Red gallate fluorescent powder as well as preparation method and application thereof

Abstract

The invention discloses red gallate fluorescent powder and a preparation method and application thereof.The chemical formula of the fluorescent powder is Gd3-xGaO6: xEu < 3 + >, x is 0.05, 0.1, 0.2, 0.3, 0.4 and 0.5, and the preparation method comprises the steps that Gd2O3, Ga2O3 and Eu2O3 are mixed, and absolute ethyl alcohol is added for grinding; and heating the ground powder to 1350 DEG C at a rate of 5 DEG C / min in an air atmosphere, sintering, preserving heat, cooling to 800 DEG C at a rate of 5 DEG C / min, naturally cooling, and grinding into powder to obtain the fluorescent powder. The problems that in the prior art, the preparation process is complex, and non-air atmosphere sintering is needed are solved. A high-temperature solid-phase synthesis method is adopted, material preparation is simple, the period is short, the cost is low, inert atmosphere or reducing atmosphere treatment is not needed, and the prepared stress luminescence fluorescent powder is good in chemical stability and not prone to deliquescence. And a red stress luminescence phenomenon can be generated under mechanical stimulation.

Description

Technical Field

[0001] The present invention relates to a stress luminescent material, in particular to a red gallate phosphor and a preparation method and application thereof. Background Art

[0002] Mechanoluminescence (ML) refers to the phenomenon in which a material, through its own physical structural properties, directly converts mechanical stimuli (such as shear, torsion, ultrasonic vibration, fluid impact, etc.) into visible light radiation, without relying on external power supply or circuit system support. As a new energy conversion technology, mechanoluminescence has shown unique application value in flexible electronic skin, structural health monitoring, intelligent sensing, biomedical testing, and self-powered displays. This zero-power, all-solid-state luminescence mechanism not only breaks through the technical bottleneck of traditional photoelectric conversion, but also provides innovative solutions for building environmentally friendly intelligent sensing systems. In recent years, it has become a research hotspot in the field of advanced functional materials.

[0003] Rare earth ion doped luminescent materials have become a research hotspot in the field of optoelectronic functional materials due to their high luminescence efficiency, excellent thermal stability and environmentally friendly properties. This type of material produces controllable luminescence through electronic transitions between rare earth ion energy levels, realizes high-density information encoding in optical data storage, builds energy-saving light sources in the field of LED lighting, and is used in currency anti-counterfeiting and intelligent optical temperature sensing through special spectral characteristics. In recent years, with the urgent demand for high-efficiency phosphors in solid-state lighting technology, and the innovative application of optical amplifiers and photonic crystals in the field of communications, especially the expectation of new labeling materials in biomedical imaging and detection, the energy level engineering design and luminescence mechanism research of rare earth ion doping systems continue to deepen, driving the rapid development of this material system towards intelligence and multifunctionality. Due to Eu 3+ The 4f electron layer properties can provide higher color purity and other characteristics, and have become common doping ions, such as: Y2Zr2O7: Bi 3+ / Eu 3+ ,Ca3Lu2Ge3O 12 :Bi 3+ ,Eu 3+ , Sr9Gd2W4O 24 :Dy 3+ / Eu 3+ , NaLnTe2O7:Eu 3+ (Ln=Y and Gd) etc.

[0004] At present, the colors of stress luminescent materials have covered the entire visible spectrum. Red light is the color that is most easily captured by the human eye, but the research on red stress luminescent materials is still in its early stages. 3+ doping[J].Materials Research Bulletin,2021,145:111535) published GaLaAl3O:Tb 3+ Phosphor has a strong mechanical luminescence intensity and is a stress luminescent material with excellent performance. However, the material preparation conditions are complex and require sintering in a nitrogen atmosphere, which is costly. In addition, the preparation process produces toxic substances that are harmful to the human body and are not environmentally friendly. 2+ ,Dy 3+ in an elastic domain[J].Measurement Science and Technology,2019,30(7):75104-75104) disclosed SrAl2O4:Eu 2+ ,Dy 3+ It has strong stress luminescence intensity and can be mixed with polydimethylsiloxane (PDMS) to prepare SrAl2O4:Eu 2+ ,Dy 3+ Fluorescent flexible films, however, have a complex preparation process, a long preparation cycle, require sintering in a reducing carbon atmosphere, and are expensive to prepare. The resulting phosphors are prone to deliquesce and difficult to preserve. Therefore, the existing technology has a complex preparation process and requires sintering in a non-air atmosphere. Summary of the Invention

[0005] The purpose of the present invention is to provide a red gallate phosphor and its preparation method and application, which solves the problem of the prior art that the preparation process is complicated and requires sintering in a non-air atmosphere.

[0006] In order to achieve the above object, the present invention provides a red gallate phosphor, the chemical formula of which is Gd 3-x GaO6:xEu 3+ , where x is 0.05~0.5.

[0007] Preferably, x is 0.05, 0.1, 0.2, 0.3, 0.4, or 0.5.

[0008] More preferably, the x is 0.1. 3+ As the doping amount increases, it first increases and then decreases. When x is 0.1, the brightness is the maximum. When x is 0.05 or 0.2, the brightness of the phosphor is slightly lower than that of the phosphor when x is 0.1.

[0009] The present invention provides a method for preparing the red gallate phosphor as described above, the method comprising:

[0010] (1) Mix Ga2O3, Gd2O3, and Eu2O3, add anhydrous ethanol and grind to obtain a uniformly ground powder;

[0011] (2) In an air atmosphere, the uniformly ground powder was heated to 1350°C at a rate of 5°C / min, sintered and held, then cooled to 800°C at a rate of 5°C / min, and then naturally cooled to obtain a sintered product;

[0012] (3) Grind the sintered product into powder to obtain phosphor powder.

[0013] Preferably, in step (1), the molar ratio of Ga2O3, Gd2O3, and Eu2O3 is (6-2x):2:x, where x is 0.05 to 0.5. The molar ratio is the most important influencing factor. If the molar ratio is other than this, the phosphor material cannot be obtained.

[0014] Preferably, in step (1), the purity of the Ga2O3, Gd2O3, and Eu2O3 is 99.99%; the purity of the anhydrous ethanol is 99.5%; and the grinding time is 30 to 60 minutes. Too low a purity of the reactants will result in an impure product, while too short a grinding time will result in uneven mixing of the raw materials and may also produce an impure product.

[0015] The purity of the reactants, grinding time, sintering temperature and holding time are all important influencing factors.

[0016] Preferably, in step (2), the holding time is 6 to 8 hours. If the holding time is too short or too long, it will lead to incomplete or excessive crystallization, and the brightness of the stress luminescence of the obtained material will be unsatisfactory.

[0017] Preferably, in step (2), the sintering temperature is 1350°C.

[0018] The present invention provides an application of the red gallate phosphor described above in preparing stress luminescent materials.

[0019] Preferably, the prepared stress luminescent material can produce red stress luminescence phenomenon under mechanical stimulation.

[0020] The present invention discloses a red gallate phosphor, a preparation method, and an application thereof. This solves the problem of the prior art, which involves a complex preparation process and requires sintering in a non-air atmosphere, and has the following advantages:

[0021] 1. The present invention is doped with rare earth ions Eu 3+ Entering into the Gd3GaO6 matrix lattice, Eu 3+ Replace Gd 3+ The doped phosphor will produce red stress luminescence under mechanical stimulation. Red is the color that is most easily captured by the human eye.

[0022] 2. The present invention adopts a high-temperature solid-phase synthesis method, which has simple material preparation, short cycle, low cost, and does not require inert atmosphere or reducing atmosphere treatment. The stress luminescent phosphor prepared has good chemical stability and is not easy to deliquesce. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ XRD pattern of phosphor.

[0024] Figure 2 Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ Excitation spectrum of phosphor.

[0025] Figure 3 Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ Emission spectrum of phosphor under 261nm excitation.

[0026] Figure 4 The Gd prepared in Example 2 of the present invention 2.90 GaO6:0.1Eu 3+ Stress luminescence spectrum of phosphor.

[0027] Figure 5 Gd prepared in Example 7 and Example 8 of the present invention 2.90 GaO6:0.1Eu 3+ XRD pattern of phosphor.

[0028] Figure 6 Gd prepared in Example 7 and Example 8 of the present invention 2.90 GaO6:0.1Eu 3+ ML spectrum of phosphor.

[0029] Figure 7 These are luminescence images of the materials prepared in Example 2 of the present invention and Comparative Examples 1-2 under a tensile force of 5N. DETAILED DESCRIPTION

[0030] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0031] Example 1

[0032] A red gallate phosphor Gd 2.95 GaO6:0.05Eu 3+ A preparation method comprising:

[0033] (1) 1.6783 g of Gd2O3 (purity of 99.99%), 0.2941 g of Ga2O3 (purity of 99.99%), and 0.0276 g of Eu2O3 (purity of 99.99%) weighed according to the stoichiometric ratio were placed in an agate mortar, and 10 mL of anhydrous ethanol (purity of 99.95%, the amount of anhydrous ethanol added should not exceed the raw materials to ensure that the raw materials are fully mixed) was added and ground for 30 to 60 minutes to obtain a uniformly ground powder.

[0034] (2) The evenly ground powder was placed in a corundum crucible, dried in an oven at 50°C for 30 min, placed in a muffle furnace, heated to 1350°C at a rate of 5°C / min and kept at this temperature for 8 h, then cooled to 800°C at a rate of 5°C / min, and then cooled naturally.

[0035] (3) The cooled sintered product was placed in an agate mortar and ground (10 min) into powder to obtain phosphor powder.

[0036] Example 2

[0037] A red gallate phosphor Gd 2.90 GaO6:0.1Eu 3+ The preparation method is basically the same as that of Example 1, except that:

[0038] In step (1), the mass of Gd2O3 was adjusted to 1.6506 g, the mass of Ga2O3 was adjusted to 0.2943 g, and the mass of Eu2O3 was adjusted to 0.0552 g.

[0039] Example 3

[0040] A red gallate phosphor Gd 2.80GaO6:0.2Eu 3+ The preparation method is basically the same as that of Example 1, except that:

[0041] In step (1), the mass of Gd2O3 was adjusted to 1.5950 g, the mass of Ga2O3 was adjusted to 0.2945 g, and the mass of Eu2O3 was adjusted to 0.1106 g.

[0042] Example 4

[0043] A red gallate phosphor Gd 2.70 GaO6:0.3Eu 3+ The preparation method is basically the same as that of Example 1, except that:

[0044] In step (1), the mass of Gd2O3 was adjusted to 1.5393 g, the mass of Ga2O3 was adjusted from 0.2948 g to 0.2143 g, and the mass of Eu2O3 was adjusted to 0.1660 g.

[0045] Example 5

[0046] A red gallate phosphor material Gd 2.60 GaO6:0.4Eu 3+ The preparation method is basically the same as that of Example 1, except that:

[0047] In step (1), the mass of Gd2O3 was adjusted to 1.4835 g, the mass of Ga2O3 was adjusted to 0.2950 g, and the mass of Eu2O3 was adjusted to 0.2215 g.

[0048] Example 6

[0049] A red gallate phosphor Gd 2.50 GaO6:0.5Eu 3+ The preparation method is basically the same as that of Example 1, except that:

[0050] In step (1), the mass of Gd2O3 was adjusted to 1.4276 g, the mass of Ga2O3 was adjusted to 0.2952 g, and the mass of Eu2O3 was adjusted to 0.2772 g.

[0051] Example 7

[0052] A red gallate phosphor Gd 2.90 GaO6:0.1Eu 3+ The preparation method is basically the same as that of Example 1, except that:

[0053] In step (3), the holding temperature is adjusted from 1350°C to 1200°C.

[0054] Example 8

[0055] A red gallate phosphor Gd 2.90 GaO6:0.1Eu 3+ The preparation method is basically the same as that of Example 1, except that:

[0056] In step (3), the holding temperature is adjusted from 1350°C to 1450°C.

[0057] Comparative Example 1

[0058] Understanding the mechanoluminescent mechanisms of manganese dopedzinc sulfide based on load effects in preparation of doped ZnS:Mn 2+ Phosphor, the method comprising:

[0059] (1) According to the stoichiometric ratio, weigh 0.9518g of ZnS (≥99.99%), 2.0719g of MnCl2·4H2O (≥ 99.0%), 0.18g of MgCl2·6H2O (≥98.0%) and 0.27g of NaCl (≥99.5%) were used as flux, accounting for 15wt% of the raw materials, and the molar ratio of MgCl2·6H2O to NaCl was 2:3; the weighed raw materials were placed in an agate mortar and ground with anhydrous ethanol until fully mixed;

[0060] (2) The mixture was placed in a corundum crucible and placed in a muffle furnace. The mixture was then sintered at 900 °C for 1 h under a nitrogen atmosphere and cooled to room temperature.

[0061] (3) The material was taken out and washed three times with deionized water to remove chloride, and then dried in an oven to obtain ZnS:Mn 2+ Phosphor.

[0062] Comparative Example 2

[0063] Intense and efficient green mechanoluminescence in GaLaAl3O7 throughTb 3+ Preparation of doped GaLaAl3O7:Tb in doping 3+ Phosphor, the method comprising:

[0064] (1) According to the stoichiometric ratio, 0.2691 g of CaCO3 (99.99%), 0.4381 g of La2O3 (99.99%), 0.4113 g of Al2O3 (99.99%), and 0.0050 g of Tb2O3 (99.99%) were weighed, and the weighed raw materials were placed in an agate mortar and anhydrous ethanol was added and ground until fully mixed.

[0065] (2) The mixture was transferred to a corundum crucible and placed in a muffle furnace. The mixture was kept warm for 5 h in a reducing atmosphere consisting of nitrogen and hydrogen (volume ratio of 90% N2 and 10% H2). After cooling to room temperature, the sample was taken out to finally obtain GaLaAl3O7:Tb 3+ .

[0066] Characterization of Examples 1 to 6

[0067] like Figure 1 As shown, the Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ XRD spectrum of the phosphor, wherein the horizontal axis is 2θ and the vertical axis is relative intensity; x=0.05 is the phosphor Gd prepared in Example 1 2.95 GaO6:0.05Eu 3+ ; x = 0.1 is the phosphor Gd obtained in Example 2 2.90 GaO6:0.1Eu 3+ ; x = 0.2 is the phosphor Gd obtained in Example 3 2.80 GaO6:0.2Eu 3+ ; x = 0.3 is the phosphor Gd obtained in Example 4 2.70 GaO6:0.3Eu 3+ ; x = 0.4 is the phosphor Gd obtained in Example 5 2.60 GaO6:0.4Eu 3+ ; x = 0.5 is the phosphor Gd obtained in Example 6 2.50 GaO6:0.5Eu 3+ .from Figure 1 It can be seen that the Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ The diffraction peaks of the phosphor correspond well to the standard card, indicating that Gd 3-x GaO6:xEu 3+ The phosphor is pure phase.

[0068] like Figure 2 As shown, the Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+Excitation spectrum of phosphor, where the horizontal axis is wavelength and the vertical axis is relative intensity; x=0.05 is the phosphor Gd prepared in Example 1 2.95 GaO6:0.05Eu 3+ ; x = 0.1 is the phosphor Gd obtained in Example 2 2.90 GaO6:0.1Eu 3+ ; x = 0.2 is the phosphor Gd obtained in Example 3 2.80 GaO6:0.2Eu 3+ ; x = 0.3 is the phosphor Gd obtained in Example 4 2.70 GaO6:0.3Eu 3+ ; x = 0.4 is the phosphor Gd obtained in Example 5 2.60 GaO6:0.4Eu 3+ ; x = 0.5 is the phosphor Gd obtained in Example 6 2.50 GaO6:0.5Eu 3+ .from Figure 2 It can be seen that the Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ The optimal excitation wavelength of the phosphor photoluminescence is 261nm.

[0069] like Figure 3 As shown, the Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ Emission spectrum of phosphor under 261nm excitation, where the horizontal axis is wavelength and the vertical axis is relative intensity; x=0.05 is the phosphor Gd prepared in Example 1 2.95 GaO6:0.05Eu 3+ ; x = 0.1 is the phosphor Gd obtained in Example 2 2.90 GaO6:0.1Eu 3+ ; x = 0.2 is the phosphor Gd obtained in Example 3 2.80 GaO6:0.2Eu 3+ ; x = 0.3 is the phosphor Gd obtained in Example 4 2.70 GaO6:0.3Eu 3+ ; x = 0.4 is the phosphor Gd obtained in Example 5 2.60 GaO6:0.4Eu 3+ ; x = 0.5 is the phosphor Gd obtained in Example 6 2.50 GaO6:0.5Eu 3+ .from Figure 3 It can be seen that the Gd prepared in Examples 1 to 6 of the present invention 3-x GaO6:xEu 3+ The emission spectrum of phosphor has six typical peaks, all of which correspond to Eu3+ The characteristic emission of Eu 3+ The increase of doping concentration of Eu first increases and then decreases. 3+ When the doping concentration is 0.1, the emission intensity of the material is the strongest.

[0070] like Figure 5 As shown, the Gd prepared in Examples 7 and 8 of the present invention 2.90 GaO6:0.1Eu 3+ XRD spectrum of the phosphor, wherein 1200°C is the sintering temperature of Example 7, and 1450°C is the sintering temperature of Example 8. Figure 5 It can be seen that when the holding time is 8 hours and the sintering temperature is 1200°C in Example 7, the sample obtained is not a pure phase; while when the sintering temperature is 1450°C in Example 8, the sample obtained is a pure phase.

[0071] like Figure 6 As shown, the Gd prepared in Examples 7 and 8 of the present invention 2.90 GaO6:0.1Eu 3+ ML spectrum of phosphor, where 1200℃ is the sintering temperature of Example 7, 1450℃ is the sintering temperature of Example 8, and 1350℃ is the sintering temperature of Example 2. Figure 6 It can be seen that the material prepared in Example 7 has no stress luminescence, and the stress luminescence intensity of the material prepared in Example 8 is much lower than that of the sample prepared at a sintering temperature of Example 2 (1350° C.).

[0072] Stress luminescence properties of the phosphor prepared in Example 2

[0073] Before characterizing the stress luminescence performance, a phosphor (the phosphor prepared in Example 2 or the material prepared in Comparative Example 1) and polydimethylsiloxanes A and B (both polydimethylsiloxanes A and B are polydimethylsiloxanes; neither A nor B alone will form a solid phase, but will solidify when mixed) in a mass ratio of 1.4:1.6:0.16 were poured into a small culture dish and stirred with a glass rod for 30 to 40 minutes until the mixture was uniform and bubble-free. The mixture was then poured into a dumbbell-shaped polytetrafluoroethylene mold and evenly spread. The mixture was then placed in a 60°C oven for 2 hours and demolded to obtain a stress luminescence material.

[0074] The materials of Comparative Example 1 and Example 2 of the present invention do not require pre-irradiation, and stress luminescence will occur when stress is directly applied. However, the materials of Comparative Example 2 require pre-irradiation to produce stress luminescence. If there is no pre-irradiation, no luminescence will occur when stress is applied.

[0075] Test and pre-irradiation steps of Comparative Example 2: SrAl2O4:Eu prepared in Comparative Example 2 2+ ,Dy 3+Phosphor was mixed with polydimethylsiloxane (PDMS) to prepare SrAl2O4:Eu 2+ ,Dy 3+ Fluorescent flexible film. Before testing, the material needs to be irradiated with a 385nm UV lamp for 5 minutes, then left for 3 minutes, and then stretched.

[0076] like Figure 4 As shown, the Gd prepared in Example 2 of the present invention 2.90 GaO6:0.1Eu 3+ The stress luminescence spectrum of the phosphor, where the horizontal axis is the wavelength and the vertical axis is the relative intensity. Figure 4 It can be seen that the Gd prepared in Example 2 of the present invention 2.90 GaO6:0.1Eu 3+ A new type of red gallate stress luminescent material Gd made from phosphor 2.90 GaO6:0.1Eu 3+ No radiation is required. When stretched (when stretching the elastomer, quantitative stretching is adopted to make the deformation of the elastomer 50%. When its deformation exceeds 50%, the elastomer is easy to break), it will emit dazzling red light, which is bright enough to be captured by the naked eye. It has self-recovery properties, and both the stress luminescence spectrum and the photoluminescence spectrum have typical emission peaks.

[0077] like Figure 7 As shown, the luminescence images of the materials prepared in Example 2 of the present invention and Comparative Examples 1-2 under a tensile force of 5N. Among them, a is the luminescence image of the material prepared in Example 2 under a tensile force of 5N; b is the luminescence image of the material prepared in Comparative Example 1 under a tensile force of 5N; c is the luminescence image of the material prepared in Comparative Example 2 under a tensile force of 5N. Figure 7 It can be seen that the color of the material prepared in Example 2 is red, the color of Comparative Example 1 is blue-green, and the color of Comparative Example 3 is green. The different colors produced by the materials prepared in Example 2 and Comparative Examples 1-2 are related to the matrix and doping elements of the materials. Different matrix and doping elements will lead to different luminescence centers, thereby emitting light of different wavelengths, resulting in different luminescence colors. Compared with Comparative Example 1, the defect of Comparative Example 1 is that it contains a sulfur source. The material of Example 2 of the present invention does not require sintering in a non-air atmosphere during the preparation process, and no toxic substances are released during the preparation process; compared with Comparative Example 2, the material of Example 2 of the present invention does not require sintering in a non-air atmosphere during the preparation process, and the prepared material can achieve stress luminescence under stress stimulation without irradiation with ultraviolet light.

[0078] Under the test conditions of Comparative Example 2, the stress luminescence phenomenon of the material prepared in Example 2 of the present invention does not change. Therefore, whether or not pre-irradiation is performed has no effect on the material prepared in Example 2 of the present invention.

[0079] Although the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description is not intended to limit the present invention. After reading the above description, various modifications and substitutions of the present invention will become apparent to those skilled in the art. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A red gallate phosphor, characterized in that: The chemical formula of this phosphor is Gd 3-x GaO6:xEu 3+ , where x is 0.05~0.

5.

2. The red gallate phosphor according to claim 1, characterized in that: The x is 0.05, 0.1, 0.2, 0.3, 0.4, or 0.

5.

3. The red gallate phosphor according to claim 2, characterized in that: The x is 0.

1.

4. A method for preparing the red gallate phosphor according to any one of claims 1 to 3, characterized in that: The method includes: (1) Mix Ga2O3, Gd2O3, and Eu2O3, add anhydrous ethanol and grind to obtain a uniformly ground powder; (2) In an air atmosphere, the uniformly ground powder was heated to 1350°C at a rate of 5°C / min, sintered and held, then cooled to 800°C at a rate of 5°C / min, and then naturally cooled to obtain a sintered product; (3) Grind the sintered product into powder to obtain phosphor powder.

5. The preparation method according to claim 4, characterized in that In step (1), the molar ratio of Gd2O3, Ga2O3 and Eu2O3 is (6-2x):2:x, wherein x is 0.05 to 0.

5.

6. The preparation method according to claim 4, characterized in that In step (1), the purity of Ga2O3, Gd2O3, and Eu2O3 is 99.99%; the purity of anhydrous ethanol is 99.5%; and the grinding time is 30 min to 60 min.

7. The preparation method according to claim 4, characterized in that In step (2), the insulation time is 8 hours.

8. The preparation method according to claim 4, characterized in that In step (2), the sintering temperature is 1350°C.

9. Use of the red gallate phosphor according to any one of claims 1 to 3 in preparing stress luminescent materials.

10. The use according to claim 9, characterized in that The prepared stress luminescent material produces red under mechanical stimulation.

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