Al2o3-ga2o3 heterojunction enhanced self-recovery near-infrared stress luminescence smart material and preparation method thereof

Abstract

The application belongs to the technical field of inorganic luminescent materials, and discloses an Al2O3-Ga2O3 heterojunction enhanced self-recovery near-infrared stress luminescence intelligent material and a preparation method thereof, the material has a chemical general formula of aAl2O3-bGa2O3:m%Cr; a and b are the mole numbers of Al2O3 and Ga2O3, a:b = η, 0 < η < 10000; 0.000001 ≤ m ≤ 10.9; m% represents the mole percentage content of Cr. The material has a simple structure and is easy to prepare, in particular, the alumina as a raw material can be obtained from natural ore, and is low in cost and stable in supply. The material not only has the characteristics of high-brightness near-infrared stress luminescence, but also can be used as a new type of low-cost luminescent light source, and is widely applied to multiple fields, and has important application potential in aspects such as large-area structure safety diagnosis, health monitoring of underground facilities, friction stress distribution detection, stress sensors and anti-counterfeiting technology.

Description

Technical Field

[0001] This invention relates to the field of inorganic luminescent materials technology, and in particular to an Al2O3-Ga2O3 heterojunction-enhanced self-recovering near-infrared stress luminescent smart material and its preparation method. Background Technology

[0002] Currently, the commonly used technologies in the industry are as follows:

[0003] Mechanoluminescence (ML) materials are a new type of optoelectronic functional material that emits light when subjected to mechanical stress. Compared to photoluminescence and electroluminescence, which require an additional light source or power supply, ML materials directly convert mechanical energy into light energy through mechanical force, making them an energy-saving and environmentally friendly smart material. Based on the magnitude of the stress and the elastic threshold of the material, ML materials can be classified into fracture-mechanical luminescence materials, plastic-mechanical luminescence materials, and elastic-mechanical luminescence materials. Furthermore, according to their properties, ML materials can also be classified into self-healing types and trap-controlled types requiring pre-excitation.

[0004] Inorganic luminescent materials, due to their structural stability and excellent performance, have become one of the most important luminescent materials. As a novel type of inorganic luminescent material, stress-luminescent smart materials have become a hot research area, demonstrating enormous potential application value in artificial intelligence, new light sources, stress sensing, touchscreen technology, and electronic skin. In recent years, with the continuous research and discovery of high-brightness stress-luminescent materials, their application fields have been constantly expanding. High-energy emitted light waves can serve as excitation sources for displays and lighting, enabling adjustable light and white light emission. Therefore, stress-luminescent materials also show promising application prospects in multicolor displays and white light illumination.

[0005] To date, various stress-luminescent materials and systems have been studied and explored. However, the stress-luminescent materials reported in the prior art are mainly based on the stress-luminescence properties of a single matrix. Currently, the developed heterojunction stress-luminescent materials and systems are still relatively rare and require further development and research. Reported heterojunction stress-luminescent materials include ZnF2-ZnO (Advanced Functional Materials, 2023, 33(32): 2301372); ZnS-CaZnOS (Advanced Materials, 2020, 32(16): 1907747); CaZnOS-ZnS-SrZnOS (Materials & Design, 2023, 225: 111589); NaNbO3 / MgNbO3 (ACS Applied Materials & Interfaces, 2023, 15(25): 30891-30901), etc. In addition, Ga2O3:Cr (Matter, 2023, 6(9): 2935-2949.) has been reported as a gallium oxide near-infrared stress luminescent material; Al2O3:Cr (CN118064139A) has been published as an aluminum oxide near-infrared stress luminescent material.

[0006] The difference between the near-infrared stress-luminescent material of the above invention and the material of this patent is as follows:

[0007] First, the wavelengths differ; the emission wavelength of this invention is in the 600nm-1000nm band, with the dominant wavelength located in the near-infrared band (NIR-I). Second, compared to other materials, alumina is less expensive; currently, over 90% of the world's primary gallium is extracted during alumina production, giving it a significant advantage in large-scale preparation and application. Third, both alumina and gallium oxide are simple oxides, with concise and straightforward synthesis steps, making them more suitable for large-scale preparation. Fourth, the Al2O3-Ga2O3 in this invention can achieve self-healing stress luminescence, requiring no light source excitation and can be directly observed under moderate mechanical force / pressure (~10kPa) with highly repeatable luminescence (>100 times). Fifth, alumina and gallium oxide exhibit stable physical properties (wear resistance, corrosion resistance, biocompatibility, and high-temperature stability), with relatively relaxed requirements for environmental conditions and excitation light sources, and a wider range of applications, including ceramic materials, electronic materials, biomedical materials, abrasive materials, and thermal barrier coating materials, etc. Sixth, compared with Al2O3:Cr, the stress luminescence intensity of the present invention is significantly improved and the emission band width is increased.

[0008] In summary, the problems with existing technologies are:

[0009] Current heterojunction stress-emitting materials cannot achieve near-infrared emission, a limitation that restricts their application in biomedical imaging, optical communication, and night vision. Existing heterojunction stress-emitting materials typically experience performance degradation after stress recovery, making long-term stable emission difficult. Furthermore, the complex and costly fabrication processes of traditional heterojunction stress-emitting materials hinder large-scale production and commercial applications. In contrast, using Ga2O3 instead of Al2O3 offers significant advantages and benefits. First, the luminescence intensity is doubled, indicating a significant increase in luminous efficiency and a stronger signal. Additionally, the shift from a narrow peak to a broad peak indicates an increased emission bandgap, covering a wider range of wavelengths, suitable for applications such as broadband lighting and multi-color displays. Simultaneously, Ga2O3's superior thermal and chemical stability improves the material's performance and lifespan under high-temperature or harsh environments. Summary of the Invention

[0010] To address the problems existing in the prior art, this invention provides an Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material and its preparation method.

[0011] The Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress-luminescent smart material of this invention is inexpensive and emits light in the 600nm to 1000nm wavelength range, with the dominant wavelength located in the near-infrared (NIR-I) band. This material emits light directly under stress without prior illumination. The purpose of this invention is to provide a near-infrared stress-luminescent material and its preparation method to address the current shortage of high-brightness near-infrared heterojunction stress-luminescent materials.

[0012] This material exhibits high-intensity elastic stress luminescence properties, a simple and inexpensive preparation process, and stable chemical properties. It can directly respond to various forms of mechanical force signals, including but not limited to compression, tension, bending, impact, friction, and torsion. In dark environments, the emitted light can be observed using an infrared camera.

[0013] The general chemical formula of the Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material of the present invention is aAl2O3-bGa2O3:m%Cr, where a and b are the molar numbers of Al2O3 and Ga2O3, respectively, and the ratio a:b = η, 0 < η < 10000; m% represents the molar percentage content of Cr element in the near-infrared stress luminescence smart material, 0.000001 ≤ m ≤ 10.9.

[0014] The Al2O3-Ga2O3 heterojunction-enhanced self-recovering near-infrared stress-luminescent smart material of the present invention is prepared by a high-temperature solid-state method, and the preparation process includes, but is not limited to, the following steps:

[0015] S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical formula of the near-infrared stress luminescent smart material, add anhydrous ethanol or deionized water to the mixed raw materials, grind and mix them evenly in an agate mortar, and then dry them in an oven to obtain mixed powder.

[0016] S2. Place the mixed powder from S1 in an alumina crucible, heat it to 1200-2050℃ in an air or oxygen atmosphere, calcine for 0.5-24 hours, and then allow it to cool naturally.

[0017] S3. Grind the cooled powder obtained in S2 to obtain Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material.

[0018] The raw materials used in S1 are as follows:

[0019] Ga2O3 uses Ga oxides, hydroxides, or carbonates as raw materials;

[0020] Al2O3 uses Al oxides, hydroxides or carbonates as raw materials or natural minerals as raw materials, including but not limited to corundum, bauxite or sphalerite.

[0021] Cr is produced from its oxides, carbonates, soluble nitrates, sulfates, or chlorides.

[0022] The mixed powder is obtained by drying in an oven at 80-300℃ in step S1.

[0023] In step S2, the temperature is increased to 1200–2050°C in an air or oxygen atmosphere at a heating rate of 1–100°C / min, which preferably leads to the melting point of Al2O3-Ga2O3 microcrystals.

[0024] The self-healing near-infrared stress-luminescent smart material is ground and sieved into powder, which is then combined with optically transparent organic polymer elastic material PET to form a composite. This composite is then made into a sheet or coated onto the surface of the component to be tested. Under the action of mechanical external force, the stress on the composite or component can be converted into light emission, realizing a high-brightness near-infrared force-light direct energy conversion.

[0025] The self-recovering near-infrared stress-luminescent smart material of the present invention has a stress-luminescence peak that is a broad-spectrum peak located in the vicinity of 600nm to 1000nm, and the material can be observed to emit light by an infrared camera in a dark environment.

[0026] The self-recovering near-infrared stress-luminescent smart material of the present invention, within its elastic limit, exhibits an elastic stress-luminescence intensity that is directly proportional to the magnitude of the applied mechanical force.

[0027] The following are the beneficial effects of the present invention:

[0028] 1) The self-recovering near-infrared stress-luminescent smart material of the present invention is prepared by the traditional high-temperature solid-state method. The material preparation method is simple, easy to prepare, and has low cost without rare earth elements.

[0029] 2) The self-recovering near-infrared stress-luminescent smart material of the present invention has near-infrared red stress-luminescent characteristics. When a certain mechanical force is applied to the material, the light emitted by it can be observed by an infrared camera.

[0030] 3) The self-healing near-infrared stress-luminescent smart material of this invention can be widely used in many fields such as force sensing, bio-imaging, anti-counterfeiting, and military applications. This type of material provides a potential solution to the current energy crisis and also broadens new horizons for multi-pathway energy conversion. Attached Figure Description

[0031] Figure 1 This is a flowchart of the near-infrared stress-luminescent material in this invention.

[0032] Figure 2 This is the stress emission spectrum of product 1Al2O3-0.2Ga2O3:1%Cr in Example 1 of the present invention.

[0033] Figure 3 These are repeatability data spectra of the stress luminescence integral intensity of the product 1Al2O3-0.2Ga2O3:1%Cr in Example 1, the product 1Al2O3-0Ga2O3:1%Cr in Example 2, and the product 0Al2O3-1Ga2O3:1%Cr in Example 7 of this invention.

[0034] Figure 4 These are the stress emission spectra of Al2O3-Ga2O3:Cr products from Examples 1 to 8 (different proportions) of the present invention.

[0035] Figure 5 These are the XRD patterns of Al2O3-Ga2O3:Cr products from Examples 1 to 8 (different proportions) of the present invention. Detailed Implementation

[0036] The present invention will be further illustrated below with reference to specific embodiments. However, it should be understood that these embodiments are for illustrative purposes only and do not constitute a limitation on the scope of the invention.

[0037] The general chemical formula of the Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material of the present invention is aAl2O3-bGa2O3:m%Cr, where a and b are the molar numbers of Al2O3 and Ga2O3, respectively, and the ratio a:b = η, 0 < η < 10000; m% represents the molar percentage content of Cr element in the near-infrared stress luminescence smart material, 0.000001 ≤ m ≤ 10.9.

[0038] The preparation method of the above-mentioned Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material includes the following steps:

[0039] S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical formula of the above near-infrared stress luminescent smart material, add anhydrous ethanol or deionized water to the mixed raw materials, grind and mix evenly in an agate mortar, and then dry in an oven to obtain mixed powder.

[0040] S2. Place the mixed powder from S1 in an alumina crucible, heat it to 1200-2050℃ in an air or oxygen atmosphere, calcine for 0.5-24 hours, and then allow it to cool naturally.

[0041] S3. Grind the cooled powder obtained in S2 to obtain Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material.

[0042] The raw materials used in S1 are as follows:

[0043] Ga2O3 uses Ga oxides, hydroxides, or carbonates as raw materials;

[0044] Al2O3 uses Al oxides, hydroxides or carbonates as raw materials or natural minerals as raw materials, including but not limited to corundum, bauxite or sphalerite.

[0045] Cr is produced from its oxides, carbonates, soluble nitrates, sulfates, or chlorides.

[0046] S1 is dried in an oven at 80-300℃ to obtain a mixed powder;

[0047] In S2, the temperature is increased to 1200–2050 °C in an air or oxygen atmosphere at a heating rate of 1–100 °C / min, which is the preferred heating temperature to reach the melting point of Al2O3-Ga2O3 microcrystals.

[0048] Specifically, such as Figure 1 As shown, the preparation method of the above-mentioned Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material includes the following steps:

[0049] Step 1: In the preparation, Ga2O3 and Al2O3 are prepared using their oxides, hydroxides, or carbonates as raw materials. Natural minerals, such as corundum, bauxite, or sphalerite, can also be used. Cr is prepared using its oxides, carbonates, or soluble nitrates, sulfates, or chlorides as raw materials. The addition amount is aAl2O3 - bGa2O3:m%Crm%, where a and b are the molar numbers of Al2O3 and Ga2O3, and the ratio a:b = η, 0 < η < 10000; 0.000001 ≤ m ≤ 10.9, where m represents the molar percentage content. An appropriate amount of anhydrous ethanol or deionized water is added to the mixed raw materials, and after grinding and mixing evenly in an agate mortar, the mixture is dried in an oven to obtain a mixed powder.

[0050] Step 2: Place the ground powder in an alumina crucible, heat it to 1200-2050℃ in an air or oxygen atmosphere, calcine for 0.5-24 hours, and then allow it to cool naturally in the furnace.

[0051] Step 3: Grind the obtained cooled powder to obtain near-infrared stress luminescent material aAl2O3-bGa2O3:m%Cr powder; the mixed powder obtained in Step 1 is dried in an oven at 80-300℃; in Step 2, the temperature is raised to 1200-2050℃ in an air or oxygen atmosphere at a heating rate of 1-100℃ / min, preferably to near the melting point of Al2O3-Ga2O3 microcrystals.

[0052] In some embodiments, the preparation method of the Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress-luminescent smart material of the present invention includes the following steps:

[0053] Step 1: In preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, each element raw material is weighed according to the stoichiometric ratio, and then an appropriate amount of anhydrous ethanol or deionized water is mixed to obtain the raw material. Next, the raw material is placed in an agate mortar for grinding and mixing until it is uniformly mixed. Subsequently, the mixed powder is placed in an oven at 80℃ to dry, finally obtaining the desired green stress luminescent material;

[0054] Step 2: Place the evenly ground powder in an alumina crucible, compact it and cover it. Heat it to 1650°C in air at a heating rate of 1-100°C / min, calcine for 4 hours, and finally let it cool naturally in the furnace.

[0055] Step 3: Crush and grind the cooled powder, and pass it through a 150-mesh sieve to obtain Al2O3-Ga2O3 heterojunction-enhanced self-healing near-infrared stress luminescence smart material.

[0056] The following specific embodiments further illustrate the Al2O3-Ga2O3 heterojunction-enhanced self-recovering near-infrared stress-luminescent smart material and its preparation method of the present invention. This section further illustrates the content of the present invention in conjunction with specific embodiments, but should not be construed as limiting the present invention. Unless otherwise specified, the technical means used in the embodiments 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.

[0057] Example 1

[0058] This embodiment provides an Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material with the general chemical formula 1Al2O3-0.2Ga2O3:1%Cr;

[0059] The preparation method of the above material is illustrated using 1Al₂O₃-0.2Ga₂O₃:1%Cr at 1650℃ as an example. The specific operation steps are as follows:

[0060] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0061] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0062] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 1Al2O3-0.2Ga2O3:1%Cr powder.

[0063] Example 2

[0064] This embodiment provides an Al2O3-Ga2O3 heterojunction-enhanced self-healing near-infrared stress luminescence smart material with the general chemical formula 1Al2O3-0Ga2O3:1%Cr;

[0065] Taking 1Al₂O₃-0Ga₂O₃:1%Cr at 1650℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0066] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0067] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0068] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 1Al2O3-0Ga2O3:1%Cr powder.

[0069] Example 3

[0070] This embodiment provides an Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material with the general chemical formula 1Al2O3-0.4Ga2O3:1%Cr;

[0071] The preparation method of the above material is illustrated using 1Al₂O₃-0.4Ga₂O₃:1%Cr at 1650℃ as an example. The specific operation steps are as follows:

[0072] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0073] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0074] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 1Al2O3-0.4Ga2O3:1%Cr powder.

[0075] Example 4

[0076] This embodiment provides an Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material with the general chemical formula 1Al2O3-0.6Ga2O3:1%Cr;

[0077] The preparation method of the above material is illustrated using 1Al₂O₃-0.6Ga₂O₃:1%Cr at 1650℃ as an example. The specific operation steps are as follows:

[0078] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0079] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0080] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 1Al2O3-0.6Ga2O3:1%Cr powder.

[0081] Example 5

[0082] This embodiment provides an Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material with the general chemical formula 1Al2O3-0.8Ga2O3:1%Cr;

[0083] The preparation method of the above material is illustrated using 1Al₂O₃-0.8Ga₂O₃:1%Cr at 1650℃ as an example. The specific operation steps are as follows:

[0084] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0085] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0086] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 1Al2O3-0.8Ga2O3:1%Cr powder.

[0087] Example 6

[0088] This embodiment provides an Al2O3-Ga2O3 heterojunction-enhanced self-healing near-infrared stress-luminescent smart material with the chemical formula 1Al2O3-1Ga2O3:1%Cr;

[0089] Taking 1Al₂O₃-1Ga₂O₃:1%Cr at 1650℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0090] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0091] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0092] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 1Al2O3-1Ga2O3:1%Cr powder.

[0093] Example 7

[0094] This embodiment provides an Al2O3-Ga2O3 heterojunction-enhanced self-healing near-infrared stress luminescence smart material with the chemical formula 0Al2O3-1Ga2O3:1%Cr;

[0095] Taking 0Al2O3-1Ga2O3:1%Cr at 1650℃ as an example, the preparation method of the above material is illustrated below. The specific operation steps are as follows:

[0096] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0097] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0098] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 0Al2O3-1Ga2O3:1%Cr powder.

[0099] Example 8

[0100] This embodiment provides an Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress luminescence smart material with the general chemical formula 0.9Al2O3-1Ga2O3:1%Cr;

[0101] The preparation method of the above material is illustrated using 0.9Al2O3-1Ga2O3:1%Cr at 1650℃ as an example. The specific operation steps are as follows:

[0102] a) Raw materials: Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as raw materials. First, the raw materials of each element are weighed according to the stoichiometric ratio. Then, the obtained raw materials are placed in an agate mortar, and sufficient anhydrous ethanol or deionized water is added to completely submerge the raw materials. Next, the mixture is ground and mixed until homogeneous. Subsequently, the mixed powder is dried in an oven at 80℃ to finally obtain the desired green stress-luminescent material.

[0103] b) Place the uniformly ground powder in an alumina crucible, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, then heat it to 1650℃ at a heating rate of 2℃ / min, calcine for 4 hours, and finally cool it down naturally with the furnace.

[0104] c) The cooled powder obtained in step b) is crushed and ground, and then passed through a 150-mesh sieve to obtain near-infrared stress-luminescent 0.9Al2O3-1Ga2O3:1%Cr powder.

[0105] Performance Characterization of Near-Infrared Stress-Emitting Smart Materials

[0106] Figure 2 This is the stress emission spectrum of product 1Al2O3-0.2Ga2O3:1%Cr in Example 1 of the present invention.

[0107] from Figure 2 As can be seen from the present invention, the emission wavelength of the Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material is in the 600nm to 1000nm band, and the main wavelength is located in the near-infrared I region (NIR-I).

[0108] Figure 3 These are repeatability data spectra of the stress luminescence integral intensity of the product 1Al2O3-0.2Ga2O3:1%Cr in Example 1, the product 1Al2O3-0Ga2O3:1%Cr in Example 2, and the product 0Al2O3-1Ga2O3:1%Cr in Example 7 of this invention.

[0109] from Figure 3 As can be seen from this, the present invention has excellent repeatability and good self-recovery characteristics.

[0110] Figure 4 These are the stress emission spectra of Al2O3-Ga2O3:Cr products from Examples 1 to 8 (different proportions) of the present invention.

[0111] from Figure 4 As can be seen from the above, the luminescence intensity of the present invention is significantly improved compared with Al2O3:Cr and Ga2O3:Cr, and the emission band width is increased.

[0112] Figure 5 These are the XRD patterns of Al2O3-Ga2O3:Cr products from Examples 1 to 8 (different proportions) of the present invention.

[0113] from Figure 5 The phase composition of the product Al2O3-Ga2O3:Cr can be seen from the diagram.

[0114] It is understood that the technical features of the above embodiments can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0115] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. An Al2O3-Ga2O3 heterojunction-enhanced self-healing near-infrared stress-luminescent smart material, characterized in that, The chemical formula of the near-infrared stress-luminescent smart material is aAl2O3-bGa2O3:m%Cr, where a and b are the molar numbers of Al2O3 and Ga2O3, respectively, and the ratio a:b=η, where a is 1 and η is 1~5; m% represents the molar percentage content of Cr element in the near-infrared stress-luminescent smart material, where m=1. The preparation method of the Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material includes the following steps: S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical formula of the near-infrared stress luminescent smart material, add anhydrous ethanol or deionized water to the mixed raw materials, grind and mix them evenly in an agate mortar, and then dry them in an oven to obtain mixed powder. S2. Place the mixed powder from S1 in an alumina crucible, in an air or oxygen atmosphere, heat it to 1000℃ at a heating rate of 10℃ / min, then heat it to 1600℃ at a heating rate of 5℃ / min, and then heat it to 1650℃ at a heating rate of 2℃ / min. Calcinate for 4 hours and allow it to cool naturally. S3. Grind the cooled powder obtained in S2 to obtain Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material. The raw materials used in S1 are as follows: Ga2O3 uses Ga oxide Ga2O3 as raw material; Al2O3 uses Al oxide Al2O3 as raw material; Cr is produced using its oxide Cr2O3 as a raw material.

2. The preparation method of the Al2O3-Ga2O3 heterojunction enhanced self-healing near-infrared stress-luminescent smart material as described in claim 1, characterized in that, Includes the following steps: S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical formula of the near-infrared stress luminescent smart material, add anhydrous ethanol or deionized water to the mixed raw materials, grind and mix them evenly in an agate mortar, and then dry them in an oven to obtain mixed powder. S2. Place the mixed powder from S1 in an alumina crucible and heat it to 1000°C in an air or oxygen atmosphere at a heating rate of 10°C / min. Then heat it to 1600°C at a heating rate of 5°C / min, and then heat it to 1650°C at a heating rate of 2°C / min. Calcinate for 4 hours and allow it to cool naturally. S3. Grind the cooled powder obtained in S2 to obtain Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material. The raw materials used in S1 are as follows: Ga2O3 uses Ga oxide Ga2O3 as raw material; Al2O3 uses Al oxide Al2O3 as raw material; Cr is produced using its oxide Cr2O3 as a raw material.

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