CN108840571A - A kind of twin crystal phase glass ceramics and preparation method thereof for fluorescence temperature probe - Google Patents

Abstract

The invention proposes a glass ceramic containing CsPbBr ₃ and EuPO ₄ crystal phases capable of realizing high-efficiency temperature detection and its preparation technology. The glass components and percentages (mol%) in the glass ceramics of the present invention are: 10-60mol% P ₂ O ₅ ; 0-40mol% SiO ₂ ; 0-40mol% Al ₂ O ₃ ; 0-30mol% Cs ₂ CO ₃ ; 0-30mol% PbBr _{2 ;} 0-30mol% SrCO ₃ ; 5-30mol% NaBr; The invention also provides the preparation technology of the glass ceramics. Under the irradiation of ultraviolet light with a wavelength of 393 nanometers, the fluorescence intensity ratio of the red emission band at 611nm of Eu ³⁺ to the green emission band of CsPbBr ₃ at 516nm changes significantly with temperature, which can achieve a certain temperature range. detection. In the temperature range of 303‑483K, the highest absolute sensitivity of CsPbBr ₃ /EuPO ₄ duplex glass ceramics reaches 0.082K ^‑1 , and the highest relative sensitivity reaches 1.8%K ^‑1 . Not only that, this material has good thermal stability and can be recycled many times. It shows that CsPbBr ₃ /EuPO ₄ dual-phase glass-ceramic is a kind of fluorescent temperature probe material that can realize high-efficiency temperature detection.

Description

A dual-phase glass-ceramic for fluorescent temperature probes and its preparation method

technical field

The invention relates to the field of solid luminescent materials, in particular to a dual crystal phase glass ceramic that can be applied to a fluorescent temperature probe and a preparation process thereof.

Background technique

Temperature is the most fundamental thermodynamic parameter, which plays an important role in industrial and scientific applications. The traditional temperature measurement method needs to be in contact with the object to be measured, representatively there are thermometers, thermocouples and so on. However, this kind of contact temperature measurement will change the actual temperature of the object, which may easily cause inaccurate temperature measurement. In addition, the effect of testing small objects and fast-moving objects is not satisfactory. Recently, fluorescent intensity-ratio-based temperature probe materials have received widespread attention. This type of fluorescent material is non-contact, has high measurement accuracy and spatial resolution, and can be used in harsh environments. An ideal fluorescence intensity ratio based fluorescent probe needs to have two distinguishable emission peaks, high sensitivity and excellent thermal stability.

Most studies have focused on rare-earth fluorescence intensity-ratio-based fluorescent temperature probes, which mainly exploit the abundant energy levels of rare earths. Traditionally, thermally coupled energy level pairs of a single rare earth (Er, Tm, Ho) are often used as fluorescence intensity ratio base fluorescent probes, and electrons move in opposite directions in the configuration of thermally coupled energy levels as the temperature changes. However, the small gap difference between thermally coupled energy levels can easily cause the two monitoring emission peaks to overlap, resulting in inaccurate temperature measurement. To address this issue, rare-earth/rare-earth-doped materials with dual emission centers were reported as fluorescent temperature probe materials. However, the parity-forbidden nature of rare earth 4f-4f determines its low absorption cross-section and weak fluorescence intensity. In addition, the price of rare earth is relatively expensive.

Therefore, people turn their attention to semiconductor nanocrystal temperature measuring materials, which have large absorption cross section, high fluorescence quantum field, high photostability and adjustable emission band. These excellent properties make them suitable as fluorescent temperature probe materials. However, semiconductor nanocrystals are unstable and easily affected by other external environmental factors (such as pH value), which is not conducive to temperature detection.

At present, most fluorescent materials based on fluorescence intensity ratios are phosphor powders and crystals. However, the phosphor powder is easy to scatter, resulting in inaccurate temperature measurement; and the preparation process of the crystal is complicated, and requires a lot of time and high cost. In recent years, glass-ceramic-based fluorescent temperature-measuring materials have attracted people's attention. They are not only simple in preparation technology, easy to mass-produce, and can be processed into various shapes, but also have excellent thermal stability and can be recycled. These excellent properties make it a potential application prospect in the field of fluorescent temperature probes.

The invention provides a dual-phase glass ceramic for high-sensitivity temperature detection and a preparation method thereof. Under the excitation of 393 nm ultraviolet light, the CsPbBr ₃ /EuPO ₄ dual-phase glass ceramics presents the fluorescence emission bands of CsPbBr ₃ and Eu ³⁺ , and the main peaks are located at the green emission band at 516 nm and 593 nm, 611 nm, and 700 nm, respectively. red emission band. In the temperature range of 303K-483K, measure its variable temperature emission spectrum, use the fluorescence intensity ratio of the two peaks at 611 nm in Eu ³⁺ and 516 nm in CsPbBr ₃ as the temperature detection signal, and the change in the fluorescence intensity ratio between the two is very obvious , the highest absolute sensitivity of this material reaches 0.082K ^-1 , and the highest relative sensitivity reaches 1.8% K ^-1 , which are higher than most of the reported fluorescent temperature probe materials. This new type of CsPbBr ₃ /EuPO ₄ dual-phase glass-ceramic is an excellent fluorescent temperature probe material.

Contents of the invention

The invention relates to the preparation of CsPbBr ₃ /EuPO ₄ dual-phase glass ceramics, aiming to prepare a glass ceramic-based fluorescent temperature probe material for temperature detection which has high sensitivity and excellent thermal stability and can be excited by ultraviolet rays.

The present invention also provides the preparation method of the above-mentioned CsPbBr ₃ /EuPO ₄ dual-phase glass-ceramics, that is, by rationally designing the precursor glass components, and adopting melt quenching technology, the required glass-ceramic is prepared by self-crystallization, and in the cooling process In the process, CsPbBr ₃ and EuPO ₄ grains precipitated in the glass matrix at the same time, forming CsPbBr ₃ /EuPO ₄ dual-phase glass ceramics. The material can be excited by purple light, the highest absolute sensitivity reaches 0.082K ^-1 , the highest relative sensitivity reaches 1.8%K ^-1 , and can effectively detect temperature.

The preparation method of CsPbBr ₃ /EuPO ₄ duplex glass ceramics, comprises the following steps:

(1) The design of the precursor glass matrix, the composition content of the glass matrix is as follows:

10-60mol% _P2O5 ; _0-40mol % _SiO2 ; 0-40mol% _Al2O3 ; 0-30mol% _{Cs2CO3 ;} 0-30mol% PbBr2 _; 0-30mol% _{SrCO3 ;} 30mol% NaBr; 5-30mol% EuCl ₃ , the total molar amount of the above components is 100mol%.

According to the present invention, the preferred content of each component is as follows:

_P2O5 is preferably _20-50mol %;

_SiO2 is preferably 5-30mol%;

_Al2O3 is preferably _5-30mol %;

_Cs2CO3 is preferably _5-25mol %;

PbBr2 is preferably _5-25mol %;

_SrCO3 is preferably 5-25mol%;

NaBr is preferably 5-25mol%;

EuCl3 is preferably _10-25mol %;

(2) Weigh P ₂ O ₅ , SiO ₂ , Al ₂ O ₃ , Cs ₂ CO ₃ , PbBr ₂ , SrCO ₃ , NaBr, EuCl ₃ and other powder materials according to a certain composition ratio, and mix them in an agate ball mill jar After being fully ground and uniform, place it in an alumina crucible, heat and keep it warm for a period of time to melt it, and then quickly pour the molten liquid into a mold to form it, and obtain a block glass ceramic through self-crystallization. Finally, the obtained The glass ceramics are annealed in a resistance furnace to eliminate internal stress, and then cut into blocks after cooling with the furnace;

According to the present invention, in step (2), heating is carried out in a resistance furnace to 900-1300°C, preferably 1000-1200°C. Heat preservation for 1-4 hours, preferably 1-3 hours to melt the powder raw material.

According to the present invention, in step (2), the glass melt is taken out and quickly poured into a mold for forming to obtain block glass ceramics.

According to the present invention, in step (2), the annealing temperature is 200-400°C.

According to the present invention, in step (2), during the heating process, the heating rate is controlled to be 1-10°C/min, preferably 2-5°C/min.

In the present invention, the glass ceramics with CsPbBr ₃ /EuPO ₄ crystal grains embedded in the glass matrix can be obtained by adopting the above material components and preparation process.

The present invention also relates to an application of glass ceramics, which is characterized in that the glass ceramic fluorescent temperature probe is used for temperature detection.

Under the excitation of 393 nm ultraviolet light, the CsPbBr ₃ /EuPO ₄ dual-phase glass ceramics presents the fluorescence emission bands of CsPbBr ₃ and Eu ³⁺ , and the main peaks are located at the green emission band at 516 nm and 593 nm, 611 nm, and 700 nm, respectively. strong red emission band. The fluorescence intensity ratio of the two peaks at 611 nm in Eu ³⁺ and at 516 nm in CsPbBr ₃ was used as the temperature detection signal. In the temperature range of 303K-483K, the fluorescence intensity ratio of the two changes very obviously. The decrease of fluorescence intensity of CsPbBr ₃ is very obvious, while the emission intensity of Eu ³⁺ is only slightly weakened. The ratio of fluorescence intensity at different temperatures is exponentially fitted, and the highest absolute sensitivity reaches 0.082K ^-1 , and the highest relative sensitivity reaches 1.8%K ^-1 , which is superior to most of the reported fluorescent temperature probe materials. The temperature of the environment can be obtained by measuring the ratio of the fluorescence intensity between the two. At the same time, as the temperature changes, the color changes from green to red, which is conducive to remote observation. Besides, CsPbBr ₃ /EuPO ₄ dual phase glass-ceramic has been proved to have excellent thermal stability. These results indicated that CsPbBr ₃ /EuPO ₄ duplex glass-ceramic is an ideal fluorescent temperature probe material, which has broad application prospects in the field of temperature detection.

Description of drawings

Figure 1: X-ray diffraction pattern of CsPbBr ₃ /EuPO ₄ dual phase glass ceramics.

Figure 2: SEM image of CsPbBr ₃ /EuPO ₄ duplex glass ceramics.

Figure 3: Excitation spectra of CsPbBr ₃ /EuPO ₄ dual phase glass ceramics, the monitoring wavelengths are 516nm and 611nm.

Figure 4: Emission spectrum of CsPbBr ₃ /EuPO ₄ dual phase glass ceramics under excitation at 393nm.

Figure 5: The temperature-variable emission spectrum of CsPbBr ₃ /EuPO ₄ dual-phase glass ceramics, the temperature changes from 303K to 483K, and the excitation is at 393nm.

Figure 6: Eu ³⁺ of CsPbBr ₃ (516nm) and Eu ³⁺ ions: ⁵ D ₀ → ⁷ F ₁ (593nm), ⁵ D ₀ → ⁷ F ₂ (611nm), ⁵ D ₀ → ⁷ F ₄ (700nm) Histogram of transition emission intensity.

Figure 7: Experimental measurements and fitted emission intensity ratio FIR _611/516 versus temperature.

Figure 8: Calculated absolute sensitivity, relative sensitivity, and corresponding fitting curves.

Detailed ways

Example 1: Pure P ₂ O ₅ , SiO ₂ , Al ₂ O ₃ , Cs ₂ CO ₃ , PbBr ₂ , SrCO ₃ , NaBr, EuCl ₃ powder, according to 30P ₂ O ₅ ; 20SiO ₂ ; 10Al ₂ O ₃ ; 10Cs ₂ CO ₃ ; 10PbBr ₂ ; 5SrCO ₃ ; 5NaBr _; Heating to 1000°C and keeping it warm for 2 hours to melt it, then quickly pour the molten liquid into a mold to form it, and obtain block glass ceramics by self-crystallization, and finally, put the obtained glass ceramics into a resistance furnace, Anneal at 200°C to eliminate internal stress, and after cooling in the furnace, cut into blocks to obtain CsPbBr ₃ /EuPO ₄ double crystal glass ceramics.

X-ray diffraction data indicated that CsPbBr ₃ and EuPO ₄ crystalline phases were precipitated in the glass matrix (as shown in Figure 1). Scanning electron micrographs show the distribution of CsPbBr ₃ and EuPO ₄ crystalline phases in the glass matrix (as shown in Figure 2). The samples were surface polished, and their excitation and emission at room temperature were measured with a FLS920 fluorescence spectrometer. On the excitation spectrum monitoring the 611 nm emission of Eu ³⁺ ions, an excitation band corresponding to Eu ³⁺ -O ^2- charge transfer and Eu ³⁺ : 4f→4f absorption transition (the wavelength with the highest intensity at 393 nm) was detected ( As shown in Figure 3). On the excitation spectrum monitoring the 516 nm emission of CsPbBr ₃ , an excitation band corresponding to the transition of CsPbBr ₃ was detected (as shown in FIG. 4 ). On the emission spectrum excited at 393 nanometers, there is a strong red light emission corresponding to the transition of Eu ³⁺ : ⁵ D ₀ → ⁷ F _J (J=1,2,3,4) (the center wavelengths correspond to 593 nanometers, respectively 611 nm, 652 nm, 700 nm). Under the excitation of ultraviolet light with a wavelength of 393 nanometers, the temperature-varying emission spectrum is measured, and the temperature range is 303K-483K. It was observed that the fluorescence intensity of CsPbBr ₃ decreased significantly, while the emission intensity of Eu ³⁺ was only slightly weakened (as shown in Figure 5). It can be further confirmed in the CsPbBr ₃ and Eu ³⁺ ion transition emission intensity histograms (as shown in Figure 6). The fluorescence intensity ratio of the two peaks at 611 nm in Eu ³⁺ and at 516 nm in CsPbBr ₃ varies significantly with temperature (as shown in Figure 7). Using the fluorescence intensity ratio between the two as the temperature detection signal, the highest absolute sensitivity reached 0.082K ^-1 , and the highest relative sensitivity reached 1.8%K ^-1 (as shown in Figure 8).

Example 2: Pure P ₂ O ₅ , SiO ₂ , Al ₂ O ₃ , Cs ₂ CO ₃ , PbBr ₂ , EuCl ₃ powders, according to 20P ₂ O ₅ ; 20SiO ₂ ; 10Al ₂ O ₃ ; 20Cs ₂ CO ₃ ; 20PbBr ₂ ; 10EuCl ₃ (molar ratio) is weighed, mixed in an agate ball mill jar and fully ground evenly, then placed in an alumina crucible, heated to 1300°C in a resistance furnace, and kept for 2 hours. Then, the molten liquid is quickly poured into the mold to form, and the block glass ceramics is obtained by self-crystallization. Finally, the obtained glass ceramics are placed in a resistance furnace and annealed at 200 ° C to eliminate internal stress. After cooling, cut into blocks to obtain CsPbBr ₃ /EuPO ₄ double crystal glass ceramics. Tested the temperature-variable emission spectrum of dual-phase glass ceramics, and used the fluorescence intensity ratio of the two peaks at 611 nm in Eu ³⁺ and 516 nm in CsPbBr ₃ as the temperature detection signal. The highest absolute sensitivity reached 0.064K ^-1 , the highest The relative sensitivity reached 1.5%K ^-1 .

Example 3: The pure P ₂ O ₅ , Al ₂ O ₃ , Cs ₂ CO ₃ , PbBr ₂ , NaBr, EuCl ₃ powder, according to 40P ₂ O ₅ ; 5Al ₂ O ₃ ; 15Cs ₂ CO ₃ ; 10PbBr ₂ ; 10NaBr; 20EuCl ₃ (molar ratio) is weighed, mixed in an agate ball mill jar and fully ground evenly, then placed in an alumina crucible, heated to 900°C in a resistance furnace, and kept for 4 hours to melt , and then, the molten liquid is quickly poured into the mold to form it, and the bulk glass ceramics are obtained by self-crystallization. Finally, the obtained glass ceramics are placed in a resistance furnace, annealed at 300 ° C to eliminate internal stress, and cooled with the furnace After that, it was cut into blocks to obtain CsPbBr ₃ /EuPO ₄ dual phase glass ceramics. Tested the temperature-variable emission spectrum of dual-phase glass ceramics, and used the fluorescence intensity ratio of the two peaks at 611 nm in Eu ³⁺ and at 516 nm in CsPbBr ₃ as the temperature detection signal. The highest absolute sensitivity reached 0.036K ^-1 , the highest The relative sensitivity reached 1.2%K ^-1 .

Example 4: Pure P ₂ O ₅ , SiO ₂ , Cs ₂ CO ₃ , PbBr ₂ , NaBr, SrCO ₃ , EuCl ₃ powder, according to 10P ₂ O ₅ ; 40SiO ₂ ; 20Cs ₂ CO ₃ ; 10PbBr ₂ ; 10NaBr ; 5SrCO ₃ ; 5EuCl ₃ (molar ratio) is weighed, mixed in an agate ball mill jar and fully ground evenly, then placed in an alumina crucible, heated to 1400°C in a resistance furnace, and kept for 4 hours. Then, the molten liquid is quickly poured into the mold to form, and the bulk glass ceramics are obtained by self-crystallization. Finally, the obtained glass ceramics are put into a resistance furnace and annealed at 400 ° C to eliminate internal stress. After cooling in the furnace, cut into blocks to obtain CsPbBr ₃ /EuPO ₄ double crystal glass ceramics. Tested the temperature-variable emission spectrum of dual crystal glass ceramics, and used the fluorescence intensity ratio of the two peaks at 611 nm in Eu ³⁺ and 516 nm in CsPbBr ₃ as the temperature detection signal. The highest absolute sensitivity reached 0.022K ^-1 , the highest The relative sensitivity reached 0.8%K ^-1 .

Claims (5)

1. A glass matrix, characterized in that: the glass component content of the glass matrix is as follows: 10-60mol% _P2O5 ; _0-40mol % _SiO2 ; 0-40mol% _Al2O3 ; 0-30mol% _{Cs2CO3 ;} 0-30mol% PbBr2 _; 0-30mol% _{SrCO3 ;} 30mol% NaBr; 5-30mol% EuCl ₃ , the total molar amount of the above components is 100mol%. 2. The glass matrix according to claim 1, characterized in that: the preferred content of the glass component of the glass matrix is as follows: 20-50% mol% _P2O5 ; _5-30mol % _SiO2 ; 5-30mol% _Al2O3 ; 5-25mol% _{Cs2CO3 ; 5-25mol} % PbBr2; 5-25mol% _{SrCO3 ;} 5-25 mol% NaBr; 10-25 mol% _EuCl3 . 3. A glass ceramic containing CsPbBr ₃ /EuPO ₄ double crystal phase, the glass matrix of the glass ceramic is as described in claim 1. 4. The CsPbBr ₃ /EuPO ₄ glass-ceramic according to claim 3, characterized in that the microstructure is characterized in that CsPbBr ₃ /EuPO ₄ crystallites are uniformly embedded in the glass matrix. 5. a claim 3-4 any one CsPbBr ₃ /EuPO ₄ application of double crystal phase glass-ceramic, it is characterized in that: be 393nm ultraviolet light irradiation CsPbBr ₃ /EuPO ₄ double crystal phase glass-ceramic with wavelength, temperature From 303K to 483K, the green emission intensity of CsPbBr ₃ decreased significantly, the red emission intensity of Eu ³⁺ was only slightly weakened, and the fluorescence changed from green to red. CsPbBr ₃ (516nm) and The fluorescence intensity ratio emitted by Eu ³⁺ : ⁵ D ₀ → ⁷ F ₂ (611 nm) changes significantly with temperature, and the ambient temperature can be measured by using the fluorescence intensity ratio as a temperature detection signal.