Stress luminescence composite film having near-infrared garnet structure and method for manufacturing the same

Abstract

This invention provides a stress-luminescent composite film with a near-infrared garnet structure and its preparation method. The stress-luminescent composite film with the near-infrared garnet structure is composed of a near-infrared stress-luminescent material and PDMS. The chemical formula of the near-infrared stress-luminescent material is: Gd3Sc 2‑x Ga3O 12 : x Fe 3+ ,in x The value ranges from 0 to 0.05. The Gd3Sc prepared in this invention... 2‑x Ga3O 12 : x Fe 3+ Near-infrared stress-emitting materials possess a wide excitation band, high near-infrared luminescence intensity, and excellent mechanical stability. Their contact charging response sensitivity is significantly improved, and the optical signal output under stress is stable with a high signal-to-noise ratio. This invention utilizes Fe... 3+ The ion-doped near-infrared stress-luminescent material system, combined with a simplified high-temperature solid-state preparation process, not only offers strong operational controllability and a short preparation cycle, but also boasts low raw material costs and minimal safety risks.

Description

Technical Field

[0001] This invention relates to the field of stress luminescent materials technology, specifically to a stress luminescent composite film with a near-infrared garnet structure and its preparation method. Background Technology

[0002] Stress-luminescent materials, as a class of functional materials that can directly convert mechanical energy into light energy, can emit light without external light sources or power supplies when subjected to mechanical forces. Compared with traditional photoluminescent and electroluminescent materials, they have significant advantages in energy saving, environmental protection, and direct response, and have become one of the core research directions in the fields of intelligent sensing and structural monitoring. In current industrial production and social development, the demand for contactless, visualized, and multi-dimensional information perception in fields such as intelligent equipment, flexible electronics, engineering structure safety monitoring, and human-computer interaction is constantly increasing. Traditional electrical signal sensing technology has shortcomings such as electromagnetic interference, complex wiring, and inability to intuitively monitor stress distribution. Stress-luminescent materials, on the other hand, can achieve accurate perception and visualization of stress through multi-dimensional photon information such as light intensity, wavelength, and decay time. At the same time, they can collect mechanical energy such as wind energy and kinetic energy in the environment to complete self-powered luminescence. They have shown irreplaceable application value in scenarios such as engineering structure damage early warning, flexible wearable devices, optical anti-counterfeiting, biomechanical monitoring, and self-powered lighting. Their research and development and performance upgrades are an inevitable requirement to meet the development of the next generation of intelligent sensing technologies.

[0003] Currently, research on stress-luminescent materials has expanded from basic phenomenon observation and single-mechanism exploration to performance optimization, structural design, and preliminary applications. Researchers have simultaneously developed multi-element stress-luminescent material systems with near-infrared bands, low strain response, and high brightness. In terms of material design, heterostructures have proven to be an effective means of improving the stress-luminescent performance of single matrices; heterojunction systems such as ZnS / CaZnOS and Al2O3-Ga2O3 have achieved a dual improvement in luminescence efficiency and stability. In terms of band expansion, near-infrared stress-luminescent materials have become a research hotspot, with ZnGa2O4:Cr... 3+ Y3Al5O 12 :Cr 3+ The development of materials has overcome the limitations of traditional visible light materials in terms of interference in bright environments and permeability to biological tissues, making them suitable for high-end applications such as bioimaging and extreme environment monitoring. Furthermore, stress-luminescent materials have been combined with flexible substrates and sensors, achieving initial application verification in scenarios such as sign language recognition, intelligent road monitoring, artificial joint stress detection, and remote human-computer interaction, forming a technological prototype from material development to device integration.

[0004] Despite the progress made in stress-luminescent materials, the existing technology system still faces numerous unresolved issues, becoming a core bottleneck for their industrialization and widespread application. Firstly, the overall performance of the materials needs improvement. Most single-matrix inorganic stress-luminescent materials suffer from insufficient luminescence intensity and high response thresholds. Some materials lose their transparency after being composited with organic elastomers, resulting in a very limited range of transparent composite systems suitable for flexible displays and high-precision sensing. Secondly, the precision of material design and performance control is insufficient. Stress-luminescent material systems with tunable emission peaks and multi-band emission are relatively lacking, making it difficult to meet the practical needs of simultaneous multi-parameter monitoring. Thirdly, the dynamic response characteristics of force-to-light conversion are not fully utilized, resulting in insufficient stability and sensitivity in dynamic, high-frequency stress monitoring scenarios. Fourthly, the industrial applicability of the materials is poor. Existing stress-luminescent material preparation processes mostly rely on laboratory preparation methods such as high-temperature solid-state methods, making large-scale mass production difficult. Furthermore, the integration depth with intelligent algorithms and integrated devices is insufficient, resulting in low miniaturization and integration levels, making them unsuitable for portable sensing and embedded monitoring scenarios. Meanwhile, mature energy conversion technologies such as downconversion in the fields of photoluminescence and electroluminescence have not yet been effectively extended to the design and preparation of stress-luminescent materials, and there is still considerable room for improvement in the energy conversion efficiency of these materials.

[0005] Therefore, addressing the technical shortcomings of existing stress-luminescent materials by further optimizing their luminescence performance, expanding their wavelength range, improving the precision of structure and performance control, developing preparation processes suitable for large-scale mass production, and promoting the deep integration of materials with flexible electronics, intelligent algorithms, and integrated devices are the core development directions for the field of stress-luminescent materials. These are also the keys to their transition from laboratory research to industrial application and to fully releasing the value of intelligent sensing applications. Summary of the Invention

[0006] The purpose of this invention is to provide a stress-luminescent composite film with a near-infrared garnet structure and its preparation method, so as to solve the technical problems of existing stress-luminescent materials, such as insufficient luminescence intensity, high response threshold, limited band adaptability, difficulty in large-scale preparation, and low integration with flexible sensor devices and intelligent algorithms, and to provide more options for the market demand of near-infrared materials.

[0007] This invention is implemented as follows: A stress-luminescent material with a near-infrared garnet structure, its general chemical formula being: Gd3Sc 2-x Ga3O 12 : x Fe 3 + ,in x The value ranges from 0 to 0.05.

[0008] By combining the prepared phosphor with polydimethylsiloxane (PDMS), a stress-luminescent composite film with a near-infrared garnet structure can be obtained.

[0009] This invention also provides a method for preparing a stress-luminescent composite film with a near-infrared garnet structure, comprising the following steps: (a) According to the general chemical formula of phosphor, Gd3Sc 2-x Ga3O 12 : x Fe 3+ The molar ratio of each element is as follows: Weigh out oxides containing Gd, Sc, Ga, and Fe elements, preferably Gd2O3 (99.9%), Sc2O3 (99.9%), Ga2O3 (99.9%), and Fe2O3 (99.9%), mix them, and grind them for 15-30 min to obtain a mixture. In the general chemical formula, 0 < x ≤ 0.050.

[0010] (b) The mixture is heated to 900 °C and calcined for 3 h, then heated to 1450 °C and calcined for 4 h at a heating rate of 5-10 °C / min, and finally cooled to room temperature to obtain a sintered body.

[0011] (c) The obtained sintered body is thoroughly ground to obtain the near-infrared stress luminescent material Gd3Sc. 2-x Ga3O 12 : x Fe 3+ .

[0012] (d) Take the prepared Gd3Sc 2-x Ga3O 12 : x Fe 3+ Add the fluorescent powder, PDMS-based resin, and curing agent to a beaker in a mass ratio of 3:10:1 and stir until they are evenly mixed.

[0013] (e) Transfer the mixed material into a polytetrafluoroethylene mold and spread it evenly to a uniform thickness.

[0014] (f) The mold was dried at 70 °C for 5 h. After curing, it was removed to obtain Gd3Sc. 2-x Ga3O 12 : x Fe 3 + @PDMS elastomer film is a stress-luminescent composite film with a near-infrared garnet structure.

[0015] The Gd3Sc prepared by this invention 2-x Ga3O 12: x Fe 3+ Near-infrared stress-emitting materials possess a wide excitation band, high near-infrared luminescence intensity, and excellent mechanical stability. Their contact charging response sensitivity is significantly improved, and the optical signal output under stress is stable with a high signal-to-noise ratio. This invention utilizes Fe... 3+ The ion-doped near-infrared stress-luminescent material system, combined with a simplified high-temperature solid-state preparation process, not only offers strong operational controllability and a short preparation cycle, but also boasts low raw material costs and minimal safety risks. Furthermore, the elastomeric film obtained by PDMS composite material balances flexibility, transparency, and stress-luminescence consistency, significantly improving its adaptability to scenarios such as intelligent sensing and human-computer interaction compared to existing materials, and facilitating large-scale industrial production and widespread application. Attached Figure Description

[0016] Figure 1 These are the X-ray diffraction patterns of the phosphors prepared in Examples 1-9 and the standard cards.

[0017] Figure 2 The excitation and emission spectra of the phosphor prepared in Example 2 (wherein the excitation wavelength λ) are shown. ex =312 nm, emission wavelength λ em =804 nm).

[0018] Figure 3 These are the emission spectra of the phosphors prepared in Examples 1, 3, 5, 7, 8, and 9.

[0019] Figure 4 These are the emission spectra of the phosphors prepared in Examples 2-7.

[0020] Figure 5 The image shows the stress emission spectrum (F=20 N) of the composite elastomer membranes prepared in Examples 2-6. Detailed Implementation

[0021] The following examples are provided to further illustrate the present invention, but they do not limit the invention in any way. Unless otherwise specified, the reagents, methods, and equipment used in this invention are conventional reagents, methods, and equipment in this technical field. Example 1

[0022] (1) Weigh each raw material according to the following weights: weigh 1.8125 g of gadolinium oxide (Gd2O3), 0.4597 g of scandium oxide (Sc2O3), and 0.9372 g of gallium oxide (Ga2O3).

[0023] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0024] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0025] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc2Ga3O 12 Near-infrared phosphor.

[0026] The matrix prepared in this embodiment is a matrix. Example 2

[0027] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4574 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.0013 g of ferric oxide (Fe2O3).

[0028] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0029] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0030] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.995 Ga3O 12 0.005Fe 3+ Near-infrared phosphor.

[0031] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0032] Compared with Example 1, this example successfully prepared near-infrared phosphor and obtained a composite film. Example 3

[0033] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4551 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.0027 g of ferric oxide (Fe2O3).

[0034] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0035] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0036] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.99 Ga3O 12 0.01Fe 3+ Near-infrared phosphor.

[0037] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0038] Compared with Example 2, the luminescence intensity of the phosphor prepared in this example begins to increase. Example 4

[0039] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4528 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.004 g of ferric oxide (Fe2O3).

[0040] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0041] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0042] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.985 Ga3O 12 0.015Fe 3+ Near-infrared phosphor.

[0043] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0044] Compared with Examples 2 and 3, the luminescence intensity of the phosphor prepared in this example is further enhanced. Example 5

[0045] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4505 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.0053 g of ferric oxide (Fe2O3).

[0046] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0047] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0048] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.98 Ga3O 12 0.02Fe 3+ Near-infrared phosphor.

[0049] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0050] Compared with the previous embodiments, the luminescence intensity of the phosphor prepared in this embodiment is further enhanced. Example 6

[0051] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4482 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.0067 g of ferric oxide (Fe2O3).

[0052] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0053] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0054] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.975 Ga3O 12 0.025Fe 3+ Near-infrared phosphor.

[0055] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0056] Compared with the previous embodiments, the phosphor prepared in this embodiment has the strongest luminescence intensity. Example 7

[0057] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4459 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.008 g of ferric oxide (Fe2O3).

[0058] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0059] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0060] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.97 Ga3O 12 0.03Fe 3+ Near-infrared phosphor.

[0061] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0062] Compared with Example 6, the luminescence intensity of the phosphor prepared in this example is reduced. Example 8

[0063] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4413 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.0106 g of ferric oxide (Fe2O3).

[0064] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0065] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0066] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.96 Ga3O 12 0.04Fe 3+ Near-infrared phosphor.

[0067] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0068] Compared with Example 7, the luminescence intensity of the phosphor prepared in this example is reduced. Example 9

[0069] (1) Weigh each raw material according to the following weights: 1.8125 g of gadolinium oxide (Gd2O3), 0.4367 g of scandium oxide (Sc2O3), 0.9372 g of gallium oxide (Ga2O3), and 0.0133 g of ferric oxide (Fe2O3).

[0070] (2) Mix the weighed raw materials evenly, place them in an agate mortar and grind them thoroughly for 30 minutes to obtain a mixture.

[0071] (3) Place the ground mixture powder in an alumina crucible and heat it to 900°C at a heating rate of 5°C / min. Sinter at this temperature for 3 h. Continue to heat it to 1450°C at a heating rate of 5°C / min and sinter again at this temperature for 4 h. Allow it to cool naturally to room temperature to obtain the sintered body.

[0072] (4) The obtained sintered body is thoroughly ground to obtain the chemical formula Gd3Sc 1.95 Ga3O 12 0.05Fe 3+ Near-infrared phosphor.

[0073] (5) Take 3 g of near-infrared phosphor material, 10 g of PDMS-based resin and 1 g of curing agent from step (4), add them to a beaker and stir evenly; transfer to a 40 mm × 40 mm polytetrafluoroethylene mold, flatten and dry at 70 ℃ for 5 h to obtain the corresponding elastomer film.

[0074] Compared with the previous embodiments, the luminescence intensity of the phosphor prepared in this embodiment continues to decrease.

[0075] The properties of the materials prepared in the above embodiments were tested.

[0076] The phosphors prepared in the above embodiments are denoted as: Gd3Sc 2-x Ga3O 12 : x Fe 3+ The phosphors prepared in Examples 1-9 are respectively: Gd3Sc2Ga3O 12 ( x = 0), Gd3Sc 1.995 Ga3O 12 0.005Fe 3+ ( x = 0.005), Gd3Sc 1.99 Ga3O 12 0.01Fe 3+ ( x = 0.010), Gd3Sc 1.985 Ga3O 12 0.015Fe 3+ ( x = 0.015), Gd3Sc 1.98 Ga3O 12 0.2Fe 3+ ( x = 0.020), Gd3Sc 1.975 Ga3O 12 0.025Fe 3+ ( x =0.025), Gd3Sc 1.97 Ga3O 12 0.03Fe 3+ ( x = 0.030), Gd3Sc 1.96 Ga3O 12 0.04Fe 3+ (x = 0.040) and Gd3Sc 1.95 Ga3O 12 0.05Fe 3+ ( x = 0.050), and the X-ray diffraction patterns of the phosphors prepared in Examples 1-9 and the standard samples were detected, such as Figure 1 As shown in the figure, each phosphor has the same properties as the standard card PDF#04-001-7111 (Gd3Sc2Ga3O). 12 The same diffraction peaks.

[0077] Gd3Sc prepared in Example 2 2-x Ga3O 12 : x Fe 3+ ,in x The excitation and emission spectra of 0.010 are as follows: Figure 2 As shown in the figure, the excitation wavelength λ ex =312 nm, emission wavelength λ em =804 nm.

[0078] Detection of the phosphor Gd3Sc2Ga3O prepared in Examples 1, 3, 5, 7, 8, and 9 12 ( x = 0), Gd3Sc 1.99 Ga3O 12 0.01Fe 3+ ( x = 0.010), Gd3Sc 1.98 Ga3O 12 0.2Fe 3+ ( x = 0.020), Gd3Sc 1.97 Ga3O 12 0.03Fe 3+ ( x =0.030), Gd3Sc 1.96 Ga3O 12 0.04Fe 3+ ( x = 0.040) and Gd3Sc 1.95 Ga3O 12 0.05Fe 3+ ( x The emission spectrum of ( = 0.050) is shown in the following figure. Figure 3 As shown. From Figure 3 As can be seen from Example 7, the near-infrared phosphor prepared in Example 7 has the strongest luminescence intensity.

[0079] Detection of Gd3Sc phosphors prepared in Examples 2-71.995 Ga3O 12 0.005Fe 3+ ( x = 0.005), Gd3Sc 1.99 Ga3O 12 0.01Fe 3+ ( x = 0.010), Gd3Sc 1.985 Ga3O 12 0.015Fe 3+ ( x = 0.015), Gd3Sc 1.98 Ga3O 12 0.2Fe 3+ ( x = 0.020), Gd3Sc 1.975 Ga3O 12 0.025Fe 3+ ( x =0.025), Gd3Sc 1.97 Ga3O 12 0.03Fe 3+ ( x The emission spectrum of ( = 0.030) is shown in the following figure. Figure 4 As shown. From Figure 4 As can be seen from Example 6, the near-infrared phosphor prepared in Example 6 has the strongest luminescence intensity.

[0080] The stress (F = 20 N) emission spectra of the elastomer films composed of phosphors and PDMS prepared in Examples 2-6 were detected, and the results are as follows: Figure 5 As shown. From Figure 5 As can be seen from Example 6, the composite film prepared in Example 6 has the strongest stress luminescence intensity, which is the same as the optimal concentration for photoemission spectrum.

Claims

1. A stress-luminescent material with a near-infrared garnet structure, characterized in that, Its general chemical formula is: Gd3Sc 2- x Ga3O 12 : x Fe 3+ , where 0 < x ≤0.

050.

2. The method for preparing the stress-luminescent material with a near-infrared garnet structure as described in claim 1, characterized in that, Includes the following steps: (a) According to the general chemical formula Gd3Sc 2-x Ga3O 12 : x Fe 3+ Weigh out oxides containing Gd, Sc, Ga, and Fe elements according to the molar ratio of each element. (b) Mix the weighed raw materials evenly and grind them to obtain a mixture; (c) The mixture is calcined at high temperature in stages to obtain a sintered body; (d) Grinding the sintered body yields the stress-luminescent material Gd3Sc with a near-infrared garnet structure. 2-x Ga3O 12 : x Fe 3+ .

3. The method for preparing the stress-luminescent material with a near-infrared garnet structure as described in claim 2, characterized in that, In step (b), the grinding time is 15-30 min.

4. The method for preparing the stress-luminescent material with a near-infrared garnet structure as described in claim 2, characterized in that, Step (c) specifically involves heating the mixture to 900 °C and calcining for 3 hours, then continuing to heat it to 1450 °C and calcining for 4 hours, and finally cooling it to room temperature to obtain the sintered body.

5. The method for preparing the stress-luminescent material with a near-infrared garnet structure as described in claim 4, characterized in that, The heating rate is 5-10 ℃ / min.

6. A stress-luminescent composite film with a near-infrared garnet structure, characterized in that, It is composed of the stress-luminescent material with a near-infrared garnet structure as described in claim 1 and PDMS.

7. A method for preparing a stress-luminescent composite film with a near-infrared garnet structure, characterized in that, Includes the following steps: (a) According to the general chemical formula Gd3Sc 2-x Ga3O 12 : x Fe 3+ Weigh out oxides containing Gd, Sc, Ga, and Fe elements according to the molar ratio of each element. (b) Mix the weighed raw materials evenly and grind them to obtain a mixture; (c) The mixture is calcined at high temperature in stages to obtain a sintered body; (d) The sintered body is ground to obtain Gd3Sc, a stress-luminescent material with a near-infrared garnet structure. 2-x Ga3O 12 : x Fe 3+ ; (e) Mix the stress-luminescent material from step (d) with the PDMS-based resin and the curing agent, and stir until homogeneous; (f) Transfer the mixed material from step (e) into a polytetrafluoroethylene mold, spread it out and dry it to obtain a stress-luminescent composite film with a near-infrared garnet structure.

8. The method for preparing the stress-luminescent composite film with a near-infrared garnet structure according to claim 7, characterized in that, The drying conditions in step (f) are: drying at 70°C for 5 h.

9. The method for preparing the stress-luminescent composite film with a near-infrared garnet structure according to claim 7, characterized in that, In step (e), the mass ratio of stress luminescent material to PDMS-based resin and curing agent is 3:10:

1.

10. The method for preparing the stress-luminescent composite film with a near-infrared garnet structure according to claim 7, characterized in that, Step (c) specifically involves heating the mixture to 900 °C and calcining for 3 hours, then continuing to heat it to 1450 °C and calcining for 4 hours, and finally cooling it to room temperature to obtain the sintered body.

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