CN114656964A - Self-calibration fluorescence temperature measurement material and preparation method thereof - Google Patents

Abstract

The invention belongs to the field of fluorescence temperature sensing, and discloses a self-calibration fluorescence temperature measurement material and a preparation method thereof. The invention aims to provide a high-efficiency fluorescence temperature measurement matrix material which is codoped with rare earth ions Er³⁺/Tm³⁺/Yb³⁺During the process, the thermal coupling energy level pair and the non-thermal coupling energy level pair from different rare earth ions can be utilized to realize self-calibration fluorescence intensity ratio temperature measurement, and the highest sensitivity is not limited by Boltzmann distribution. The rare earth doped lithium lutetium molybdate has small emission peak overlap of corresponding temperature measuring energy levels under the excitation of near-infrared laser, can keep higher relative sensitivity in different temperature regions, and is beneficial to realizing the application of fluorescence temperature measurement with high sensitivity, high precision and extremely wide temperature regions.

Description

A kind of self-calibration fluorescent temperature measurement material and preparation method thereof

technical field

The invention belongs to the field of fluorescence temperature sensing, in particular to a self-calibration fluorescence temperature measurement material with high sensitivity and a preparation method thereof.

Background technique

Accurate and real-time temperature monitoring plays an important role in ensuring product quality, saving energy, and promoting production. Compared with traditional thermocouple and infrared radiation temperature measurement, fluorescence temperature measurement technology has the characteristics of non-contact temperature measurement, large-scale imaging, wide dynamic range, fast response speed and high precision. Therefore, it has a wide range of applications in the field of temperature measurement. prospect. Fluorescence thermometry uses the dependence between luminescence characteristics and temperature, and obtains the corresponding temperature conditions by monitoring physical quantities such as luminescence intensity, fluorescence lifetime, emission bandwidth, peak shift, polarization properties, and fluorescence intensity ratio. Among them, the fluorescence intensity ratio (FIR) temperature measurement has self-calibration characteristics and is not disturbed by the external environment, and is mostly realized by a pair of thermally coupled energy levels of rare earth ions. However, based on the fluorescence intensity ratio thermometry of the thermal coupling energy level, the thermal coupling energy level difference ΔE is limited by the Boltzmann distribution in the range of 200-2000 cm ^-1 , which determines the theoretical maximum relative sensitivity Sr (Sr=ΔE /kT ² ) should not exceed 2878/T ² , which restricts the application of fluorescence thermometry with high sensitivity requirements.

In order to further improve the temperature measurement performance, it is considered to use thermally coupled energy level pairs and non-thermally coupled energy level pairs to perform fluorescence temperature measurement for different temperature regions. The vast majority of rare earth ions are non-thermally coupled energy levels, so the choice of non-thermally coupled energy level pairs is more abundant, the energy range is not limited by the Boltzmann distribution, and the non-thermally coupled energy levels of different ions also show certain The temperature-dependent properties of , are mostly caused by differences in their thermal quenching or energy transfer processes. Therefore, the use of non-thermally coupled energy level pairs from different ions for fluorescence temperature measurement is beneficial to further improve sensitivity, ensure temperature measurement accuracy, reduce temperature measurement errors, and achieve high-performance fluorescence intensity ratio temperature measurement.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide an efficient fluorescence temperature measurement host material, which can utilize the thermal coupling energy level pair and non-thermal energy from different rare earth ions when co-doping rare earth ions Er ³⁺ /Tm ^{3 +} /Yb ³⁺ Coupled energy level pairs achieve high sensitivity fluorescence intensity ratio thermometry.

In order to achieve the above object, the technical solution adopted in the present invention is as follows: a self-calibration fluorescent temperature measurement material, the chemical formula of the self-calibration fluorescence temperature measurement material is: LiLu _0.93-xy (MoO ₄ ) ₂ : xEr ³⁺ , yTm ³⁺ , 0.07Yb ³⁺ , wherein 0.002≤x≤0.01, 0<y≤0.02; the x, y both represent the molar content of Er ³⁺ and Tm ³⁺ substituted for Lu ³⁺ .

A preparation method of a self-calibrating fluorescent temperature measurement material, comprising the following steps:

1) According to the chemical formula LiLu _0.93-xy (MoO ₄ ) ₂ : xEr ³⁺ , yTm ³⁺ , 0.07Yb ³⁺ in the stoichiometric ratio of each element, respectively weigh the lithium-containing compound, lutetium oxide, molybdenum-containing compound, oxide Erbium, thulium oxide and ytterbium oxide;

2) put the powder weighed in step 1) into an agate mortar, add a small amount of dehydrated alcohol, grind to make it evenly mixed to obtain a mixture;

3) the obtained mixture of step 2) is placed in a corundum crucible and placed in a muffle furnace, sintered at high temperature, and cooled to room temperature;

4) The solid sample obtained in step 3) is ground in an agate mortar to obtain the target product.

Preferably, in the above preparation method, the lithium-containing compound is selected from lithium carbonate or lithium oxide.

Preferably, in the above preparation method, the molybdenum-containing compound is selected from molybdenum trioxide or molybdenum trioxide.

Preferably, in the above preparation method, in step 2), the grinding time is 30-60 min.

Preferably, in the above preparation method, in step 3), the atmosphere for high temperature sintering is air atmosphere.

Preferably, in the above preparation method, in step 3), the high temperature sintering is performed at a temperature of 900-1100°C, a heating rate of 3-5°C/min, and a calcination time of 3-6h.

Preferably, in the above preparation method, in step 4), the grinding time is 5-10 min.

The beneficial effects of the present invention are:

The present invention uses lithium lutetium molybdate as a matrix material, and the material has stable physical and chemical properties, simple preparation process, high temperature resistance and environmental friendliness. When Er ³⁺ /Tm ³⁺ /Yb ³⁺ is co-doped, under the excitation of near-infrared 972nm laser, the emission peak overlap is small, which can improve the signal discrimination of fluorescence temperature measurement and reduce the temperature measurement error; Er ³ The thermally coupled energy level pair and the non-thermally coupled energy level pair composed of ⁺ and Tm ³⁺ can achieve high sensitivity and high precision temperature measurement in different temperature regions.

Description of drawings

FIG. 1 is the XRD patterns of the fluorescent temperature measuring materials prepared in Example 1 and Example 2.

FIG. 2 is an up-conversion temperature-variable spectrogram of a fluorescent temperature measuring material under near-infrared excitation in Example 5. FIG.

FIG. 3 is a graph showing the variation of fluorescence thermometry sensitivity with temperature calculated according to the Er ³⁺ : ² H _11/2 / ⁴ S _3/2 thermal coupling energy level pair in Example 5. FIG.

FIG. 4 is a graph showing the change of the fluorescence intensity ratio of Er ³⁺ /Tm ³⁺ non-thermally coupled energy level pair with temperature T in Example 5. FIG.

Detailed ways

Example 1

The chemical formula composition of the fluorescent temperature measuring material in this embodiment is LiLu _0.915 (MoO ₄ ) ₂ : 0.005Er ³⁺ , 0.01Tm ³⁺ , 0.07Yb ³⁺ , and the preparation method is as follows:

Weigh respectively 0.0739g of lithium carbonate, 0.3641g of lutetium oxide, 0.5758g of molybdenum trioxide, 0.0019g of erbium oxide, 0.0039g of thulium oxide and 0.0276g of ytterbium oxide; put the weighed powder into an agate mortar and add absolute ethanol 1ml, grind clockwise for 30min to make it evenly mixed, then transfer it to a corundum crucible, place the crucible in a high-temperature muffle furnace, heat up at a rate of 3°C/min, heat up to 900°C and calcinate for 4h, then cool to room temperature with the furnace; The obtained solid sample was ground in an agate mortar for 5 min to obtain the target product fluorescent thermometric material.

The phase analysis of the sample was carried out, and the XRD pattern was obtained as shown in the figure of Tm ³⁺ : 1% in Figure 1. Compared with the standard pdf card (JPCDS no. 23-1192), the diffraction peak positions and diffraction intensities corresponded one-to-one, which proved the synthesis of Pure phase rare earth doped fluorescent thermometric material.

Example 2

The chemical formula of the fluorescent temperature measuring material in this embodiment is LiLu _0.905 (MoO ₄ ) ₂ : 0.005Er ³⁺ , 0.02Tm ³⁺ , 0.07Yb ³⁺ , and the preparation method is as follows:

Weigh out 0.0739g of lithium carbonate, 0.3601g of lutetium oxide, 0.5758g of molybdenum trioxide, 0.0019g of erbium oxide, 0.0077g of thulium oxide and 0.0276g of ytterbium oxide respectively; put the weighed powder into an agate mortar and add absolute ethanol 2ml, grind clockwise for 40min to make it evenly mixed, then transfer it to a corundum crucible, place the crucible in a high temperature muffle furnace, the heating rate is 5°C/min, heat up to 900°C and calcinate for 4h, then cool to room temperature with the furnace; The obtained solid sample was ground in an agate mortar for 10 min to obtain the target product fluorescent thermometric material.

The phase analysis of the sample was carried out, and the XRD pattern was obtained as shown in the figure of Tm ³⁺ : 2% in Figure 1. Compared with the standard pdf card (JPCDS no. 23-1192), the diffraction peak positions and diffraction intensities corresponded one-to-one, which proved the synthesis of Pure phase rare earth doped fluorescent thermometric material.

Example 3

The chemical formula composition of the fluorescent temperature measuring material in this embodiment is LiLu _0.91 (MoO ₄ ) ₂ : 0.01Er ³⁺ , 0.01Tm ³⁺ , 0.07Yb ³⁺ , and the preparation method is as follows:

Weigh respectively 0.0739g of lithium carbonate, 0.3621g of lutetium oxide, 0.4798g of molybdenum trioxide, 0.0038g of erbium oxide, 0.0039g of thulium oxide and 0.0276g of ytterbium oxide; put the weighed powder into an agate mortar, add anhydrous 1ml of ethanol, grind clockwise for 35min to make it evenly mixed, then transfer it to a corundum crucible, place the crucible in a high temperature muffle furnace, the heating rate is 3 ℃/min, heat up to 1100 ℃ and calcine for 3 hours, then cool to room temperature with the furnace ; The obtained solid sample was ground in an agate mortar for 15 min to obtain the target product fluorescent thermometric material.

Example 4

The chemical formula composition of the fluorescent temperature measuring material in this embodiment is LiLu _0.916 (MoO ₄ ) ₂ : 0.004Er ³⁺ , 0.01Tm ³⁺ , 0.07Yb ³⁺ , and the preparation method is as follows:

Weigh out 0.0299g of lithium oxide, 0.3645g of lutetium oxide, 0.5758g of molybdenum trioxide, 0.0015g of erbium oxide, 0.0039g of thulium oxide and 0.0276g of ytterbium oxide respectively; put the weighed powder into an agate mortar and add absolute ethanol 2ml, grind clockwise for 45min to make it evenly mixed, then transfer it to a corundum crucible, place the crucible in a high temperature muffle furnace, heat up at a rate of 4°C/min, heat up to 1000°C and calcinate for 4h, then cool to room temperature with the furnace; The obtained solid sample was ground in an agate mortar for 10 min to obtain the target product fluorescent thermometric material.

Example 5

The fluorescent temperature measurement material prepared in Example 1 was placed in a test device, and a near-infrared laser with a center wavelength of 972 nm was used as the pump light source, the optical path was adjusted, and it was excited to obtain an up-conversion temperature-variable spectrum in the range of 300.3-563K such as: As shown in Fig. 2, the sensitivity calculation is performed using the thermally coupled energy level pair and the non-thermally coupled energy level pair, respectively. Fig. 3 shows the variation law of sensitivity with temperature based on Er ³⁺ : ² H _11/2 / ⁴ S _3/2 thermal coupling energy level calculation. It is found that the relative sensitivity of Er ³⁺ reaches the maximum value when the temperature is 563K. The value is 4.54×10 ^-3 K ^-1 . Figure 4 shows the function fitting relationship between the fluorescence intensity ratio of Er ³⁺ : ² H _11/2 and Tm ³⁺ : ¹ G ₄ to form a non-thermally coupled energy level pair and the temperature T, and the highest relative sensitivity is calculated at 463K reached, with a value of 9.9×10 ^-2 K ^-1 .

Claims (8)

1. A self-calibration fluorescence temperature measurement material is characterized in that the chemical general formula of the self-calibration fluorescence temperature measurement material is as follows: LiLu_0.93-x-y(MoO₄)₂：xEr³⁺,yTm³⁺,0.07Yb³⁺(ii) a Wherein x is more than or equal to 0.002 and less than or equal to 0.01, and y is more than 0 and less than or equal to 0.02; x and y both represent Er³⁺、Tm³⁺Substituted Lu³⁺The molar content of (a).

2. The method for preparing a self-calibrating fluorescent temperature measuring material of claim 1, which is characterized by comprising the following steps:

1) according to the general chemical formula LiLu_0.93-x-y(MoO₄)₂：xEr³⁺,yTm³⁺,0.07Yb³⁺The stoichiometric ratio of each element in the composition is respectively called lithium-containing compound, lutetium oxide, molybdenum-containing compound, erbium oxide, thulium oxide and ytterbium oxide;

2) putting the powder weighed in the step 1) into an agate mortar, adding a small amount of absolute ethyl alcohol, and grinding to uniformly mix the materials to obtain a mixture;

3) placing the mixture obtained in the step 2) in a corundum crucible, then placing the corundum crucible in a muffle furnace, sintering at high temperature, and cooling to room temperature;

4) and (3) grinding the solid sample obtained in the step 3) in an agate mortar to obtain the target product.

3. The method of claim 2, wherein: the lithium-containing compound is selected from lithium carbonate or lithium oxide.

4. The method of claim 2, wherein: the molybdenum-containing compound is selected from molybdenum trioxide or molybdenum sesquioxide.

5. The method of claim 2, wherein: in the step 2), the grinding time is 30-60 min.

6. The production method according to claim 2, characterized in that: in the step 3), the atmosphere of the high-temperature sintering is air atmosphere.

7. The method of claim 2, wherein: in the step 3), the high-temperature sintering is carried out at the temperature of 900-1100 ℃, the heating rate is 3-5 ℃/min, and the calcining time is 3-6 h.

8. The production method according to claim 2, characterized in that: in the step 4), the grinding time is 5-10 min.

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