A method for realizing multi-state cycle conversion of tungstate fluorescent powder by multiple stimulations and application thereof

Abstract

The present application relates to the technical field of multiple stimulus response color change, and particularly relates to a conversion method for realizing multiple states of tungstate fluorescent powder and application, S1: tungstate fluorescent powder is colored under the action of 5-30Mpa pressure for 10min, and the tungstate fluorescent powder changes from orange yellow to black; S2: the black sample obtained in step S1 changes from black to white after being irradiated under a 532nm laser for 1-5min; S3: the white sample obtained in step S2 is heated in a reducing atmosphere to restore to the original orange yellow, and the orange yellow fluorescent powder changes from orange yellow to white after being irradiated under 808 / 980 / 473 / 532nm laser for 1-5min. The present application realizes the three-state cycle conversion of tungstate fluorescent powder through high pressure, laser irradiation and reducing atmosphere heating, and the thermal stability and mechanical stability are excellent; it is beneficial to realize industrialization and can realize the cycle switching of multicolor color change by using light, heat and mechanical field, and the present application widens the types of multiple stimulus induced color change materials and the types of color change.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of multi-stimulus response color change, in particular to a conversion method for realizing multi-state cycle of tungstate fluorescent powder by multi-stimulus and application thereof. BACKGROUND

[0002] At present, the realization of multi-stimulus color change by a single unit mainly focuses on the research in the field of organic matter. The photochromic molecules showing multiple photochromic states in a single photochromic unit are considered to be more attractive than traditional bistable photochromic molecules, because they can provide more multifunctionality and controllability in the light response system. The realization of triangular cycle conversion in a single unit has attracted much attention in various research fields due to their ability to switch between different states.

[0003] However, the current research on triangular cycle switching mainly focuses on organic matter, and is mainly stimulated by light field. In addition, the photodynamic study of photochromic molecules of organic matter shows that the ring structure deformation caused by isomerization of a photochromic unit significantly affects the photoisomerization efficiency and thermal reverse reaction rate of another photochromic unit. Based on this, a multi-field stimulus response color inorganic material is researched to realize the three-state cycle color change, which can broaden its application field. SUMMARY

[0004] The purpose of the present application is to provide a conversion method for realizing multi-state cycle of tungstate fluorescent powder by multi-stimulus and application thereof. In view of the problems existing in the prior art, the tungstate fluorescent powder is prepared by high-temperature solid-phase method. The prepared fluorescent powder changes from orange yellow to black under pressure. The black sample changes from black to white under the action of a 532nm laser. The white sample restores the original orange yellow color by heating in a reducing atmosphere. The present application realizes the three-state cycle conversion of tungstate fluorescent powder color change.

[0005] In order to achieve the above technical purpose and achieve the above technical effect, the present application is realized by the following technical scheme:

[0006] A conversion method for realizing multi-state cycle of tungstate fluorescent powder by multi-stimulus, comprising the following steps:

[0007] S1: color the tungstate fluorescent powder under a pressure of 5-30Mpa for 10min, so that the tungstate fluorescent powder changes from orange yellow to black;

[0008] S2: irradiate the black sample obtained in step S1 under a 532nm laser for 1-5min, so that the black sample changes from black to white;

[0009] S3: The white sample obtained in step S2 is heated in a reducing atmosphere to restore the original orange yellow color, and the orange yellow phosphor is irradiated under 808 / 980 / 473 / 532 nm laser for 1-5 min, and the sample changes from orange yellow to white.

[0010] Further, the power of the 473 / 532 nm laser in step S3 is 30-80 W / cm 2 , and the power of the 808 / 980 nm laser is 5-20 W / cm 2 .

[0011] Further, the heating temperature in the reducing atmosphere in step S3 is 500-800 DEG C, and the heating time is half an hour.

[0012] Further, the preparation method of the tungstate phosphor comprises: according to the chemical formula EuWO4, WO3 and Eu2O3 are weighed according to the molar ratio, added into anhydrous ethanol, uniformly ground, dried to obtain a mixture; and the uniformly ground mixture is sintered at 1150 DEG C for 4 hours in a reducing atmosphere, and cooled to room temperature with the furnace to obtain the tungstate phosphor.

[0013] Further, the reducing atmosphere is nitrogen-hydrogen reducing gas, and the hydrogen content is 5%-10%.

[0014] In another aspect, the application provides the application of the above method in the color change three-state cycle conversion of the tungstate phosphor.

[0015] The beneficial effects of the application are:

[0016] The application realizes the three-state cycle conversion of the color change of the tungstate phosphor, and provides a new possibility of multi-parameter sensing. The tungstate phosphor changes from orange yellow to black under high pressure of 5-30 Mpa, and due to the mutual conversion of Eu valence states under pressure, in order to maintain the valence state balance in the system, the color change is caused by the conversion of W from high valence to low valence; the color of the black sample rapidly changes to white under the irradiation of a 532 nm laser, which is mainly due to the phase change caused by the heat generated by the laser. Finally, the white sample restores the original orange yellow color under the heating of a reducing atmosphere at 500-800 DEG C, which is because the heating of the reducing atmosphere restores the sample to the original phase. Compared with the method for preparing a force-induced color-changing phosphor for adjusting rare earth ion luminescence and its application, the application adds the stimulation of light field and heat field to realize multi-color change. This complete three-state cycle process enables the material to be used in a complex multi-functional sensor system, and different parameters such as pressure, light intensity and atmosphere composition can be accurately detected through different external stimulations. In addition, at present, multi-stimulus color change mainly focuses on organic materials, and inorganic materials have not been involved. The tungstate material has good structural stability, can maintain the integrity of the crystal structure under various environmental conditions, and can ensure the stability and long service life of the color-changing sample.

[0017] The three-state cycle of tungstate fluorescent powder presented by the application can be used in intelligent display devices, providing rich color output and dynamic display effects by controlling external stimuli. The orange to black change under high pressure is suitable for static background display; the black to white change under laser irradiation is suitable for fast dynamic display; the white to orange recovery under reducing atmosphere heating ensures color stability and durability in multiple cycles. The display device can provide the best visual effect in different working modes.

[0018] In the field of information storage and security identification, the three-state cycle conversion of tungstate fluorescent powder can realize the design of multi-state storage medium and anti-counterfeiting label. Through three different external stimuli of high pressure, laser and reducing atmosphere heating, multiple color states can be realized, each color state representing different data bits and information content, improving the data storage density and the complexity of anti-counterfeiting technology. This process enhances the security and reliability of the storage and identification system, verifies the authenticity of the material through multi-state cycle, and realizes efficient anti-counterfeiting and information protection.

[0019] During high pressure treatment, the orange material quickly turns black; under 532nm laser irradiation, the black sample turns white within 1-5 minutes, the color change process is fast and efficient, and the use of laser to quickly regulate the color state of the material can improve the information processing speed and the dynamic response ability of the display; reducing atmosphere heating provides a reliable recovery method, through 500-800℃ N2-H2 reducing atmosphere, the white sample recovers to orange, providing stability and reliability for multiple cycles, suitable for sensors and display devices that need to operate stably for a long time.

[0020] In summary, the three-state cycle conversion of tungstate fluorescent powder realized by high pressure, laser irradiation and reducing atmosphere heating has excellent thermal stability and mechanical stability; in addition, compared with the current single organic photochromic molecule that exhibits multiple photochromic states in a single photochromic unit, the preparation process is simple and efficient, the cost is low, it is conducive to industrialization, and it can realize the cycle switching of multicolor color change by using light, heat and mechanical field, which broadens the types of multiple stimulus-induced color-changing materials and the types of color changes.

[0021] Of course, implementing any product of the present application does not necessarily require all the advantages described above. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0023] Figure 1 is the X-ray diffraction pattern of the orange, pressure color-changing black, white sample under laser stimulation prepared;

[0024] Figure 2 is the cycle switching diagram of the tungstate obtained by the application between orange, black and white;

[0025] Figure 3 is the diffuse reflection spectrum corresponding to the multicolor reversible color change of the tungstate fluorescent powder obtained by the application under the stimulation of light field, stress field and thermal field. DETAILED DESCRIPTION

[0026] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only part of the embodiments of the application, rather than all the embodiments of the application. Based on the embodiments in the application, all other embodiments obtained by a person of ordinary skill in the art without creative labor fall within the protection scope of the application.

[0027] Embodiment 1

[0028] The conversion method of the multiple-stimulation-achieved multistate cycle of the tungstate fluorescent powder described in this embodiment comprises the following steps:

[0029] S1: Color the tungstate fluorescent powder under a pressure of 5-30 MPa for 10 min, and change the tungstate fluorescent powder from orange to black;

[0030] S2: Change the black sample obtained in step S1 from black to white under the irradiation of a 532 nm laser for 1-5 min;

[0031] S3: Change the white sample obtained in step S2 to the original orange by heating the sample in a reducing atmosphere, and change the orange fluorescent powder from orange to white under the exposure of 808 / 980 / 473 / 532 nm lasers as the irradiation time prolongs.

[0032] In this embodiment, the power of the 473 / 532 nm laser in S3 is 30-80 W / cm 2 , the power of the 808 / 980 nm laser is 5-20 W / cm 2 , and the irradiation time is 1-5 min.

[0033] In this embodiment, the heating temperature in the reducing atmosphere in S3 is 500-800 DEG C, and the heating time is half an hour.

[0034] In this embodiment, the preparation method of the tungstate phosphor includes: weighing WO3 and Eu2O3 according to the chemical formula EuWO4 in molar ratio, adding anhydrous ethanol, mixing and grinding evenly until dry to obtain a mixture; sintering the evenly ground mixture at 1150°C for 4 hours in a reducing atmosphere, and cooling it to room temperature in the furnace to obtain the tungstate phosphor.

[0035] In this embodiment, the reducing atmosphere is a nitrogen-hydrogen reducing gas, with hydrogen accounting for 5%-10%.

[0036] On the other hand, this invention proposes the application of the above method in the three-state cyclic conversion of tungstate phosphor color change.

[0037] Example 2

[0038] like Figure 1 As shown, the EuWO4 phosphor obtained by the method provided in this invention was subjected to X-ray diffraction testing, and an X-ray diffraction pattern was obtained. The pattern shows that the target crystalline phase was synthesized. Further X-ray diffraction testing was performed on the black sample under pressure, and the results showed that its phase was the same as the orange-yellow sample, but its diffraction peaks were broadened, mainly due to the distortion of the polyhedrons under pressure. The black sample was subjected to 66.37 W / cm²... 2 Irradiation with a 532nm laser for 1 minute turned the sample white. Phase analysis revealed a change in phase composition, primarily related to the thermal effect of the laser. Testing of the orange sample with an 808nm laser revealed the same phase as the sample irradiated with a 532nm laser, indicating that the prepared sample can achieve one cycle.

[0039] Example 3

[0040] like Figure 2 As shown, tungstate phosphors exhibit a cyclic color change under pressure, light, and heat. An orange-yellow sample turns black under pressure; the black sample recovers its orange-yellow color upon heating in a reducing atmosphere; and the black sample turns white under a 532nm laser. The white sample recovers its orange-yellow color upon heating in a reducing atmosphere, while the orange-yellow sample turns white under 808nm laser irradiation. Compared to organic materials, it exhibits superior stability. It can be applied in fields such as optical switches, storage, and sensing.

[0041] Example 4

[0042] like Figure 3As shown, the diffuse reflectance spectra of EuWO4 phosphor before and after light / pressure stimulation were measured by a spectrophotometer (U-4100) equipped with an integrating sphere; the color of EuWO4 phosphor changed to white by exposing it under 808 nm laser for 10 seconds, the diffuse reflectance spectra of the sample after color change was measured, it can be seen that the diffuse reflectance spectra of the phosphor after color change under UV light was higher than that before color change. The sample changed from orange yellow to black under 30 MPa for 10 min, the diffuse reflectance spectra of the sample after color change was measured. It is shown that the sample can realize obvious color change under light / pressure stimulation.

[0043] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details and limit the application to the specific embodiments. Obviously, many modifications and variations can be made according to the content of the present application. The present application is selected and described in detail in order to better explain the principles and practical application of the present application, so that those skilled in the art can well understand and use the present application. The present application is limited by the claims and their full scope and equivalents.

Claims

1. A method for achieving polymorphic cycling of tungstate phosphors through multiple stimuli, characterized in that, Includes the following steps: S1: The tungstate phosphor is subjected to a pressure of 5-30 MPa for 10 minutes to color it, and the tungstate phosphor changes from orange-yellow to black. S2: The black sample obtained in step S1 is irradiated with a 532nm laser for 1-5 minutes and then turns from black to white; S3: The white sample obtained in step S2 is heated in a reducing atmosphere to restore the original orange-yellow color. The orange-yellow phosphor is exposed to 808 / 980 / 473 / 532nm laser for 1-5 minutes, and the sample changes from orange-yellow to white. In step S3, the reducing atmosphere heating temperature is 500-800℃; The preparation method of the tungstate phosphor includes: weighing WO3 and Eu2O3 according to the chemical formula EuWO4 in molar ratio, adding anhydrous ethanol, mixing and grinding evenly until dry to obtain a mixture; sintering the evenly ground mixture at 1150℃ for 4 hours in a reducing atmosphere, and cooling it to room temperature in the furnace to obtain the tungstate phosphor.

2. The method for achieving polymorphic cycling of tungstate phosphors through multiple stimuli as described in claim 1, characterized in that: In step S3, the power of the 473 / 532nm laser is 30-80W / cm². 2 The power of 808 / 980nm lasers is 5-20 W / cm². 2 .

3. The method for achieving polymorphic cycling of tungstate phosphors through multiple stimuli as described in claim 1, characterized in that: The heating time for the reducing atmosphere in step S3 is half an hour.

4. The method for achieving polymorphic cycling of tungstate phosphors through multiple stimuli as described in claim 1, characterized in that: The reducing atmosphere is a nitrogen-hydrogen reducing gas, with hydrogen accounting for 5%-10%.

5. The application of the method according to any one of claims 1-4 in the three-state cyclic conversion of tungstate phosphor color change.

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