Manganese ion doped calcium aluminate photoluminescence-free and afterglow-free stress luminescent material as well as preparation method and application thereof

Abstract

The invention belongs to the field of inorganic stress luminescent materials, and relates to a manganese ion doped calcium aluminate photoluminescence-free and afterglow-free stress luminescent material as well as a preparation method and application thereof. The chemical general formula of the material is Ca (1-x) Al2O4: xMn < 2 + >, wherein x is more than or equal to 0.5% and less than or equal to The ZnS: Cu < + > fluorescent powder does not generate photoluminescence under irradiation of ultraviolet to blue light, has no afterglow after excitation is stopped, can emit high-brightness green stress luminescence under mechanical stimulation, and has the strength superior to that of a commercial ZnS: Cu < + > material (1.5 times of that of the commercial ZnS: Cu < + > material). The afterglow-free characteristic can effectively avoid residual luminescence interference of a traditional material, and the detection accuracy and sensitivity are remarkably improved. The matrix is a core component of calcium aluminate cement, so that the material shows unique advantages which other stress luminescent materials do not have in the structural health field such as crack monitoring. By virtue of the characteristics of bright green luminescence and quick response, the material also shows wide application prospects in the fields of motion monitoring, mechanical visualization and the like.

Description

Technical Field

[0001] The present invention belongs to the field of inorganic stress luminescent materials, and in particular relates to a manganese ion-doped calcium aluminate stress luminescent material with no photoluminescence and no afterglow, as well as a preparation method and application thereof. Background Art

[0002] Mechanoluminescence is a special physical phenomenon in which a material emits light when it is mechanically stimulated. In recent years, with the development of smart materials and sensing technology, mechanoluminescence materials have been widely used in cutting-edge fields such as stress monitoring, mechanical energy conversion, structural health monitoring, and smart display. Compared with photoluminescent materials, the types of mechanoluminescence materials are still relatively limited. Research mainly focuses on doped ZnS systems (such as Cu + , Mn 2+ ), doped CaZnOS system (Mn 2+ ,Bi 3+ , Tb 3+ , Nd 3+ etc.), SrAl2O4:Eu 2+ ,Dy 3+ and CaF2:Eu 2+ More new stress-luminescent materials are still needed to be developed.

[0003] Most stress luminescent materials are doped trap-controlled materials. When excited by ultraviolet to blue light, part of the excitation energy of this type of material is released in the form of radiant luminescence (photoluminescence), while the other part is stored in the intrinsic defects of the material. After the excitation stops, the stored energy will be slowly released in the form of afterglow under the action of environmental thermal disturbances, and the duration varies from seconds to hours. At the same time, if mechanical stimulation is applied to the material, the stored energy can also be released in the form of stress luminescence. However, static afterglow and dynamic stress luminescence coexist, and the two are difficult to distinguish during detection. The residual afterglow interferes with the signal, significantly reducing the accuracy and sensitivity of the detection.

[0004] This patent proposes a new green stress luminescent material - CaAl2O4:Mn 2+ , which can effectively avoid the above problems. On the one hand, the luminescence center Mn 2+ The ions undergo forbidden transitions in the CaAl2O4 matrix, and do not produce photoluminescence under ultraviolet to blue light excitation, indicating that all the excitation energy is stored in the material, giving it extremely high stress luminescence intensity. On the other hand, the material has no afterglow after the excitation stops, significantly reducing background interference. Experiments have shown that the material is sensitive to mechanical stimulation, with a low mechanical response threshold (about 1N can be triggered), and the stress luminescence intensity shows an excellent linear relationship with the external force in the range of 0 to 50N (R 2=0.998), making it suitable for high-precision dynamic stress monitoring. This material has broad application prospects in fields such as motion monitoring and mechanical visualization.

[0005] In addition, since CaAl2O4 is the core component of calcium aluminate cement, the prepared CaAl2O4:Mn 2+ The material can be further processed into cement or ceramics, thereby demonstrating engineering adaptability and advantages that other stress-luminescent materials do not have in structural health monitoring scenarios such as crack detection. Summary of the Invention

[0006] In response to the shortcomings of the existing technology, the present invention provides a manganese ion-doped calcium aluminate stress luminescent material with no photoluminescence and no afterglow, as well as a preparation method and application thereof. The stress luminescent material prepared in the present invention has almost no photoluminescence under ultraviolet to blue light irradiation, and no continuous afterglow when the irradiation is stopped. When mechanical action is applied, it has a bright green stress luminescent response. It is sensitive to mechanical stimulation and has a low mechanical response threshold. It can be used to detect building cracks or monitor motion.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] Manganese ion doped calcium aluminate non-photoluminescent, non-afterglow stress luminescent material, the chemical formula of the stress luminescent material is Ca 1-x Al2O4:xMn 2+ , where: 0.5%≤x≤50%, x is the mole fraction.

[0009] Preferably, the chemical formula of the stress luminescent material is Ca 1-x Al2O4:xMn 2+ , 0.5%≤x≤7%, where x is the mole fraction.

[0010] Furthermore, the chemical formula of the stress luminescent material is Ca 0.95 Al2O4:5%Mn 2+ .

[0011] A method for preparing a stress-luminescent material with no photoluminescence and no afterglow of manganese ion-doped calcium aluminate, wherein the preparation method is a sol-gel assisted solid-phase reaction method.

[0012] The Ca-containing precursor, the Al-containing precursor and the Mn-containing precursor are weighed in a stoichiometric ratio, stirred into a gel state, dried, ground into powder, calcined and cooled to obtain the powder;

[0013] The Ca-containing precursor is Ca nitrate, the Al-containing precursor is Al nitrate, and the Mn precursor is oxide, nitrate, and carbonate as raw materials.

[0014] Preferably, the stirring speed is 300-500 r / min, the stirring temperature is 60-80°C, the stirring time is 50-60 min, the pH is adjusted to 3-5 with ammonia water, the drying time is 24-48 h, and the drying temperature is 120-150°C.

[0015] Pre-oxidation: The calcination temperature in air is 700-1000°C, the heating rate is 8-10°C / min, and the calcination time is 4-8h. The obtained product is an oxide containing Ca, Al, and O. The purpose of pre-oxidation is to remove organic matter and nitrate ions in the gel-state substance.

[0016] Calcination of the finished product: calcination temperature is 500-1500° C. under protective atmosphere, heating rate is 3-6° C. / min, calcination time is 3-10 hours, then cooling to room temperature with the furnace, taking out the product and grinding it to obtain the stress luminescent material.

[0017] Preferably, the particle size of the stress luminescent material after grinding is 50-200 μm.

[0018] Furthermore, the particle size of the stress luminescent material is 3 to 5 μm.

[0019] A stress luminescent film comprises the stress luminescent material as claimed in claim 1.

[0020] A method for preparing a stress luminescent film is provided, which is obtained by mixing and drying the stress luminescent material and a polymer mixed liquid.

[0021] Preferably, the preparation method specifically comprises the following steps:

[0022] 1. Preparation of polymer mixture

[0023] The curing agent and the polymer material are mixed in a mass ratio of 1:2 to 15 and subjected to ultrasound to prepare the product;

[0024] 2. Preparation of Stress-induced Luminescent Films

[0025] The polymer mixture in step 1 is mixed with the stress luminescent material described above at a mass ratio of 1:2-4, and then dried.

[0026] Furthermore, in step 1, the mass ratio of the curing agent to the polymer material is 1:10, the ultrasonic frequency is 40-50 kHz, the ultrasonic power is 90-100 W, and the ultrasound is performed for 20-30 minutes; in step 2, the mass ratio of the polymer mixture to the above-mentioned stress luminescent material is 0.12:0.25, the drying temperature is 70-90°C, and the drying time is 3-4 hours.

[0027] Furthermore, the curing agent is one of dibutyltin dilaurate, hexamethylenediamine, and tetrabutyl titanate, and the polymer material is one of ER, SG, or PDMS.

[0028] Application of the above-mentioned stress luminescent material or the above-mentioned stress luminescent film in the preparation of building crack detection material or motion monitoring material.

[0029] Preferably, the motion monitoring material includes a wearable device sensor, smart sportswear, a plantar pressure sensor, or a golf club grip sensor.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] The stress luminescent material prepared by the present invention does not produce photoluminescence under ultraviolet to blue light irradiation, and has no afterglow after the excitation stops. However, under mechanical force stimulation, it can produce high-brightness green stress luminescence, and the intensity is better than that of commercial ZnS:Cu + Materials (1.5 times as much);

[0032] The lack of afterglow effectively avoids the afterglow interference common in traditional materials, significantly improving the accuracy and sensitivity of stress luminescence detection. Thanks to its core component, calcium aluminate cement, this material exhibits advantages unmatched by other stress luminescence materials in structural health monitoring applications such as crack detection. Furthermore, its bright green stress luminescence also holds broad application prospects in motion monitoring and mechanical visualization. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 This is the SEM image of Example 1 of the present invention;

[0034] Figure 2 The CIE color coordinates corresponding to the stress luminescence of Example 1 of the present invention are shown. The inset is a photograph of the friction marks of a glass rod recorded using a mobile phone time-lapse mode after rubbing the PDMS composite films prepared in Example 1 and Example 6 with the glass rod.

[0035] Figure 3 The stress luminescent material Ca prepared in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ Stress luminescence spectra of the PDMS composite film prepared with Example 6 under different mechanical forces; the inset is a photograph of the friction traces of the glass rod recorded using a mobile phone time-lapse mode in response to mechanical force when the glass rod was rubbed against the composite film prepared with Example 1 and PDMS;

[0036] Figure 4 for Figure 3Correspondingly, the relationship between the integrated intensity of stress luminescence intensity and force under different mechanical forces, including experimental values, linear fitting results, and error bars;

[0037] Figure 5 Stress luminescence photographs recorded using a mobile phone's time-lapse mode under different forces, including rupture, impact, stretching, and friction, of the composite membranes prepared from Example 1 of the present invention and the PDMS, PR, and SG polymer matrices prepared from Example 6;

[0038] Figure 6 is the XRD pattern of Examples 1 to 5 of the present invention;

[0039] Figure 7 is a stress luminescence spectrum diagram of Examples 1 to 5 of the present invention;

[0040] Figure 8 The different Mn prepared in Examples 11 to 17 of the present invention 2+ Ca doping concentration 1-x Al2O4:xMn 2+ XRD pattern of (0.5%≤x≤7%);

[0041] Figure 9 The Ca of Comparative Examples 1 to 3 of the present invention 0.95 Al2O4:5%Eu 2+ , Ca 0.95 Al2O4:5%Ce 3+ , Ca 0.95 Al2O4:5%Tb 3+ , Ca 0.95 Al2O4:5%Mn 2+ The photoluminescence spectrum of the prepared four powders is shown in the inset, which is a histogram of the photoluminescence intensity and real-time photos taken under UV irradiation.

[0042] Figure 10 The different Mn prepared in Examples 11 to 17 of the present invention 2+ Ca doping concentration 1-x Al2O4:xMn 2+ The stress luminescence spectrum of the product (0.5%≤x≤7%) (top), and the integral total intensity of the corresponding stress luminescence spectrum with Mn 2+ Changes in doping concentration;

[0043] Figure 11 is the Ca in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ Afterglow spectrum of the product, the comparison sample is (SrAl2O4:Eu 2+ ,Dy 3+,Sr2MgSi2O7:Eu 2+ , ZnS:Cu + ) and the afterglow spectra of commercial powders. The inset is a photo taken with a mobile phone of the four powders immediately after the UV excitation light source (365nm UV lamp) was turned off.

[0044] Figure 12 for Figure 11 The normalized spectrum of the afterglow spectrum in ;

[0045] Figure 13 The Ca2O3 calcined in nitrogen atmosphere in Example 1 of the present invention is 0.95 Al2O4:5%Mn 2+ The product was combined with the PDMS composite membrane prepared in Example 6 and compared with the comparative example 4 (commercial powder SrAl2O4:Eu 2+ ,Dy 3+ ) and Comparative Example 6 (commercial powder ZnS:Cu + ) Stress luminescence spectra under the same test conditions (F = 20N). The inset shows a photo of the friction traces of a glass rod rubbing the composite film made of the three powders and PDMS, recorded using a mobile phone's time-lapse mode.

[0046] Figure 14 The relationship between the integrated intensity of stress luminescence intensity and force under different mechanical forces after the three samples of Example 1, Comparative Example 4, and Comparative Example 6 were combined with the PDMS composite film made from Example 6, including experimental values, linear fitting results, and error bars;

[0047] Figure 15 The stress luminescent powder Ca prepared in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ , after subsequent process treatment, it is prepared into composite membrane, cement, or ceramics for application in building crack detection;

[0048] Figure 16 The stress luminescent powder Ca prepared in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ , after subsequent process treatment, it is prepared into composite membranes or ceramics and then demonstrated in the application of building crack detection;

[0049] Figure 17 The stress luminescent material Ca prepared in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ , after subsequent process treatment, it is prepared into a composite film, which can be used in the application scenario of electronic skin in motion monitoring and sensing;

[0050] Figure 18The stress luminescent material Ca prepared in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ , prepared into composite membranes, and demonstrated the application of cement in motion monitoring and sensing;

[0051] Figure 19 The stress luminescent material Ca prepared in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ , after subsequent process treatment, it is prepared into a detection principle diagram of the composite membrane during crack detection;

[0052] Figure 20 The stress luminescent material Ca prepared in Example 1 of the present invention 0.95 Al2O4:5%Mn 2+ , after subsequent process treatment, it is prepared into a detection principle diagram including the composite membrane during motion monitoring. DETAILED DESCRIPTION

[0053] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the following examples are combined with the accompanying drawings to specifically illustrate the technical solutions of the present invention. It should be noted that the description of these implementation methods is used to help understand the present invention, but does not constitute a limitation of the present invention.

[0054] The following terms need to be explained in the present invention, see Table 1 below.

[0055] Table 1 Comparison table of stress luminescent powder and composite names of different materials (Example 1)

[0056]

[0057]

[0058] Example 1

[0059] A preparation method of a stress luminescent material with no photoluminescence and no afterglow, which is doped with manganese ions and calcium aluminate. The chemical formula of the stress luminescent material is Ca 0.95 Al2O4:5%Mn 2+ , comprising the following steps: the preparation method is a sol-gel assisted solid phase reaction method,

[0060] Weigh 15.0052 g (0.0200 mol) of aluminum nitrate nonahydrate (Al(NO3)3·9H2O), 17.2908 g (0.0200 mol) of anhydrous citric acid, 19.0 mL (0.0190 mol) of 1 mol / L calcium nitrate Ca(NO3)2, and 10 mL (0.0010 mol) of manganese nitrate Mn(NO3)2.

[0061] The above raw materials are placed in a beaker at 80°C and stirred at a speed of 400 r / min for 50 minutes until they are completely uniform. Then, ammonia water is added to adjust the overall pH value of the raw materials to 3. After reaching a gel state, the raw materials are placed in a 150°C oven and kept warm for 48 hours. The dried materials are first ground into a fluorescent powder state and pre-oxidized: the calcination temperature is 900°C in air, the heating rate is 10°C / min, and the calcination time is 6 hours to remove organic matter and nitrate ions in the precursor. The resulting product is an oxide containing Ca, Al, and O; the finished product is calcined: the calcination temperature is 1400°C in a protective atmosphere, the heating rate is 5°C / min, and the calcination time is 3 to 10 hours. After that, the product is cooled to room temperature in the furnace, and the product is taken out and ground to obtain the stress luminescent material.

[0062] The stress luminescent material prepared above was scanned by scanning electron microscope, and the results were as follows: Figure 1 As shown, the surface of the powdered stress luminescent material is slightly rough and presents an irregular shape, and the particle size is 3 to 5 μm.

[0063] Examples 2 to 5

[0064] The above embodiments are basically the same as embodiment 1, except that the powders in embodiments 2 to 5 are placed in a tube furnace through a boron carbide crucible and heated at the same heating rate as that in embodiment 1. The final heating temperatures are shown in Table 2.

[0065] Table 2 Effect of different sintering temperatures on the crystallization properties of stress luminescent materials (Examples 2 to 5)

[0066] Example Final heating temperature (℃) 2 1350 3 1375 4 1425 5 1450

[0067] Combined with Examples 1 to 5, the stress luminescent materials prepared in each example were subjected to XRD tests, and the test results are as follows: Figure 2 As shown, the comparison results with the standard card show that the material is Ca 0.95 Al2O4:5%Mn 2+ The pure phase belongs to the monoclinic phase with the space group of P21. In addition, with the increase of the sintering temperature, the XRD diffraction peak moves to a lower angle. In a higher temperature environment, some impurity phases appear after high-temperature sintering. At higher temperatures, some impurity phases will bring some new optical effects. Therefore, in order to improve the crystallization quality of the material, a sintering process of 1400°C is adopted (i.e., Example 1).

[0068] Example 6

[0069] A stress luminescent film is obtained by mixing the stress luminescent material in Example 1 with a polymer mixed solution and drying.

[0070] The preparation of the stress luminescent film comprises the following steps:

[0071] 1. Preparation of polymer mixture

[0072] Dibutyltin dilaurate and PDMS were mixed at a mass ratio of 1:10, and ultrasonicated at a frequency of 40 kHz and a power of 90 W for 20 min to obtain a polymer mixture.

[0073] 2. Preparation of Stress-induced Luminescent Films

[0074] The polymer mixture in step 1 is mixed with the above stress luminescent material Ca 0.95 Al2O4:5%Mn 2+ The mixture was mixed in a mass ratio of 0.12:0.25 g and dried at 80 ° C for 3 h.

[0075] Related tests of the stress luminescent film:

[0076] (1) According to the device described in Zhang JC et al. Trap-controlled mechanoluminescent materials [J]. Progress in Materials Science, 2019, 103: 678-742, the stress luminescent film was pre-irradiated under a 365nm UV lamp for 5 minutes, and then the UV lamp was turned off to allow the stress luminescent film to replenish energy. A push-pull dynamometer was used to apply 0-50N and slide 1cm. Under different friction forces (3N, 5N, 10N, 15N, 20N, 30N, 35N, 40N and 50N), the stress luminescence spectrum was as follows: Figure 3 As shown,

[0077] Depend on Figure 3 As we know, the stress light intensity gradually increases with the applied force, indicating that there is a positive relationship between the stress luminescence response and the applied force. To ensure the accuracy of the experimental results, three repeated tests were performed and the intensity of the luminescence spectrum was integrated. The results are summarized as follows: Figure 4 As shown;

[0078] Depend on Figure 4 As we know, there is an obvious linear relationship between the total integrated intensity (y-axis) of the stress-luminescent film and the applied force (x-axis), where the +b term of the linear fitting is used to ensure the system equipment error range, and there is no afterglow when no stress is applied. That is:

[0079] y=62.97x-33.37;

[0080] Therefore, it is shown that the stress luminescent film has excellent mechanical responsiveness to applied force (R 2 =0.998), which can be used for mechanical sensing detection.

[0081] (2) According to the device described in Zhang JC et al. Trap-controlled mechanoluminescent materials [J]. Progress in Materials Science, 2019, 103: 678-742, in a dark environment with no windows, closed doors and lights off, the stress luminescent film can be stretched, compressed, broken, rubbed, compressed, and the powder alone can be mechanically stimulated to produce high-brightness green stress luminescence;

[0082] Among them, such as Figure 5 As shown in iii~v, in order to facilitate the stretching, the tensile test is to put the powdered stress luminescent material Ca 0.95 Al2O4:5%Mn 2+ Compounded with PDMS, SG or ER, and made into a 4*80mm cylindrical or long strip stress luminescent composite film using a 4*80mm polytetrafluoroethylene mold, the film adopts a biaxial tensile stress at 20N;

[0083] The compression test is to put the powdered stress luminescent material Ca 0.95 Al2O4:0.05Mn 2+ Composite with epoxy resin Figure 5 As shown in (vi), a 2*2 cylindrical mold epoxy resin block was made using a mold with a diameter of 4 mm.

[0084] like Figure 5 As shown in (i), the fracture experiment is to use scissors to cut the 4*80mm long strip of stress luminescent composite film into cracks, and then tear it in opposite directions with both hands.

[0085] like Figure 5 As shown in (ii), the friction experiment is to use a 6*300mm steel ball dropped from different heights and rubbed the same position on a 4*80mm round stress-luminescent composite film three times;

[0086] like Figure 5 As shown in (v), the powder grinding experiment is to grind the stress luminescent material powder directly with a spoon. Specifically, the powder is placed in a beaker and triboluminescence is performed on the powder with a spoon in a dark environment.

[0087] like Figure 5 As shown in (vi), the compression test is to use a universal testing machine to press the epoxy resin block hard, and the spectrometer is used to collect the data.

[0088] like Figure 5As shown, the stress luminescence color coordinates of the stress luminescent film in this embodiment show that its luminescent color is green. When displayed in an environment with no windows, closed doors and lights off, green traces and dim photoluminescence can be clearly seen.

[0089] Examples 7 to 10

[0090] The above embodiment is basically the same as embodiment 6, except that the stress luminescent films prepared in embodiments 7 to 10 correspond to the stress luminescent materials in embodiments 1 to 5, respectively, as shown in Table 3.

[0091] Table 3 Performance of stress luminescent films under different driving modes (Examples 7 to 10)

[0092] Example Embodiments using stress luminescent materials 7 2 8 3 9 4 10 5

[0093] In Examples 7 to 10, the relevant test (1) of the stress luminescent film in Example 6 is adopted:

[0094] In this test, the friction force is 50N and the test results are as follows: Figure 7 As shown, Figure 7 In the embodiment, the stress luminescence spectrum is composed of an emission peak with a peak value located at a wavelength of 550 nm, producing a green emission light in colorimetry. The stress luminescence intensity of Examples 6 to 10 is shown in Table 4 below.

[0095] Table 4 Comparison of integrated intensity of stress luminescent films under different driving modes (Examples 6 to 10)

[0096] Example 6 7 8 9 10 Stress luminescence integrated intensity 16659.754 7632.0860 13536.496 13726.721 11534.723

[0097] As shown in Table 4, the total integrated intensity of the stress-luminescence in Example 6 reached a high of 16659.754, indicating that the stress-luminescence intensity of the stress-luminescence film in Example 6 was the highest. (Note: The above data is derived from the integrated intensity of the stress-luminescence spectrum, which was collected by a photon counter and therefore has no specific units.)

[0098] Examples 11 to 17

[0099] The above embodiment is basically the same as embodiment 6, except that the amount of manganese ion doping is different, that is, the value of x is different, see Table 5 for details.

[0100] Table 5 Ca doping concentrations at different 1-x Al2O4:xMn 2+ (x = 0.5% to 7%) Luminescent Material Composition (Examples 11 to 17)

[0101] Example x Chemical formula 11 0.5％ <![CDATA[Ca 0.995 Al2O4:0.5%Mn 2+ ]]> 12 1％ <![CDATA[Ca 0.99 Al2O4:1%Mn 2+ ]]> 13 2％ <![CDATA[Ca 0.98 Al2O4:2%Mn 2+ ]]> 14 3％ <![CDATA[Ca 0.97 Al2O4:3%Mn 2+ ]]> 15 4％ <![CDATA[Ca 0.96 Al2O4:4%Mn 2+ ]]> 16 6％ <![CDATA[Ca 0.94 Al2O4:6%Mn 2+ ]]> 17 7％ <![CDATA[Ca 0.93 Al2O4:7%Mn 2+ ]]>

[0102] In Examples 11 to 17, Figure 8As shown, the XRD patterns of samples calcined in nitrogen atmosphere (x = 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%),

[0103] The test results are as follows Figure 8 As shown, the material parameters and the total integrated intensity of stress luminescence in Examples 11 to 17 are specifically shown in Table 6 below.

[0104] Table 6 Ca doping concentrations at different 1-x Al2O4:xMn 2+ Comparison of Stress Luminescence Integrated Intensity of Stress Luminescence Films (x = 0.5% to 7%) (Examples 11 to 17)

[0105]

[0106] (Note: The above data are from the integrated intensity of stress luminescence spectrum. The spectrum is collected by a photon counter, so there is no clear unit)

[0107] Figure 8 The comparison results with the standard card show that the material is a pure phase of CaAl2O4, which belongs to the monoclinic phase type and has a space group of P21.

[0108] and from Figure 8 The bar graph shows that under the same external mechanical force stimulation conditions, all different Mn 2+ Ca doping concentration (x) 1-x Al2O4:xMn 2+ The fluorescent material systems all showed remarkable (ML) performance.

[0109] Under the action of mechanical force, it can produce bright green luminescence phenomenon, and the luminescence color is uniform and stable. Through systematic research on the influence of different doping concentrations on ML performance, it can be found that when Mn 2+ When the doping concentration x=5%, the material exhibits the most excellent mechanical luminescence intensity, indicating that this doping concentration achieves the best energy level matching between the luminescence center and the matrix lattice.

[0110] It is worth noting that the ML spectra of all samples show a clear emission peak at a wavelength of 550nm, and the peak position of this characteristic peak is highly consistent with the peak position of the photoluminescence (PL) spectrum. This consistency of spectral characteristics fully confirms that mechanoluminescence and photoluminescence have the same luminescence mechanism, that is, both are derived from Mn 2+ Characteristic d~d electronic transition in crystal field environment ( 4 T1→ 6 A1).

[0111] The above findings not only verify that Mn 2+Its effectiveness as a luminescence center also provides important experimental basis for a deeper understanding of the force-to-light conversion mechanism of this type of material.

[0112] Comparative Examples 1 to 3

[0113] The preparation method of the stress luminescent material in the above comparative example is the same as that in Example 1, with the following differences:

[0114] The selection of stress luminescent materials and the parameters of each substance in the above comparative examples are mainly shown in Table 7.

[0115] Table 7 Different rare earth ions (Eu 2+ ,Ce 3+ ,Tb 3+ ) Preparation of CaAl2O4-based luminescent materials (Examples 1 to 3)

[0116]

[0117] The photoluminescence test was carried out on Example 1 and Comparative Examples 1 to 3 of the present invention respectively. The instrument used for the test was a Hitachi F4700 fluorescence spectrophotometer. The test results are shown in FIG. Figure 9 As shown, when Mn 2+ When the doping concentration is x=5%, that is, in Example 1, Ca 0.95 Al2O4:5%Mn 2+ The total integrated photoluminescence intensity of the sample is 126.061, compared with Ca 0.95 Al2O4:5%Eu 2+ , Ca 0.95 Al2O4:5%Ce 3+ , Ca 0.95 Al2O4:5%Tb 3+ The total integrated photoluminescence intensities are 320263.564, 85583.847, and 5188.471, respectively. 0.95 Al2O4:5%Mn 2+ There is no photoluminescence phenomenon. No photoluminescence is generated under ultraviolet to blue light irradiation. There is no afterglow after the excitation stops. And from the illustration, we cannot observe the photoluminescence of Example 1 with the naked eye.

[0118] Note: The above data are from the integrated intensity of stress luminescence spectrum. The spectrum is collected by a photon counter, so there is no clear unit.)

[0119] Comparative Examples 4 to 6

[0120] The above comparative examples use commercial powder on the market, as shown in Table 8.

[0121] Table 8 Comparison of commercial stress luminescent powder materials (Comparative Examples 4-5)

[0122]

[0123]

[0124] The stress luminescent materials of Example 1 and Comparative Examples 4 to 6 were subjected to afterglow spectrum test. The instrument used for the test was an Ocean Optics QE pro fiber optic spectrometer. The test results are as follows: Figure 11 As shown in the figure, the excitation wavelength is 365nm, and the emission spectrum of the sample is composed of four emission peaks with peaks at wavelengths of 550nm, 510nm, 520nm and 470nm, mainly producing green or blue emission light in chromaticity. 2+ When the doping concentration is x=0.05, that is, in Example 1, Ca 0.95 Al2O4:5%Mn 2+ The afterglow intensity of the sample area is monitored in real time and is 0, which means that the stress luminescent material has no afterglow performance. 2+ ,Dy 3+ The afterglow integral intensity is 2720682.69, ZnS:Cu + The afterglow integral intensity is 34104.01; Sr2MgSi2O7:Eu 2+ The afterglow integral intensity is 2720682.69. (Note: The above data comes from the integrated intensity of the stress luminescence spectrum. The spectrum is collected by a photon counter, so there is no clear unit.)

[0125] Comparative Examples 4 to 6 were prepared according to the method of Example 6, namely, Comparative Film 1 and Comparative Film 2, wherein Comparative Film 1 was composed of SrAl2O4:Eu 2+ ,Dy 3+ Prepared.

[0126] The film prepared in Example 6 and comparative films 1-2 were subjected to a drop ball test according to the following method (the apparatus used was the apparatus described in Zhang JC et al. Trap controlled mechanoluminescent materials [J]. Progress in Materials Science, 2019, 103: 678-742, mainly Figures c and g).

[0127] The test results are as follows Figure 13 To ensure the accuracy of the experimental results, three repeated tests were performed.

[0128] Depend on Figure 13 It can be seen that under the same mechanical stimulation conditions, Ca 0.95 Al2O4:5%Mn 2+The fluorescent material shows significantly better mechanical luminescence (ML) performance than a variety of commercial luminescent powders. Through quantitative comparative analysis, it can be found that its luminescence intensity reaches that of commercial ZnS:Cu + 1.5 times the material, and the long afterglow phosphor SrAl2O4:Eu 2+ ,Dy 3+ 3.27 times of Ca 0.95 Al2O4:5%Mn 2+ Its outstanding advantages in mechanoluminescent materials also show that it has great potential in application fields such as stress sensing, structural health monitoring, and anti-counterfeiting labels.

[0129] In order to more intuitively show the differences in luminescence properties of different materials,

[0130] Attachment Figure 13 The optical responses of various stress-luminescent materials under real-time mechanical excitation (such as friction, compression or impact) are compared.

[0131] It can be clearly observed that Ca 0.95 Al2O4:5%Mn 2+ When subjected to external force, it can quickly produce high-intensity green light, and its brightness is significantly better than ZnS:Cu + and SrAl2O4:Eu 2+ ,Dy 3+ This difference is not only reflected in the initial luminescence intensity, but also in the response speed and stability of luminescence, further highlighting the Ca 0.95 Al2O4:5%Mn 2+ Superiority in dynamic stress detection and visual mechanical sensing.

[0132] In addition, this significant performance improvement may be attributed to the unique crystal structure of the CaAl2O4 matrix, which can provide a 2+ The ions provide a more optimized local coordination environment, thereby enhancing the electron transition efficiency and luminescence intensity.

[0133] At the same time, compared with SrAl2O4:Eu 2+ ,Dy 3+ Long afterglow materials such as Ca 0.95 Al2O4:5%Mn 2+ Based on transition metal Mn 2+ The luminescence mechanism of the nanostructured PDMS has a faster response speed and higher mechanical-photoelectric conversion efficiency, which provides important advantages for its application in emerging fields such as high-speed stress monitoring and transient mechanical visualization.

[0134] There is an obvious linear relationship between the total integrated intensity of stress luminescence (B) and the applied force (A), indicating that the material has a highly sensitive response to the applied force and can be used for mechanical sensing detection. The error bars are the result of three identical tests on the sample. It can be seen that Ca 0.95 Al2O4:5%Mn 2+ The error is significantly smaller than that of the other two commercial powders.

[0135] Depend on Figure 14 As we know, there is an obvious linear relationship between the total integrated intensity (y-axis) of the stress luminescent film and the applied force (x-axis), namely:

[0136] y=62.97x-33.37;(Ca 0.95 Al2O4:5%Mn 2+ )(R 2 =0.998)

[0137] y=41.52x-19.81;(ZnS:Cu + )(R 2 =0.996)

[0138] y=20.92x-10.41; (SrAl2O4:Eu 2+ ,Dy 3+ )(R 2 =0.986)

[0139] Therefore, it is shown that the stress luminescent film has a highly sensitive response to the applied force, R 2 =0.998 can be used for mechanical sensing detection.

[0140] The results are as follows Figure 14 As shown, due to Ca 0.95 Al2O4:5%Mn 2+ It does not have significant photoluminescence properties, avoiding interference of light signals caused by ambient light or other external light sources, making its light signal in stress perception purer and easier to analyze, and is different from many traditional stress luminescent materials (such as SrAl2O4:Eu 2+ ,Dy 3+ ) exhibits different long afterglow, Ca 0.95 Al2O4:5%Mn 2+ There is no afterglow effect; it has a low and its preparation method and application, this feature greatly improves the time response speed of the stress luminescence signal, making it suitable for high-frequency dynamic stress detection and transient stress distribution analysis; In addition, it can be seen that the stress luminescence material Ca in the stress luminescence composite film in Example 6 0.95 Al2O4:5%Mn 2+The stress luminescence of the powder is stronger than that of other commercial powders and has the potential for high-contrast stress luminescence display.

[0141] Calcium aluminate, as a basic material, has a broad market and promising applications. In building materials, it can be used as an additive to improve the durability and shrinkage of cement and concrete, reducing the formation of shrinkage cracks. It can be integrated into the structures of buildings, bridges, or industrial equipment to monitor stress changes in real time and provide highly sensitive stress distribution visualization.

[0142] Example 18

[0143] The stress luminescent material in Example 1 is prepared into the stress luminescent film in Example 6 and used in detecting building cracks or monitoring movement.

[0144] That is, Figure 19 As shown, (1) in terms of detecting building cracks, the stress luminescent material in Example 1 is prepared into the stress luminescent film in Example 6 as a light-emitting module, which is installed on the engineering building structure to emit light on the engineering building structure;

[0145] It also includes a light signal capture module, which is electrically connected to the output end of the light emitting module and is used to capture the light signal emitted by the light emitting module on the engineering building structure;

[0146] A signal transmission module is electrically connected to the output end of the optical signal capture module and is used to receive and transmit the luminous signal;

[0147] The data processing and analysis module is electrically connected to the output end of the signal transmission module, and is used to receive the data transmitted by the signal transmission module, and extract the strength, frequency and distribution information of the signal through data processing and analysis, and generate a stress distribution map and a crack location map;

[0148] The visualization and early warning module is electrically connected to the output end of the data processing and analysis module, and is used to display the results analyzed by the data processing and analysis module and issue an early warning when an abnormality is detected.

[0149] That is Figure 15 、 16 As shown, when cracks appear in building structures, stress concentration areas (such as cracks) will emit abnormal light signals. By capturing and analyzing these signals, the crack positions can be accurately located and their expansion can be monitored in real time. This technology has the advantages of high sensitivity, real-time monitoring, non-destructiveness, and visual detection, and can effectively improve the efficiency and accuracy of building structure health monitoring.

[0150] (2) Figure 20As shown, in terms of monitoring sports, the stress luminescent material in Example 1 is prepared into the stress luminescent film in Example 6 as a light-emitting module, which is installed on sports equipment, and is used for the stress luminescent material or light-emitting film to emit light signals due to mechanical deformation (i.e., Figure 17 and 18 shown);

[0151] Also included is a photoelectric sensor electrically connected to the output end of the light emitting module, for capturing the light signal emitted by the light emitting module and converting the light signal into an electrical signal;

[0152] A data processing module is connected to the output of the photoelectric sensor and is used to extract the intensity, frequency and distribution information of the signal to monitor the amount of exercise, heart rate and respiratory rate during exercise in real time;

[0153] The visualization and early warning module is electrically connected to the output end of the data processing module, and is used to display the results analyzed by the data processing module and issue an early warning when an abnormality is detected.

[0154] The above-mentioned embodiments are preferred cases of the present invention and are not intended to limit the scope of protection of the present invention. Various deformations or modifications that can be made by ordinary technicians in this field without creative work within the scope of the attached claims are still within the scope of protection of this patent.

Claims

1. A manganese ion-doped calcium aluminate stress-luminescent material with no photoluminescence and no afterglow, characterized in that: The chemical formula of the stress luminescent material is Ca 1-x Al2O4:xMn 2+ , where: 0.5%≤x≤50%, x is the mole fraction.

2. The stress luminescent material according to claim 1, characterized in that 0.5%≤x≤7%, where x is the mole fraction.

3. The method for preparing the stress-luminescent material of manganese ion-doped calcium aluminate with no photoluminescence and no afterglow according to claim 1 or 2, characterized in that: The preparation method is a sol-gel assisted solid phase reaction method. According to the stoichiometric ratio, a Ca-containing precursor, an Al-containing precursor and a Mn-containing precursor are weighed, stirred into a gel state, and then pre-oxidized, calcined and cooled to obtain the product; Among them, the Ca-containing precursor is Ca nitrate, the Al-containing precursor is Al nitrate, and the Mn precursor is oxide, nitrate, or carbonate.

4. The preparation method according to claim 3, wherein: The stirring speed is 300-500 r / min, the stirring temperature is 60-80°C, the stirring time is 50-60 min, the pH is adjusted to 3-5 with ammonia water, the drying time is 24-48 h, and the drying temperature is 120-150°C.

5. The preparation method according to claim 3, wherein: Pre-oxidation: calcination temperature in air state is 700-1000℃, heating rate is 8-10℃ / min, calcination time is 4-8h, and product containing Ca, Al, O oxides is obtained; Calcination of the finished product: calcination temperature is 500-1500° C. under protective atmosphere, heating rate is 3-6° C. / min, calcination time is 3-10 hours, cooling to room temperature, and then grinding to obtain the stress luminescent material.

6. The stress luminescent material according to claim 5, characterized in that: The particle size of the stress luminescent material after grinding is 50 to 200 μm.

7. A stress luminescent film, characterized in that: Contains the stress luminescent material according to claim 1 or 2.

8. A method for preparing a stress luminescent film, characterized in that: The stress luminescent material according to claim 1 or 2 is mixed with a polymer mixture and dried.

9. Use of the stress luminescent material according to claim 1 or 2 or the stress luminescent film according to claim 7 in the preparation of building crack detection materials or motion monitoring materials.

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