Cobalt-based MOF material ethanol dispersion liquid, preparation method thereof and application of cobalt-based MOF material ethanol dispersion liquid in third-order nonlinear optics

Abstract

The invention discloses a cobalt-based MOF material ethanol dispersion liquid, a preparation method thereof and an application of the cobalt-based MOF material ethanol dispersion liquid in third-order nonlinear optics. The preparation method comprises the following steps: reacting a cobalt source with an organic ligand to prepare a cobalt-based MOF material; wherein the organic ligand comprises 1, 3, 5-tri (4-carboxyl phenyl ethynyl) benzene, and the organic ligand comprises 1, 3, 5-tri (4-carboxyl phenyl ethynyl) benzene; mixing the cobalt-based MOF material with ethanol, and performing crushing treatment by adopting a cell crushing device to prepare a cobalt-based MOF material ethanol dispersion liquid; wherein the power adopted in the crushing treatment is 30%-50%, and the temperature of condensate water in the cell crushing device is controlled to be 1-5 DEG C. The prepared cobalt-based MOF material ethanol dispersion liquid has excellent performance and reliability in the aspect of optical third-order nonlinear characteristics, lays a solid practical foundation for wide application of all-optical devices in the future, and is expected to promote further development of the optical technology in the fields of communication, sensing, information processing and the like.

Description

Technical Field

[0001] The invention relates to a cobalt-based MOF material ethanol dispersion liquid and a preparation method thereof and application in third-order nonlinear optics, belonging to the technical field of optical materials. Background Art

[0002] The application of macroporous metal-organic framework (MOF) materials in optical third-order nonlinearity is of great significance. MOF materials have attracted much attention due to their unique porous structure, high specific surface area and structural adjustability. The high porosity and adjustable chemical composition of macroporous MOF enable it to accommodate guest molecules, thereby enhancing the optical properties. In addition, the coordination between the metal ions of MOF and the organic ligands and the weakening of non-radiative transitions caused by the restricted conformation of the organic units will induce the enhancement of photophysical behavior. Through structural design, composite material preparation and external stimulus response, macroporous MOF can effectively regulate its third-order nonlinear optical properties to meet the needs of optical devices such as optical limiting and optical switching. However, the stability, processing performance and cost of the material are still the current challenges. In the future, its structure and performance need to be further optimized to promote its widespread application in the optical field. Summary of the invention

[0003] The main purpose of the present invention is to provide a cobalt-based MOF material ethanol dispersion and a preparation method thereof and application in third-order nonlinear optics to overcome the deficiencies in the prior art.

[0004] In order to achieve the above-mentioned invention object, the technical solution adopted by the present invention includes: The embodiment of the present invention provides a method for preparing a cobalt-based MOF material ethanol dispersion, which comprises: Reacting a cobalt source with an organic ligand to obtain a cobalt-based MOF material; wherein the organic ligand comprises 1,3,5-tris(4-carboxyphenylethynyl)benzene; And, the cobalt-based MOF material is mixed with ethanol and crushed by a cell crushing device to obtain a cobalt-based MOF material ethanol dispersion; wherein the power used in the crushing process is 30% to 50%, and the temperature of the condensed water in the cell crushing device is controlled to be 1-5°C.

[0005] The embodiment of the present invention also provides an ethanol dispersion of the cobalt-based MOF material prepared by the aforementioned preparation method.

[0006] The embodiment of the present invention also provides the application of the aforementioned cobalt-based MOF material ethanol dispersion in third-order nonlinear optics.

[0007] The embodiment of the present invention further provides a third-order nonlinear optical material, which at least includes the aforementioned cobalt-based MOF material ethanol dispersion.

[0008] The embodiment of the present invention further provides an optical switch, which includes the aforementioned cobalt-based MOF material ethanol dispersion; wherein the threshold optical power of the optical switch is 50 mW.

[0009] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention adopts a simple solution method to synthesize Co-BTE macroporous MOF materials; compared with traditional methods for preparing MOF materials such as hot solvent method and liquid phase epitaxy method, this simple synthesis method has significant advantages; (2) The present invention utilizes a cell crusher in conjunction with low-temperature control technology to achieve MOF particle nano-sizing and avoid structural collapse through power regulation and low-temperature crushing; (3) The present invention utilizes the MOF pore confinement effect to enhance the local electric field and achieve third-order nonlinear controllable activation at a low threshold power of 50 mW. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0011] Figure 1 is a schematic diagram of the process for preparing Co-BTE precipitate in Example 1 of the present invention; Figure 2 is a scanning electron microscope image of the Co-BTE precipitate in step 1 of Example 1 of the present invention; Figure 3 is a scanning electron microscope image of Co-BTE in the Co-BTE ethanol dispersion in step 2 of Example 1 of the present invention; Figure 4 The Co-BTE ethanol dispersion in Example 1 of the present invention generates different numbers of emission light spots under different incident light powers at 532 nm laser excitation; Figure 5 1 is an optical system diagram of using a linear function to fit the optical power and the number of exit light spot rings in Example 1 of the present invention. DETAILED DESCRIPTION

[0012] In view of the defects of the prior art, the inventor of this case has proposed the technical solution of the present invention after long-term research and extensive practice. The present invention adopts a simple solution synthesis method to prepare a cobalt-based MOF material (Co-BTE MOF material) with a large pore structure and high stability. The MOF material is processed into an ethanol dispersion by a cell crusher, and the prepared ultrafine MOF particles can significantly improve its stability in the solution. At the same time, the highly dispersed MOF solution is more conducive to exciting optical third-order nonlinear phenomena.

[0013] For ease of understanding of the present application, the present application will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0014] Specifically, as one aspect of the technical solution of the present invention, a method for preparing a cobalt-based MOF material ethanol dispersion is provided, which comprises: A cobalt source is reacted with an organic ligand to prepare a cobalt-based MOF material (denoted as: Co-BTE); wherein the organic ligand includes 1,3,5-tris(4-carboxyphenylethynyl)benzene (H3BTE); And, the cobalt-based MOF material is mixed with ethanol and crushed by a cell crushing device to obtain a cobalt-based MOF material ethanol dispersion; wherein the power used in the crushing process is 30% to 50%, and the temperature of the condensed water in the cell crushing device is controlled to be 1-5°C.

[0015] In some preferred embodiments, the cobalt source comprises a divalent cobalt source.

[0016] Further, the divalent cobalt source includes any one or more combinations of cobalt acetate tetrahydrate, cobalt chloride dihydrate, cobalt chloride hexahydrate, and cobalt nitrate hexahydrate, but is not limited thereto.

[0017] In some preferred embodiments, the molar ratio of the cobalt source to the organic ligand is 10-1:1-10.

[0018] In some preferred embodiments, the preparation method specifically comprises: Dissolving a cobalt source and an organic ligand in ethanol respectively to form a cobalt source ethanol solution and an organic ligand ethanol solution; The cobalt source ethanol solution and the organic ligand ethanol solution are fully mixed and allowed to react for 12 to 36 hours, and then centrifuged and washed to obtain a cobalt-based MOF material.

[0019] Furthermore, the concentration of the cobalt source ethanol solution is 0.1~2 mmol / L, specifically 0.1mM, 0.2mM, 0.3 mM, 0.4 mM, 0.5 mM, 0.6 mM, 0.7 mM, 0.8 mM, 0.9 mM, 1.0 mM, 1.1 mM, 1.2 mM, 1.3mM, 1.4 mM, 1.5 mM, 1.6 mM, 1.7 mM, 1.8 mM, 1.9 mM, and 2.0 mM.

[0020] Furthermore, the concentration of the organic ligand ethanol solution is 0.1-2 mmol / L.

[0021] In some preferred embodiments, the crushing process lasts for 5 to 10 minutes.

[0022] As another aspect of the technical solution of the present invention, it relates to an ethanol dispersion of a cobalt-based MOF material prepared by the aforementioned preparation method.

[0023] The present invention successfully prepared Co-BTE macroporous MOF material, and further processed it into an ethanol dispersion of ultrafine particles. In the preparation process, the Co-BTE material synthesized by a simple solution method was used as the raw material, and the Co-BTE precipitate immersed in ethanol was crushed by a cell crusher, which significantly reduced the particle size, so that it could be evenly dispersed in the ethanol solution, effectively avoiding the generation of precipitation. Subsequently, the morphology, optical properties, crystal structure and internal atomic composition of the sample were comprehensively characterized using a variety of advanced instruments. Reducing the particle size of the MOF material not only helps its dispersibility in the ethanol solution, but also significantly improves the high temperature resistance and time stability of the dispersion. Under 532nm laser irradiation, the properties of the Co-BTE ethanol dispersion remain stable, and no obvious precipitation appears at the bottom, indicating that its quality fully meets the requirements of the study of optical third-order nonlinear characteristics. In the study of nonlinear characteristics, when the laser power is gradually increased from 20 mW to 150 mW, obvious diffraction rings appear in the output light spot, which clearly proves that the Co-BTE ethanol dispersion has significant optical third-order nonlinear phenomena. When the incident light intensity reaches 50 mW, diffraction rings begin to appear, indicating that the threshold power of the third-order nonlinear phenomenon of Co-BTE ethanol dispersion is 50 mW. Therefore, Co-BTE ethanol dispersion can be used as a new type of optical switch material. When the light power is lower than 50 mW, the third-order nonlinear phenomenon is turned off; when the light power is higher than 50 mW, the third-order nonlinear phenomenon is activated. The present invention uses large-pore MOF materials to explore optical third-order nonlinear phenomena and develops a new type of optical switch, laying a solid scientific foundation for the widespread application of all-optical devices in the future.

[0024] As another aspect of the technical solution of the present invention, it involves the application of the aforementioned cobalt-based MOF material ethanol dispersion in third-order nonlinear optics.

[0025] As another aspect of the technical solution of the present invention, it relates to a third-order nonlinear optical material, which at least includes the aforementioned cobalt-based MOF material ethanol dispersion.

[0026] As another aspect of the technical solution of the present invention, it relates to an optical switch, which includes the aforementioned cobalt-based MOF material ethanol dispersion; wherein the threshold optical power of the optical switch is 50 mW.

[0027] In some preferred embodiments, when the optical switch is irradiated with an optical power less than 50 mW, the third-order nonlinear phenomenon of the optical switch is turned off; when the optical switch is irradiated with an optical power greater than 50 mW, the third-order nonlinear phenomenon of the optical switch is activated.

[0028] The present invention adopts a simple solution method to synthesize Co-BTE macroporous MOF materials; compared with traditional methods for preparing MOF materials such as hot solvent method and liquid phase epitaxy method, the simple synthesis method has significant advantages. Through the ligand pre-dispersion strategy (ethanol dissolving H3BTE) and the dynamic coordination of metal ions, the limitation of traditional MOF synthesis requiring multi-step reactions is broken. It does not need to strictly control the growth temperature of the material, nor does it need to add a large amount of organic matter, and it does not need to accurately control the actual concentration of metal ions and ligand ions. During the synthesis process, it is only necessary to mix a certain concentration of metal ion ethanol solution with a ligand ion ethanol solution, and then shake the mixed ethanol solution vigorously to ensure that the mixed solution is fully uniform. After standing, a MOF precipitate can be generated. This process not only greatly saves time and operating costs, but also effectively avoids the problem of increased difficulty in cleaning MOF precipitates due to excessive organic matter participating in the reaction, thereby significantly improving the efficiency and feasibility of material preparation.

[0029] The present invention utilizes a cell crusher in coordination with low-temperature control technology, and realizes MOF particle nano-sizing and avoids structural collapse through power regulation and low-temperature crushing. Due to its unique porous structure, the MOF material that has just been cleaned may adsorb a small amount of foreign impurity ions in the pores, which makes it difficult for the MOF material to be evenly dispersed in the ethanol solution, but in a precipitation state. However, after the crushing treatment of the cell crusher, the particle size of the MOF material is significantly reduced, so that it can be better dispersed in the ethanol solution. Even in a static state, the crushed MOF ethanol dispersion is difficult to precipitate. This feature is crucial for the application of the dispersion in space light irradiation. It not only ensures that the dispersion can maintain a uniform and stable state during the light irradiation process, but also can keep the properties of the solution basically unchanged after repeated laser irradiation. This provides an important basic guarantee for subsequent optical property research and practical applications.

[0030] The present invention utilizes the MOF pore confinement effect to enhance the local electric field and realize the controllable activation of the third-order nonlinearity at a low threshold power of 50 mW. Compared with many organic materials, MOF materials have significantly higher time stability and can maintain their performance unchanged for a long time. In addition, compared with the harsh synthesis conditions and high preparation costs of two-dimensional materials, the MOF materials in the present invention do not require complex processes and expensive reagents during the preparation process, thereby greatly reducing costs and improving the economy and scalability of materials. With the support of many advantages, the MOF materials in the present invention can not only effectively excite optical third-order nonlinear phenomena, but also in repeated experiments, its excitation effect remains stable without showing an obvious attenuation trend. This shows that the MOF material has excellent performance and reliability in optical third-order nonlinear characteristics. This discovery has laid a solid practical foundation for the widespread application of all-optical devices in the future, and is expected to promote the further development of optical technology in the fields of communication, sensing and information processing.

[0031] The present invention is further described by the following examples: The present invention can be better understood according to the following examples. However, it is easy for those skilled in the art to understand that the specific material ratios, process conditions and results described in the examples are only used to illustrate the present invention, and should not and will not limit the present invention described in detail in the claims.

[0032] Unless otherwise specified, the various raw materials, reaction equipment, testing equipment and testing methods used in the following examples are all well known in the art.

[0033] Example 1 Step 1: Preparation of Co-BTE MOF precipitate: First, dissolve the ligand H3BTE and cobalt acetate tetrahydrate powder in anhydrous ethanol to form a solution with a concentration of 0.5 mM. Then, take 25 mL of each solution in equal volumes and mix them in a 50 mL centrifuge tube. Seal the mouth of the centrifuge tube and shake the centrifuge tube up and down for 2 min to ensure that the solution is fully mixed. Then let the mixed solution stand for 24 hours to promote the complete reaction between the ligand ions and metal ions, and finally form a Co-BTE precipitate in the solution; Figure 1 The schematic diagram of the preparation of MOF precipitate in this example is shown below. The Co-BTE solution is then centrifuged at 8000-12000 rpm for 5-10 minutes to separate the precipitate. The precipitate is then washed with clean ethanol to remove any impurities. The process is repeated twice to ensure that the Co-BTE precipitate is thoroughly clean.

[0034] Step 2: Preparation of Co-BTE ethanol dispersion: The cleaned Co-BTE precipitate in step 1 was placed in 25 mL of ethanol solution, and then crushed using a cell crusher. The power of the cell crusher was set to 40%, the crushing time was 7 minutes, and the temperature of the condensed water was controlled at 3 °C. After the crushing treatment, the ethanol solution will turn into a light yellow MOF dispersion. The dispersion was left to stand for more than 5 hours, and no obvious precipitation was produced, indicating that the dispersion treatment was successful.

[0035] The Co-BTE precipitate prepared above and the crushed Co-BTE ethanol dispersion were taken out and transferred to a clean silicon wafer. After drying overnight at room temperature 25°C, a scanning electron microscope was turned on at a voltage of 20 KV and secondary electron emission was used for microscopic observation under a high vacuum environment to obtain optical fiber photos of the MOF structure before and after treatment ( Figure 2-Figure 3 The Co-BTE precipitate synthesized by the simple solution method exhibits a matchstick-like microrod morphology, with an average length of about ten micrometers (as shown in Figure 2 After being treated by the cell disruptor, the Co-BTE in the dispersion no longer maintains the microrod shape, but transforms into particles (as shown in Figure 3 As shown in Figure 2, the Co-BTE material can be more evenly dispersed in the ethanol solution due to the significant reduction in particle size, and is less likely to form precipitation. This improvement in dispersion effect makes the treated Co-BTE dispersion show better performance in exciting optical nonlinear phenomena.

[0036] Step 3: Excitation of the third-order optical nonlinear phenomenon of Co-BTE ethanol dispersion: Take 3 mL of the Co-BTE ethanol dispersion prepared in step 2 and put it into a four-way quartz cuvette. Focus the laser with a wavelength of 532 nm through a focusing lens so that the focus falls accurately on the cuvette containing the Co-BTE ethanol dispersion. Then adjust the power of the incident light and use a camera to record the number of diffraction rings of the outgoing light spot, such as Figure 4 As shown. When the incident light power exceeds the threshold power of 50 mW, the optical third-order nonlinear phenomenon of the Co-BTE ethanol dispersion is effectively excited, and obvious diffraction rings appear in the output light spot. As the power increases further, the number of diffraction rings gradually increases. In the process of MOF dispersion exciting the third-order nonlinear phenomenon, the adjustment range of the incident light power is 20-150 mW.

[0037] In order to evaluate the temporal stability of Co-BTE ethanol dispersion when exciting optical nonlinear phenomena, three repeated experiments were carried out. During the experiment, the laser power was first gradually increased from 20 mW to 150 mW, and the diffraction ring image of the output light spot was recorded with a camera. Subsequently, the laser power was gradually reduced from 150 mW to 20 mW, and the diffraction ring image of the output light spot was recorded again. The third experiment repeated the process of gradually increasing the laser power from 20 mW to 150 mW, and recorded the corresponding diffraction ring image. By sorting out the data recorded in the three experiments, a plot was drawn. Figure 5 The image shown in the figure is fitted with a linear function. The fitting results show that the three straight lines almost completely overlap, which strongly indicates that the Co-BTE ethanol dispersion has good temporal stability under the cyclic irradiation of the laser. In addition, the number of diffraction rings presented in the three experimental data is highly consistent, further confirming that the Co-BTE ethanol dispersion can stably excite the optical third-order nonlinear phenomenon.

[0038] In summary, the present invention successfully prepared Co-BTE materials through a simple solution method, and used a cell crusher to further process the cleaned MOF material into a highly stable and high-temperature resistant ethanol dispersion. In the experiment, a laser with a wavelength of 532 nm was used to irradiate the MOF ethanol dispersion to excite its optical third-order nonlinear phenomenon. As the incident laser power gradually increased, the appearance and enhancement of the diffraction rings in the outgoing laser spot were clearly visible, indicating that the Co-BTE ethanol dispersion had significant optical switching characteristics. In the process of exciting the optical third-order nonlinear phenomenon, the experimentally set incident laser power range was 20-150 mW, and the threshold optical power for the third-order nonlinear phenomenon to be turned on was observed to be 50 mW. This discovery not only confirms the application potential of MOF ethanol dispersion in the field of optical switching, but also provides an important experimental basis for its further development and application in all-optical devices.

[0039] Example 2 Step 1: Preparation of Co-BTE MOF precipitate: First, dissolve the ligand H3BTE and cobalt nitrate hexahydrate powder in anhydrous ethanol to form a solution with a concentration of 0.1 mM. Then, take 25 mL of each solution in equal volumes and mix them in a 50 mL centrifuge tube. Seal the mouth of the centrifuge tube and shake the centrifuge tube up and down for 2 min to ensure that the solution is fully mixed. Then let the mixed solution stand for 12 h to promote the complete reaction between the ligand ions and metal ions, and finally form a Co-BTE precipitate in the solution.

[0040] Step 2: Preparation of Co-BTE ethanol dispersion: The cleaned Co-BTE precipitate in step 1 was placed in 25 mL of ethanol solution, and then crushed using a cell crusher. The power of the cell crusher was set to 30%, the crushing time was 10 minutes, and the temperature of the condensed water was controlled at 3 °C. After the crushing treatment, the ethanol solution will turn into a light yellow MOF dispersion. The dispersion was left to stand for more than 5 hours, and no obvious precipitation was produced, indicating that the dispersion treatment was successful.

[0041] Example 3 Step 1: Preparation of Co-BTE MOF precipitate: First, dissolve the ligand H3BTE and cobalt chloride hexahydrate powder in anhydrous ethanol to form a solution with a concentration of 2.0 mM. Then, take 25 mL of each solution and mix them in an equal volume in a 50 mL centrifuge tube. Seal the mouth of the centrifuge tube and shake the centrifuge tube up and down for 2 min to ensure that the solution is fully mixed. Then let the mixed solution stand for 36 h to promote the complete reaction between the ligand ions and metal ions, and finally form a Co-BTE precipitate in the solution.

[0042] Step 2: Preparation of Co-BTE ethanol dispersion: The cleaned Co-BTE precipitate in step 1 was placed in 25 mL of ethanol solution, and then crushed using a cell crusher. The power of the cell crusher was set to 50%, the crushing time was 5 minutes, and the temperature of the condensed water was controlled at 3 °C. After the crushing treatment, the ethanol solution will turn into a light yellow MOF dispersion. The dispersion was left to stand for more than 5 hours, and no obvious precipitation was produced, indicating that the dispersion treatment was successful.

[0043] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0044] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing a cobalt-based MOF material ethanol dispersion, characterized in that: include: Reacting a cobalt source with an organic ligand to obtain a cobalt-based MOF material; wherein the organic ligand comprises 1,3,5-tris(4-carboxyphenylethynyl)benzene; And, the cobalt-based MOF material is mixed with ethanol and crushed by a cell crushing device to obtain a cobalt-based MOF material ethanol dispersion; wherein the power used in the crushing process is 30% to 50%, and the temperature of the condensed water in the cell crushing device is controlled to be 1-5°C.

2. The preparation method according to claim 1, characterized in that: The cobalt source includes a divalent cobalt source; preferably, the divalent cobalt source includes any one or more combinations of cobalt acetate tetrahydrate, cobalt chloride dihydrate, cobalt chloride hexahydrate, and cobalt nitrate hexahydrate; And / or, the molar ratio of the cobalt source to the organic ligand is 10-1:1-10.

3. The preparation method according to claim 1, characterized in that: Specifically include: Dissolving a cobalt source and an organic ligand in ethanol respectively to form a cobalt source ethanol solution and an organic ligand ethanol solution; The cobalt source ethanol solution and the organic ligand ethanol solution are fully mixed and allowed to react for 12 to 36 hours, and then centrifuged and washed to obtain a cobalt-based MOF material.

4. The preparation method according to claim 3, characterized in that: The concentration of the cobalt source ethanol solution is 0.1-2 mmol / L; and / or the concentration of the organic ligand ethanol solution is 0.1-2 mmol / L.

5. The preparation method according to claim 1, characterized in that: The crushing process takes 5 to 10 minutes.

6. An ethanol dispersion of a cobalt-based MOF material prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the cobalt-based MOF material ethanol dispersion according to claim 6 in third-order nonlinear optics.

8. A third-order nonlinear optical material, characterized in that: At least comprising the cobalt-based MOF material ethanol dispersion according to claim 6.

9. An optical switch, characterized in that: It comprises the cobalt-based MOF material ethanol dispersion according to claim 6; wherein the threshold optical power of the optical switch is 50 mW.

10. The optical switch according to claim 9, characterized in that: When the optical switch is irradiated with an optical power less than 50 mW, the third-order nonlinear phenomenon of the optical switch is turned off; when the optical switch is irradiated with an optical power greater than 50 mW, the third-order nonlinear phenomenon of the optical switch is activated.

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