Luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence and preparation method thereof

Abstract

The invention provides a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence and a preparation method of the luminescent material. The general chemical formula of the luminescent material is SrAl2O4: m% Eu-n% Dy-z% B4C, 0.001 < = m < = 10; 0.001 < = n < = 10; 0.125 < = z < = 5; m, n and z represent molar percentage contents. According to the invention, the stress luminescence and photoluminescence properties of the SrAl2O4-based luminescent material are enhanced by introducing a B4C inorganic compound and regulating and controlling the concentration of doped B4C, and the SrAl2O4-based luminescent material has huge potential for the commercial application value of a strontium aluminate material.

Description

Technical Field

[0001] The invention belongs to the technical field of inorganic luminescent materials, and in particular relates to a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence and a preparation method thereof. Background Art

[0002] Strontium aluminate (SrAl2O4) is an inorganic fluorescent material with excellent optical properties, widely used in luminous, stress luminescent and other optoelectronic materials. Its basic chemical formula is SrAl2O4, often doped with Eu 2+ and Dy 3+ Rare earth elements such as strontium aluminate can significantly improve its luminescence performance. Strontium aluminate has a significant long afterglow effect. Even after the light source disappears, it can continue to glow for several hours. It has excellent luminescence brightness and long-term light persistence.

[0003] Due to the long afterglow characteristics of strontium aluminate, it has mature commercial applications in the following fields: Lighting field: strontium aluminate phosphor is widely used in fluorescent lamps, which can efficiently convert ultraviolet light into visible light; strontium aluminate phosphor can also be used as a laser medium for solid-state lasers to provide efficient laser output. Safety signs and emergency instructions: Strontium aluminate can be made into emergency evacuation signs, fire equipment signs, traffic signs, etc., which can provide good visibility even in power outages or low light at night. Decorations: Strontium aluminate can also be used to make various decorations, such as luminous stickers, luminous toys and luminous watches. Sports equipment: Strontium aluminate can be used to make luminous sports shoes, sportswear, etc., and its long-term luminous effect enhances the visibility of night sports and improves the safety of night travel.

[0004] Although strontium aluminate is well known for its long afterglow characteristics, its stress luminescence characteristics have also received widespread attention in recent years, making its application prospects and development space broader. Stress luminescence (Mechanoluminescence, referred to as ML) refers to the phenomenon of dynamic optical response of materials when subjected to mechanical forces such as tension, compression, bending and friction. Compared with traditional electroluminescence, photoluminescence and chemiluminescence, stress luminescence can directly convert the mechanical energy of an object into light energy, and is a new type of luminescence.

[0005] At present, the research on the stress luminescence properties of strontium aluminate includes: Japan's National Institute of Advanced Industrial Science and Technology reported the use of SrAl2O4:Eu 2+ (SAOE) powder and epoxy resin form an ML sensor that visualizes the dynamic strain distribution and fracture phenomenon of carbon fiber reinforced plastic composites during tensile tests. Lanzhou Institute of Chemical Physics reported the use of SrAl2O4:Eu 2+ ,Dy 3+(SAOED) is compounded with commercial denture base resin (DBR). ML can be directly observed from the constructed standard oral model, and occlusal mechanics can be detected from the artificial tooth occlusal examination, guiding clinicians to purposefully treat the occlusal surface to achieve occlusal balance. Kyungpook National University reported the development of an integrated system that combines a SAOED-based ML module to detect the exact location of the crack tip and introduces a plastic stress intensity factor (PSIF) to assess the severity of existing cracks. The system also includes dual artificial intelligence modules, generative adversarial networks (GAN) and convolutional neural networks (CNN), as well as finite element method (FEM) simulations, which can provide reference results of PSIF for comparative verification. The system is capable of on-site structural health monitoring and instant verification. The Shenzhen University applicant team reported that ML speed bumps were made using SAOED composite materials. When vehicles pass by, bright luminous traces will appear, and the long afterglow effect of SAOED plays a good warning role; the team also compounded SAOED powder with PDMS to make a new type of artificial green turf, which produces a bright afterglow when pressed with fingers or feet and decays slowly. Applicants from Shenzhen University also reported that they have used the characteristics of stress luminescent materials such as strontium aluminate in many products and applied for many patents, such as the invention patent for stress luminescent carpet and its preparation method: CN202010928312.4; the invention patent for composite lawn and sermon based on sensitive stress luminescent materials and their preparation method: CN202110774482.6. The above patented products have the advantages of not requiring an external power supply, luminescing when under pressure, being safe and environmentally friendly, and being able to visualize a person's walking trajectory. This shows that strontium aluminate has broad application prospects and huge potential in the field of stress luminescence.

[0006] According to a Business Research report, the global fluorescent pigment market size was $380 million in 2023 and is expected to reach $870 million by 2032, with a compound annual growth rate of 9.5% during the forecast period, of which strontium aluminate fluorescent materials accounted for a significant share. In addition, the stress luminescence properties of strontium aluminate are receiving more and more attention, and its application prospects are expected to expand further, and the market value will also rise accordingly.

[0007] Although strontium aluminate has a broad industrial base as a mature commercial phosphor, with the advancement of science and technology and the increase in application needs, SAOED materials have also exposed some shortcomings: people have always had a demand for stronger luminous brightness. Higher luminous brightness can enhance the recognition and visibility of strontium aluminate materials, and meet the needs of fields such as high-precision stress measurement and monitoring, thereby broadening its scope of application. Although methods such as adding doping chemicals can improve the luminous brightness of materials to a certain extent, excessive dopants may cause problems such as unstable material structure and luminous position offset. There are currently many manufacturers producing strontium aluminate. Improving the luminescent performance of strontium aluminate can help it stand out in the fierce market competition, and research and development of strontium aluminate materials can also promote the increase of its market value.

[0008] In summary, the problems existing in the prior art are: phosphor SrAl2O4:Eu 2+ ,Dy 3+ Stronger stress luminescence brightness and photoluminescence brightness are needed to meet the growing market demand. Adding dopants to enhance the luminescence intensity will not cause structural instability of the strontium aluminate material or displacement of the luminescence position. Summary of the invention

[0009] In order to improve the stress luminescence and photoluminescence performance of strontium aluminate phosphor without changing its luminescence position, the present invention provides a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence, wherein the chemical general formula of the luminescent material is: SrAl2O4:m%Eu-n%Dy-z%B4C, wherein m%Eu represents that the doping amount of Eu is the molar percentage of SrAl2O4:m%Eu-n%Dy, n%Dy represents that the doping amount of Dy is the molar percentage of SrAl2O4:m%Eu-n%Dy, and z%B4C represents that the doping amount of B4C is the molar percentage of SrAl2O4:m%Eu-n%Dy;

[0010] Among them, 0.001≤m≤10, 0.001≤n≤10, 0.125≤z≤5.

[0011] Another object of the present invention is to provide a method for preparing the above-mentioned luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence, comprising the following steps:

[0012] S1. Weighing raw materials according to the stoichiometric ratio of each element in the chemical formula of the luminescent material, placing the raw materials in a container, and adding water and / or an organic solvent into the container to obtain a mixed raw material after mixing;

[0013] S2, removing water and / or organic solvent from the mixed raw materials and separating to obtain solid components; placing the solid components in a reducing gas and calcining them at a temperature greater than or equal to 1000° C.;

[0014] S3. Take out the calcined sample to obtain a luminescent material that enhances SrAl2O4-based stress luminescence and photoluminescence.

[0015] Preferably, the raw material corresponding to Sr or Al includes at least one of oxides, hydroxides, chlorides, carbonates and nitrates corresponding to Sr or Al;

[0016] The raw material corresponding to Eu or Dy includes at least one of the oxide, chloride, carbonate and nitrate corresponding to Eu or Dy;

[0017] The raw material corresponding to B4C is B4C.

[0018] Preferably, the reducing gas comprises nitrogen and hydrogen or comprises argon and hydrogen;

[0019] The volume fraction of hydrogen in the reducing gas is 2-20%, and the rest is nitrogen or argon.

[0020] Preferably, the solid component is placed in a reducing gas and calcined at a temperature greater than or equal to 1000° C. Specifically, the process is as follows:

[0021] The solid component is placed in a reducing gas, heated from room temperature to 1000-1600°C at a rate of 1-20°C / min, and calcined at this temperature for 1-12 hours.

[0022] Preferably, the organic solvent includes at least one of anhydrous ethanol and isopropanol.

[0023] Preferably, water and / or organic solvent are removed from the mixed raw materials, and a drying treatment is performed to separate and obtain a solid component; the drying includes at least one of hot air drying and vacuum drying.

[0024] Preferably, the equipment for heat-insulating and calcining the solid components includes any one of a rotary kiln, a high-temperature reduction furnace, and a muffle furnace.

[0025] Preferably, the calcined sample is taken out, crushed and sieved to obtain a luminescent material that enhances SrAl2O4-based stress luminescence and photoluminescence; wherein the crushing equipment includes any one of a ball mill and a hammer mill, and the screening equipment includes any one of a vibrating screen and a screen.

[0026] Preferably, the container comprises any one of a mortar, a mixer, and a ball mill.

[0027] The luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence and the preparation method thereof of the present invention have the following beneficial effects compared with the prior art:

[0028] The luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence of the present invention has a chemical formula of: SrAl2O4: m% Eu-n% Dy-z% B4C, 0.001≤m≤10, 0.001≤n≤10, 0.125≤z≤5, and SrAl2O4:Eu without B4C 2 + ,Dy 3+ Compared with conventional materials, the addition of B4C can significantly improve the stress luminescence and photoluminescence properties of strontium aluminate materials, without changing the luminescence position, and the change in brightness can be observed with the naked eye; compared with ordinary strontium aluminate powder, the luminescent material of the present invention has the characteristics of high brightness, high sensitivity, and fast response to force. It is expected to meet the needs of safety signs, structural health monitoring, sports equipment and other fields for stronger stress luminescence and photoluminescence properties, achieve a higher level of functionality and recognizability, and enhance user experience and satisfaction. It is also expected to stand out in the fiercely competitive market and meet the growing market demand for strontium aluminate fluorescent powder. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0030] Figure 1 A flow chart of a method for preparing a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence provided in an embodiment of the present invention;

[0031] Figure 2 The stress luminescence spectra of the stress luminescence materials provided in Examples 1 to 7 and Comparative Example 1 of the present invention under an applied stress of 30N;

[0032] Figure 3 The integrated intensity graph is obtained by integrating the 400-750nm band after obtaining the stress luminescence spectrum graph of the stress luminescence materials provided in Examples 1 to 7 and Comparative Example 1 of the present invention;

[0033] Figure 4 This is an excitation spectrum diagram of the stress luminescent material provided in Examples 1 to 7 and Comparative Example 1 of the present invention at an absorption wavelength of 524 nm;

[0034] Figure 5 This is an emission spectrum diagram of the stress luminescent material provided in Examples 1 to 7 and Comparative Example 1 of the present invention at an excitation wavelength of 363 nm;

[0035] Figure 6After obtaining the emission spectrum of the stress luminescent materials provided in Examples 1 to 7 and Comparative Example 1 of the present invention at an excitation wavelength of 363 nm, an integrated intensity graph is obtained by integrating the wavelength range of 400 to 750 nm. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] In order to better understand the present invention but not to limit the scope of the present invention, all the numbers used in this application to express the amount, percentage, and other numerical values ​​should be understood as modified by the word "about" in all cases. Therefore, unless otherwise specified, the numerical parameters listed in the specification and the appended claims are approximate values, which may be changed according to the different ideal properties attempted to be obtained. Each numerical parameter should at least be regarded as obtained based on the reported significant figures and by conventional rounding methods.

[0038] It should be noted that the order of description of the following embodiments is not intended to limit the preferred order of the embodiments. In addition, in the description of the present application, the term "including" means "including but not limited to". Various embodiments of the present invention may be in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present invention; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the numbered range, such as 1, 2, 3, 4, 5 and 6, which applies regardless of the range. In addition, whenever a numerical range is indicated in this article, it is meant to include any cited numbers (fractions or integers) within the indicated range.

[0039] The present invention provides a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence, wherein the general chemical formula is: SrAl2O4: m%Eu-n%Dy-z%B4C, wherein m%Eu represents that the doping amount of Eu is the molar percentage of SrAl2O4: m%Eu-n%Dy, n%Dy represents that the doping amount of Dy is the molar percentage of SrAl2O4: m%Eu-n%Dy, and z%B4C represents that the doping amount of B4C is the molar percentage of SrAl2O4: m%Eu-n%Dy;

[0040] Among them, 0.001≤m≤10, 0.001≤n≤10, 0.125≤z≤5.

[0041] Another object of the present invention is to provide a method for preparing the above-mentioned luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence, comprising the following steps:

[0042] S101, weighing raw materials according to the stoichiometric ratio of each element in the chemical formula of the luminescent material, placing the raw materials in a container, adding water and / or an organic solvent into the container, and mixing to obtain a mixed raw material;

[0043] S102, removing water and / or organic solvent from the mixed raw materials and separating to obtain a solid component; placing the solid component in a reducing gas and calcining it at a temperature greater than or equal to 1000° C.;

[0044] S103. Take out the calcined sample to obtain a luminescent material that enhances SrAl2O4-based stress luminescence and photoluminescence.

[0045] Specifically, Figure 1 As shown, the preparation method for enhancing SrAl2O4-based stress luminescence and photoluminescence provided by the embodiment of the present invention comprises the following steps:

[0046] S101, selecting raw materials, wherein Sr and Al are in the form of oxides, hydroxides, chlorides, carbonates, nitrates, etc.; Eu is in the form of oxides, chlorides, carbonates, nitrates, etc., the molar percentage of Eu in SrAl2O4:m%Eu-n%Dy is m%, 0.001≤m≤10; Dy is in the form of oxides, chlorides, carbonates, nitrates, etc., the molar percentage of Dy in SrAl2O4:m%Eu-n%Dy is n%, 0.001≤n≤10; the doping amount of B4C is in the form of SrAl2O4:m%Eu-n%Dy, the molar percentage is z%, 0.125≤z≤5; weighing raw materials of each element according to the stoichiometric ratio and pouring them into a container; adding an appropriate amount of water and / or an organic solvent to the mixed raw materials, and mixing them thoroughly and evenly in the container;

[0047] S102, removing water and / or organic solvent from the obtained uniformly mixed raw materials, performing drying, purification and other treatments as needed, thereby separating solid components; placing the obtained solid components in a reducing atmosphere and calcining them at a temperature above 1000° C.;

[0048] S103, taking out the calcined sample, and performing operations such as crushing and screening as needed, thereby obtaining the doped SrAl2O4-based semiconductor stress luminescent material of the present invention.

[0049] In some embodiments, in step S101, the raw materials used to prepare strontium aluminate include Sr and Al in the form of their oxides, hydroxides, chlorides, carbonates, nitrates, etc.; Eu and Dy in the form of their oxides, chlorides, carbonates, nitrates, etc., and B4C is an inorganic compound; for example, the raw material corresponding to Sr is SrCO3, the raw material corresponding to Al is Al2O3, the raw material corresponding to Eu is Eu2O3, and the raw material corresponding to Dy is DyCl3.

[0050] In some embodiments, in step S101, the container can be any container with a stirring function capable of mixing raw materials without any special requirements, such as a mortar, a mixer, a ball mill, etc.

[0051] In some embodiments, in step S101, the water and / or organic solvent used to mix the raw materials uniformly is not particularly limited, and for example, deionized water, anhydrous ethanol, isopropanol, etc. can be used.

[0052] In some embodiments, in step S102, there are no special requirements for drying and purification treatments, for example, drying can be performed by hot air drying, vacuum drying, etc.; purification can be performed by filtering to remove impurities.

[0053] In some embodiments, in step S102, the mixed raw material is calcined in a reducing gas, and the reducing gas is not particularly limited. For example, a reducing gas including nitrogen and hydrogen or a reducing gas including argon and hydrogen can be used. The volume fraction of nitrogen or argon in the reducing gas is 80-98%, and the corresponding volume fraction of hydrogen gas is 20-2%.

[0054] In some embodiments, in step S102, there is no particular limitation on the machine for calcining the mixed raw materials, for example, a rotary kiln, a high-temperature reduction furnace, a muffle furnace, etc. may be used; taking muffle furnace calcination as an example, the calcination is specifically as follows: heating from room temperature (25°C) to 1000-1600°C at a rate of 1-20°C / min, and calcining at this temperature for 1-12 hours.

[0055] In some embodiments, in step S103, the calcined sample is taken out, and as the content of B4C added increases, the color of strontium aluminate gradually changes from light yellow to yellow-green, and the hardness also gradually increases.

[0056] In some embodiments, in step S103, there is no particular limitation on the machine used for crushing and screening, for example, a ball mill, a hammer mill, a vibrating screen, etc. may be used; or the sample may be crushed in a mortar manually and then transferred to a sieve for screening.

[0057] The luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence prepared by the present invention can significantly improve the stress luminescence and photoluminescence properties of strontium aluminate materials compared with ordinary strontium aluminate powder, without changing its luminescence position, and the change in brightness can be observed by naked eyes.

[0058] The following further describes the luminescent material and preparation method of the enhanced SrAl2O4-based stress luminescence and photoluminescence of the present application with specific examples. This section further describes the content of the present invention in conjunction with specific examples, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the examples are conventional means well known to those skilled in the art. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the art.

[0059] Example 1

[0060] The present embodiment provides a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence, and the general chemical formula thereof is: SrAl2O4:m%Eu-n%Dy-z%B4C, wherein m%Eu represents that the doping amount of Eu is the molar percentage of SrAl2O4:m%Eu-n%Dy, n%Dy represents that the doping amount of Dy is the molar percentage of SrAl2O4:m%Eu-n%Dy, and z%B4C represents that the doping amount of B4C is the molar percentage of SrAl2O4:m%Eu-n%Dy;

[0061] Wherein, m=1, n=0.05, z=0.025;

[0062] The method for preparing the above-mentioned luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence comprises the following steps:

[0063] S101, weighing raw materials according to the stoichiometric ratio of each element in the chemical formula of the luminescent material, specifically, the raw materials are SrCO3, Al2O3, Eu2O3, DyCl3·6H2O, and B4C, the molar ratio of SrCO3, Al2O3, Eu2O3, DyCl3·6H2O and B4C is 98.95:100:0.5:0.05:0.025, and the corresponding mass of SrCO3 is 14.6080g, the mass of Al2O3 is 10.1960g, the mass of Eu2O3 is 0.1760g, the mass of DyCl3·6H2O is 0.0188g, and the mass of B4C is 0.0014g;

[0064] S102, pouring the mixed raw materials of the above formula into a container, adding 30 ml of anhydrous ethanol to the mixed raw materials, and mixing them evenly in the container; removing water and / or organic solvent from the obtained mixed raw materials, performing hot air drying treatment, thereby separating solid components; placing the obtained solid components in a crucible, passing a reducing gas containing 95% by volume of nitrogen and 5% by volume of hydrogen, heating from room temperature to 1000°C at a heating rate of 10°C / min, and then heating from 1000°C to 1400°C at a heating rate of 5°C / min, and calcining for 5 hours, and finally cooling naturally with the furnace;

[0065] S103, taking out the calcined sample, crushing and screening it, thereby obtaining the stress luminescent material SrAl2O4:Eu 2+ ,Dy 3+ ,B4C powder is a luminescent material that enhances SrAl2O4-based stress luminescence and photoluminescence.

[0066] Embodiments 2 to 7

[0067] The preparation method of the luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence provided in Examples 2 to 7 is the same as that in Example 1, except that the molar ratio and mass of the raw materials used are different. The molar ratio and mass of the raw materials used in Examples 1 to 7 are shown in Table 1 below. The preparation process of Examples 2 to 7 is the same as that of Example 1.

[0068] Table 1 - Molar ratios and raw material masses of the raw materials used in Examples 1 to 7

[0069]

[0070]

[0071] Among them, in Examples 2 to 7, m is 1, n is 0.05, and the z values ​​in Examples 2 to 7 are 0.125, 0.25, 0.5, 0.75, 1.25, and 1.75, respectively.

[0072] Comparative Example 1

[0073] This comparative example provides a SrAl2O4:Eu 2+ ,Dy 3+ The preparation method of the powder is the same as that of Example 1, except that B4C is not added during the preparation. The specific preparation method comprises the following steps:

[0074] S101, weighing raw materials according to the stoichiometric ratio of each element in the chemical formula of the luminescent material, specifically, the raw materials are SrCO3, Al2O3, Eu2O3, DyCl3·6H2O, and B4C, the molar ratio of SrCO3, Al2O3, Eu2O3, DyCl3·6H2O and B4C is 98.95:100:0.5:0.05:0, and the corresponding mass of SrCO3 is 14.6080g, the mass of Al2O3 is 10.1960g, the mass of Eu2O3 is 0.1760g, the mass of DyCl3·6H2O is 0.0188g, and the mass of B4C is 0g (i.e., no B4C is added);

[0075] S102, pouring the mixed raw materials of the above formula into a container, adding 30 ml of anhydrous ethanol to the mixed raw materials, and mixing them evenly in the container; removing water and / or organic solvent from the obtained mixed raw materials, performing hot air drying treatment, thereby separating solid components; placing the obtained solid components in a crucible, passing a reducing gas containing 95% by volume of nitrogen and 5% by volume of hydrogen, heating from room temperature to 1000°C at a heating rate of 10°C / min, and then heating from 1000°C to 1400°C at a heating rate of 5°C / min, and calcining for 5 hours, and finally cooling naturally with the furnace;

[0076] S103, taking out the calcined sample, crushing and screening it, thereby obtaining SrAl2O4:Eu 2+ ,Dy 3+ Powder.

[0077] The molar ratio and mass of the raw materials used in Comparative Example 1 are shown in Table 2 below.

[0078]

[0079] The stress luminescence integral intensity and photoluminescence integral intensity in Tables 1 to 2 above are the integral intensity data obtained by integrating the luminescent materials prepared in Examples 1 to 7 and Comparative Example 1 in the 400 to 750 nm band (i.e. Figure 3 ), and the emission spectrum at an excitation wavelength of 363 nm, the integrated intensity data obtained by integrating the 400-750 nm band (i.e. Figure 6 corresponding data).

[0080] Test analysis

[0081] Weigh the strontium aluminate powder material obtained in Examples 1 to 7 and Comparative Example 1, place it in a centrifuge tube, and add a small amount of light-curing UV glue, then add anhydrous ethanol, shake it evenly and pour it into a mold, and place it in an oven at 80 to 100°C to dry the anhydrous ethanol, then use a plastic sealing machine to thermoform the stress luminescent sheet required for the test, and test its stress luminescent performance.

[0082] Specifically, stress luminescence characteristic test: the prepared stress luminescence sheet is tested using a spectrometer-dynamometer-sliding motor. First, the prepared stress luminescence test sheet is attached to a high-transparent acrylic plate fixed vertically in a homemade stress luminescence test device, and the pressure applied by the sliding motor on the test sheet is set. Then the sliding motor is controlled to slide left and right perpendicular to the sheet. During the sliding process, the light emitted by the stress luminescence sheet will be collected and transmitted to the spectrometer through optical fiber, and finally the luminescence intensity of the collected stress luminescence material will be displayed on the computer. The test results are as follows: Figures 2-3 .

[0083] Figure 2 Schematic diagram of stress luminescence spectra of strontium aluminate luminescent materials with different doping ratios of B4C in Examples 1 to 7 and Comparative Example 1 under a stress of 30N. Figure 2 It can be seen that the emission wavelength of the material stress luminescence is about 524nm. Compared with comparative example 1, the stress luminescence performance is basically enhanced after adding B4C, and the luminescence position does not change.

[0084] Figure 3 The stress luminescence spectra of strontium aluminate luminescent materials with different doping ratios of B4C in Examples 1 to 7 and Comparative Example 1 are stress luminescence integrated intensity diagrams at 400 to 750 nm. By comparison, it can be found that Example 5 (SAOED doped with 0.75% B4C) has the strongest stress luminescence intensity at 30 N, which is about 349.92% of that in Comparative Example 1, as shown in Table 3.

[0085] Table 3 shows the growth of the integral intensity of the stress luminescence spectrum of the luminescent materials prepared in Examples 1 to 7 of the present invention compared with that of Comparative Example 1.

[0086] Table 3 - Growth of integrated intensity of stress luminescence spectra of luminescent materials prepared in Examples 1 to 7

[0087] Example Enhanced ratio Example 1 -26.62％ Example 2 17.14％ Example 3 86.41％ Example 4 258.39％ Example 5 349.92％ Example 6 255.69％ Example 7 188.56％

[0088] The Edinburgh FLS steady-state fluorescence spectrometer was used to test the strontium aluminate luminescent materials with different doping ratios of B4C obtained in Examples 1 to 7 and Comparative Example 1 to obtain their excitation spectra and emission spectra. Figures 4 to 6 .

[0089] Figure 4The excitation spectra of strontium aluminate luminescent materials with different doping ratios of B4C prepared in Examples 1 to 7 of the present invention and Comparative Example 1 at an absorption wavelength of 524 nm; Figure 5 The emission spectra of strontium aluminate luminescent materials with different doping ratios of B4C prepared in Examples 1 to 7 of the present invention and Comparative Example 1 at an excitation wavelength of 363 nm. Compared with Comparative Example 1, the photoluminescence performance is enhanced after adding B4C, and the luminescent position does not change; Figure 6 After the emission spectra of the strontium aluminate luminescent materials with different doping ratios of B4C prepared in Examples 1 to 7 of the present invention and Comparative Example 1 at an excitation wavelength of 363nm, the integrated intensity diagram is obtained by integrating the band of 400 to 750nm; by comparison, it can be found that the photoluminescence intensity of Comparative Example 1 (SAOED without B4C) is the lowest, and the photoluminescence intensities of other strontium aluminate powders doped with B4C are stronger than that of Comparative Example 1, among which Example 5 (SAOED doped with 0.75% B4C) has the highest photoluminescence intensity, which is about 22.35% of that of Comparative Example 1, as shown in Table 4.

[0090] Table 4 shows the growth of the integrated intensity of the photoluminescence emission spectra of the luminescent materials prepared in Examples 1 to 7 compared with the integrated intensity of the photoluminescence emission spectra of Comparative Example 1.

[0091] Table 4 - Growth of the integrated intensity of the photoluminescence emission spectra of the luminescent materials prepared in Examples 1 to 7

[0092] Example Enhanced ratio Example 1 6.68％ Example 2 2.03％ Example 3 19.43％ Example 4 15.6％ Example 5 22.35％ Example 6 15.04％ Example 7 13.55％

[0093] From the above test results, it can be seen that the overall stress luminescence intensity and photoluminescence intensity of the B4C-doped strontium aluminate powder prepared by the present invention are stronger than those of the strontium aluminate powder not doped with B4C, that is, compared with Comparative Example 1. The stress luminescence intensity of the luminescent material prepared in the best embodiment 5 is about 3.5 times stronger than that in Comparative Example 1, which can meet the requirements of structural health monitoring, transportation facilities, sports equipment and other fields for its stress luminescence intensity; and the photoluminescence intensity of the luminescent material prepared in the best embodiment 5 is also 22.35% stronger than that in Comparative Example 1, which can also better meet the market demand for the photoluminescence intensity of strontium aluminate phosphor. In general, the B4C-doped strontium aluminate powder shows strong market competitiveness.

[0094] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence, characterized in that: The chemical formula of the luminescent material is: SrAl2O4:m%Eu-n%Dy-z%B4C, wherein m%Eu represents the molar percentage of Eu doping amount of SrAl2O4:m%Eu-n%Dy, n%Dy represents the molar percentage of Dy doping amount of SrAl2O4:m%Eu-n%Dy, and z%B4C represents the molar percentage of B4C doping amount of SrAl2O4:m%Eu-n%Dy; Among them, 0.001≤m≤10, 0.001≤n≤10, 0.125≤z≤5.

2. A method for preparing a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence as claimed in claim 1, characterized in that: The following steps are involved: S1. Weighing raw materials according to the stoichiometric ratio of each element in the chemical formula of the luminescent material, placing the raw materials in a container, and adding water and / or an organic solvent into the container to obtain a mixed raw material after mixing; S2, removing water and / or organic solvent from the mixed raw materials and separating to obtain solid components; placing the solid components in a reducing gas and calcining them at a temperature greater than or equal to 1000° C.; S3. Take out the calcined sample to obtain a luminescent material that enhances SrAl2O4-based stress luminescence and photoluminescence.

3. The method for preparing the luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The raw material corresponding to Sr or Al includes at least one of oxides, hydroxides, chlorides, carbonates, and nitrates corresponding to Sr or Al; The raw material corresponding to Eu or Dy includes at least one of the oxide, chloride, carbonate and nitrate corresponding to Eu or Dy; The raw material corresponding to B4C is B4C.

4. The method for preparing the luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The reducing gas comprises nitrogen and hydrogen or argon and hydrogen; The volume fraction of hydrogen in the reducing gas is 2-20%, and the rest is nitrogen or argon.

5. The method for preparing the luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The solid component is placed in a reducing gas and calcined at a temperature greater than or equal to 1000°C. Specifically: The solid component is placed in a reducing gas, heated from room temperature to 1000-1600°C at 1-20°C / min, and calcined at this temperature for 1-12 hours.

6. The method for preparing the luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The organic solvent includes at least one of anhydrous ethanol and isopropanol.

7. The method for preparing a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The water and / or organic solvent in the mixed raw materials are removed, and a drying treatment is performed to separate and obtain a solid component; the drying includes at least one of hot air drying and vacuum drying.

8. The method for preparing a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The equipment for heat-insulating and calcining the solid components includes any one of a rotary kiln, a high-temperature reduction furnace, and a muffle furnace.

9. The method for preparing a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The calcined sample is taken out, crushed and sieved to obtain a luminescent material that enhances SrAl2O4-based stress luminescence and photoluminescence; wherein the crushing equipment includes any one of a ball mill and a hammer mill, and the screening equipment includes any one of a vibrating screen and a screen.

10. The method for preparing a luminescent material for enhancing SrAl2O4-based stress luminescence and photoluminescence according to claim 2, characterized in that: The container includes any one of a mortar, a mixer, and a ball mill.

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