A phosphorescent carbon dot material, a preparation method and application to preparation of a phosphorescent polymer material

Abstract

The application discloses a phosphorescent carbon dot material, a preparation method and application in preparation of a phosphorescent high polymer material, relates to the technical field of chemiluminescent materials, and comprises the following steps: taking 2-imidazolidone and diaphosphorus pentoxide as raw materials, and synthesizing intermediate phosphorescent carbon dot material one through a heating carbonization method; coating the surface of the intermediate phosphorescent carbon dot material one with silicon dioxide through tetraethyl orthosilicate to obtain intermediate phosphorescent carbon dot material two with a core-shell structure; and using a silane coupling agent to modify the surface to obtain phosphorescent carbon dot material containing hydrophobic groups on the surface; mixing the phosphorescent carbon dot material with ultraviolet light polymerizable monomers and a photoinitiator, and obtaining the phosphorescent high polymer material through ultraviolet light curing; the application has the advantages of simple process, easy operation and control, mild preparation conditions, easy availability of raw materials, and easiness in large-scale batch production; the prepared phosphorescent carbon dot material has long phosphorescent lifetime and stable luminescent properties, can be uniformly fixed in a polymer matrix through covalent crosslinking, and solves the problem of phase separation of doped phosphors in polymers.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemiluminescent materials, in particular to a phosphorescent carbon dot material, a preparation method and application in preparation of a phosphorescent polymer material. BACKGROUND

[0002] Phosphorescent materials are materials that can emit phosphorescence under electromagnetic radiation and ionizing radiation excitation. Phosphorescent materials have attracted extensive attention due to their long luminescence lifetime, large Stokes shift and wide application range. Phosphorescence is the radiation produced by the transition from the excited state triplet to the ground state. As a spin-forbidden process, the luminescence time is very long, and the phosphorescence emission can still be observed within a few seconds after the excitation light source is turned off. There are two key factors for realizing phosphorescence emission, one is to improve the intersystem crossing ability of the material, which can be achieved by enhancing the spin-orbit coupling; the other is to reduce non-radiative transitions as much as possible. However, phosphorescence is easily quenched by oxygen, solvents and high temperature environment. In general, constructing a rigid environment can effectively inhibit non-radiative transitions.

[0003] Most of the polymer phosphorescent materials are amorphous structures, have unique optical properties, good processability, thermal stability, flexibility, low cost and other advantages, effectively solving the problems of poor processability and weak stability of small molecule crystals. They can be applied to produce various complex optical devices, and have potential application prospects in the fields of sensing, information encryption and anti-counterfeiting. However, the flexible structure of the polymer is not conducive to the formation of a rigid environment, and oxygen and water vapor in the external environment can easily quench the triplet exciton.

[0004] At present, the main methods for preparing polymer phosphorescent materials are chemical synthesis and physical doping, both of which need to introduce chromophoric groups. Among them, the chemical synthesis method has complex synthesis process, high purification difficulty and the proportion of phosphorescent chromophoric groups is not easy to control accurately; the physical doping method produces mainly thin films, which have poor thermal stability, and the luminescent groups are easy to aggregate, which can cause quenching effect, thereby reducing the phosphorescent efficiency and luminescence lifetime.

[0005] In the invention patent application with the publication number CN116948641A and the title of an alumina matrix enhanced carbon quantum dot phosphor material and its preparation and application, a carbon quantum dot solution with fluorescent properties is prepared by mixing and heating a carbon source and a nitrogen source, then it is added to an aluminum salt solution containing a nano dispersant, an alkaline solution is added, and aluminum hydroxide coated carbon quantum dots are obtained by reaction, and an alumina matrix enhanced carbon quantum dot phosphor material is obtained by calcination. The material has good light stability and processability, and the light recognition performance is suitable for application in the field of anti-counterfeiting. However, the preparation method is relatively complex and difficult to control. The aluminum hydroxide coated carbon quantum dots need to be preserved in an inert environment after washing and drying. The preservation temperature and time have a great influence on the phosphorescence intensity of the material. In addition, the dispersibility and particle size of the prepared aluminum hydroxide coated carbon quantum dots are difficult to control. Moreover, the preparation process requires a high temperature environment of 200 to 900°C. Changes in calcination temperature will cause changes in the content of carbon and nitrogen elements in the product, and the phosphorescence emission wavelength will also change. All the above will make it difficult to control the consistency of products produced by different equipment, different batches and different environmental factors, which is not conducive to industrial production control and application.

[0006] In the invention patent application with the publication number CN115404071A and the title of an organic room temperature phosphorescent cross-linked composite film, a preparation method and application, it is disclosed that the boronic acid-polyhydroxy polymer cross-linked network inhibits the non-radiative decay of phosphorescent guest molecules, thereby achieving ultra-long lifetime and high quantum yield in the organic room temperature phosphorescent cross-linked composite film. However, the phosphorescent cross-linked composite film prepared by doping has a phosphorescent lifetime of only 2 seconds at most. In addition, environmentally unfriendly raw materials such as dimethyl sulfoxide are used in the method, which may hinder industrial production.

[0007] In summary, it is of great significance to develop a phosphor with simple process, stable structure and luminescence performance, and to use it to prepare a high molecular phosphor material. SUMMARY

[0008] The present application aims to provide a phosphorescent carbon dot material, a preparation method and application in the preparation of a phosphorescent high molecular material to solve the problems mentioned in the background art.

[0009] To achieve the above-mentioned purpose, the present application provides the following technical solution: a preparation method of a phosphorescent carbon dot material, comprising the following specific steps:

[0010] 1) Mix 2-imidazolidone solution with phosphorus pentoxide, heat and evaporate to dryness, add water dispersion after the reaction reaches a certain degree, adjust the pH to neutral, filter to obtain intermediate phosphorescent carbon dot material one;

[0011] 2) mixing the intermediate phosphorescent carbon dot material 1 with deionized water, adjusting the pH to an alkaline environment, adding tetraethyl orthosilicate, and reacting under constant temperature and magnetic stirring, and then separating and drying to obtain a silica-coated core-shell structure intermediate phosphorescent carbon dot material 2;

[0012] 3) dispersing the intermediate phosphorescent carbon dot material 2 in ethanol, mixing with a surface modifier at a certain mass ratio, and stirring to obtain a phosphorescent carbon dot material with hydrophobic functional groups introduced on the surface.

[0013] Preferably, in the above step 1), the molar ratio of 2-imidazolidone to phosphorus pentoxide is between 0.1 and 10.

[0014] Preferably, in the above step 1), the heating and drying is performed by using an electric heating furnace to boil until the solid color darkens to brown.

[0015] Preferably, in the above step 3), the surface modifier is vinyltrimethoxysilane, and the mass ratio of the intermediate phosphorescent carbon dot material 2 to the surface modifier is (2-15):1.

[0016] Another technical solution provided by the present application is a phosphorescent carbon dot material prepared by the above method.

[0017] Preferably, the microstructure of the above phosphorescent carbon dot material is a core-shell structure nanoparticle with carbon dots inside and silica outside.

[0018] Preferably, the particle size of the above nanoparticle is 9-11 nm.

[0019] Still another technical solution provided by the present application is the application of the above phosphorescent carbon dot material in preparing a phosphorescent polymer material, which includes the following specific content: irradiating a mixture of an ultraviolet light polymerizable monomer, a phosphorescent carbon dot material, and a photoinitiator with ultraviolet light to cure and obtain a phosphorescent polymer material modified by the phosphorescent carbon dot material.

[0020] Preferably, the above ultraviolet light polymerizable monomer includes one or more of polyethylene glycol diacrylate (PEGDA), 4-acryloylmorpholine (AMP), methoxy polyethylene glycol acrylate (MPGA), ethoxylated trihydroxymethyl propane triacrylate, styrene, methacrylic acid, and methyl methacrylate.

[0021] Preferably, in the above mixture, the mass fraction of the photoinitiator is 1-10%, and the mass fraction of the phosphorescent carbon dot material is 1-8%.

[0022] Compared with the prior art, the present application has the following beneficial effects:

[0023] 1. The preparation method of the phosphorescent carbon dot material is simple, easy to operate and control, has mild preparation conditions, raw materials are easy to obtain, only needs short-time heating, and is easy to mass-produce; and the phosphorescent carbon dot material prepared by the method has a unique core-shell structure, good monodispersity, and uniform particle size.

[0024] 2. The phosphorescent carbon dot material has a fluorescent carbon dot NPCDs synthesized by hydrothermal carbonization as an inner core, a three-dimensional network structure of silica coated on the surface of the fluorescent carbon dot as an outer shell, and the three-dimensional network structure of silica inhibits non-radiative transition of triplet excitons by shielding external factors such as external water and oxygen, thereby guaranteeing phosphorescent emission of the prepared carbon dot functional material, and the phosphorescent carbon dot material has long phosphorescent lifetime, stable luminescent properties, and excellent phosphorescent properties in a solid state and in an aqueous solution.

[0025] 3. The phosphorescent carbon dot material has hydrophobic functional groups introduced on the surface, enhances the solubility of the phosphorescent material coated with silica in monomers and oligomers, is suitable for various polymerizable polymer material systems, has excellent dispersibility, has a certain universality, and has the advantages of small toxicity and excellent biocompatibility compared with other organic phosphors.

[0026] 4. The phosphorescent carbon dot material can be fixed in a polymer matrix through covalent cross-linking, solves the problem of phase separation of doped phosphors in polymers, has simple process in the preparation of phosphorescent polymer materials, stable photoluminescent properties, and wide application, and the prepared phosphorescent polymer material can be applied to various fields such as polymer anti-counterfeiting materials, information storage materials, and production and manufacturing of complex optical devices. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is a synthesis route diagram of the phosphorescent carbon dot functional material NPCDs@SiO2(V) of the application.

[0028] Figure 2 is a TEM image of the phosphorescent carbon dot material NPCDs@SiO2 prepared in Example 1 of the application.

[0029] Figure 3 is a fluorescence spectrum of the phosphorescent carbon dot material NPCDs@SiO2 prepared in Example 1 of the application under different excitation wavelengths.

[0030] Figure 4 is a phosphorescent spectrum of the phosphorescent carbon dot material NPCDs@SiO2 prepared in Example 1 of the application under different excitation wavelengths.

[0031] Figure 5 is an infrared spectrum of NPCDs@SiO2 prepared in Example 1 of the application and NPCDs@SiO2(V).

[0032] Figure 6 is the luminescence photo of the phosphorescent carbon dot functional material NPCDs@SiO2(V) prepared in Example 1 of the present application, wherein the left photo is the powder photo under the irradiation of 365 nm ultraviolet LED lamp, and the right photo is the phosphorescent photo after the 365 nm ultraviolet LED lamp is turned off for 1 second.

[0033] Figure 7 is the photo of the room temperature phosphorescent homopolymer material prepared from NPCDs@SiO2(V) in Example 2 of the present application under different light conditions, wherein the left photo is under natural light, the middle photo is under ultraviolet light, and the right photo is after the ultraviolet light is turned off.

[0034] Figure 8 is the photo of the room temperature phosphorescent copolymer material prepared from NPCDs@SiO2(V) in Example 3 of the present application under different light conditions, wherein the left photo is under natural light, the middle photo is under ultraviolet light, and the right photo is after the ultraviolet light is turned off.

[0035] Figure 9 is the photo of the room temperature phosphorescent homopolymer material prepared from NPCDs@SiO2 in Comparative Example 1 of the present application under different light conditions, wherein the left photo is under natural light, the middle photo is under ultraviolet light, and the right photo is after the ultraviolet light is turned off.

[0036] Figure 10 is the photo of the high polymer material added with different contents of phosphorescent carbon dots in Comparative Examples 2.1-2.6 of the present application under natural light.

[0037] Figure 11 is the photo of the high polymer material added with different contents of phosphorescent carbon dots in Comparative Examples 2.1-2.6 of the present application under the irradiation of ultraviolet lamp.

[0038] Figure 12 is the phosphorescent photo of the high polymer material added with different contents of phosphorescent carbon dots in Comparative Examples 2.1-2.6 of the present application after the irradiation of ultraviolet lamp is turned off.

[0039] Figure 13 is the phosphorescent emission spectrum of the high polymer material added with 6 mg of phosphorescent carbon dots in Comparative Example 2.5 of the present application under the excitation of 350 nm. DETAILED DESCRIPTION

[0040] Reference Figure 1 , the phosphorescent carbon dot material is prepared by the following method:

[0041] The 2-imidazolidone solution is mixed with phosphorus pentoxide, heated and evaporated to dryness, and after the reaction reaches a certain degree (for reference, the solid color can be deepened to brown by heating and boiling with an electric heater until the solid color is deepened to brown, or other methods can be used to judge, such as heating and boiling for 0.5-20 minutes, and the heating time is determined by experience), water is added for dispersion, and the pH is adjusted to neutral (alkaline agents or reagents such as anhydrous sodium carbonate can be added for adjustment), and after filtration, intermediate phosphorescent carbon dot material one is obtained;

[0042] The intermediate phosphorescent carbon dot material one is mixed with deionized water, the pH is adjusted to an alkaline environment, tetraethyl orthosilicate is added, and after reaction under constant temperature and magnetic stirring, the silica-coated core-shell structure intermediate phosphorescent carbon dot material two is obtained after separation and drying; in this step, the silica coating is performed by hydrolysis of tetraethyl orthosilicate and ammonia water, which is a common coating method;

[0043] The intermediate phosphorescent carbon dot material two is dispersed in ethanol, mixed with a surface modifier in a certain mass ratio, and stirred to obtain a phosphorescent carbon dot material, wherein the surface modifier can be preferably vinyltrimethoxysilane, and other surface modifiers that can introduce hydrophobic groups and have good solubility of the target product in monomers and oligomers can also be used.

[0044] The obtained phosphorescent carbon dot material has hydrophobic functional groups introduced on the surface, which enhances the solubility in monomers and oligomers, and is suitable for various photopolymerizable polymer material systems. Specifically, a mixture of ultraviolet light polymerizable monomers, phosphorescent carbon dot materials, and photoinitiators is irradiated with ultraviolet light to obtain a phosphorescent polymer material modified by the phosphorescent carbon dot material.

[0045] The specific content of the present application will be further explained in combination with examples, comparative examples and drawings. Obviously, the following examples are only a part of the examples of the present application, but not all the examples.

[0046] Example 1:

[0047] Preparation of a core-shell microsphere structure phosphorescent carbon dot functional material NPCDs@SiO2(V) with fluorescent carbon dots NPCDs (nitrogen and phosphorus co-doped carbon dots) as the core and a surface vinylated shell

[0048] 1. Preparation of fluorescent carbon dots NPCDs, specifically including the following steps:

[0049] 1) Weigh 3.52g of phosphorus pentoxide into a beaker, then add 2mL of 4mol / L 2-imidazolidone solution, and immediately generate a large amount of white vapor. Use an electric heater to heat and evaporate to dryness, and stop heating when the solid color in the beaker is deepened to brown.

[0050] 2) After the reaction solution is cooled, 10 mL of ultrapure water is added, ultrasonic dispersion is performed, anhydrous sodium carbonate is added to adjust the pH to neutral, and a light yellow solution is obtained after filtration using a 0.22 μm needle filter.

[0051] 2. Preparation of phosphorescent carbon dot material NPCDs@SiO2, specifically comprising the following steps:

[0052] 1) 200 μL of the light yellow carbon dot solution prepared above is taken into a 50 mL round-bottom flask, 20 mL of deionized water is added, the pH is adjusted to 9.5 with ammonia water, and finally 3.2 mL of tetraethyl orthosilicate is added, sealed with a stopper, and magnetically stirred at 80°C in a metal bath constant temperature for 24 hours. After cooling to room temperature, a light white clear solution is obtained after filtration using a 0.22 μm needle filter, which is a phosphorescent carbon dot solution coated with silicon dioxide.

[0053] 2) The phosphorescent carbon dot solution prepared above is taken, isopropanol is added for precipitation, centrifugation is performed at a speed of 10,000 r / min for 15 minutes, ethanol is washed twice, and drying is performed at 60°C to obtain a white powder of the phosphorescent carbon dot material with a core-shell structure coated with silicon dioxide on the outer layer.

[0054] 3) The size and morphology of the NPCDs@SiO2 sample prepared are characterized by transmission electron microscopy, as shown in FIG. 1, the TEM image of the phosphorescent carbon dot material shows that the NPCDs@SiO2 is a uniform spherical structure with good monodispersity and a particle size uniformly distributed at about 10 nm. Figure 2

[0055] 4) The fluorescence emission spectrum of the NPCDs@SiO2 ethanol solution under different excitation wavelengths is measured using a fluorescence protractor, as shown in FIG. 2. In the excitation wavelength range of 315-365 nm, the fluorescence emission peak position is basically unchanged, all at 510 nm, and with the increase of the excitation wavelength, the fluorescence intensity first increases and then decreases, and 345 nm is the optimal excitation wavelength of the NPCDs@SiO2. Figure 3 5) The phosphorescent spectrum of the NPCDs@SiO2 under three excitation wavelengths of 285 nm, 350 nm and 365 nm is measured using a fluorescence protractor, as shown in FIG. 3. 350 nm is the optimal excitation wavelength of the phosphorescence of the NPCDs@SiO2, which is similar to the optimal excitation wavelength of the fluorescence, and the phosphorescence of the NPCDs@SiO2 has no dependence on the excitation wavelength, and the phosphorescence absorption peak position is stable at 510 nm.

[0056] Figure 4 3. Preparation of further vinylated phosphorescent carbon dot functional material NPCDs@SiO2(V), specifically comprising the following steps:

[0057] 3. Preparation of further vinylated phosphorescent carbon dot functional material NPCDs@SiO2(V), specifically comprising the following steps:

[0058] ​​1) Take 0.1 g of the above silica-coated phosphorescent carbon dot material and mix with 10 mL of anhydrous ethanol, magnetic stirring for 30 minutes, to obtain an ethanol dispersion of phosphorescent carbon dot material NPCDs@SiO2.

[0059] 2) Take 0.01 g of vinyltrimethoxysilane and mix with 5 mL of anhydrous ethanol, magnetic stirring for 30 minutes, then mix with the above prepared ethanol dispersion of phosphorescent carbon dot material NPCDs@SiO2 in a 25 mL round-bottom flask, add ammonia to adjust the pH to 9.5, and magnetic stirring at 40°C metal bath constant temperature for 2.5 hours.

[0060] 3) After the reaction is completed, centrifuge at 10000 r / min for 20 minutes, and wash twice with anhydrous ethanol. After grinding at 60°C constant temperature drying, a white powder of the new phosphorescent carbon dot functional material NPCDs@SiO2(V) is obtained.

[0061] 4) Verify the structure of the above prepared material, and characterize the FTIR spectra of phosphorescent carbon dot material NPCDs@SiO2 and further vinylated phosphorescent carbon dot functional material NPCDs@SiO2(V), as shown in 5:

[0062] NPCDs@SiO2 has multiple characteristic absorption peaks of SiO2, 467, 800 cm -1 Si-O asymmetric contraction vibration, 972 cm -1 Si-OH bending vibration, 1120 cm -1 Strong and wide absorption peak at 1630 cm -1 H-O-H asymmetric stretching vibration, 3420 cm -1 Broad peak at -OH anti-stretching vibration. It is fully verified that the carbon dots have been completely wrapped into the SiO2 nanoparticles, forming a fluorescent microsphere structure with stable photoluminescence properties, and realizing the long-life luminescence of carbon dots

[0063] The characteristic absorption peaks of further vinylated NPCDs@SiO2(V) are obviously increased compared with those before modification, among which the sharp absorption peak at 1400 cm -1 and multiple absorption peaks near 3000 cm -1 are most obvious. The absorption peak at 1400 cm -1 is derived from the symmetric bending vibration of C-H, while the absorption peaks near 3000 cm -1 are related to the introduced vinyl group, among which 2960 cm -1 is the stretching vibration of -CH3, 3030 cm -1 is the stretching vibration of unsaturated double bond =C-H, and 3065 cm -1for the stretching vibration of the terminal =CH2, an absorption peak at 696 cm -1 indicates that the double bond moiety incorporated is in the cis configuration.

[0064] 5) Illumination with a 365 nm UV LED lamp, the above prepared phosphorescent carbon dots functional material NPCDs@SiO2(V) powder shows blue light emission, after the LED lamp is turned off, obvious green phosphorescence can be observed, as shown in Figure 6 , with a duration of about 8 seconds, long phosphorescent lifetime.

[0065] Example 2:

[0066] Application of the phosphorescent carbon dots functional material NPCDs@SiO2(V) prepared in Example 1 in the synthesis of room temperature phosphorescent homopolymer materials.

[0067] Take 1 mg of phosphorescent carbon dots functional material NPCDs@SiO2(V), 1 g of polyethylene glycol diacrylate, mix, add 0.04 g of photoinitiator HMPP, ultrasonic dispersion for 10 min, then transfer to a polytetrafluoroethylene mold, irradiate under an 8 W 365 nm ultraviolet lamp, and solidify to form a room temperature phosphorescent copolymer material.

[0068] As shown in Figure 7 , the above prepared room temperature phosphorescent homopolymer material has good light transparency, emits blue-green fluorescence under 365 nm ultraviolet lamp irradiation, emits green phosphorescence after the ultraviolet lamp is turned off, and the phosphorescent carbon dots functional material is uniformly distributed in the system.

[0069] Example 3:

[0070] Application of the phosphorescent carbon dots functional material NPCDs@SiO2(V) prepared in Example 1 in the synthesis of room temperature phosphorescent copolymer materials.

[0071] Take 1 mg of phosphorescent carbon dots functional material NPCDs@SiO2(V), 0.8 g of ethoxylated trihydroxymethyl propane triacrylate, and 0.2 g of 4-acryloyl morpholine, mix, add 0.04 g of photoinitiator HMPP, ultrasonic dispersion for 10 min, then transfer to a polytetrafluoroethylene mold, irradiate under an 8 W 365 nm ultraviolet lamp, and solidify to form a room temperature phosphorescent copolymer material.

[0072] As shown in Figure 8 , the above prepared room temperature phosphorescent homopolymer material has good light transparency, emits blue fluorescence under 365 nm ultraviolet lamp irradiation, emits green phosphorescence after the ultraviolet lamp is turned off, and the phosphorescent carbon dots functional material is uniformly distributed in the system.

[0073] Comparative Example 1:

[0074] Synthesis of doped surface non-vinylized phosphorescent carbon dots material NPCDs@SiO2 high molecular material.

[0075] Take 1 mg of phosphorescent carbon dots material NPCDs@SiO2 prepared in the second step of Example 1, 0.8 g of ethoxylated trihydroxymethyl propane triacrylate, 0.2 g of 4-acryloyl morpholine, mix, add 0.04 g of photoinitiator HMPP, ultrasonic dispersion for 10 min, then transfer to a polytetrafluoroethylene mold, irradiate under an 8 W 365 nm ultraviolet lamp, and solidify to form a room temperature phosphorescent high molecular material.

[0076] The doped high molecular material prepared above has phosphorescent carbon dots material NPCDs@SiO2 that agglomerates in the system, is unevenly distributed, excludes the background fluorescence of the high molecular material, and only the doped phosphorescent carbon dots emit strong blue fluorescence under ultraviolet light irradiation, and emit strong green phosphorescence after the ultraviolet lamp is turned off, as shown in Figure 9 .

[0077] Comparative Example 2.1:

[0078] Application of phosphorescent carbon dots functional material NPCDs@SiO2(V) prepared in Example 1 in synthesis of room temperature phosphorescent copolymer high molecular material

[0079] Take 1 mg of phosphorescent carbon dots functional material NPCDs@SiO2(V), 0.9 g of ethoxylated trihydroxymethyl propane triacrylate, and 0.1 g of methoxy polyethylene glycol acrylate, mix, add 0.04 g of photoinitiator HMPP, ultrasonic dispersion, then transfer to a polytetrafluoroethylene mold, irradiate under an 8 W 365 nm ultraviolet lamp, and solidify to form a room temperature phosphorescent copolymer high molecular material.

[0080] Comparative Example 2.2:

[0081] Application of phosphorescent carbon dots functional material NPCDs@SiO2(V) prepared in Example 1 in synthesis of room temperature phosphorescent copolymer high molecular material.

[0082] The other conditions are the same as in Comparative Example 2.1, and the only difference is that the content of the added phosphorescent carbon dots functional material is 0 mg.

[0083] Comparative Example 2.3;

[0084] Application of phosphorescent carbon dots functional material NPCDs@SiO2(V) prepared in Example 1 in synthesis of room temperature phosphorescent copolymer high molecular material.

[0085] The other conditions are the same as in Comparative Example 2.1, and the only difference is that the content of the added phosphorescent carbon dots functional material is 2 mg.

[0086] Comparative Example 2.4:

[0087] Application of the phosphorescent carbon dot functional material NPCDs@SiO2(V) prepared in Example 1 in the synthesis of room temperature phosphorescent copolymer polymer materials.

[0088] Other conditions were the same as in Comparative Example 2.1, the only difference being that the content of the added phosphorescent carbon dot functional material was 4 mg.

[0089] Comparative Example 2.5:

[0090] Application of the phosphorescent carbon dot functional material NPCDs@SiO2(V) prepared in Example 1 in the synthesis of room temperature phosphorescent copolymer polymer materials.

[0091] Other conditions were the same as in Comparative Example 2.1, the only difference being that the content of the added phosphorescent carbon dot functional material was 6 mg.

[0092] Comparative Example 2.6:

[0093] Application of the phosphorescent carbon dot functional material NPCDs@SiO2(V) prepared in Example 1 in the synthesis of room temperature phosphorescent copolymer polymer materials.

[0094] Other conditions were the same as in Comparative Example 2.1, the only difference being that the content of the added phosphorescent carbon dot functional material was 8 mg.

[0095] like Figure 10 As shown, the room-temperature phosphorescent copolymer materials obtained through the above comparative examples 2.1, 2.2, 2.3, 2.4, 2.5, and 2.6 all exhibit good optical transparency.

[0096] like Figure 11 As shown, the obtained polymer material emits blue-green fluorescence under 365nm ultraviolet excitation light.

[0097] like Figure 12 As shown, after the excitation light source is turned off, the polymer materials without phosphorescent carbon dot functional materials do not exhibit phosphorescence, while the polymer materials with phosphorescent carbon dot functional materials all exhibit phosphorescence. This indicates that by modifying the phosphorescent carbon dots, polymer materials can acquire phosphorescent properties.

[0098] like Figure 13 As shown, using a spectrophotometer, the maximum phosphorescence emission wavelength of the phosphorescent carbon dot-functionalized polymer material was measured to be 510 nm under 350 nm excitation.

[0099] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope defined in the claims.

[0100] The invention is not detailed in all respects, which are known to those skilled in the art.

Claims

1. A method for preparing phosphorescent carbon dot material, characterized in that, The method comprises the following specific steps: 1) mixing 2-imidazolidone solution with phosphorus pentoxide, heating and boiling to dryness by using an electric furnace until the solid color darkens to brown, then stopping heating, adding water to disperse, adjusting pH to neutral, and obtaining intermediate phosphorescent carbon dot material I after filtration; 2) mixing the intermediate phosphorescent carbon dot material I with deionized water, adjusting pH to alkaline environment, adding tetraethyl orthosilicate, and obtaining silica-coated core-shell structure intermediate phosphorescent carbon dot material II after reaction under constant temperature magnetic stirring, separation and drying; 3) dispersing the intermediate phosphorescent carbon dot material II in ethanol, mixing with a surface modifier vinyltrimethoxysilane according to a certain mass ratio, and stirring to obtain phosphorescent carbon dot material with hydrophobic functional groups introduced on the surface.

2. The method of claim 1, wherein: In the step 1), the reaction molar ratio of 2-imidazolidone to phosphorus pentoxide is between 0.1 and 10.

3. The method of claim 1, wherein: In the step 3), the mass ratio of the intermediate phosphorescent carbon dot material II to the surface modifier is (2-15):

1.

4. A phosphorescent carbon dot material, characterized by, The phosphorescent carbon dot material is prepared by using the preparation method in any one of claims 1 to 3.

5. The phosphorescent carbon dot material of claim 4, wherein: The microstructure of the phosphorescent carbon dot material is a core-shell structure nanoparticle with carbon dot inside and silica outside.

6. The phosphorescent carbon dot material of claim 5, wherein: The particle size of the nanoparticle is 9-11 nm.

7. The phosphorescent carbon dot material prepared by the preparation method of any one of claims 1 to 3, or the phosphorescent carbon dot material of any one of claims 4 to 6, in the application of preparing a phosphorescent polymer material, characterized in that, The method comprises the following specific steps: irradiating a mixture of ultraviolet light polymerizable monomers, phosphorescent carbon dot material and a photoinitiator with ultraviolet light to cure and obtain phosphorescent polymer material modified by the phosphorescent carbon dot material.

8. Use according to claim 7, characterized in that: The ultraviolet light polymerizable monomers include one or more of polyethylene glycol diacrylate, 4-acryloylmorpholine, methoxy polyethylene glycol acrylate, ethoxylated trihydroxymethyl propane triacrylate, styrene, methacrylic acid and methyl methacrylate.

9. Use according to claim 7, characterized in that: In the mixture, the mass fraction of the photoinitiator is 1-10%, and the mass fraction of the phosphorescent carbon dot material is 1-8%.

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