Preparation method and application of white light excited aqueous long afterglow carbon dot material

Abstract

The present invention belongs to the field of luminescent carbon materials, specifically relating to a method for preparing and applying a white-light-excited aqueous long-lasting carbon dot material. The method comprises the following steps: Step 1: dissolving m-phenylenediamine, boric acid, and silicic acid in a reaction solvent to form a uniform mixed solution; Step 2: subjecting the mixed solution A to a solvothermal reaction to obtain a product; Step 3: subjecting the product to thorough dialysis in a dialysis bag to obtain a solution; Step 4: injecting silicic acid and aqueous ammonia into the solution to form a uniform mixed solution, and ultrasonically obtaining a white-light-excited aqueous long-lasting carbon dot solution. The present invention can simultaneously achieve white-light and ultraviolet light excitation. Under white-light excitation, the afterglow is visible to the naked eye for approximately 5 seconds, and under 365nm ultraviolet light excitation, the afterglow is visible to the naked eye for approximately 9 seconds. The preparation method is simple to operate, employs mild and environmentally friendly reaction conditions, uses non-toxic and harmless raw materials, is operator-friendly and environmentally friendly, and has low preparation costs. The method has great potential for applications in fields such as information encryption and bioimaging.

Description

Technical field:

[0001] The present invention belongs to the field of luminescent carbon materials, and in particular relates to a preparation method and application of a white light excited aqueous phase long afterglow carbon dot material. Background technology:

[0002] Afterglow materials are photoluminescent materials that continue to emit light for a period of time after the external stimulus is removed. Room-temperature afterglow exhibits excellent application prospects in fields such as information security, sensing, and bioimaging due to its long triplet lifetime, high sensitivity to the environment, and minimal interference from background fluorescence. Carbon dots, a class of nanoscale, quasi-spherical particles less than 10 nm in size, are considered a novel luminescent material due to their excellent optical properties, environmental friendliness, biocompatibility, low toxicity, readily available raw materials, and simple synthesis process. Compared to ultraviolet light, white light has lower energy, less photodamage, deeper tissue penetration, lower phototoxicity, and greater safety, offering greater potential for practical applications.

[0003] The solution provided by CN202010111134 is to dissolve the imine guest molecule in acetonitrile to obtain an acetonitrile solution of the imine guest molecule; then add the dicarboxylic acid main molecule thereto, add deionized water or methanol or ethanol or glacial acetic acid, heat and stir to obtain a clear solution; let it stand at room temperature to precipitate crystals or amorphous powder. Wash with water or ethanol to obtain an imine-doped dicarboxylic acid long afterglow material. The problems are: 1. The obtained product can only produce afterglow in the solid state and cannot emit afterglow in the liquid state; 2. The afterglow lifetime of the obtained product is short, with a maximum afterglow lifetime of only 416ms; 3. The obtained product can only produce afterglow under ultraviolet excitation, but cannot excite afterglow under white light; 4. The prepared product is a solid-phase powder, which can only produce solid-state room temperature afterglow under ultraviolet light, and the afterglow lifetime is short, which greatly limits its application field.

[0004] Therefore, it is of great significance to develop long-afterglow carbon dot materials, especially aqueous materials, that can be excited by both white light and ultraviolet light. Summary of the invention:

[0005] The purpose of the present invention is to provide a preparation method and application of a white light excited aqueous phase long afterglow carbon dot material, so as to solve the problem in the prior art that the carbon dot solution cannot emit aqueous phase long afterglow under white light excitation.

[0006] To achieve the above object, the present invention adopts the following technical solution: a method for preparing a white light excited aqueous long afterglow carbon dot material, comprising the following steps:

[0007] Step 1: dissolving m-phenylenediamine, boric acid and silicic acid in a reaction solvent according to a certain proportion, and stirring thoroughly to form a uniform mixed solution A;

[0008] Step 2: placing the mixed solution A in a reactor for solvothermal reaction to obtain product B;

[0009] Step 3: The product B is fully dialyzed in a dialysis bag for 12 to 60 hours to remove small molecules to obtain solution C;

[0010] Step 4: Take solution C, inject silicic acid and ammonia water into the above solution C to form a mixed solution, and ultrasonicate for 2 to 8 hours to obtain a white light excited aqueous long afterglow carbon dot solution.

[0011] Furthermore, in the above step 1, m-phenylenediamine, boric acid and silicic acid are prepared according to the ratio of 0.05-0.3 g: 0.06-0.4 g: 2-10 mL.

[0012] Furthermore, in the above step 1, the reaction solvent is water, ethanol, ether, benzene, THF or CCl4.

[0013] Furthermore, in the above step 2, the solvent thermal reaction time is 4 to 12 hours.

[0014] Furthermore, in the above step 3, the molecular weight cut-off of the dialysis bag is 500 to 5000 Da.

[0015] Furthermore, in the above step 4, solution C, silicic acid and ammonia water are prepared in the ratio of 5-50 mL: 0.5-3 mL: 1-6 mL.

[0016] Furthermore, in the above step 4, the temperature during ultrasound examination using an ultrasound machine is 25 to 55°C, and the temperature is 160 to 250°C;

[0017] Furthermore, the above-mentioned white light excited water-phase long afterglow carbon dot material is used in the field of information encryption.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1. The present invention uses m-phenylenediamine, boric acid, and silicic acid as precursors to obtain a mixed solution via a solvothermal method. The dialyzed mixed solution is then ultrasonically mixed with silicic acid and aqueous ammonia. The entire preparation process is simple, with mild reaction conditions and low raw material costs, resulting in a high-purity carbon dot solution. The introduction of boric acid causes the dehydration condensation of phenylenediamine to form a dense core structure, which can produce a long-lasting afterglow in the aqueous phase under white light excitation. The successful introduction of silane provides a covalent network structure, resulting in stable optical properties and long-term storage of the carbon dots, expanding their applications in fields such as information encryption and bioimaging.

[0020] 2. The carbon dot solution produced by this invention produces a long afterglow in aqueous solution, exhibiting excellent water solubility and biocompatibility, making it widely applicable in the biomedical field. It can be excited by both white light and ultraviolet light. Under white light excitation, the afterglow is visible to the naked eye for approximately 5 seconds, and under 365nm ultraviolet light excitation, the afterglow is visible to the naked eye for approximately 9 seconds.

[0021] 3. The preparation method of the present invention is simple to operate, with mild and environmentally friendly reaction conditions. The raw materials used are non-toxic and harmless, operator-friendly and environmentally friendly, and the preparation cost is low. The white light-excited aqueous long-lasting carbon dot material prepared by the present invention has great application potential in fields such as information encryption and bioimaging. Description of the drawings:

[0022] Figure 1 These are photos of the white light excited aqueous long afterglow carbon dot solution of the present invention under white light flashlight and 365nm ultraviolet irradiation and under off conditions;

[0023] Figure 2 The transmission electron microscope (TEM) spectrum of the white light excited aqueous long afterglow carbon dot solution of the present invention;

[0024] Figure 3 The X-ray diffraction (XRD) pattern of the white light excited aqueous long afterglow carbon dot solution of the present invention;

[0025] Figure 4 The Fourier transform infrared (FT-IR) spectrum of the white light excited aqueous long afterglow carbon dot solution of the present invention;

[0026] Figure 5 The fluorescence emission diagrams of the white light excited aqueous long afterglow carbon dot solution under different excitations of the present invention;

[0027] Figure 6 This is the phosphorescence emission diagram of the white light excited aqueous long afterglow carbon dot solution under different excitations of the present invention;

[0028] Figure 7 This is a graph of the afterglow lifetime of the white light excited aqueous long afterglow carbon dot solution of the present invention under 365nm excitation;

[0029] Figure 8 This is an example diagram of the application of the white light excited aqueous long afterglow carbon dot solution of the present invention in information encryption. Specific implementation method:

[0030] The specific contents of the present invention are further explained in detail below in conjunction with the embodiments, but are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0031] The present invention provides a preparation method and application of a white light-excited water-phase long-lasting carbon dot material, which uses m-phenylenediamine, boric acid and silicic acid as raw materials and is prepared by a solvent-thermal two-step reaction.

[0032] Example 1, a method for preparing a white light excited aqueous long afterglow carbon dot material, comprising the following steps:

[0033] Step 1: Dissolve 0.1 g of m-phenylenediamine, 0.2 g of boric acid, and 2 mL of silicic acid in 15 mL of ethanol and stir thoroughly to form a uniform mixed solution A;

[0034] Step 2: Place the mixed solution A in a reactor and react at 180°C for 8 hours to obtain product B;

[0035] Step 3: Product B was dialyzed for 48 h (MWCO: 2000 Da) to remove small molecules to obtain solution C;

[0036] Step 4: Take 30 mL of solution C, inject 3 mL of silicic acid and 2 mL of ammonia water into solution C, and ultrasonicate at 40°C for 5 h to obtain a white light-excited aqueous long-lasting carbon dot solution.

[0037] Example 2, a method for preparing a white light excited aqueous long afterglow carbon dot material, comprising the following steps:

[0038] Step 1: Dissolve 0.1 g of m-phenylenediamine, 0.2 g of boric acid, and 2 mL of silicic acid in 10 mL of ethanol and stir thoroughly to form a uniform mixed solution A;

[0039] Step 2: Place the mixed solution A in a reactor and react at 180°C for 5 hours to obtain product B;

[0040] Step 3: Product B was dialyzed for 24 h in dialysis (MWCO: 1000 Da) to remove small molecules to obtain solution C;

[0041] Step 4: Take 45 mL of solution C, inject 1 mL of silicic acid and 4 mL of ammonia water into the above solution. Ultrasonicate at 50 ° C for 2 h to obtain a white light excited aqueous long afterglow carbon dot solution.

[0042] Example 3, a method for preparing a white light excited aqueous long afterglow carbon dot material, comprising the following steps:

[0043] Step 1: Dissolve 0.2 g of m-phenylenediamine, 0.4 g of boric acid, and 5 mL of silicic acid in 25 mL of ethanol and stir thoroughly to form a uniform mixed solution A;

[0044] Step 2: Place the mixed solution A in a reactor and react at 200°C for 8 hours to obtain product B;

[0045] Step 3: Product B was dialyzed for 60 h (MWCO: 2000 Da) to remove small molecules to obtain solution C;

[0046] Step 4: Take 35 mL of solution C, inject 2 mL of silicic acid and 3 mL of ammonia water into the above solution. Ultrasonicate at 35 ° C for 6 h to obtain a white light excited aqueous long afterglow carbon dot solution.

[0047] Example 4, a method for preparing a white light excited aqueous long afterglow carbon dot material, comprising the following steps:

[0048] Step 1: Dissolve 0.1 g of m-phenylenediamine, 0.3 g of boric acid, and 3 mL of silicic acid in 15 mL of ethanol and stir thoroughly to form a uniform mixed solution A;

[0049] Step 2: Place the mixed solution A in a reactor and react at 180°C for 8 hours to obtain product B;

[0050] Step 3: Product B was dialyzed for 48 h in dialysis (MWCO: 3000 Da) to remove small molecules to obtain solution C;

[0051] Step 4: Take 20 mL of solution C, inject 2 mL of silicic acid and 1 mL of ammonia water into the above solution. Ultrasonicate at 35 ° C for 4 h to obtain a white light excited aqueous long afterglow carbon dot solution.

[0052] Example 5, a method for preparing a white light excited aqueous long afterglow carbon dot material, comprising the following steps:

[0053] Step 1: Dissolve 0.5 g of m-phenylenediamine, 0.2 g of boric acid, and 3 mL of silicic acid in 25 mL of ethanol and stir thoroughly to form a uniform mixed solution A;

[0054] Step 2: Place the mixed solution A in a reactor and react at 180°C for 8 hours to obtain product B;

[0055] Step 3: Product B was dialyzed for 48 h (MWCO: 5000 Da) to remove small molecules to obtain solution C;

[0056] Step 4: Take 30 mL of solution C, inject 3 mL of silicic acid and 5 mL of ammonia water into the above solution. Ultrasonicate at 30 ° C for 6 h to obtain a white light excited aqueous long afterglow carbon dot solution.

[0057] The above embodiment 1 is the best embodiment. Figure 1It can be seen that the aqueous afterglow carbon dot solution prepared in this embodiment exhibits bright blue fluorescence under both white light flashlight and 365nm ultraviolet lamp irradiation, and a period of blue afterglow is still produced after the white light flashlight is turned off, which is visible to the naked eye for about 5 seconds; after removing the 365nm ultraviolet lamp, a blue afterglow of about 8 seconds can be produced.

[0058] Depend on Figure 2 It can be seen that the white light excited aqueous long afterglow carbon dots prepared in this embodiment are uniformly dispersed spherical particles with a lattice spacing of 0.22 nm corresponding to the (001) plane of graphene and a grain size of 1.96 nm.

[0059] Depend on Figure 3 It can be seen that the aqueous long-lasting carbon dot solution excited by white light prepared in this example produces a characteristic diffraction peak at 22.84°, which proves that the product maintains amorphous properties.

[0060] Depend on Figure 4 It can be seen that the aqueous long afterglow carbon dot solution prepared in this embodiment excited by white light has a wavelength of 791 cm -1 Hechu 1101cm -1 The characteristic peaks of silicon were generated at 467 cm-1, which were attributed to the stretching vibrations of Si-OC and Si-O-Si, respectively, confirming the successful introduction of silane. -1 、1628cm -1 The peak at 3200-3600cm is caused by the stretching vibration of NH and CN bonds. -1 The broad absorption peak shown at is attributed to the stretching vibration of OH / NH.

[0061] Depend on Figure 5 It can be seen that the fluorescence emission peak of the white light-excited aqueous long-lasting carbon dot solution prepared in this embodiment is located at about 485 nm in the excitation range of 350 to 420 nm.

[0062] Depend on Figure 6 It can be seen that the afterglow emission peak of the white light-excited aqueous long afterglow carbon dot solution prepared in this embodiment is located at about 460 nm in the excitation range of 300-450 nm.

[0063] Depend on Figure 7 It can be seen that the afterglow lifetime of the white light excited aqueous long afterglow carbon dot solution prepared in this embodiment under 400nm excitation is 944ms, which shows that the present invention has an ultra-long afterglow lifetime.

[0064] Figure 8This diagram illustrates the application of the white-light-excited, aqueous, long-lasting carbon dot solution prepared in this example. To expand practical applications, the carbon dot solution was used to dye silkworm cocoons, gauze, and cotton. The results showed that the carbon dot solution adsorbed well onto these natural fibers, expanding its application in information encryption across a variety of materials.

[0065] The above are merely specific embodiments of the present invention and are not intended to limit the present invention. Those skilled in the art will readily appreciate that the present invention is susceptible to various modifications and variations. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing a white light-excited aqueous long-lasting carbon dot material, characterized by: It consists of the following steps: Step 1: dissolving m-phenylenediamine, boric acid and silicic acid in a reaction solvent according to a certain proportion, and stirring thoroughly to form a uniform mixed solution A; Step 2: placing the mixed solution A in a reactor for solvothermal reaction to obtain product B; Step 3: dialyze product B in a dialysis bag for 12 to 60 hours to obtain solution C; Step 4: Take solution C, inject silicic acid and ammonia water into the above solution C to form a uniform mixed solution, and ultrasonicate for 2 to 8 hours to obtain a white light excited aqueous long afterglow carbon dot solution; In the step 1, m-phenylenediamine, boric acid, and silicic acid are prepared according to the ratio of 0.05-0.3 g: 0.06-0.4 g: 2-10 mL; In the step 2, the solvent thermal reaction time is 4 to 12 hours, and the temperature is 160 to 250°C; In the step 4, solution C, silicic acid and ammonia water are prepared in the ratio of 5 to 50 mL: 0.5 to 3 mL: 1 to 6 mL.

2. The method for preparing a white light-excited aqueous long-lasting carbon dot material according to claim 1, characterized in that: In the step 1, the reaction solvent is water, ethanol, ether, benzene, THF or CCl4.

3. The method for preparing a white light-excited aqueous long-lasting carbon dot material according to claim 2, characterized in that: In the step 3, the molecular weight cut-off of the dialysis bag is 500 to 5000 Da.

4. The method for preparing a white light-excited aqueous long-lasting carbon dot material according to claim 3, characterized in that: In the step 4, the temperature during ultrasonication by an ultrasonic instrument is 25 to 55°C.

5. Application of the white light excited aqueous long afterglow carbon dot material according to claim 1 in the field of information encryption.

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