Pure organic polymer material with high room-temperature phosphorescence efficiency as well as preparation method and application of pure organic polymer material

Abstract

The invention discloses a pure organic polymer material with high room-temperature phosphorescence efficiency as well as a preparation method and application thereof, and belongs to the field of preparation of pure organic room-temperature phosphorescence materials. The pure organic room-temperature phosphorescent material is prepared by doping heterocyclic organic small molecules containing one or two carboxyl groups into polyacrylamide, has the characteristics of cheap raw materials and simple preparation method, and the obtained material has high room-temperature phosphorescent efficiency, time-dependent colorful room-temperature phosphorescent luminescence and the like, and can be applied to pattern display, anti-counterfeiting and data storage. And the method has huge commercial potential.

Description

Technical Field

[0001] The present invention belongs to the field of preparation of pure organic long afterglow materials, and specifically relates to the preparation of a highly efficient time-dependent colorful pure organic room temperature phosphorescent material, and the application of such material in long afterglow pattern display, anti-counterfeiting and data storage. Background Art

[0002] Pure organic room temperature phosphorescent materials have the advantages of long life, large Stokes shift, high exciton utilization, etc., and have broad application prospects in data encryption and anti-counterfeiting, bio-imaging, visual chemical sensing, long afterglow light-emitting diodes, etc. However, for pure organic materials, due to the weak orbital coupling of themselves and the fact that triplet excitons are easily deactivated by non-radiative transitions caused by molecular thermal motion at room temperature, or quenched by oxygen or water in the air, it is difficult to achieve high-efficiency pure organic room temperature phosphorescence. To address this problem, researchers currently mainly obtain high-efficiency pure organic room temperature phosphorescence by promoting the intersystem crossing process of singlet excitons from singlet excited states to triplet excited states, and inhibiting the quenching or non-radiative transition deactivation process of triplet excitons. Usually, heavy atoms (such as Cl, Br, S, etc.) or aromatic carbonyls and aromatic sulfones are introduced to promote spin-orbit coupling, thereby promoting the intersystem crossing process; the non-radiative transition process of triplet excitons is inhibited by crystal engineering, H-aggregation, doping into rigid matrices, and constructing metal-organic frameworks. At present, the reported high-efficiency pure room temperature phosphorescent materials are mainly organic small molecule crystals, ionic crystals and organic small molecule host-guest doping systems, which have poor processing performance and greatly limit practical applications. Polymers have the advantages of flexibility, large-area preparation, light weight and easy processing. However, the general polymer molecular chain is in an amorphous state, the intermolecular force is weak, and the molecular thermal motion is violent, which makes the triplet excitons easily deactivated by non-radiative transitions. Therefore, it is a huge challenge to develop a high-efficiency room temperature phosphorescent polymer material system. Summary of the invention

[0003] In view of the above problems, the object of the present invention is to provide a pure organic polymer material with high room temperature phosphorescence efficiency and a preparation method thereof.

[0004] To achieve the above object, the present invention adopts the following technical solution: The first object of the present invention is to protect a pure organic polymer material with high room temperature phosphorescence efficiency, which is prepared by using a small heterocyclic organic molecule containing one or two carboxyl groups as a guest molecule and incorporating it into a polyacrylamide host.

[0005] Furthermore, the mass ratio of the heterocyclic organic small molecules containing one or two carboxyl groups to polyacrylamide in the pure organic polymer material is 1:99.

[0006] Furthermore, the heterocyclic organic small molecule containing one or two carboxyl groups is any one of the following molecular formulas: .

[0007] Furthermore, the room temperature phosphorescence quantum efficiency of the pure organic polymer material reaches 69%, and the room temperature phosphorescence has time-dependent colorful phosphorescence emission.

[0008] The second purpose of the present invention is to protect the preparation method of the pure organic polymer material with high room temperature phosphorescence efficiency. A heterocyclic organic small molecule containing one or two carboxyl groups and polyacrylamide are added to deionized water in a mass ratio of 1:99, heated and stirred at 140°C for 2 hours, and then dried to obtain a pure organic polymer material with high room temperature phosphorescence efficiency.

[0009] The third object of the present invention is to protect the application of the pure organic polymer material with high room temperature phosphorescence efficiency in display, anti-counterfeiting and information storage.

[0010] Heterocyclic organic small molecules containing carboxyl groups contain electron-rich heteroatoms (S, O and N), which can trigger n-π transitions, generate a large number of triplet excitons, and reduce intermolecular interactions and electronic coupling. Polyacrylamide has a large number of amide groups, which can provide a rigid environment for hydrogen bonds. Doping organic heterocyclic small molecules into polyacrylamide can effectively inhibit the non-radiative transition process of organic heterocyclic small molecules, thereby achieving high-efficiency room temperature phosphorescence properties. At the same time, polyacrylamide has the advantages of environmental protection, easy processing, and low cost. Therefore, the organic phosphorescent material prepared by using polyacrylamide as the main material in the present invention has important properties such as time dependence, long life, high efficiency, and adjustable afterglow luminescence color, which is conducive to meeting the practical application needs of room temperature phosphorescent materials in display, anti-counterfeiting and other aspects.

[0011] The beneficial effects of the present invention are as follows: the present invention uses a small amount of phosphorescent small molecules as the guest and polyacrylamide as the host molecule, and through physical doping, can easily prepare a polymer phosphorescent material with time dependence, long life, high efficiency and adjustable afterglow luminescence color. The preparation method of the present invention is simple to operate, low in cost and environmentally friendly, and the prepared polymer material has ultra-long room temperature phosphorescence and time-dependent characteristics, making it have great prospects in the fields of pattern display, anti-counterfeiting and data encryption. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 The graphs show the luminescence of the guest molecules used in Examples 1-4 and the phosphorescent materials prepared therefrom under natural light, ultraviolet light and after irradiation.

[0013] Figure 2 The phosphorescence spectra of the pure organic phosphorescent materials prepared in Examples 1-4 are shown.

[0014] Figure 3 These are graphs showing the luminescence of the pure organic phosphorescent materials prepared in Examples 1-4 under natural light, ultraviolet light, and after irradiation.

[0015] Figure 4 This is a room temperature lifetime decay curve diagram of the pure organic phosphorescent material prepared in Examples 1-4.

[0016] Figure 5 This is the delayed phosphorescence emission spectrum of the pure organic phosphorescent material prepared in Example 2; the inset photo is a diagram of its luminescence at different delay times.

[0017] Figure 6 These are graphs showing the luminescence of the phosphorescent materials prepared in Examples 1-3, screen-printed into patterns of different shapes, under and after irradiation with a 302 nm ultraviolet lamp.

[0018] Figure 7 The pure organic room temperature phosphorescent material prepared in Example 4 was used to soak cotton thread with the aqueous solution of Example 4 as the dye solution. After drying at 80° C., the application status of the cotton thread before and after irradiation with natural light and 302 nm ultraviolet light was shown. DETAILED DESCRIPTION

[0019] A method for preparing a pure organic polymer material with high room temperature phosphorescence efficiency comprises the following steps: adding a small organic molecule containing one or two carboxyl groups and polyacrylamide into deionized water at a mass percentage ratio of 1:99, heating and stirring at 140°C for 2 h, and drying at 80°C for 48 h to obtain a dry white powder.

[0020] Wherein, the heterocyclic organic small molecule containing one or two carboxyl groups is any one of the following molecular formulas: .

[0021] In order to make the contents of the present invention easier to understand, the technical solution of the present invention is further described below in conjunction with specific implementation methods, but the present invention is not limited thereto.

[0022] Example 1 1 mg of 4-oxo-1,4-dihydroquinoline-3-carboxylic acid (ODA) and 99 mg of polyacrylamide (PAM) were weighed into a 20 mL glass bottle, 4 mL of deionized water was added, and the mixture was heated to 140 °C for 2 h. After the solution was completely clarified, it was moved to an oven at 80 °C for 48 h and dried into powder to obtain 1 wt.% of pure organic long afterglow material ODA@PAM.

[0023] Example 2 1 mg of benzofuran-2-carboxylic acid (THA) and 99 mg of polyacrylamide (PAM) were weighed into a 20 mL glass bottle, 4 mL of deionized water was added, and the mixture was heated to 140 °C for 2 h. After the solution was completely clarified, it was moved to an oven at 80 °C for 48 h and dried into powder to obtain a 1 wt.% pure organic long afterglow material THA@PAM.

[0024] Example 3 1 mg of thiophene[3,2-B]thiophene-2,5-dicarboxylic acid (FFA) and 99 mg of polyacrylamide (PAM) were weighed into a 20 mL glass bottle, 4 mL of deionized water was added, and the mixture was heated to 140 °C for 2 h. After the solution was completely clarified, it was moved to an oven at 80 °C for 48 h and dried into powder to obtain 1 wt.% of pure organic long afterglow material FFA@PAM.

[0025] Example 4 1 mg of 3,5-pyrazoledicarboxylic acid (BNA) and 99 mg of polyacrylamide (PAM) were weighed into a 20 mL glass bottle, 4 mL of deionized water was added, and the mixture was heated to 140 °C for 2 h. After the solution was completely clarified, it was moved to an oven at 80 °C for 48 h and dried into powder to obtain a 1 wt.% pure organic long afterglow material BNA@PAM.

[0026] Figure 1 The following is a diagram showing the luminescence of the guest molecules used in Examples 1-4 and the pure organic room temperature phosphorescent materials prepared therefrom under natural light, ultraviolet light and after irradiation. As can be seen from the figure, the guest molecules used in Examples 1-4 are all white powders under natural light, and exhibit weak fluorescence under 365 nm ultraviolet light. When the ultraviolet light is turned off, no room temperature phosphorescence phenomenon is observed or the luminescence is weak (left figure). The pure organic long afterglow material prepared therefrom emits bright fluorescence under ultraviolet light, and strong room temperature phosphorescence emission occurs after turning off the 302 nm ultraviolet light, proving that the preparation of colorful ultra-long room temperature phosphorescent materials can be achieved by using different guest doping (right figure).

[0027] Figure 2 The phosphorescence spectra of the pure organic long afterglow materials prepared in Examples 1 to 4 are shown in the figure. As can be seen from the figure, the phosphorescence spectra peaks of the pure organic long afterglow materials prepared in Examples 1 to 4 are located at 430 nm, 492 nm, 470 nm and 414 nm, respectively.

[0028] Figure 3The luminescence diagram of the pure organic room temperature phosphorescent material prepared in Examples 1-4 under natural light, 302 nm ultraviolet light and after irradiation can be seen from the figure that the pure organic long afterglow material prepared in Examples 1-4 is a white powdery solid under natural light, and emits blue, yellow and cyan fluorescence under 302 nm ultraviolet light. After turning off the ultraviolet lamp, a room temperature phosphorescence phenomenon with the same afterglow color as before illumination can be observed.

[0029] Figure 4 The lifetime decay curves of the pure organic room temperature phosphorescent materials prepared in Examples 1 to 4 are shown. The lifetimes of the phosphorescent emission peaks were monitored respectively, and the corresponding lifetime decay curves were drawn, showing that the room temperature phosphorescent emission lifetimes reached 798.3 ms, 427.9 ms, 604.1 ms and 839.5 ms, respectively.

[0030] Figure 5 The different delayed phosphorescence emission spectra of the pure organic room temperature phosphorescent material prepared in Example 2. It can be seen from the figure that after excitation by a 302 nm ultraviolet lamp, the pure organic room temperature phosphorescent material prepared in Example 2 is mainly yellow-green afterglow when the delay is <1.5 s, and exhibits obvious blue persistent luminescence phenomenon after a delay of >2 s, indicating that the material has obvious time-dependent luminescence behavior.

[0031] Example 5 Preparation of color-adjustable long afterglow pattern and its long afterglow display process: Add 4-6 drops of deionized water to the PAM powder (100 mg) prepared in Examples 1-3 respectively, stir quickly into a gel state, use filter paper as a substrate, use screen printing technology to brush into display patterns of different shapes, and dry in an oven at 80°C for 12 hours to prepare the desired long afterglow pattern.

[0032] Figure 6 The luminescence of the prepared patterns of different shapes under and after irradiation with 302 nm ultraviolet light is shown in the figure. As can be seen from the figure, the patterns of different shapes prepared by screen printing present bright patterns under 302 nm ultraviolet light. After turning off the ultraviolet light, blue, yellow-green and cyan patterns can be observed respectively.

[0033] Example 6 The aqueous solution of Example 4 was used as a dye solution to soak cotton thread for 4 h, and then dried at 80° C. for 12 h.

[0034] Figure 7 100 mg of the solid powder of Example 4 was placed in 4 mL of water and stirred evenly. The prepared aqueous solution was used as a dye solution to soak cotton thread. After drying at 80°C, a blue afterglow was seen before and after natural light and 302 nm irradiation, indicating that the material has potential application prospects in display, recording and other fields.

[0035] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made according to the scope of the patent application of the present invention should fall within the scope of the present invention.

Claims

1. A pure organic polymer material with high room temperature phosphorescence efficiency, characterized in that: The pure organic polymer material is prepared by taking a heterocyclic organic small molecule containing one or two carboxyl groups as a guest molecule and incorporating it into a polyacrylamide main body.

2. A pure organic polymer material with high room temperature phosphorescence efficiency according to claim 1, characterized in that: The mass ratio of the heterocyclic organic small molecules containing one or two carboxyl groups to the polyacrylamide in the pure organic polymer material is 1:

99.

3. A pure organic polymer material with high room temperature phosphorescence efficiency according to claim 1 or 2, characterized in that: The heterocyclic organic small molecule containing one or two carboxyl groups is any one of the following molecular formulas: 。 4. The pure organic polymer material with high room temperature phosphorescence efficiency according to claim 1, characterized in that: The room temperature phosphorescence quantum efficiency of the pure organic polymer material reaches 69%, and the room temperature phosphorescence has time-dependent colorful phosphorescence emission.

5. The method for preparing a pure organic polymer material with high room temperature phosphorescence efficiency according to claim 1, characterized in that: A heterocyclic organic small molecule containing one or two carboxyl groups and polyacrylamide were added into deionized water in a mass ratio of 1:99, heated and stirred at 140°C for 2 h, and then dried to obtain a pure organic polymer material with high room temperature phosphorescence efficiency.

6. Application of the pure organic polymer material with high room temperature phosphorescence efficiency according to claim 1 in display, anti-counterfeiting and information storage.

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