Polyphosphazene-based long-life room-temperature phosphorescent material and application thereof

Abstract

The invention discloses a long-life room-temperature phosphorescent material based on polyphosphazene and application thereof. The phosphorescent material is obtained by functionalizing tripolyphosphazene and doping the functionalized phosphor with a polyvinyl alcohol matrix. The functionalized phosphor obtained by functionalization of the tripolyphosphazene comprises THMD, THDD, THMOD or THDOD. The invention also discloses a phosphorescent film prepared from the phosphorescent material. The phosphorescent film shows excellent luminescence performance, high transparency and good processing performance. The film is applied to a flexible electronic device and a fingerprint recording technology, the doped film has extremely high mechanical flexibility and transparency, large-area preparation can be realized without generating cracks, and the application field of an organic long-life room-temperature phosphorescent material is expanded.

Description

Technical Field

[0001] The invention relates to the technical field of organic room temperature phosphorescent luminescent materials, and in particular to a phosphorescent material, a phosphorescent film and applications thereof. Background Art

[0002] Long afterglow luminescent materials are a type of material that absorbs energy and can continue to emit light after the excitation stops. It has a wide range of applications in bioimaging, information encryption, optoelectronic devices, etc. At present, organic long afterglow materials are still dominated by small molecule room temperature phosphorescent materials. Organic small molecules generally show phosphorescent properties in the crystal state. However, crystalline materials have problems such as poor processing performance and instability when used. Moreover, in the current phosphorescent system, from the lowest excited singlet state (S1) to the triplet state (T n ) and the long-lived triplet state (T n ) is consumed rapidly, making it difficult to achieve organic room temperature phosphorescence with high brightness, long life and high quantum yield. However, polymer materials are easy to synthesize, have low cost and toxicity, are easy to modify functional groups, and have many advantages such as flexibility, transparency, light weight, and strong tensile properties. Therefore, the development of polymer-based long afterglow materials has become a hot topic in the field of optical functional materials.

[0003] In recent years, the application of room temperature phosphorescent materials is often limited to information anti-counterfeiting and encryption under atmospheric conditions. Therefore, it is urgent to develop new technologies to broaden the application scope of phosphorescent materials. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, an object of the present invention is to provide a phosphorescent material to solve the problems of low brightness and short phosphorescent life of the prior phosphorescent materials.

[0005] Furthermore, the present invention also provides a method for preparing the phosphorescent material, which solves the problems of harsh preparation conditions and high cost of existing organic room temperature phosphorescent materials.

[0006] Furthermore, the present invention also makes the phosphorescent material into a phosphorescent film, and uses the phosphorescent film in fingerprint recording technology, thereby broadening the application scope of the phosphorescent material.

[0007] Furthermore, the present invention provides application of the phosphorescent film in the field of flexible electronics.

[0008] To achieve the above purpose, the present invention adopts the following technical solutions: A long-life room temperature phosphorescent material based on polyphosphazene, characterized in that it is prepared by the following method: firstly, tripolyphosphazene is functionalized, and then the functionalized phosphor is doped with a polyvinyl alcohol matrix to obtain the long-life room temperature phosphorescent material.

[0009] Furthermore, the preparation method specifically includes: firstly, selecting four phosphors, namely, 2-methyl-4-hydroxybenzaldehyde, 2,6-dimethyl-4-hydroxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde or 3,5-dimethoxy-4-hydroxybenzaldehyde, and respectively carrying out a one-step synthesis reaction with tripolyphosphazene at 70°C; then, synthesizing a polyphosphazene derivative small molecule containing a benzene unit with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide at 80°C; and finally, doping the phosphor with a polyvinyl alcohol matrix to obtain four similar long-life room temperature phosphorescent materials.

[0010] The functionalized phosphor obtained by functionalizing the tripolyphosphazene includes THMD, THDD, THMOD or THDOD, and its structural formula is as follows: Fig. 9 shown.

[0011] Furthermore, the mass ratio of the functionalized phosphor to polyvinyl alcohol is 1:28-32.

[0012] Furthermore, the preparation method of the functionalized phosphor THMD, THDD, THMOD or THDOD is as follows: Fig.10 Wherein, the molar ratio of the tripolyphosphazene, 2-methyl-4-hydroxybenzaldehyde, 2,6-dimethyl-4-hydroxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde or 3,5-dimethoxy-4-hydroxybenzaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:6-7:7-8:6-7.

[0013] The present invention also provides an application of the long-life room temperature phosphorescent material, wherein the long-life room temperature phosphorescent material is used to prepare a room temperature phosphorescent film, and is used in the field of flexible electronic devices and latent fingerprint detection technology.

[0014] Furthermore, the preparation method of the room temperature phosphorescent film is as follows: Fig.11 shown.

[0015] In the application of the long-life room temperature phosphorescent film, the latent fingerprint detection method comprises the following steps: (1) Recording fingerprints: placing the long-life room temperature phosphorescent film under ambient temperature conditions, and pressing the surface of the film with a finger; (2) Fingerprint recognition: By irradiating with 254 nm ultraviolet light, a fingerprint image with clear lines can be seen on the surface of the film.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention proposes a new strategy for preparing phosphorescent materials, which can effectively promote intersystem crossing and stabilize triplet excitons. First, a phosphor is prepared by functionalizing tripolyphosphazene, and then the functionalized phosphor is doped into a polyvinyl alcohol matrix. A large number of hydroxyl groups in the phosphor structure can effectively form intermolecular hydrogen bonds with the hydroxyl groups in the polyvinyl alcohol, thereby effectively compressing the non-radiative transition pathway of T1→S0 and achieving organic long afterglow. In addition, after the phosphorescent film is thermally annealed, the polymer matrix has a high rigidity and can inhibit radiation attenuation. At the same time, part of the -OH between the PVA molecular chains will be dehydrated to form ether bonds with the phosphor or the PVA molecular chain itself to complete cross-linking, thereby further compressing the non-radiative transition of T1→S0. The phosphorescent film prepared by the phosphorescent material of the present invention has a phosphorescence lifetime of up to 1047.1 ms.

[0017] 2. The phosphorescent film prepared by the present invention has excellent luminescent properties and processing properties. The polymer (PVA) and functionalized phosphor contained in the doping system both contain a large number of benzene ring structures, which increase the rigidity of the system and further suppress the molecular vibration of the system. The synthesis method of the phosphorescent molecule is simple and easy to obtain. This series of doped films has extremely high mechanical flexibility and transparency, and can be prepared over a large area without cracks, which expands the application field of organic long-life room temperature phosphorescent materials and lays a solid foundation for organic long afterglow materials in the field of flexible electronics. In addition, a fingerprint recording device is designed using the dual-luminescence properties of fluorescence and phosphorescence of the material. Under 254 nm ultraviolet light, a clearly visible fingerprint pattern can be easily obtained by gently pressing the surface of the doped film with a finger. The application simplifies the process of real-time fingerprint recording capture and provides a practical and valuable solution.

[0018] 3. The organic room temperature phosphorescent material prepared by the present invention overcomes the shortcomings of the scarce rare earth element resources and high biological toxicity of inorganic phosphorescent materials. Compared with other organic phosphorescent materials, the present invention overcomes the problems of harsh preparation conditions, high brittleness and poor stability in the process of preparing phosphorescent materials by crystal engineering. More importantly, the high brightness and long life phosphorescent film of the present invention has low production cost and simple preparation process, which not only enriches the preparation method of room temperature phosphorescent materials, but also provides new theoretical guidance and technical support for the simple and efficient industrial production of organic room temperature phosphorescent film materials with excellent luminescent properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is the hydrogen nuclear magnetic resonance spectrum of the functionalized phosphor THMD in Example 1 of the present invention; Figure 2 is the hydrogen nuclear magnetic resonance spectrum of the functionalized phosphor THDD in Example 2-4 of the present invention; Figure 3is the hydrogen nuclear magnetic resonance spectrum of the functionalized phosphor THMOD in Examples 2-4 of the present invention; Figure 4 is the hydrogen nuclear magnetic resonance spectrum of the functionalized phosphor THDOD in Example 2-4 of the present invention; Figure 5 This is a photo of the phosphorescence of the THMD room temperature phosphorescent film in Example 5 of the present invention under a 254 nm ultraviolet lamp; Figure 6 is the phosphorescence spectrum of the THMD room temperature phosphorescent film excited at 254 nm in Example 5 of the present invention; Figure 7 is the phosphorescence lifetime decay curve of the THMD room temperature phosphorescent film excited by 254 nm in Example 5 of the present invention; Figure 8 Schematic diagrams of Application Example 1 and Application Example 2 of the present invention; Fig. 9 is a structural diagram of a functionalized phosphor THMD, THDD, THMOD or THDOD; Fig.10 A flow chart for preparing functionalized phosphors THMD, THDD, THMOD or THDOD; Fig.11 This is the flow chart for the preparation of room temperature phosphorescent films. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with embodiments.

[0021] The numerical ranges in the present invention are understood to also specifically disclose each intermediate value between the upper and lower limits of the range. Each smaller range between any intermediate value in the stated value or stated range and any other stated value or intermediate value in the stated range is also included in the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded in the range.

[0022] Unless otherwise stated, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art described in the present invention are generally understood. Although the present invention only describes preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials related to the documents. In the event of conflict with any incorporated document, the content of this specification shall prevail. Regarding "comprising", "including", "having", "containing", etc. used herein, they are all open terms, which means including but not limited to.

[0023] Unless otherwise specified, the experimental methods used in the present invention are all conventional methods.

[0024] Unless otherwise specified, the materials, reagents, etc. used in the present invention can be purchased or synthesized by known methods.

[0025] The quantitative tests in the present invention were all repeated three times, and the results were averaged.

[0026] A long-life room temperature phosphorescent material based on polyphosphazene, the preparation method of which comprises: firstly selecting four phosphors, namely 2-methyl-4-hydroxybenzaldehyde, 2,6-dimethyl-4-hydroxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde or 3,5-dimethoxy-4-hydroxybenzaldehyde, respectively carrying out a one-step synthesis reaction with tripolyphosphazene at 70°C, then synthesizing a polyphosphazene derivative small molecule containing a benzene unit with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide at 80°C, and finally doping the phosphors with a polyvinyl alcohol matrix to obtain four similar long-life room temperature phosphorescent materials. Example

[0027] A long-life room temperature phosphorescent material containing a functionalized phosphor THMD is prepared by the following method: Preparation of functionalized phosphor THMD: 4-hydroxy-2-methylbenzaldehyde (1 g, 0.0073 mol), potassium carbonate (1.1609 g, 0.0084 mol) and tetrahydrofuran (100 mL) were added to a 250 mL three-necked flask. The solution was stirred at 65 °C under argon for 30 min, and then tripolyphosphazene (0.4172 g, 0.0012 mol) was dissolved in tetrahydrofuran (3 ml) and added dropwise to the above solution. Stirred at 70 °C under argon protection for 12 h, cooled to room temperature, and the excess tetrahydrofuran was removed by a rotary evaporator. The obtained residue was dissolved in dichloromethane and extracted five times with deionized water. The organic layer was dried and filtered in anhydrous magnesium sulfate, and the filtrate was removed from dichloromethane by a rotary evaporator to obtain the intermediate product. Then 9,10-dihydro-9-oxygen-10-phosphophanthenanthrene-10-oxide (1.5564 g, 0.0072 mol) was dissolved in tetrahydrofuran (150 mL) at 60 °C. The intermediate product was added to the mixture and stirred at 80 °C under argon for 12 h. After cooling to room temperature, the crude product was reprecipitated with petroleum ether (500 mL) and vacuum dried at 65 °C for 12 h to obtain the functionalized phosphor THMD. The molar ratio of the tripolyphosphazene, 4-hydroxy-2-methylbenzaldehyde, potassium carbonate and 9,9,10-dihydro-9-oxygen-10-phosphophanthrene-10-oxide was 1:7:8:7.

[0028] Preparation of long-life room temperature phosphorescent material: doping the above functionalized phosphor THMD with a polyvinyl alcohol matrix to obtain a long-life room temperature phosphorescent material, wherein the mass ratio of the functionalized phosphor THMD to the polyvinyl alcohol is 1:30.

[0029] First, referring to the method of Example 1, functionalized phosphors THDD, THMOD and THDOD were prepared respectively. The dosage ratios were the same, except that 4-hydroxy-2-methylbenzaldehyde was replaced by 2,6-dimethyl-4-hydroxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde and 3,5-dimethoxy-4-hydroxybenzaldehyde respectively. It can be seen that this method has a certain universality.

[0030] Secondly, the functionalized phosphors THDD, THMOD and THDOD are doped with a polyvinyl alcohol matrix to obtain a long-life room temperature phosphorescent material, wherein the mass ratio of the functionalized phosphors THDD, THMOD and THDOD to the polyvinyl alcohol is 1:30. Example

[0031] First, 1.5 g of PVA was dissolved in 50 mL of dimethyl sulfoxide solution and stirred in an oil bath at 95 °C for 1.5 h to prepare a PVA solution with a concentration of 30 mg / mL. Then, any of the functionalized phosphors was dispersed in the PVA solution at a concentration of 1 mg / mL, and ultrasonic treatment was performed for 1 min to obtain a uniform solution. The solution was then dropped onto a 75 mm × 25 mm glass slide and dried on a heating table at 90 °C for 40 minutes. The vacuum oven temperature was set to a predetermined temperature (180 °C), and after the vacuum oven temperature reached the predetermined temperature, the doped film was placed in the vacuum oven. After 30 minutes, the doped film was taken out of the vacuum oven to obtain a room temperature phosphorescent film.

[0032] In order to verify whether the functionalized phosphors THMD, THDD, THMOD and THDOD in Examples 1-4 were successfully synthesized, the H NMR spectra of the products in the steps of Examples 1-4 were as follows: Figure 1-4 As shown, the H signal of the product THMD at 2.0-2.2 ppm comes from -CH3, the H signal at 5.4-5.6 ppm comes from -OH, the H signal at 6.2-6.4 ppm comes from -CH, and the H signal at 6.6-8.4 ppm comes from the aromatic ring. The integrated intensity ratio is 3:1:1:10. This shows that the phosphor THMD has been successfully synthesized. Similarly, the phosphors THDD, THMOD and THDOD have been successfully synthesized, respectively. Fig. 9 The structure shown.

[0033] Under room temperature and atmospheric environment, the THMD room temperature phosphorescent film of Example 5 was irradiated with a 254 nm ultraviolet lamp. Figure 5 As shown in the figure, the afterglow photos of the room temperature phosphorescent film before and after ultraviolet irradiation, the afterglow time shows a trend of first increasing and then decreasing, and reaches the best when the thermal annealing temperature is 180 ℃. The photophysical properties of the room temperature phosphorescent film were tested using a spectrometer, and the phosphorescence emission spectrum was obtained as shown in Figure 6 As shown in the figure, the phosphorescence intensity of the phosphorescent film also shows a trend of first increasing and then decreasing, reaching the optimum when the thermal annealing temperature is 180 °C, which is consistent with the visual observation results. Figure 7 The phosphorescence lifetime decay curve also further confirms that this temperature is the optimal temperature for thermal annealing of the phosphorescent film, and the maximum phosphorescence lifetime is 1047.1 ms.

[0034] like Figure 8 ab, the film prepared in Example 5 has high transparency, and can be bent and folded to prepare large-area, transparent 3D products. The long-life room temperature phosphorescent film shows remarkable flexibility, allowing repeated bending and tension without delamination or damage. The afterglow color and duration of these phosphorescent films do not change. The above results show that this room temperature phosphorescent film with the advantages of large area, flexibility and transparency has great potential for the development of flexible electronic devices.

[0035] Figure 8 c is the process of recording fingerprints using phosphorescent film. We gently press the surface of the doped film with our fingers, and the fingerprints can be seen before and after 254 nm ultraviolet light irradiation. As shown in the figure, the fingerprint pattern can be clearly recorded by the phosphorescent film. This method of recording fingerprints using fluorescent and phosphorescent dual-luminescent materials can effectively simplify the fingerprint recording process.

[0036] 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. A long-life room temperature phosphorescent material based on polyphosphazene, characterized in that: The preparation method is as follows: firstly, the tripolyphosphazene is functionalized, and then the functionalized phosphor is doped with a polyvinyl alcohol matrix to obtain a long-life room temperature phosphorescent material.

2. The long-life room temperature phosphorescent material according to claim 1, characterized in that: The preparation method specifically comprises: firstly, selecting four phosphors, namely, 2-methyl-4-hydroxybenzaldehyde, 2,6-dimethyl-4-hydroxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde or 3,5-dimethoxy-4-hydroxybenzaldehyde, respectively, and carrying out a one-step synthesis reaction with tripolyphosphazene at 70°C; then, synthesizing a polyphosphazene derivative small molecule containing a benzene unit with 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide at 80°C; and finally, doping the phosphors with a polyvinyl alcohol matrix to obtain four similar long-life room temperature phosphorescent materials.

3. The long-life room temperature phosphorescent material according to claim 1, characterized in that: The functionalized phosphor obtained by functionalizing the trimerphosphazene is THMD, THDD, THMOD or THDOD.

4. The long-life room temperature phosphorescent material according to claim 1, characterized in that: The mass ratio of the functionalized phosphor to polyvinyl alcohol is 1:28-32.

5. The long-life room temperature phosphorescent material according to claim 1, characterized in that: The molar ratio of the tripolyphosphazene, 2-methyl-4-hydroxybenzaldehyde, 2,6-dimethyl-4-hydroxybenzaldehyde, 4-hydroxy-2-methoxybenzaldehyde or 3,5-dimethoxy-4-hydroxybenzaldehyde and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide is 1:6-7:7-8:6-7.

6. Application of a long-life room temperature phosphorescent material, characterized in that: The long-life room temperature phosphorescent material according to any one of claims 1 to 4 is used to prepare a room temperature phosphorescent film, and is used in the field of flexible electronic devices and latent fingerprint detection technology.

7. The use of the long-life room temperature phosphorescent film according to claim 6, characterized in that: The latent fingerprint detection method comprises the following steps: (1) Recording fingerprints: placing the long-life room temperature phosphorescent film under ambient temperature conditions, and pressing the surface of the film with a finger; (2) Fingerprint recognition: By irradiating with 254 nm ultraviolet light, a fingerprint image with clear lines can be seen on the surface of the film2.

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