An organic long afterglow luminescent material and its application

Abstract

The present invention discloses an organic long afterglow luminescent material and its application, wherein the organic long afterglow luminescent material contains a biphenyl polymer mBPipQ. The present invention also discloses a preparation method of the organic long afterglow luminescent material, wherein the biphenyl polymer mBPipQ is doped into an epoxy resin matrix, and the hard epoxy resin matrix after being fully cured provides a protective layer for the internal mBPipQ powder, preventing all quenchers that interfere with phosphorescence emission from entering the interior; the hard epoxy resin protective layer gives the long afterglow material excellent stability in strong acid (PH=1) or strong base (PH=14) solutions. The present invention synthesizes biphenyl-type polymer chromophores, uses ordinary small molecules as raw materials, has simple ingredients, and has a simple and easy-to-control preparation method. It has the advantages of low production cost and wide sources of raw materials, etc., and provides new theoretical guidance and technical support for the simple and efficient industrial production of strong acid and strong base resistant long-life organic long afterglow materials, and also broadens the application scope of long-life organic long afterglow materials.

Description

Technical Field

[0001] The invention relates to an organic long afterglow luminescent material, in particular to an acid and alkali resistant, high-efficiency, long-life polymer-based long afterglow luminescent material and application thereof. Background Art

[0002] Room temperature phosphorescence is a unique photoluminescence phenomenon with broad application prospects in bioimaging, data security, organic light-emitting diodes, chemical sensing, etc. However, the triplet excitons required for phosphorescence emission need to transfer from the lowest excited singlet state to the triplet state through intersystem crossing, and this process is spin-forbidden; in addition, the hard-won triplet excitons can also be non-radiatively inactivated due to molecular rotation and vibration, or quenched by water and molecular oxygen. Therefore, the preparation of efficient organic room temperature materials under ambient conditions remains a daunting task. So far, researchers have proposed effective strategies such as crystallization, self-assembly, and H-aggregation to promote the intersystem crossing process to produce more triplet excitons and suppress non-radiative transitions to stabilize triplet excitons.

[0003] In recent years, the preparation of efficient room temperature phosphorescent materials has been achieved by rationally selecting or designing the polymer matrix and chromophore molecular structure, using rigid steroid compounds, covalent crosslinking, free radical copolymerization, phosphor doping matrix and other methods. Among them, the rigid structure provided by the polymer matrix is ​​an indispensable guarantee for the efficient emission of room temperature phosphorescence by such materials. Polyvinyl alcohol, as the most commonly used polymer matrix, contains hydroxyl groups, which can form hydrogen bond interactions with phosphors, greatly inhibiting molecular motion and compressing non-radiative transition paths. However, the polyvinyl alcohol matrix is ​​extremely sensitive to air and humidity, and the abundant non-covalent interactions such as hydrogen bonds and ionic bonds in the matrix are easily decomposed in air or water, resulting in phosphorescence quenching. This means that these room temperature phosphorescent materials require a strict storage environment and cannot be stored for a long time in the atmosphere or even in a harsher environment. Therefore, to broaden the application range of polymer room temperature phosphorescent materials, it is necessary to develop long-life room temperature phosphorescent materials with excellent stability in harsh environments. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a long-life organic long afterglow luminescent material with good stability, which solves the problems of poor stability and short life of the existing polymer-based long afterglow luminescent materials in acid and alkali solvents.

[0005] At the same time, the present invention also provides a method for preparing the organic long afterglow luminescent material, which solves the problems of difficulty in preparing high-efficiency organic long afterglow luminescent materials under ambient conditions and high cost.

[0006] Furthermore, the present invention also provides the application of the above-mentioned long-life organic long afterglow luminescent material in realizing data encryption and anti-counterfeiting.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] An organic long afterglow luminescent material, characterized by containing a biphenyl polymer mBPiPQ having the following structure:

[0009]

[0010] Furthermore, the organic long afterglow luminescent material is prepared by the following method:

[0011] S1, synthesis of biphenyl type polymer mBPiPQ;

[0012] S2. Dope the biphenyl polymer mBPiPQ into the epoxy resin matrix, then transfer it to a silicone mold, place it in a water-free and oxygen-free glove box and let it stand and cure for 15-48 hours at a temperature of 20-30°C to obtain an organic long afterglow luminescent material.

[0013] Further, the step S1 comprises:

[0014] S11. Synthesis of biphenyl type polymer mBPip:

[0015]

[0016] S12. Synthesis of polymer precursor QDHB:

[0017]

[0018] S13. Synthesis of biphenyl type polymer mBPiPQ, the synthesis route is as follows:

[0019]

[0020] The molar ratio of the polymer precursor to the biphenyl polymer is 1:2.5-3.5, and the reaction time is 4-6 days.

[0021] Further, the step S2 comprises:

[0022] S21, preparing epoxy resin matrix: epoxy resin and auxiliary materials are uniformly mixed at a mass ratio of 2.8-3.2:1; wherein the auxiliary materials are curing agent, diluent and accelerator;

[0023] S22, doping the biphenyl polymer mBPiPQ into the epoxy resin matrix of step S21, then transferring it to a silicone mold, placing it in a water-free and oxygen-free glove box and curing it for 15-48 hours to obtain a high-efficiency organic long afterglow luminescent material.

[0024] Furthermore, in step S22, the relative mass ratio of the biphenyl polymer doped into the epoxy resin matrix is ​​1:1400-600.

[0025] Furthermore, the epoxy resin is E51 epoxy resin or similar functional resin.

[0026] The present invention also provides an application of the organic long afterglow luminescent material, that is, applying the organic long afterglow luminescent material to the fields of data storage and anti-counterfeiting technology.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The organic long afterglow luminescent material of the present invention contains a biphenyl polymer chromophore; the biphenyl polymer chromophore is doped into an epoxy resin matrix, and the fully cured hard epoxy resin matrix provides a protective layer for the internal mBPipQ powder, preventing any quencher that interferes with phosphorescence emission from entering the interior; the hard epoxy resin protective layer gives the organic long afterglow luminescent material excellent stability in strong acid (PH=1) or strong base (PH=14) solutions, and even after immersion for 10 days, it can still emit a yellow-green afterglow visible to the naked eye.

[0029] 2. The invention is simple to prepare and has low cost. The synthesized biphenyl polymer chromophore uses common small molecules as raw materials, has simple ingredients, and the preparation method is simple and easy to control. It has the advantages of low production cost and wide source of raw materials, and provides new theoretical guidance and technical support for the simple and efficient industrial production of long-life organic long-lasting luminescent materials with poor solvent resistance, and also broadens the application scope of long-life organic long-lasting luminescent materials.

[0030] 3. The epoxy resin matrix used in the present invention is purchased from commercial channels at low cost and with simple method, which provides a new idea for realizing organic long afterglow luminescent materials with high efficiency and stability in harsh environments, and also increases the diversity of polymer-based organic long afterglow luminescent materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The actual phosphorescence images of the high-efficiency organic long afterglow luminescent materials with different mass ratios prepared in Example 1 under a 365nm ultraviolet lamp;

[0032] Figure 2 The photophysical properties of the high-efficiency organic long afterglow luminescent materials with different mass ratios prepared in Example 1 measured under the same conditions;

[0033] Figure 3 The phosphorescence spectra of the high-efficiency organic long afterglow luminescent material prepared in Example 2 at different immersion times in strong acid and strong alkali and the corresponding phosphorescence comparison photos under 365nm ultraviolet light irradiation;

[0034] Figure 4 This is a photo of the high-efficiency organic long afterglow luminescent material with multiple information encryption prepared in Example 3 and a demonstration of the corresponding anti-counterfeiting process. DETAILED DESCRIPTION

[0035] The present invention is further described in detail below in conjunction with embodiments.

[0036] 1. An organic long afterglow luminescent material, comprising a biphenyl polymer mBPiPQ having the following structure:

[0037]

[0038] Table 1 shows specific organic long afterglow luminescent materials, which are cured according to the following ratios.

[0039] Example mBPiPQ: Epoxy resin (mass ratio) Epoxy resin A glue / epoxy resin B glue (mass ratio) Example 1 1:1400 3:1 Example 2 1:1200 3.2:1 Example 3 1:1000 3:1 Example 4 1:800 2.8:1 Example 5 1:600 3:1

[0040] Among them, epoxy resin A glue and epoxy resin B glue are both crystal glue purchased from commercial channels. The main component of epoxy resin A glue is E51 type epoxy resin, and the main components of epoxy resin B glue are curing agent, diluent and accelerator.

[0041] 2. A method for preparing an organic long afterglow luminescent material comprises the following steps:

[0042] (1) Synthesis of biphenyl polymer mBPip:

[0043]

[0044] (2) Synthesis of polymer precursor QDHB:

[0045]

[0046] (3) Synthesis of biphenyl type polymer mBPiPQ, the synthesis route is as follows:

[0047]

[0048] The molar ratio of the polymer precursor QDHB to the biphenyl polymer (chromophore precursor) mBPip is 1:2.5-1:3.5, and the reaction time is 4-6 days;

[0049] (4) Prepare epoxy resin matrix: epoxy resin A glue and epoxy resin B glue are uniformly mixed in a mass ratio of 2.8:1-3.2:1; wherein, epoxy resin A glue and epoxy resin B glue are both crystal drop glues purchased from commercial channels, the main component of epoxy resin A glue is E51 type epoxy resin, and the main components of epoxy resin B glue are curing agent, diluent and accelerator.

[0050] (5) The biphenyl polymer mBPiPQ is doped into the epoxy resin matrix of step (4), and then transferred to a silicone mold, and placed in a water-free and oxygen-free glove box for curing for 15-48 hours to obtain a high-efficiency organic long afterglow luminescent material.

[0051] Example 6

[0052] (1) 0.237 g of 1,4-di(4-pyridyl)benzene and 14 mL of 1,6-dibromohexane were used as raw materials. Without a catalyst, the reaction was stirred at 80 °C for 20 h in acetonitrile as a solvent and under argon protection. Finally, the product was ultrasonically washed and filtered with ether and ethyl acetate, and then collected and dried in a vacuum oven for 24 h to obtain the precursor small molecule QDHB.

[0053] (2) Using 3 g of biphenyl and 2.91 mL of N-methyl-4-piperidone as raw materials, a Friedel-Krad polycondensation reaction was carried out under the catalysis of 36.6 mL of trifluoromethanesulfonic acid. After the reaction was completed, it was placed in a 5 mol / L sodium hydroxide solution for purification, then filtered and ultrasonically rinsed three times with deionized water, then soaked in a 1 mol / L potassium carbonate solution for 48 hours, then rinsed three times with deionized water and placed in an oven for drying. After drying, the precursor polymer mBPip was obtained, which was purified by Soxhlet to prepare for the next reaction.

[0054] (3) The two precursor products QDHB (0.059 g) and mBPip (0.6 g) obtained in steps (1) and (2) were weighed and added to a 100-mL round-bottom flask containing 15 mL of N-methylpyrrolidone. Under argon protection, the temperature was maintained at 80° C. and stirred for 6 days to obtain a brown uniform solution. The brown solution was then added dropwise to ethyl acetate for reprecipitation to obtain a crude solid phase. The orange-red solid phase crude product was collected by filtration; it was then repeatedly washed with methanol for further purification, and finally dried in a vacuum oven at 60° C. to obtain the biphenyl-type polymer mBPipQ.

[0055] (4) The biphenyl polymer mBPipQ obtained in step (3) is added to 10g of epoxy resin matrix in the mass of 7.1mg, 8.3mg, 10mg, 12.5mg and 16.7mg respectively, and mechanically stirred and mixed to obtain colloids with different mass ratios (about 1:1400, 1:1200, 1:1000, 1:800, 1:600). Then it is transferred to a silicone mold through a rubber dropper, and is placed in a water-free and oxygen-free glove box for curing for 15-48h to obtain an organic long afterglow luminescent material. Wherein, the epoxy resin matrix is ​​obtained by uniformly mixing epoxy resin A glue and epoxy resin B glue in a mass ratio of 2.8:1-3.2:1, epoxy resin A glue and epoxy resin B glue are both crystal glue, purchased from commercial channels, epoxy resin A glue mainly contains E51 type epoxy resin, and epoxy resin B glue mainly contains curing agent, diluent and accelerator.

[0056] like Figure 1 As shown, in the atmospheric environment, the wavelength of ultraviolet light is 365nm and the power of ultraviolet light is 30μw / cm 2 The organic long afterglow luminescent materials with different mass ratios obtained in the above steps are irradiated with ultraviolet light, and bright yellow-green phosphorescence of different degrees can be observed by naked eyes.

[0057] like Figure 2 Shown are the photophysical properties of high-efficiency organic long afterglow luminescent materials with different mass ratios measured under the same conditions. Figure 2 In the figure, Figure a represents the fluorescence emission peaks of organic long afterglow luminescent materials with different mass ratios (1:1400, 1:1200, 1:1000, 1:800, 1:600); Figure b represents the phosphorescence emission peaks of organic long afterglow luminescent materials with different mass ratios (1:1400, 1:1200, 1:1000, 1:800, 1:600); Figure c represents a bar column comparison chart of the phosphorescence lifetime values ​​of organic long afterglow luminescent materials with different mass ratios (1:1400, 1:1200, 1:1000, 1:800, 1:600); Figure d represents the lifetime decay curve of the organic long afterglow luminescent material with a mass ratio of 1:1000; Figure e represents the time-resolved emission spectrum of the organic long afterglow luminescent material with a mass ratio of 1:1000; Figure f represents the excitation-emission phosphorescence mapping spectrum of the organic long afterglow luminescent material with a mass ratio of 1:1000.

[0058] from Figure 2 It can be seen from Figures a, b, and c that the fluorescence intensity, phosphorescence intensity, and phosphorescence lifetime of the organic long afterglow luminescent material with a mass ratio of 1:1000 are the best compared to those of organic long afterglow luminescent materials with other ratios.

[0059] from Figure 2 As can be seen from Figure d, the phosphorescence lifetime of the organic long afterglow luminescent material with a mass ratio of 1:1000 can reach 1472ms.

[0060] from Figure 2 As can be seen from Figure e, the phosphorescence lifetime of the organic long afterglow luminescent material with a mass ratio of 1:1000 reaches the best in the emission wavelength range of 425-525nm.

[0061] from Figure 2 It can be seen from the f diagram that the optimal phosphorescence excitation wavelength range of the organic long afterglow luminescent material with a mass ratio of 1:1000 is 300-340nm, and the optimal phosphorescence emission wavelength range is 425-525nm.

[0062] Example 7 Acid and alkali resistance (poor solvent resistance) test

[0063] The acid and alkali resistance of the organic long afterglow luminescent material obtained in Example 6 was studied. The organic long afterglow luminescent material with a mass ratio of 1:1000 was immersed in a strong acid (PH=1) and a strong alkali (PH=14) solution, taken out every 24 hours, and its phosphorescence spectrum was measured under the same test conditions (tested on a FS1000 fluorescence spectrometer, the test conditions were: excitation wavelength of 317nm, excitation slit of 20nm, emission slit of 10nm, voltage of 700V) for a total of 10 days.

[0064] like Figure 3 As shown in Figure a, the phosphorescence intensity slowly decreases after being immersed in a strong acid / base solution, and finally drops to about 80% of the initial intensity. After 10 days of immersion, the organic long afterglow luminescent material can still emit yellow-green phosphorescence visible to the naked eye under 365nm ultraviolet light excitation.

[0065] like Figure 3 From b and c, we can see that the strength of the organic long afterglow luminescent material decreases after being immersed in strong acid (PH=1) and strong alkali (PH=14), and drops to 80% of the initial strength after 10 days, which shows that it has excellent solvent resistance and stability.

[0066] Example 8

[0067] The biphenyl polymer mBPipQ (20 mg) obtained in Example 6 was uniformly dispersed in the pre-mixed epoxy resin matrix (20 g) by mechanical stirring, and transferred to a special silicone mold with numbers and letters through a rubber-tipped dropper. One part was cured in an anhydrous and oxygen-free glove box for 48 h, and the other part was left to cure in an atmospheric environment for 48 h, to obtain organic long afterglow luminescent materials with different afterglow properties.

[0068] like Figure 4 As shown in the figure, under sunlight and 365nm ultraviolet light, the material shows two clearly visible flower shapes, which is wrong information; this is because the presence of oxygen inside the material will quench phosphorescence, so the organic long afterglow luminescent material solidified in the atmosphere has no phosphorescence emission, and the cured epoxy resin can block all external quenchers from entering the material to interfere with the phosphorescence emission of the biphenyl polymer, so bright yellow-green phosphorescence can be emitted after the ultraviolet light stops exciting. Therefore, "72YT" can be observed after turning off the ultraviolet light, which is correct information.

[0069] Furthermore, even if the organic long afterglow luminescent material is placed in a poor solvent such as a strong acid or a strong base, the anti-counterfeiting pattern can still stably emit phosphorescence, thereby realizing multiple information encryption. It can be seen that the fully cured hard epoxy resin matrix provides a protective layer for the internal mBPipQ powder, preventing all quenchers that interfere with phosphorescence emission from entering the interior. The hard epoxy resin protective layer gives the organic long afterglow luminescent material excellent stability in strong acid (PH=1) or strong base (PH=14) solutions, and even after immersion for 10 days, it can still emit a yellow-green afterglow visible to the naked eye.

[0070] Similarly, the organic long afterglow luminescent material obtained by using Examples 1-5 has different colors and states under 365nm ultraviolet light excitation and after stopping excitation, and can be used for anti-counterfeiting encryption of information. In addition, it has a stable phosphorescent emission effect in poor solvents such as strong acids or strong bases, and can be used to realize multiple information encryption in the fields of data storage and anti-counterfeiting technology.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the technical solution. Those skilled in the art should understand that those modifications or equivalent substitutions of the technical solution of the present invention that do not depart from the purpose and scope of the technical solution should be included in the scope of the claims of the present invention.

Claims

1. An organic long afterglow luminescent material, characterized in that: A biphenyl polymer mBPiPQ having the following structure, wherein the biphenyl polymer mBPiPQ is doped into an epoxy resin matrix; Wherein, y, p, nx, x are the polymerization degrees of the corresponding structural units.

2. The organic long afterglow luminescent material according to claim 1, characterized in that: It is prepared by the following method: S1, synthesis of biphenyl type polymer mBPiPQ; S2. Dope the biphenyl polymer mBPiPQ into the epoxy resin matrix, then transfer it to a silicone mold, place it in a water-free and oxygen-free glove box and let it stand and cure for 15-48 hours at a temperature of 20-30°C to obtain an organic long afterglow luminescent material.

3. The organic long afterglow luminescent material according to claim 2, characterized in that: The step S1 comprises: S11. Synthesis of biphenyl type polymer mBPip: S12. Synthesis of polymer precursor QDHB: S13. Synthesis of biphenyl type polymer mBPiPQ, the synthesis route is as follows: The molar ratio of the polymer precursor to the biphenyl polymer is 1:2.5-3.5, and the reaction time is 4-6 days.

4. The organic long afterglow luminescent material according to claim 2, characterized in that: The step S2 comprises: S21, preparing epoxy resin matrix: epoxy resin and auxiliary materials are uniformly mixed at a mass ratio of 2.8-3.2:1; wherein the auxiliary materials are curing agent, diluent and accelerator; S22, doping the biphenyl polymer mBPiPQ into the epoxy resin matrix of step S21, then transferring it to a silicone mold, placing it in a water-free and oxygen-free glove box and curing it for 15-48 hours to obtain a high-efficiency organic long afterglow luminescent material.

5. The organic long afterglow luminescent material according to claim 4, characterized in that: In the step S22, the relative mass ratio of the biphenyl polymer doped into the epoxy resin matrix is ​​1:1400-600.

6. The organic long afterglow luminescent material according to claim 4, characterized in that: The epoxy resin is E51 epoxy resin.

7. An application of an organic long afterglow luminescent material, characterized in that: The organic long afterglow luminescent material according to any one of claims 1 to 6 is applied in the fields of data storage and anti-counterfeiting technology.

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