as specific implementation examples 1 to 9.

[0048] The following examples are used to verify the beneficial effects of the present invention:

[0049] Embodiment 1:

[0050] A ratiometric temperature sensing method based on Sm ion / Tb ion luminescence is carried out in the following steps:

[0051] 1. Preparation of temperature sensitive materials:

[0052] Preparation of Tb 3+ and Sm 3+ Doped CaWO4 to obtain temperature-sensitive materials;

[0053] 2. Determination of the functional relationship between the fluorescence intensity ratio A / B and temperature:

[0054] The temperature sensitive material was excited by a laser with a power of 100 mW and a wavelength of 405 nm, and the emission spectrum of the temperature sensitive material at different calibration temperatures was recorded by a spectrometer; Tb 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+ The red fluorescence band at the central wavelength of the ion is located at 648nm and integrated, recorded as fluorescence intensity B; the ratio of fluorescence intensity A to fluorescence intensity B is calculated, and a fluorescence intensity ratio A / B is obtained at each calibration temperature. The fitting curve is obtained after processing using the least squares principle, and the functional relationship between the fluorescence intensity ratio A / B and temperature is obtained according to the fitting curve:

[0055] A / B=-0.06173+4.91×10 -4 ×T-1.29×10 -6 ×T 2 +1.13×10 -9 ×T 3 , where T is the absolute temperature;

[0056] 3. Ambient temperature detection:

[0057] The temperature sensitive material is placed in the test environment, and then the temperature sensitive material is excited by a laser with a power of 100 mW and a wavelength of 405 nm. The emission spectrum of the temperature sensitive material is collected by a spectrometer, and the Tb 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+The red light fluorescence band at the central wavelength of the ion is located at 648nm and is integrated; the ratio A / B of the fluorescence intensity A to the fluorescence intensity B is calculated, and the ratio A / B is substituted into the functional relationship obtained in step 2, and T is calculated as the ambient temperature, thus completing the ratio temperature sensing method based on Sm ion / Tb ion luminescence.

[0058] Tb described in step 1 3+ and Sm 3+ Tb in doped CaWO4 3+ The molar percentage of ions is 10%; the Tb 3+ and Sm 3+ Sm in doped CaWO4 3+ The molar percentage of ions is 1.5%.

[0059] Tb described in step 1 3+ and Sm 3+ Doped CaWO4 is prepared by a high temperature solid phase method as follows:

[0060] 1. CaO, WO3, Sm2O3 and Tb4O7 are weighed as raw materials according to the stoichiometric ratio, and then the raw materials are put into an agate crucible and ground evenly to obtain a mixed material;

[0061] Second, the mixture was heated to 773K at a heating rate of 5K / min, and kept at 773K for 1h, then heated to 1523K at a heating rate of 5K / min, and kept at 1523K for 8h, to obtain Tb 3+ and Sm 3+ Doped CaWO4.

[0062] Tb described in step 1 3+ and Sm 3+ The crystal phase of doped CaWO4 is tetragonal.

[0063] The average particle size of the temperature sensitive material described in step 1 is 5 microns.

[0064] In step 2, the temperature sensitive material is heated by a hot and cold stage to achieve different calibration temperatures. The range of different calibration temperatures is 303K to 803K, and the temperature interval between adjacent calibration temperatures is 50K. Each calibration temperature is kept warm for 3 minutes.

[0065] Tb in step 2 and step 3 3+ The green light at 545nm comes from Tb 3+ of 5 D4→ 7 F5 transition, Sm 3+ The red light at 648 nm comes from Sm 3+of 4 G5 / 2→ 6 H 9 / 2 Transition.

[0066] Figure 1 The XRD diffraction result of the temperature sensitive material prepared in step 1 of Example 1 is shown; it can be seen that the diffraction peaks of the sample correspond one-to-one with the standard peak positions, indicating that Tb 3+ and Sm 3+ Doped CaWO4 was successfully prepared and was tetragonal in structure.

[0067] Figure 2 The emission spectrum of the temperature sensitive material prepared in step 1 of Example 1 in the range of 303K to 803K, the excitation wavelength is 405nm, and the temperature change interval is 50K. As can be seen from the figure, under the excitation of 405nm laser, CaWO4:10%Tb 3+ ,1.5%Sm 3+ The emission spectrum of the phosphor in the temperature range of 303K to 803K is mainly composed of two parts: the first part is the emission peak at 545nm, which comes from Tb 3+ of 5 D4→ 7 The second part is composed of three emission peaks at 562nm, 602nm and 648nm, which are derived from Sm 3+ of 4 G 5 / 2 → 6 H 5 / 2 , 4 G 5 / 2 → 6 H 7 / 2 and 4 G5 / 2→ 6 H 9 / 2 As the temperature rises, the green light at 545nm increases sharply to 76 times of the initial value, while the red light at 648nm only shows weak thermal quenching, and can still maintain 80% of the room temperature even at 803K.

[0068] Figure 3 The intensity ratio variation law of 545nm green light and 648nm red light of the temperature sensitive material prepared in step 1 of Example 1 in the range of 303K to 803K, with a temperature variation interval of 50K; at each temperature, the intensity ratio of Tb 3+ The green light intensity of the ion at 545 nm is integrated and recorded as A. 3+ The red light intensity of the ion at 648nm is integrated and recorded as B. By dividing these two intensities, the corresponding fluorescence intensity ratio A / B can be obtained. The change rules of these ratios with temperature are as follows Figure 3 As shown, the temperature information can be inferred by monitoring this ratio.

[0069] Figure 4 For Example 1 based on Sm 3+ / Tb 3+ The variation law of relative sensitivity of the luminescence ratio temperature sensing method in the range of 303K to 803K; the relative sensitivity of this method is up to 1.67%K at 473K -1 At the same time, the relative sensitivity in the high temperature range of 500K~803K is better than 0.5%K -1 The traditional use of Er 3+ of 2 H 11 / 2 → 4 I 15 / 2 and 4 S 3 / 2 → 4 I 15 / 2 The relative sensitivity of the fluorescence intensity ratio temperature measurement method of the transition is only 0.15% K at 803 K. -1 , and 3+ of 2 H 11 / 2 → 4 I 15 / 2 and 4 S 3 / 2 → 4 I 15 / 2 The intensity of the transition at 803K is almost undetectable and therefore no longer applicable. This embodiment effectively solves this defect.

[0070] Figure 5 For Example 1 based on Sm 3+ / Tb 3+ The variation law of temperature resolution of the ratiometric temperature sensing method based on luminescence in the range of 303K to 803K. 3+ / Tb 3+ The temperature resolution of the luminescence ratio temperature sensing method is better than 1K in the higher temperature range of 500K to 803K (the resolution is less than 1K).

Claims

1. A ratio temperature sensing method based on Sm ion / Tb ion luminescence, characterized in that It is carried out in the following steps:

1. Preparation of temperature sensitive materials: Preparation of Tb 3+ and Sm 3+ Doped CaWO4 to obtain temperature-sensitive materials; 2. Determination of the functional relationship between the fluorescence intensity ratio A / B and temperature: The temperature sensitive material is excited by laser with a wavelength of 405nm, and the emission spectrum of the temperature sensitive material at different calibration temperatures is recorded by a spectrometer; Tb 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+ The red fluorescence band at the central wavelength of the ion is located at 648nm and integrated, which is recorded as the fluorescence intensity B. The ratio of fluorescence intensity A to fluorescence intensity B is calculated, and a fluorescence intensity ratio A / B is obtained at each calibration temperature. After processing, a fitting curve is obtained, and the functional relationship between the fluorescence intensity ratio A / B and temperature is obtained according to the fitting curve: A / B=-0.06173+4.91×10 -4 ×T-1.29×10 -6 ×T 2 +1.13×10 -9 ×T 3 , where T is the absolute temperature; 3. Ambient temperature detection: The temperature sensitive material is placed in the test environment, and then the temperature sensitive material is excited by a laser with a wavelength of 405nm. The emission spectrum of the temperature sensitive material is collected by a spectrometer, and Tb is recorded. 3+ The green fluorescence band with the central wavelength of the ion at 545nm is integrated and recorded as the fluorescence intensity A; record Sm 3+ The red light fluorescence band at the central wavelength of the ion is located at 648nm and is integrated; the ratio A / B of the fluorescence intensity A to the fluorescence intensity B is calculated, and the ratio A / B is substituted into the functional relationship obtained in step 2, and T is calculated as the ambient temperature, thus completing the ratio temperature sensing method based on Sm ion / Tb ion luminescence.

2. A temperature sensing method based on the ratio of Sm ion / Tb ion luminescence according to claim 1, characterized in that Tb described in step 1 3+ and Sm 3+ Tb in doped CaWO4 3+ The molar percentage of ions is 10%; the Tb 3+ and Sm 3+ Sm in doped CaWO4 3+ The molar percentage of ions is 1.5%.

3. A ratio temperature sensing method based on Sm ion / Tb ion luminescence according to claim 2, characterized in that Tb described in step 1 3+ and Sm 3+ Doped CaWO4 was prepared by high temperature solid phase method.

4. A ratiometric temperature sensing method based on Sm ion / Tb ion luminescence according to claim 3, characterized in that Tb described in step 1 3+ and Sm 3+ The doped CaWO4 is specifically prepared in the following steps:

1. CaO, WO3, Sm2O3 and Tb4O7 are weighed as raw materials according to the stoichiometric ratio, and then the raw materials are put into an agate crucible and ground evenly to obtain a mixed material; 2. The mixture is heated to 770K-780K at a heating rate of 4K / min-6K / min, and kept at 770K-780K for 0.5h-1.5h. Then, the mixture is heated to 1500K-1600K at a heating rate of 4K / min-6K / min, and kept at 1500K-1600K for 5h-10h to obtain Tb 3+ and Sm 3+ Doped CaWO4.

5. A temperature sensing method based on the ratio of Sm ion / Tb ion luminescence according to claim 4, characterized in that Tb described in step 1 3+ and Sm 3+ The crystal phase of doped CaWO4 is tetragonal.

6. A ratio temperature sensing method based on Sm ion / Tb ion luminescence according to claim 1, characterized in that The particle size of the temperature sensitive material described in step 1 is 1 micron to 10 microns.

7. A temperature sensing method based on the ratio of Sm ion / Tb ion luminescence according to claim 1, characterized in that In step 2, the temperature sensitive material is heated by a hot and cold stage to achieve different calibration temperatures, the range of different calibration temperatures is 303K to 803K, and the temperature interval between adjacent calibration temperatures is 50K.

8. A temperature sensing method based on the ratio of Sm ion / Tb ion luminescence according to claim 7, characterized in that In step 2, each calibration temperature is kept for 3 minutes.

9. A temperature sensing method based on the ratio of Sm ion / Tb ion luminescence according to claim 1, characterized in that Tb in step 2 and step 3 3+ The green light at 545nm comes from Tb 3+ of 5 D4→ 7 F5 transition, Sm 3+ The red light at 648 nm comes from Sm 3+ of 4 G5 / 2→ 6 H 9 / 2 Transition.

10. A temperature sensing method based on the ratio of Sm ion / Tb ion luminescence according to claim 1, characterized in that In step 2, the fitting curve is obtained by processing using the least squares method.

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