Preparation method and application of white light excited water-phase long afterglow carbon dot material

Abstract

The invention belongs to the field of luminescent carbon materials, and particularly relates to a preparation method and application of a white light excited water-phase long afterglow carbon dot material. The method comprises the following steps: 1, dissolving m-phenylenediamine, boric acid and silicic acid in a reaction solvent to form a uniformly mixed solution; 2, the mixed solution A is subjected to a solvothermal reaction, and a product is obtained; 3, fully dialyzing the product in a dialysis bag to obtain a solution; and 4, injecting silicic acid and ammonia water into the solution to form a uniformly mixed solution, and carrying out ultrasonic treatment to obtain the white light excited water-phase long afterglow carbon dot solution. According to the invention, the excitation of white light and ultraviolet light can be realized at the same time, under the excitation of white light, the persistence duration visible to naked eyes is about 5s, and under the excitation of 365nm ultraviolet light, the persistence duration visible to naked eyes is about 9s. The preparation method is simple and convenient to operate, mild and environment-friendly in reaction condition, nontoxic and harmless in adopted raw materials, friendly and environment-friendly to operators and low in preparation cost; the method can be applied to the fields of information encryption, biological imaging and the like and has great application potential.

Description

Technical field:

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

[0002] Afterglow material is a photoluminescent material, which means that it can still maintain the luminescence phenomenon for a period of time after the external stimulus is removed. Room temperature afterglow has the advantages of long triplet lifetime, high sensitivity to the environment, and little interference from background fluorescence, showing very excellent application prospects in the fields of information security, sensing, and bioimaging. Carbon dots are a type of nano-quasi-spherical particles with a size of less than 10nm. They are considered to be a new type of luminescent material because of their excellent optical properties, environmental friendliness, good biocompatibility, low toxicity, easy access to raw materials, and simple synthesis process. Compared with ultraviolet light, white light has lower energy, less light damage, deeper tissue penetration, less phototoxicity, and higher safety, and has greater room 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 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 existing 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 life of the obtained product is short, and the maximum afterglow life is 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 room temperature afterglow under ultraviolet light, and the afterglow life 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 water phase long afterglow carbon dot material, so as to solve the problem that the carbon dot solution existing in the prior art cannot emit water phase long afterglow under white light excitation.

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

[0007] Step 1, dissolving m-phenylenediamine, boric acid and silicic acid in a reaction solvent according to a proportion, and stirring sufficiently 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: fully dialyze product B 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 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 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 three, 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 of the ultrasonic instrument during ultrasonication 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 by a solvothermal method, and then the dialyzed mixed solution is mixed with silicic acid and ammonia water by ultrasonication. The entire preparation process is simple, the reaction conditions are mild, the raw material cost is low, and the obtained carbon dot solution has a high purity. Due to the introduction of boric acid, the dehydration condensation of phenylenediamine forms a dense core structure, so that a long afterglow in the water phase can be generated under white light excitation. Due to the successful introduction of silane, it has a covalent network structure wrapping, and the optical properties of the obtained carbon dots are stable and can be stored for a long time, which expands the application in the fields of information encryption and biological imaging.

[0020] 2. The carbon dot solution prepared by the present invention can produce a long afterglow in an aqueous solution, has good water solubility and biocompatibility, and can therefore be widely used in the biomedical field. It can simultaneously achieve white light and ultraviolet light excitation. Under white light excitation, the afterglow visible to the naked eye lasts for about 5 seconds, and under 365nm ultraviolet light excitation, the afterglow visible to the naked eye lasts for about 9 seconds.

[0021] 3. The preparation method of the present invention is simple to operate, the reaction conditions are mild and environmentally friendly, and the raw materials used are non-toxic and harmless, operator-friendly and environmentally friendly, and the preparation cost is low. The white light-excited water-phase long-lasting carbon dot material prepared by the present invention can be applied to information encryption, biological imaging and other fields, and has great application potential. 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 It is a transmission electron microscope (TEM) spectrum of the white light excited aqueous phase long afterglow carbon dot solution of the present invention;

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

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

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

[0027] Figure 6 This is a 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 the afterglow lifetime diagram 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 implementation, but are not intended to be limiting of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0031] The present invention provides a preparation method and application of a white light excited water phase long afterglow carbon dot material, using m-phenylenediamine, boric acid and silicic acid as raw materials, and preparing the white light excited water phase afterglow carbon dot material through a solvent thermal two-step reaction.

[0032] Embodiment 1, a method for preparing a water-phase long afterglow carbon dot material excited by white light, comprising the following steps:

[0033] Step 1: dissolve 0.1 g m-phenylenediamine, 0.2 g boric acid and 2 mL silicic acid in 15 mL 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: The product B was dialyzed for 48 h in dialysis (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 afterglow carbon dot solution.

[0037] Embodiment 2, a method for preparing a water-phase long afterglow carbon dot material excited by white light, comprising the following steps:

[0038] Step 1: dissolve 0.1 g m-phenylenediamine, 0.2 g boric acid and 2 mL silicic acid in 10 mL 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: The 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] Embodiment 3, a method for preparing a water-phase long afterglow carbon dot material excited by white light, comprising the following steps:

[0043] Step 1: dissolve 0.2 g m-phenylenediamine, 0.4 g boric acid and 5 mL silicic acid in 25 mL 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: The product B was dialyzed for 60 h in dialysis (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 for 6 hours at a temperature of 35 ° C to obtain a white light excited aqueous long afterglow carbon dot solution.

[0047] Embodiment 4, a method for preparing a water-phase long afterglow carbon dot material excited by white light, comprising the following steps:

[0048] Step 1: dissolve 0.1 g m-phenylenediamine, 0.3 g boric acid and 3 mL silicic acid in 15 mL 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: The product B was dialyzed in dialysis (MWCO: 3000Da) for 48 hours 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 water-phase long afterglow carbon dot material excited by white light, comprising the following steps:

[0053] Step 1: dissolve 0.5 g m-phenylenediamine, 0.2 g boric acid and 3 mL silicic acid in 25 mL 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: The product B was dialyzed in dialysis (MWCO: 5000Da) for 48 hours 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 for 6 hours at a temperature of 30°C 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 the irradiation of a white light flashlight and a 365nm ultraviolet lamp, 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 water phase long afterglow carbon dots prepared in this embodiment are uniformly dispersed spherical particles, the interplanar spacing is 0.22nm corresponding to the (001) crystal plane of graphene, and the grain size is 1.96nm.

[0059] Depend on Figure 3 It can be seen that the aqueous long afterglow 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 characteristics.

[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 and 1101cm -1 The characteristic peaks related to silicon were generated at 467cm-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 peaks at 3200-3600cm are 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 afterglow carbon dot solution prepared in this example is located at about 485 nm in the excitation range of 350-420 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 in the excitation range of 300-450nm has a fluorescence emission peak located at about 460nm.

[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 is an application example of the white light-excited aqueous long-lasting carbon dot solution prepared in this embodiment. In order to expand practical applications, the carbon dot solution was used to dye silk cocoons, gauze and cotton cloth. The results showed that the carbon dot solution can be well adsorbed on these natural fibers, expanding its information encryption application on different materials.

[0065] The above are only specific embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a water-phase long-lasting carbon dot material excited by white light, characterized in that: It consists of the following steps: Step 1, dissolving m-phenylenediamine, boric acid and silicic acid in a reaction solvent according to a proportion, and stirring sufficiently 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: fully 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 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.

2. The method for preparing a white light excited water phase long afterglow carbon dot material according to claim 1, characterized in that: In the step 1, m-phenylenediamine, boric acid and silicic acid are prepared according to 0.05-0.3 g: 0.06-0.4 g: 2-10 mL.

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

4. The method for preparing a white light excited water phase long afterglow carbon dot material according to claim 3, characterized in that: In the step 2, the solvent thermal reaction time is 4 to 12 hours, and the temperature is 160 to 250°C.

5. The method for preparing a white light excited water phase long afterglow carbon dot material according to claim 4, characterized in that: In the step 3, the molecular weight cut-off of the dialysis bag is 500 to 5000 Da.

6. The method for preparing a white light excited water phase long afterglow carbon dot material according to claim 5, characterized in that: 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.

7. The method for preparing a white light excited water phase long afterglow carbon dot material according to claim 6, characterized in that: In the step 4, the temperature during ultrasonication by an ultrasonicator is 25 to 55°C.

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

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