Al2O3-Ga2O3 heterojunction enhanced self-recovery near-infrared stress luminescence intelligent material and preparation method thereof

Abstract

The invention belongs to the technical field of inorganic luminescent materials. The invention discloses an Al2O3-Ga2O3 heterojunction enhanced self-recovery near-infrared stress luminescence intelligent material and a preparation method thereof. The chemical general formula of the material is aAl2O3-bGa2O3: m% Cr, a and b are mole numbers of Al2O3 and Ga2O3, and a: b = eta, 0lt; eta < lt >; 10000, 10000; m is greater than or equal to 0.000001 and less than or equal to And m% represents the molar percentage content of Cr. The material disclosed by the invention is simple in structure and easy to prepare, and particularly, aluminum oxide serving as a raw material can be obtained from natural ore and is low in cost and stable in supply. The material not only has a high-brightness near-infrared stress luminescence characteristic, but also can be used as a novel low-cost luminescent light source, is widely applied to multiple fields, and has important application potential in the aspects of safety diagnosis of a large-area structure, health monitoring friction stress distribution detection of underground facilities, stress sensors, anti-counterfeiting technologies and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of inorganic luminescent materials, and in particular to an Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescent intelligent material and a preparation method thereof. Background Art

[0002] At present, the commonly used existing technologies in the industry are as follows:

[0003] Mechanoluminescence (ML) materials are an emerging optoelectronic functional material that emits light when subjected to mechanical stress. Compared with photoluminescence and electroluminescence, which require additional light sources or power supplies, mechanoluminescence materials directly convert mechanical energy into light energy through mechanical force, making them energy-saving and environmentally friendly smart materials. According to the magnitude of stress and the elastic threshold of the stressed material, mechanoluminescence materials can be divided into fracture mechanoluminescence materials, plastic mechanoluminescence materials, and elastic mechanoluminescence materials. In addition, according to the characteristics of the material, mechanoluminescence materials can also be divided into self-recovering types and trap-controlled types that require pre-excitation.

[0004] Inorganic luminescent materials have become one of the important luminescent materials due to their stable structure and excellent performance. As a new type of inorganic luminescent body, the research on stress luminescent smart materials has become a hot area and has shown great potential application value in artificial intelligence, new light sources, stress sensing, touch screen technology and electronic skin. In recent years, with the continuous research and discovery of high-brightness stress luminescent materials, their application fields have been continuously broadened. High-energy emitted light waves can be used as excitation light sources for display and lighting, realizing the adjustable light and the emission of white light. Therefore, stress luminescent materials also show attractive application prospects in the fields of multicolor display and white light illumination.

[0005] So far, a variety of 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 luminescent properties of a single matrix. At present, the developed heterojunction stress luminescent materials and systems are still relatively scarce and urgently need further development and research. The 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) and so on. In addition, the reported gallium oxide near-infrared stress luminescent materials include Ga2O3:Cr (Matter, 2023, 6(9):2935-2949.); the published aluminum oxide near-infrared stress luminescent materials include Al2O3:Cr (CN118064139A).

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

[0007] First, the wavelength is different. The luminescent wavelength of the present invention is in the 600nm-1000nm band, and the main wavelength is in the near-infrared band (NIR-I); second, compared with other materials, aluminum oxide is cheaper. More than 90% of the world's native gallium is extracted in the process of producing aluminum oxide, which makes it have obvious advantages in large-scale preparation and application; third, aluminum oxide and gallium oxide are both simple oxides, and the synthesis steps are simple and not cumbersome, which is more suitable for large-scale preparation; fourth, the Al2O3-Ga2O3 in the present invention can realize self-recovering stress luminescence, and can be directly observed under medium mechanical force / pressure (~10kPa) without light source excitation, and has highly repeatable luminescence (>100 times); fifth, aluminum oxide and gallium oxide exhibit stable physical properties (wear resistance, corrosion resistance, biocompatibility and high-temperature stability), have relatively loose requirements on environmental conditions and excitation light sources, and have a wider range of application scenarios. They can be used as ceramic materials, electronic materials, biomedical materials, grinding materials, thermal barrier coating materials, etc. Sixth, compared with Al2O3:Cr, the stress luminescence intensity of the present invention is greatly improved and the emission band width is increased.

[0008] In summary, the problems existing in the prior art are:

[0009] The current heterojunction stress luminescent materials cannot achieve luminescence in the near-infrared band. This technical limitation restricts its application in biomedical imaging, optical communications, and night vision technology. The existing heterojunction stress luminescent materials usually have a decaying luminescence performance after stress recovery, making it difficult to achieve long-term stable luminescence. The preparation process of traditional heterojunction stress luminescent materials is complex and costly, which is not conducive to large-scale production and commercial application. In addition, the use of Ga2O3 instead of Al2O3 brings significant advantages and effects. First, the luminescence intensity of the material has increased by two times, which means that the luminescence efficiency has been significantly improved and a stronger signal can be provided. In addition, the phenomenon of changing from a narrow peak to a wide peak indicates that the emission band width has increased, which can cover a wider range of light wavelengths and is suitable for application scenarios such as broad-spectrum lighting and multi-color display. At the same time, the superior thermal stability and chemical stability of Ga2O3 improve the performance and service life of the material under high temperature or harsh environments. Summary of the invention

[0010] In view of the problems existing in the prior art, the present invention provides an Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material and a preparation method thereof.

[0011] The Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescent smart material of the present invention is low in price, has a luminescent wavelength in the range of 600nm to 1000nm, and a dominant wavelength in the near-infrared band (NIR-I). The material will directly emit light under stress without prior illumination. The purpose of this invention is to provide a near-infrared stress luminescent material and a preparation method thereof to solve the current problem of the lack of high-brightness near-infrared heterojunction stress luminescent materials.

[0012] The material has high-intensity elastic stress luminescence properties, simple preparation process, low cost, and stable chemical properties. It can directly respond to various forms of mechanical force signals, including but not limited to compression, stretching, bending, collision, friction and torsion. In a dark environment, the light emitted by the material can be observed by an infrared camera.

[0013] The chemical formula of the Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material of the present invention is aAl2O3-bGa2O3: m%Cr, wherein a and b are the molar numbers of Al2O3 and Ga2O3 respectively, and the ratio of the two is a:b=η, 0<η<10000; m% represents the molar percentage content of the 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 phase method, and the preparation process includes but is not limited to the following steps:

[0015] S1. Weighing raw materials according to the stoichiometric ratio of each element in the chemical formula of the near-infrared stress luminescent smart material, adding anhydrous ethanol or deionized water to the mixed raw materials, grinding and mixing in an agate bowl, and drying in an oven to obtain a mixed powder;

[0016] S2, placing the mixed powder in S1 in an alumina crucible, heating it to 1200-2050°C in air or oxygen atmosphere, burning it for 0.5-24 hours, and cooling it naturally;

[0017] S3, grinding 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 oxide, hydroxide or carbonate of Ga as raw material;

[0020] Al2O3 uses Al oxide, hydroxide or carbonate as raw material or uses natural ore as raw material, and the natural ore includes but is not limited to corundum, bauxite or sphalerite;

[0021] Cr uses its oxide, carbonate, soluble nitrate, sulfate or chloride as raw material;

[0022] In S1, drying in an oven at 80-300° C. obtains a mixed powder;

[0023] The S2 is heated to 1200-2050°C at a heating rate of 1-100°C / min in air or oxygen atmosphere, preferably heating to the melting point of Al2O3-Ga2O3 microcrystals.

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

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

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

[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 a traditional high-temperature solid-phase method. The material preparation method is simple, easy to prepare, and has no rare earth and low cost.

[0029] 2) The self-recovering near-infrared stress luminescent smart material of the present invention has near-infrared red stress luminescent properties. 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-recovering near-infrared stress luminescent smart material of the present invention can be widely used in many fields such as force sensing, bio-imaging, anti-counterfeiting, military, etc. This type of material provides a potential solution to the current energy crisis and also broadens new horizons for multi-path energy conversion. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a flow chart of the near-infrared stress luminescent material in the present invention.

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

[0033] Figure 3 It is a repetitive data spectrum of the stress luminescence integrated 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 the present invention.

[0034] Figure 4 It is the stress luminescence spectrum of Al2O3-Ga2O3:Cr products of Examples 1 to 8 (different proportions) of the present invention.

[0035] Figure 5 It is the XRD spectrum of the products Al2O3-Ga2O3:Cr in Examples 1 to 8 (different proportions) of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with specific examples. However, it should be understood that these examples are only used to illustrate the present invention and do not constitute a limitation on the scope of the present invention.

[0037] The chemical formula of the Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material of the present invention is aAl2O3-bGa2O3: m%Cr, wherein a and b are the molar numbers of Al2O3 and Ga2O3 respectively, and the ratio of the two is a:b=η, 0<η<10000; m% represents the molar percentage content of the 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 comprises the following steps:

[0039] S1. Weigh the raw materials according to the stoichiometric ratio of each element in the chemical formula of the above-mentioned 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 bowl, and then dry them in an oven to obtain a mixed powder;

[0040] S2, placing the mixed powder in S1 in an alumina crucible, heating it to 1200-2050°C in air or oxygen atmosphere, burning it for 0.5-24 hours, and cooling it naturally;

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

[0042] Among them, the raw materials used in S1 are as follows:

[0043] Ga2O3 uses oxide, hydroxide or carbonate of Ga as raw material;

[0044] Al2O3 uses Al oxide, hydroxide or carbonate as raw material or uses natural ore as raw material, and the natural ore includes but is not limited to corundum, bauxite or sphalerite;

[0045] Cr uses its oxide, carbonate, soluble nitrate, sulfate or chloride as raw material;

[0046] The mixed powder is dried in an oven at 80-300°C in S1;

[0047] S2 is heated to 1200-2050°C at a heating rate of 1-100°C / min in air or oxygen atmosphere, preferably heating to the melting point of Al2O3-Ga2O3 microcrystals.

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

[0049] Step 1, during the preparation, Ga2O3 and Al2O3 are prepared by using their oxides, hydroxides or carbonates as raw materials, and natural ores, such as but not limited to corundum, bauxite or sphalerite, and Cr is prepared by using its oxides, carbonates or soluble nitrates, sulfates, chlorides as raw materials, and the addition amount is aAl2O3-bGa2O3:m%Cr, a and b are the molar numbers of Al2O3 and Ga2O3, and the ratio of the two is a:b=η, 0<η<10000; 0.000001≤m≤10.9, m represents the molar percentage content; add an appropriate amount of anhydrous ethanol or deionized water to the mixed raw materials, grind and mix them evenly in an agate bowl, and then dry them in an oven to obtain a mixed powder;

[0050] Step 2, placing the ground powder in an alumina crucible, heating it to 1200-2050° C. in an air or oxygen atmosphere, burning it for 0.5-24 hours, and cooling it naturally with the furnace;

[0051] Step 3, grinding the obtained cooled powder to obtain aAl2O3-bGa2O3: m%Cr powder with near-infrared stress luminescent material; drying in an oven at 80-300°C to obtain a mixed powder; heating to 1200-2050°C at a heating rate of 1-100°C / min in air or oxygen atmosphere in step 2, preferably heating 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 luminescence smart material of the present invention comprises the following steps:

[0053] Step 1: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and the matrix is ​​prepared using Al2O3 and Ga2O3 as the raw materials. First, weigh the raw materials of each element according to the stoichiometric ratio, and then mix an appropriate amount of anhydrous ethanol or deionized water to obtain the raw materials. Next, grind and mix the raw materials in an agate bowl until they are evenly mixed. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

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

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

[0056] The following further illustrates the Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescent smart material and its preparation method of the present invention with specific examples. This section further illustrates the content of the present invention in conjunction with specific examples, but should not be construed as a limitation of 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 1Al2O3-0.2Ga2O3:1%Cr;

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

[0060] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0061] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0062] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 1Al2O3-0Ga2O3:1%Cr;

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

[0066] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0067] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0068] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 1Al2O3-0.4Ga2O3:1%Cr;

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

[0072] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0073] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0074] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 1Al2O3-0.6Ga2O3:1%Cr;

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

[0078] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0079] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0080] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 1Al2O3-0.8Ga2O3:1%Cr;

[0083] Taking 1650°C 1Al2O3-0.8Ga2O3:1%Cr as an example, the preparation method of the above material is described. The specific operation steps are as follows:

[0084] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0085] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0086] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 1Al2O3-1Ga2O3:1%Cr;

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

[0090] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0091] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0092] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 0Al2O3-1Ga2O3:1%Cr;

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

[0096] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0097] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0098] c) crushing and grinding the cooled powder obtained in step b), and passing it 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-recovering near-infrared stress luminescence smart material, the chemical formula of which is 0.9Al2O3-1Ga2O3:1%Cr;

[0101] Taking 0.9Al2O3-1Ga2O3:1%Cr at 1650°C as an example, the preparation method of the above material is described. The specific operation steps are as follows:

[0102] a) Raw materials: During the preparation, Cr is prepared using its oxide Cr2O3 as the raw material, and Al2O3 and Ga2O3 are used as the raw materials for the matrix. First, the raw materials of each element are weighed according to the stoichiometric ratio, and then the obtained raw materials are placed in an agate bowl, and sufficient anhydrous ethanol or deionized water is added to completely immerse the raw materials. Then the mixture is ground and mixed until it is mixed evenly. Subsequently, the mixed powder is placed in an oven at 80°C to dry, and finally the desired green stress luminescent material is obtained;

[0103] b) placing the uniformly ground powder in an alumina crucible, heating it to 1000°C at a heating rate of 10°C / min, then heating it from 1000°C to 1600°C at a heating rate of 5°C / min, then heating it from 1600°C to 1650°C at a heating rate of 2°C / min, burning for 4 hours, and finally cooling it naturally with the furnace;

[0104] c) crushing and grinding the cooled powder obtained in step b), and passing it through a 150-mesh sieve to obtain near-infrared stress luminescent 0.9Al2O3-1Ga2O3:1%Cr powder.

[0105] Performance characterization of near-infrared stress-luminescent smart materials

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

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

[0108] Figure 3 It is a repetitive data spectrum of the stress luminescence integrated 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 the present invention.

[0109] from Figure 3 It can be seen that the present invention has excellent repeatability and good self-recovery properties.

[0110] Figure 4 It is the stress luminescence spectrum of Al2O3-Ga2O3:Cr products of Examples 1 to 8 (different proportions) of the present invention.

[0111] from Figure 4 It can be seen that the luminous 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 It is the XRD spectrum of the products Al2O3-Ga2O3:Cr in Examples 1 to 8 (different proportions) of the present invention.

[0113] from Figure 5 It can be seen from the figure that the phase composition of the product of the present invention, Al2O3-Ga2O3:Cr,

[0114] It can be understood that the technical features of the above-described embodiments can be arbitrarily combined. In order to make the description concise, not all possible combinations of the technical features in the above-described 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 only preferred embodiments of the present application, and only specifically describe the technical principles of the present application. These descriptions are only for explaining the principles of the present application and cannot be interpreted as limiting the scope of protection of the present application in any way. Based on the explanation here, any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application, and other specific implementation methods of the present application that can be associated with the technicians in this field without creative work, should be included in the scope of protection of the present application.

Claims

1. An Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material, characterized in that: The chemical formula of the near-infrared stress luminescent smart material is aAl2O3-bGa2O3:m%Cr, wherein a and b are the molar numbers of Al2O3 and Ga2O3 respectively, and the ratio of the two is a:b=η, 0<η<10000; m% represents the molar percentage content of the Cr element in the near-infrared stress luminescent smart material, 0.000001≤m≤10.

9.

2. The method for preparing the Al2O3-Ga2O3 heterojunction enhanced self-recovering near-infrared stress luminescence smart material according to claim 1, characterized in that: The following steps are involved: S1. Weighing raw materials according to the stoichiometric ratio of each element in the chemical formula of the near-infrared stress luminescent smart material, adding anhydrous ethanol or deionized water to the mixed raw materials, grinding and mixing in an agate bowl, and drying in an oven to obtain a mixed powder; S2, placing the mixed powder in S1 in an alumina crucible, heating it to 1200-2050°C in air or oxygen atmosphere, burning it for 0.5-24 hours, and cooling it naturally; S3, grinding 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 oxide, hydroxide or carbonate of Ga as raw material; Al2O3 uses Al oxide, hydroxide or carbonate as raw material or uses natural ore as raw material, and the natural ore includes but is not limited to corundum, bauxite or sphalerite; Cr uses its oxide, carbonate, soluble nitrate, sulfate or chloride as raw material; In S1, drying in an oven at 80-300° C. obtains a mixed powder; The S2 is heated to 1200-2050°C at a heating rate of 1-100°C / min in air or oxygen atmosphere, preferably heating to the melting point of Al2O3-Ga2O3 microcrystals.

Images