Metal organic framework composite material with circular polarization room temperature phosphorescence characteristic and preparation method thereof
By ball milling the metal salt, organic ligand and axial chiral molecules at room temperature, MOFs composite materials with circular polarization room temperature phosphorescence characteristics were prepared, which solved the problems of short life and low luminous efficiency of MOFs-based circular polarization luminescent materials in the prior art, and achieved efficient and long-lived circular polarization room temperature phosphorescence performance.
Patent Information
- Application Number
- CN202510299713.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-13
- Publication Date
- 2025-05-27
AI Technical Summary
It is difficult to prepare MOFs composite materials with circular polarization room temperature phosphorescence characteristics in the prior art, and the existing MOFs-based circular polarization luminescent materials have short lifetime and low luminescence efficiency, which hinder their application and development.
The metal salt, organic ligand and axial chiral molecules were added to the centrifuge tube at room temperature, and the samples were subjected to ball milling reaction, and then the samples were centrifuged with organic solvent and dried to obtain a MOFs composite material with circular polarization room temperature phosphorescence characteristics.
The prepared S-type and R-type chiral MOFs composites exhibit excellent circular polarization room temperature phosphorescence performance, with luminescence lifetimes of 392.2ms and 395.2ms, the maximum luminescence asymmetry factor glum is 1.2×10-3, the reaction conditions are mild, the yield is high, and it is suitable for large-scale production.
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Figure CN120040785A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of functional materials, relates to the field of metal-organic framework materials, and particularly relates to a metal-organic framework composite material with circularly polarized room temperature phosphorescence characteristics and a preparation method thereof. Background Art
[0002] In recent years, circularly polarized luminescent materials mainly composed of chiral molecules, as a new type of optical functional material, have attracted much attention due to their characteristics such as optical activity, polarized light selective emission, and circular dichroism, and can be used in multiple research fields such as three-dimensional display, photocatalytic asymmetric synthesis, and encryption detection. Traditionally, circularly polarized light can be generated from unpolarized light by physical methods. The emitted unpolarized light is first converted into linearly polarized light by a linear polarizer, and then further decomposed into left-handed or right-handed circularly polarized light by a quarter-wave plate. In this indirect physical process, at least 50% of the energy will be lost. Therefore, it is necessary to develop new luminescent materials that can directly generate circularly polarized light.
[0003] Room temperature phosphorescent materials have a wide range of applications in anti-counterfeiting encryption, display, and information storage due to their long luminescence lifetime. Compared with circularly polarized fluorescent materials, the research on circularly polarized room temperature phosphorescent materials is relatively less, mainly because the current methods for synthesizing circularly polarized room temperature phosphorescent materials will change the structure and interaction of luminescent molecules, causing the inactivation of highly sensitive triplet excitons and unable to generate circularly polarized room temperature phosphorescence.
[0004] Metal-organic frameworks (MOFs) materials have excellent optical properties, good light resistance, and good biocompatibility. The rigid environment provided by the strong coordination interaction in the MOF structure can inhibit the non-radiative decay of excitons, and due to the heavy atom effect of metal ions and heteroatoms (such as N, O, P, and S) in organic ligands, the intersystem crossing rate can be accelerated by enhancing spin-orbit coupling, thereby stabilizing triplet excitons. Therefore, MOFs are very promising for constructing long-lived circularly polarized room temperature phosphorescent systems.
[0005] Currently, the research on chiral MOF composite materials with circularly polarized room temperature phosphorescence characteristics is relatively less. The reported lifetimes of MOF-based circularly polarized luminescent materials at room temperature are relatively short, and the luminescence efficiency is low. These defects have greatly hindered the application and development of MOF-based circularly polarized luminescent materials. Therefore, the design and synthesis of MOF-based circularly polarized room temperature phosphorescent materials with stable structures and high luminescence efficiencies are one of the research focuses in this field. Summary of the Invention
[0006] The object of the present invention is to provide a preparation method of a MOFs composite material with circularly polarized room temperature phosphorescence characteristics in view of the technical defect that it is difficult to prepare circularly polarized room temperature phosphorescent materials in the prior art, and to solve one or more of the above-mentioned problems in the prior art.
[0007] The technical solution adopted to achieve the object of the present invention is as follows:
[0008] A preparation method of a MOFs composite material with circularly polarized room temperature phosphorescence characteristics, and the specific operation of the preparation method is as follows: at room temperature, a metal salt, an organic ligand and an axially chiral molecule are added into a centrifuge tube, and then ball milling reaction is carried out. After the reaction is completed, the sample is centrifuged and washed with an organic solvent and then dried to obtain a MOFs composite material with circularly polarized room temperature phosphorescence characteristics.
[0009] In some embodiments, the MOFs material is preferably ZIF-8, and the metal salt and the organic ligand are zinc oxide and 2-methylimidazole.
[0010] In some embodiments, the molar ratio of the metal salt to the organic ligand is 1:2.
[0011] In some embodiments, the axially chiral molecule is at least one of (S)-1,1'-bi-2-naphthol, (R)-1,1'-bi-2-naphthol, (S)-6,6'-dibromo-1,1'-bi-2-naphthol, and (R)-6,6'-dibromo-1,1'-bi-2-naphthol. The common point of the structures of these axially chiral molecules is that they have a hydroxyl functional group.
[0012] In some embodiments, the molar ratio of the metal salt to the axially chiral molecule is 1:0.01 - 1:1. Among them, 1:0.5 is preferred. When the molar ratio is higher or lower than this ratio, the luminescence performance of the composite material is not the most excellent.
[0013] In some embodiments, the type of the ball mill is a vibration ball mill.
[0014] In some embodiments, the ball milling speed is 1200 - 1800 revolutions per minute, and the time is 10 - 90 minutes.
[0015] In some embodiments, the organic solvent is absolute ethanol.
[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0017] 1. The S-type and R-type chiral MOFs composites of the present invention both exhibit yellow phosphorescent emission under excitation. The lifetime of the S-type chiral MOFs composite is 392.2 ms, and that of the R-type chiral MOFs composite is 395.2 ms. The S-type and R-type chiral MOFs composites show excellent circularly polarized room-temperature phosphorescence properties, and the luminescence dissymmetry factor g lum is up to 1.2×10 -3 .
[0018] 2. The chiral MOFs composites of the present invention have a well-defined coordination structure, providing a good platform for revealing the relationship between structure and properties and broadening the way for further preparation of high-performance circularly polarized room-temperature phosphorescent materials.
[0019] 3. The advantages of the present invention are that the reaction conditions for preparing the MOFs composites with circularly polarized room-temperature phosphorescent properties are mild, the reaction is rapid, the yield is high, and no large amount of organic solvents need to be added.
[0020] 4. The advantages of the present invention are that the reaction process for preparing the MOFs composites with circularly polarized room-temperature phosphorescent properties is simple, the required equipment is simple, and scale-up production can be achieved using a ball mill. BRIEF DESCRIPTION OF THE DRAWINGS
[0021] Figure 1 is the optical photograph of the S-type chiral MOFs composite obtained in Example 1;
[0022] Figure 2 is the optical photograph of the R-type chiral MOFs composite obtained in Example 2;
[0023] Figure 3 is the phosphorescence spectrum of the S-type chiral MOFs composite obtained in Example 3;
[0024] Figure 4 is the phosphorescence lifetime diagram of the S-type chiral MOFs composite obtained in Example 3;
[0025] Figure 5 is the phosphorescence spectrum of the R-type chiral MOFs composite obtained in Example 3;
[0026] Figure 6 is the phosphorescence lifetime diagram of the R-type chiral MOFs composite obtained in Example 3;
[0027] Figure 7 is the CD spectrum of the S- and R-type chiral MOFs composites obtained in Example 3;
[0028] Figure 8 is the CPL spectrum of the S- and R-type chiral MOFs composites obtained in Example 3;
[0029] Figure 9The g of the S and R chiral MOFs composite materials obtained in Example 3 lum Figure Specific implementation manners
[0030] The present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.
[0031] Example 1
[0032] A metal-organic framework composite material with circularly polarized room temperature phosphorescence (S-type chiral MOFs composite material, denoted as S-Binol@ZIF-8) is prepared by the following steps:
[0033] Put zinc oxide (0.04 g), 2-methylimidazole (0.0807 g) and (S)-1,1'-bi-2-naphthol (70.30 mg) (molar ratio 1:2:0.5) into a 2 mL plastic centrifuge tube, and add 3 zirconia balls with a diameter of 7 mm.
[0034] Place the plastic centrifuge tube in a vibratory ball mill and grind it at a frequency of 30 Hz for 50 min. Centrifuge to collect the product and wash it five times with ethanol. The obtained product is placed in a vacuum oven and dried overnight at 60 °C to obtain the S-Binol@ZIF-8 powder material.
[0035] The optical photograph of the circularly polarized room temperature phosphorescent chiral MOFs composite material prepared in Example 1 is as Figure 1 shown Figure 1 a is the optical photograph of the S-Binol@ZIF-8 material after excitation by a 360 nm ultraviolet lamp. It can be seen from the figure that the S-Binol@ZIF-8 material exhibits blue fluorescence emission and yellow afterglow emission when the ultraviolet excitation stops ( Figure 1 b).
[0036] Example 2
[0037] A MOFs composite material with circularly polarized room temperature phosphorescence (R-type chiral MOFs composite material, denoted as R-Binol@ZIF-8) is prepared by the following steps:
[0038] Put zinc oxide (0.04 g), 2-methylimidazole (0.0807 g) and (R)-1,1'-bi-2-naphthol (70.30 mg) (molar ratio 1:2:0-5) into a 2 mL plastic centrifuge tube, and add 3 zirconia balls with a diameter of 7 mm.
[0039] Place the plastic centrifuge tube in a vibrating ball mill and grind it at a frequency of 30 Hz for 50 min. Centrifuge to collect the product and wash it five times with ethanol. Place the obtained product in a vacuum oven and dry it overnight at 60 °C to obtain the R-Binol@ZIF-8 powder material.
[0040] The optical photograph of the circularly polarized room temperature phosphorescent chiral MOFs composite material prepared in Example 2 is as Figure 2 shown Figure 2 a is the optical photograph of the R-Binol@ZIF-8 material after being excited by a 360 nm ultraviolet lamp. It can be seen from the figure that the R-Binol@ZIF-8 material exhibits blue fluorescence emission and shows yellow afterglow emission when the ultraviolet excitation stops ( Figure 2 b).
[0041] Example 3
[0042] Perform steady-state / transient fluorescence spectroscopy tests on the S-type and R-type chiral MOFs composite materials obtained in Example 1 and Example 2. Among them Figure 3 is the phosphorescence spectrum of the S-type chiral MOFs composite material S-Binol@ZIF-8, Figure 4 is the luminescence lifetime diagram of S-Binol@ZIF-8 at 560 nm, and its lifetime is 392.2 ms. Figure 5 is the phosphorescence spectrum of the R-type chiral MOFs composite material R-Binol@ZIF-8, Figure 6 is the luminescence lifetime diagram of R-Binol@ZIF-8 at 560 nm, and its lifetime is 395.2 ms.
[0043] Figure 7 is the CD spectrum comparison of the S-type and R-type chiral MOFs composite materials S-Binol@ZIF-8 and R-Binol@ZIF-8. From Figure 7 it can be seen that obvious CD signals can be exhibited after forming the composite material, and the intensity is significantly improved.
[0044] Figure 8 is the CPL spectrum comparison of the S-type and R-type chiral MOFs composite materials S-Binol@ZIF-8 and R-Binol@ZIF-8. From Figure 8 it can be seen that obvious CPL signals can be exhibited after forming the composite material, and the intensity is significantly improved.
[0045] Figure 9 is the g lum value of the S-type and R-type chiral MOFs composite materials S-Binol@ZIF-8 and R-Binol@ZIF-8. The performance of the chiral composite material is significantly improved compared with that of the chiral molecule. From Figure 9It can be seen that the g values of S-Binol@ZIF-8 and R-Binol@ZIF-8 are lum 1.2×10 -3 and 1.1×10 -3 respectively.
[0046] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.
Claims
1. A method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties, characterized in that: The specific operation of the preparation method is: adding metal salt, organic ligand and axial chiral molecule into a centrifuge tube at room temperature, then performing ball milling reaction, washing the sample by centrifugation with organic solvent after the reaction is completed, and drying to obtain a metal organic framework composite material with circularly polarized room temperature phosphorescence characteristics.
2. The method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties according to claim 1, characterized in that: The metal organic framework material is a type of porous coordination polymer formed by self-assembly of metal ions or metal clusters and organic ligands, and the metal salt and organic ligand are zinc oxide and 2-methylimidazole.
3. The method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties according to claim 1, characterized in that: The molar ratio of the metal salt to the organic ligand is 1:
2.
4. The method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties according to claim 1, characterized in that: The axial chiral molecule is at least one of (S)-1,1′-bi-2-naphthol, (R)-1,1′-bi-2-naphthol, (S)-6,6′dibromo-1,1′-bi-2-naphthol and (R)-6,6′dibromo-1,1′-bi-2-naphthol.
5. The method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties according to claim 1, characterized in that: The molar ratio of the metal salt to the axial chiral molecule is 1:0.01-1:
1.
6. The method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties according to claim 1, characterized in that: The ball mill type is a vibrating ball mill.
7. The method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties according to claim 1, characterized in that: The ball milling speed is 1200-1800 rpm, and the time is 10-90 minutes.
8. The method for preparing a metal organic framework composite material having circularly polarized room temperature phosphorescence properties according to claim 1, characterized in that: The organic solvent is anhydrous ethanol.
9. Application of the material prepared by the method for preparing a metal organic framework composite material with circularly polarized room temperature phosphorescence property according to claim 1 in the field of luminescence.