Rare earth Er < 3 + > doped Cs2KYbCl6 fluorescent powder material as well as preparation method and application thereof

Abstract

The invention discloses a rare earth Er < 3 + > doped Cs2KYbCl6 fluorescent powder material as well as a preparation method and application thereof, and belongs to the technical field of luminescent materials. According to the invention, the white Cs2KYb (1-x) Cl6: xEr fluorescent powder is obtained by calcining through a solid phase method. Different from a common thermal quenching material, the luminous intensity and the service life of Cs2KYbCl6: xEr visible light of the product are enhanced to different extents under the excitation of 980nm and 365nm exciting light modes along with the rise of the environment temperature, and by utilizing the characteristic that the luminous intensity and the service life have positive response to temperature change, the Cs2KYbCl6: xEr visible light can be used for detecting the temperature change of the Cs2KYbCl6: xEr visible light. The material disclosed by the invention has relatively high optical temperature sensitivity in a fluorescence intensity mode and a fluorescence lifetime mode, and is an optical temperature sensing material with a wide temperature measurement range, which can be used for high-temperature environment detection.

Description

Technical Field

[0001] The present invention relates to a rare earth Er 3+ The invention relates to a doped Cs2KYbCl6 phosphor material and a preparation method and application thereof, belonging to the technical field of luminescent materials. Background Art

[0002] In recent years, fluorescence intensity ratio technology has made significant progress in fields such as materials, biomedicine, and environmental monitoring. Non-contact temperature measurement methods using thermally dependent luminescent materials have attracted widespread research interest in various fields of natural science due to their non-contact monitoring, fast response time, and high measurement accuracy. Among them, the fluorescence intensity ratio (FIR) technology based on thermally coupled energy levels doped with metal ions is widely used in optical thermometer sensors. However, most of these FIR-based UC luminescent materials will experience thermal quenching, that is, the photoluminescence (PL) intensity will decrease at high temperatures. This is because the vibration intensifies with increasing temperature, promoting the dominance of the non-radiative multi-phonon transition probability. This phenomenon greatly limits the application of luminescent materials in high temperature areas, leading to device performance degradation and ultimately system failure. Therefore, it is crucial to develop high-sensitivity temperature sensing DPs that can adapt to higher temperature environments. Summary of the Invention

[0003] In order to provide a fluorescent material with anti-thermal quenching performance, the present invention provides a rare earth Er 3+ Phosphor material doped with Cs2KYbCl6, its chemical formula is: Cs2KYb (1-x) Cl6:xEr, where 0.005≤x≤0.05.

[0004] The rare earth Er 3+ The preparation method of the doped Cs2KYbCl6 phosphor material comprises the following steps: firstly, weighing the corresponding CsCl, KCl, YbCl3·6H2O and ErCl3·6H2O according to the molar ratio of the chemical formula, adding anhydrous ethanol and grinding, then drying the anhydrous ethanol, taking it out and further grinding it into powder, and finally calcining the powder to obtain white Cs2KYbCl6:Er phosphor.

[0005] Preferably, the grinding time after adding anhydrous ethanol is 25 to 35 minutes.

[0006] Preferably, the temperature for drying the anhydrous ethanol is 60° C. and the time is 3 to 7 minutes.

[0007] Preferably, the calcination conditions are calcination at 350° C. for 3 hours and a heating rate of 5° C. / min.

[0008] The present invention also provides a rare earth Er 3+ Application of doped Cs2KYbCl6 phosphor in the preparation of high-temperature temperature transmission materials.

[0009] Beneficial effects of the present invention

[0010] (1) The rare earth Er prepared by the present invention 3+ The phosphor material doped with Cs2KYbCl6 exhibited good resistance to high-temperature thermal quenching under 980nm light excitation and showed an anomalous thermal enhancement phenomenon under 365nm light excitation, indicating that the material prepared by the present invention has strong resistance to thermal quenching. Therefore, this material has great application potential in the field of high-temperature temperature sensing.

[0011] (2) The present invention uses Cs2KYbCl6 as the matrix, and Yb 3 + and Er 3 +, the synergy enables the luminescent material to undergo cross-relaxation at different energy levels, and the number of particles in each excited state can be dynamically controlled to achieve adjustable emission color.

[0012] (3) A rare earth Er provided by the present invention 3+ The preparation method of the phosphor material doped with Cs2KYbCl6 has mild preparation conditions and simple operation. The phosphor provided by the present invention has good luminescence performance and is expected to be applied in fluorescence temperature measurement.

[0013] (4) Rare earth Er provided by the method of the present invention 3+ The Cs2KYbCl6-doped phosphor achieves efficient green upconversion luminescence under 980nm excitation and red emission under 365nm excitation. Based on this, a fluorescent anti-counterfeiting application was designed. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 For Examples 1 to 4 and Comparative Example 1, different rare earth Er 3+ X-ray diffraction (XRD) patterns of the phosphors prepared under doping.

[0015] Figure 2 The fluorescence spectra of the phosphor materials prepared in Examples 1 to 4 and Comparative Example 1 under 980 nm excitation and 365 nm at room temperature are shown.

[0016] Figure 3 This is the temperature-dependent emission spectrum of Example 3 under 980nm light excitation.

[0017] Figure 4 This is the temperature-dependent emission spectrum of Example 4 under 365nm light excitation.

[0018] Figure 5 The material prepared in Comparative Example 2 was subjected to a temperature-dependent emission spectrum analysis under 980 nm excitation.

[0019] Figure 6 A sensitivity factor fitting diagram based on fluorescence intensity and lifetime was performed for the material prepared in Example 3.

[0020] Figure 7 This is an application diagram of the anti-counterfeiting "little flower" made of fluorescent powder in Example 3. DETAILED DESCRIPTION

[0021] The present invention is further described in detail below with reference to the accompanying drawings and specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0022] Example 1

[0023] A rare earth 3+ Preparation of phosphor materials doped with Cs2KYbCl6:

[0024] CsCl, KCl, YbCl3·6H2O and ErCl3·6H2O were weighed in an agate mortar according to the molar ratio of 2:1:0.995:0.005, and an appropriate amount of anhydrous ethanol was added (enough to submerge all the weighed solids). The mixture was ground for 30 minutes, dried in a 60°C oven for 5 minutes, and then further ground into powder. The powder was poured into an alumina crucible, placed in a muffle furnace, heated to 350°C at a rate of 5°C / min, and calcined for 3 hours to obtain Cs2KYb 0.995 Cl6:0.5% Er phosphor.

[0025] Example 2

[0026] A rare earth 3+ Preparation of Cs2KYbCl6-doped phosphor materials:

[0027] CsCl, KCl, YbCl3·6H2O, and ErCl3·6H2O were weighed in an agate mortar according to a molar ratio of 2:1:0.99:0.01. An appropriate amount of anhydrous ethanol was added (enough to submerge all the weighed solids). The mixture was ground for more than 35 minutes, dried in a 60°C oven for 7 minutes, and then further ground into powder. The powder was poured into an alumina crucible, placed in a muffle furnace, heated to 350°C at a rate of 5°C / min, and calcined for 3 hours to obtain Cs2KYb 0.99 Cl6:1% Er phosphor.

[0028] Example 3

[0029] A rare earth 3+ Preparation of Cs2KYbCl6-doped phosphor materials:

[0030] CsCl, KCl, YbCl3·6H2O and ErCl3·6H2O were weighed in an agate mortar according to the molar ratio of 2:1:0.97:0.03, and an appropriate amount of anhydrous ethanol was added (enough to submerge all the weighed solids). The mixture was ground for 40 minutes, dried in a 60°C oven for about 3 minutes, and then further ground into powder. The powder was poured into an alumina crucible and calcined in a muffle furnace at 350°C for 3 hours at a heating rate of 5°C / min to obtain Cs2KYb 0.97 Cl6:3% Er phosphor.

[0031] Example 4

[0032] A rare earth 3+ Preparation of Cs2KYbCl6-doped phosphor materials:

[0033] CsCl, KCl, YbCl3·6H2O and ErCl3·6H2O were weighed in an agate mortar according to the molar ratio of 2:1:0.95:0.05, and an appropriate amount of anhydrous ethanol was added (to cover all the weighed solids). The mixture was ground for 30 minutes, dried in a 60°C oven for 5 minutes, and then ground into powder. The powder was poured into an alumina crucible, placed in a muffle furnace, heated to 350°C at a rate of 5°C / min, and calcined for 3 hours. The heating rate was 0.05, and the original Cs2KYb 0.95 Cl6:5% Er phosphor.

[0034] Comparative Example 1

[0035] Preparation method and application of Cs2KYbCl6 phosphor material

[0036] As a comparison, the difference between this comparative example and Example 1 is that rare earth Er is not doped. 3+ , the preparation steps are as follows:

[0037] CsCl, KCl, and YbCl3·6H2O were weighed in an agate mortar at a molar ratio of 2:1:1. An appropriate amount of anhydrous ethanol was added (enough to submerge all the weighed solids). The mixture was ground for 30 minutes, dried in a 60°C oven for 5 minutes, and then further ground into powder. The powder was poured into an alumina crucible, placed in a muffle furnace, heated to 350°C at a rate of 5°C / min, and calcined for 3 hours to obtain Cs2KYbCl6 phosphor.

[0038] Comparative Example 2

[0039] A rare earth 3+ Preparation of Cs2NaYbCl6-doped phosphor materials

[0040] CsCl, NaCl, YbCl3·6H2O and ErCl3·6H2O were weighed in an agate mortar according to the molar ratio of 2:1:0.97:0.03, and an appropriate amount of anhydrous ethanol was added (enough to submerge all the weighed solids). The mixture was ground for 30 minutes, dried in a 60°C oven for 5 minutes, and then further ground into powder. The powder was poured into an alumina crucible, placed in a muffle furnace, heated to 350°C at a rate of 5°C / min, and calcined for 3 hours to obtain Cs2NaYb 0.97 Cl6:3% Er phosphor.

[0041] Performance Testing

[0042] The materials prepared in Examples 1 to 4 and Comparative Example 1 were subjected to relevant performance tests. First, the prepared materials were subjected to X-ray diffraction analysis. The results are as follows: Figure 1 As shown in the figure, it can be seen that the samples synthesized with different Er doping concentrations are all pure phases, and changing the conditions and doping concentrations does not affect their phase purity.

[0043] The materials prepared in Examples 1 to 4 and Comparative Example 1 were subjected to room temperature spectral analysis under 980 nm and 365 nm excitation. The results are as follows: Figure 2 As shown in the figure, it can be seen that Er doped 3+ The characteristic emission peak of Er appears after the ions, and the luminescence intensity first increases and then decreases with the increase of doping concentration. In Example 3, the up-conversion luminescence is the strongest when the doping concentration is 3%, and in Example 4, the down-conversion luminescence is the strongest when the doping concentration is 5%.

[0044] The material prepared in Example 3 was subjected to temperature-dependent emission spectroscopy analysis under 980 nm light excitation. The results are as follows: Figure 3 As shown in the figure, it can be seen that under 980nm light excitation, the material prepared in Example 3 shows stable luminescence performance as the temperature increases.

[0045] The material prepared in Example 4 was subjected to temperature-dependent emission spectroscopy analysis under 365 nm light excitation. The results are as follows: Figure 4 As shown in the figure, it can be seen that the emission intensity at 657 nm increases monotonically, and its fluorescence lifetime also changes with temperature. This correlation between lifetime and temperature is conducive to fluorescence temperature measurement based on fluorescence lifetime.

[0046] The temperature-dependent emission spectrum of the material prepared in Comparative Example 2 under 980nm light excitation was analyzed. The results are as follows: Figure 5As shown in the figure, it can be seen that as the temperature increases from 333K to 573K, the up-conversion 524nm emission intensity is proportional to the temperature, resulting in resistance to thermal quenching. At the same time, the temperature-dependent emission spectrum of the material prepared in Comparative Example 2 under 365nm light excitation is analyzed, and it is found that the luminescence intensity of the material prepared in Comparative Example 2 does not increase with increasing temperature.

[0047] The material prepared in Example 3 was fitted with a sensitivity factor based on fluorescence intensity and lifetime, and the results were as follows: Figure 6 As shown in the figure, it can be seen that the relative sensitivity (Sr) based on fluorescence intensity is the maximum value of 1.20% K at 333 K. -1 The absolute sensitivity (Sa) is 15.05% K at 493K. -1 The relative sensitivity (Sr) based on fluorescence lifetime is 1.31% K at 333 K. -1 The absolute sensitivity (Sa) is 3.70μsK at 493K. -1 .

[0048] The material prepared in Example 3 was subjected to anti-counterfeiting application under 980nm and 365nm excitation, and the results were as follows: Figure 7 As shown, under different excitation modes, the samples emit completely different colors, which provides anti-counterfeiting application potential for the phosphor provided by the present invention.

Claims

1. A rare earth Er 3+ Doped Cs2KYbCl6 phosphor material, characterized by: Its chemical formula is: Cs2KYb (1-x) Cl6:xEr, where 0.005≤x≤0.

05.

2. The rare earth Er according to claim 1 3+ The preparation method of the doped Cs2KYbCl6 phosphor material comprises the following steps: firstly, weighing the corresponding CsCl, KCl, YbCl3·6H2O and ErCl3·6H2O according to the molar ratio in the chemical formula, adding anhydrous ethanol and grinding, then drying the anhydrous ethanol, taking it out and further grinding it into powder, and finally calcining the powder to obtain white Cs2KYb (1-x) Cl6:Er phosphor.

3. Rare earth Er according to claim 2 3+ The preparation method of doped Cs2KYbCl6 phosphor material is characterized by: The grinding time after adding anhydrous ethanol is 25 to 35 minutes.

4. The rare earth Er according to claim 2 3+ The preparation method of doped Cs2KYbCl6 phosphor material is characterized by: The calcination conditions are calcination at 350-390° C. for 2-3 hours and a heating rate of 4-7° C. / min.

5. The rare earth Er according to claim 1 3+ Application of doped Cs2KYbCl6 phosphor in the preparation of high-temperature temperature sensing materials.

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