1. A fluoride-based stress luminescent material is characterized in that the chemical general formula of the fluoride-based stress luminescent material is M_1-xF₂:A_xWherein x represents the mole percentage content, and x is more than 0 and less than or equal to 0.05; m is at least one of alkaline earth metals Mg and Ca; a is Bi or a transition metal ion.

2. The fluoride-based stressor of claim 1, wherein the transition metal ion is Sc, Ti, Mn, Cu, or Zn.

3. The fluoride-based stressor of claim 1, wherein x is specifically 0.02.

4. A preparation method of a fluoride-based stress luminescent material is characterized by comprising the following steps: according to the formula M in claim 1_1-xF₂:A_xWeighing raw materials according to the chemical dose ratio of the elements; selecting corresponding fluoride as a raw material for the M element, selecting corresponding oxide as the raw material for the A element except Mn, and selecting manganese carbonate as the raw material if the A is Mn; putting the weighed raw materials into an agate mortar, adding ethanol to fully mix the raw materials, and fully grinding the raw materials to be in a powder state; and placing the ground powder in a crucible, placing the crucible in a high-temperature atmosphere tube furnace, calcining the crucible for 2 hours at 1100 ℃ in a weak reducing atmosphere and a nitrogen or argon protective atmosphere, naturally cooling the crucible to room temperature, taking out the crucible, and grinding the crucible to obtain the required luminescent material.

5. The method of claim 4, wherein the weakly reducing atmosphere is H of 5% by volume₂And 95% of N₂。

6. A fluoride-based stress luminescent material is characterized in that the chemical general formula of the fluoride-based stress luminescent material is M_1-x-yF₂:B_x,Mn²⁺ _yWherein x is more than or equal to 0 and less than or equal to 0.05, y is more than or equal to 0 and less than or equal to 0.05, x and y respectively represent molar percentage content, and x and y are not zero at the same time; m is at least one of alkaline earth metals Mg and Ca; b is at least one of rare earth ions.

7. The fluoride-based stress phosphor of claim 6, wherein the rare earth ions comprise Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, and Yb.

8. The fluoride-based stressor phosphor of claim 6, wherein x and y are each 0.02.

9. A preparation method of a fluoride-based stress luminescent material is characterized by comprising the following steps: according to the formula M in claim 6_1-x-yF₂:B_x,Mn²⁺ _yWeighing raw materials according to the chemical dose ratio of the elements; the element M is selected to be the corresponding fluoride as the raw material, the element B is selected to be the corresponding oxide as the raw material, and the element Mn is selected to be manganese carbonate as the raw material; putting the weighed raw materials into an agate mortar, adding ethanol to fully mix the raw materials, and fully grinding the raw materials to be in a powder state; and placing the ground powder in a crucible, placing the crucible in a high-temperature atmosphere tube furnace, calcining the crucible for 2 hours at 1100 ℃ in a weak reducing atmosphere and a nitrogen or argon protective atmosphere, naturally cooling the crucible to room temperature, taking out the crucible, and grinding the crucible to obtain the required luminescent material.

10. Use of a fluoride-based stressor as claimed in any one of claims 1 to 9 in the field of structural damage detection, electronic signature systems, electronic skin, and in relation to stress monitoring.

Background

Stress luminescence has been discovered as early as the 16 th century, for example: the light can be emitted when earthquake or volcano eruption. Its earliest documented fact was written by Francis Bacon in 1605 in his work "The Advancement of Learning": "flashing is seen when a knife is used to quickly cut across the surface of the sugar cube". For many solid materials, when a mechanical stress is applied to them, they emit light, which is known as mechanoluminescence (ml) or Tribouminescence (TL), and such a material emitting light under mechanical stress is called a stressor. The term stress luminescence was not used until 1978.

The popular way is that: by collecting the light, the distribution of the light is converted into a distribution of stress. Stress refers to the mechanical force used to cause a material to luminesce and includes impact, tension, deformation, pressure, tension, shear, friction, fracture, and the like. In recent years, research on elastic stress luminescent materials has become a leading edge discipline. Although the conversion of mechanical stress into light distribution is quite complicated, some experiments have succeeded in applying the stress luminescence phenomenon to pressure sensors, mechanical force visualization and some other different kinds of intelligent systems, which have attracted worldwide attention, but: 1. the types of stress luminescent materials known today are very limited and are only seen in some silicates and piezoelectric materials; 2. the mechanism is not clear; 3. the trap type has not been specified.

Disclosure of Invention

The invention aims to provide a fluoride-based stress luminescent material, a preparation method and application thereof, which are used for supplementing new materials for the existing limited types of stress luminescent materials and increasing new research directions for research on the stress luminescent materials.

The invention is realized by the following steps: a fluoride-based stress luminescent material has a chemical general formula as shown in the following two expression forms, (1) M_1-x F₂:A_xWherein x represents the mole percentage content, and x is more than 0 and less than or equal to 0.05; m is at least one of alkaline earth metals Mg and Ca; a is Bi or transition metal ions; the transition metal ions are Sc, Ti, Mn, Cu or Zn and the like; (2) m_1-x-yF₂:B_x,Mn²⁺ _yWherein x is more than or equal to 0 and less than or equal to 0.05, y is more than or equal to 0 and less than or equal to 0.05, x and y respectively represent molar percentage content, and x and y are not zero at the same time; m is at least one of alkaline earth metals Mg and Ca; b is rare earth ions Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and the likeAt least one of (1).

The preparation method of the fluoride-based stress luminescent material comprises the following steps: according to the general formula M_1-x F₂:A_xOr M_1-x-yF₂:B_x,Mn²⁺ _yWeighing raw materials according to the chemical dose ratio of the elements; selecting corresponding fluoride as a raw material for the M element, selecting corresponding oxide as the raw material for the A element except Mn, and selecting manganese carbonate as the raw material if the A is Mn; b element is selected as a corresponding oxide of the element B, and Mn element is selected as a manganese carbonate material; putting the weighed raw materials into an agate mortar, adding ethanol to fully mix the raw materials, and fully grinding the raw materials to be in a powder state; the ground powder was placed in a crucible and placed in a high temperature atmosphere tube furnace under a weakly reducing atmosphere (5% H)₂-95％N₂) Calcining at 1100 deg.C under nitrogen or argon atmosphere for 2 hr, naturally cooling to room temperature, taking out, and grinding to obtain the desired luminescent material.

The invention provides a fluoride-based stress luminescent material, which directly applies stress to powder or a film prepared by mixing the powder and an elastic high polymer material without carrying out prior ultraviolet light or visible light irradiation, and generates stress luminescence within the elastic limit of the material. On one hand, the luminescent performance of the stress luminescent material is excellent; on the other hand, the invention provides new possibility for further research and development of the mechanism of stress luminescence.

The fluoride-based stress luminescent material is prepared by adopting a traditional solid-phase reaction method, and has the advantages of simple process, low equipment requirement, easily controlled conditions, low cost, no toxic or harmful substances in the preparation process and environmental friendliness.

The stress luminescent material has high luminous efficiency and simple preparation method, and has potential application value in the application fields of structural damage detection, electronic signature systems, electronic skins and the like which relate to stress monitoring.

Drawings

Figure 1 is an XRD pattern of a sample of example 1 of the present invention.

FIG. 2 is an X-ray emission spectrum of a sample in example 1 of the present invention.

FIG. 3 is a diagram of an ML spectrum measured at a pressure of 40N for a sample in example 1 of the present invention.

FIG. 4 is a graph showing the relationship between the stress level and the emission intensity of the sample in example 1 of the present invention.

Figure 5 is an XRD pattern of a sample of example 2 of the invention.

FIG. 6 is an X-ray emission spectrum of a sample in example 2 of the present invention.

FIG. 7 is a real shot of stress luminescence phenomenon of six samples prepared in example 3 of the present invention.

FIG. 8 is a real shot of stress luminescence phenomenon of the samples prepared in examples 2 and 4 of the present invention.

Detailed Description

The fluoride-based stress luminescent material provided by the invention can realize luminescence adjustable stress luminescence by doping transition metal ions or different rare earth ions.

Specifically, the general chemical expression formula of the fluoride-based stress luminescent material of the present invention can be represented by the following two expression forms: (1) m_1-x F₂:A_xWherein x represents the mole percentage content, and x is more than 0 and less than or equal to 0.05; m is at least one of alkaline earth metals Mg and Ca; a is transition metal ion or Bi; the transition metal ions are Sc, Ti, Mn, Cu or Zn, etc. (2) M_1-x-yF₂:B_x,Mn²⁺ _yWherein x is more than or equal to 0 and less than or equal to 0.05, y is more than or equal to 0 and less than or equal to 0.05, x and y represent molar percentage, and x and y are not zero at the same time; m is at least one of alkaline earth metals Mg and Ca; b is at least one of rare earth ions Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm or Yb.

The fluoride-based stress luminescent material provided by the invention adopts a typical high-temperature solid phase method during preparation, and specifically comprises the following steps: selecting raw materials, namely selecting magnesium fluoride and calcium fluoride for alkaline earth metals Mg and Ca; selecting manganese carbonate for Mn element; selecting corresponding transition metal oxide for the transition metal ions; selecting bismuth oxide as Bi element; for rare earth ions, selecting corresponding rare earth ion oxides; after the raw materials are selected, the chemical of each element in the chemical general formula is adoptedWeighing the raw materials according to the dosage ratio; putting the weighed raw materials into an agate mortar, adding a proper amount of ethanol to fully mix, and fully grinding the mixture to be in a powder state. The ground powder was placed in a crucible and placed in a high temperature atmosphere tube furnace under a weakly reducing atmosphere (5% H)₂-95％N₂) Or calcining at 1100 deg.C under nitrogen or argon gas protective atmosphere for 2h, naturally cooling to room temperature, taking out, and grinding to obtain the desired luminescent material.

Example 1 preparation of Mg_0.98F₂：0.02Mn²⁺A stress luminescent material.

According to the formula Mg_0.98F₂：0.02Mn²⁺(the doping amount of 0.02 is usually written before the doping element) weighing magnesium fluoride and manganese carbonate as raw materials according to the stoichiometric ratio of each element, putting the weighed raw materials into an agate mortar, adding a proper amount of ethanol to fully mix, and fully grinding to be in a powder state. Placing the ground powder in a crucible, placing the crucible in a high-temperature atmosphere tube furnace, calcining for 2h at 1100 ℃ under the protection of nitrogen, naturally cooling to room temperature, taking out, and grinding to obtain Mg_0.98F₂：0.02Mn²⁺A stress luminescent material.

For Mg prepared in this example_0.98F₂：0.02Mn²⁺The stress luminescent material was subjected to XRD and X-ray emission spectrum tests, and the results are shown in fig. 1 and 2. In FIGS. 1 and 2, for convenience of representation, the term "MgF" is used₂：Mn²⁺"to show, the same is true below.

Mg prepared in this example_0.98F₂：0.02Mn²⁺A40N pressure was applied to the stressed phosphor and the ML spectrum was measured as shown in FIG. 3.

The applied pressure was reduced to 30N and 20N, and then ML spectroscopy after light emission was performed, and the result was compared with the pressure of 40N, as shown in FIG. 4. Therefore, the stress luminescence intensity of the luminescent material is in a direct proportion relation with the applied stress, so that the application of the luminescent material to the detection of stress distribution is not problematic at all.

Example 2 preparation of Ca_0.98F₂：0.02Mn²⁺A stress luminescent material.

According to the formula Ca_0.98F₂：0.02Mn²⁺Weighing calcium fluoride and manganese carbonate as raw materials according to the stoichiometric ratio of the elements, putting the weighed raw materials into an agate mortar, adding a proper amount of ethanol to fully mix the raw materials, and fully grinding the raw materials to be in a powder state. Placing the ground powder in a crucible, placing the crucible in a high-temperature atmosphere tube furnace, calcining for 2h at 1100 ℃ under the protection of argon, naturally cooling to room temperature, taking out, and grinding to obtain Ca_0.98F₂：0.02Mn²⁺A stress luminescent material.

Ca prepared in this example_0.98F₂：0.02Mn²⁺The stress luminescent material was subjected to XRD and X-ray emission spectrum tests, and the results are shown in fig. 5 and 6.

Example 3 preparation of Mg_0.98F₂: 0.02A stress luminescent material.

The preparation of the compound of the formula Mg according to the above method_0.98F₂: 0.02A, wherein a is Bi, Sc, Ti, Mn, Cu, Zn, thus six samples were prepared in total.

The prepared six samples were applied with a certain force (the force applied here was about the same) to obtain a stress luminescence phenomenon of each sample as shown in fig. 7.

Example 4 preparation of Ca_0.96F₂：0.02B，0.02Mn²⁺A stress luminescent material.

The preparation method in this example can refer to the above description. B are Tb, Eu, Ho, Ce, Nd, Er, Tm, Gd, Sm, Dy, Yb and Pr, respectively, so that 12 samples in total were obtained.

The 12 samples of this example and the samples prepared in example 2 were tested in a stress luminescence experiment, and the luminescence phenomenon was shown in fig. 8.

The crystal structure of the fluoride-based stress luminescent material prepared by the invention belongs to a tetragonal system. Stress luminescence occurs when stress is directly applied on the fluoride-based stress luminescent material; the stress can be directly applied to the powder, or the stress can be applied to a film or a cylinder prepared by mixing the powder and the elastic high polymer material, and the stress luminescence can occur within the elastic limit of the material. Furthermore, the stress luminescence intensity of the fluoride-based stress luminescent material has a linear relationship with the magnitude of the applied stress. The applied stress includes, but is not limited to, friction, compression, tension, bending, impact, torsion, ultrasound, and the like.

The stress luminescent material has high luminous efficiency and simple preparation method, and has potential application value in the application fields of structural damage detection, electronic signature systems, electronic skins and the like which relate to stress monitoring.