Preparation method of fluorescent powder based on garlic skin and anti-counterfeiting ink

Abstract

The invention provides a preparation method of fluorescent powder based on garlic skin and anti-forgery ink, and the preparation method of the fluorescent powder comprises the following steps: mixing the garlic skin and water, and carrying out microwave reaction to obtain a crude product containing fluorescent carbon dots; mixing the crude product with water, and performing suction filtration to obtain a fluorescent carbon dot solution; and mixing the fluorescent carbon dot solution with soluble starch, and then performing freeze drying and crushing to obtain the fluorescent powder. The invention provides the green and environment-friendly fluorescent powder with good luminescence performance, and the fluorescent powder can be used for preparing anti-counterfeiting ink with good performance.

Description

Technical Field

[0001] This invention relates to the field of anti-counterfeiting ink technology, specifically to a method for preparing fluorescent powder based on garlic peel and an anti-counterfeiting ink. Background Technology

[0002] Information security is crucial to the safety of individuals and society, making anti-counterfeiting measures paramount. Fluorescent materials, with their superior luminescent properties and excellent visual contrast, hold great application potential in the field of information security. As information security standards continue to improve, their application in various environments is receiving increasing attention. Fluorescent ink printing offers advantages such as ease of operation, high production volume, and convenient design, making it the most widely used method for anti-counterfeiting.

[0003] With advancements in printing technology, fluorescent ink printing has gradually emerged as an innovative technology, demonstrating significant potential in anti-counterfeiting and information encryption. Therefore, it is necessary to explore more types of anti-counterfeiting inks that offer good protection while remaining environmentally friendly, thus enriching the variety of inks available. Summary of the Invention

[0004] In view of the technical problems existing in the background art, this application provides a method for preparing fluorescent powder based on garlic peel and anti-counterfeiting ink, and provides a fluorescent powder with good luminescence performance and environmental protection, which can be used to prepare anti-counterfeiting ink with good performance.

[0005] In a first aspect, embodiments of this application provide a method for preparing a phosphor based on garlic peel, the preparation method comprising the following steps: Garlic peels and water were mixed and subjected to a microwave reaction to obtain a crude product containing fluorescent carbon dots. The crude product was mixed with water and filtered to obtain a fluorescent carbon dot solution. The fluorescent carbon dot solution was mixed with soluble starch, then freeze-dried and pulverized to obtain fluorescent powder.

[0006] Optionally, in some embodiments of this application, in the step of mixing garlic peel and water and performing a microwave reaction to obtain a crude product containing fluorescent carbon dots, the power of the microwave reaction is 290~1160 W and the time is 3~9 min.

[0007] Optionally, in some embodiments of this application, in the step of mixing garlic peel and water and performing a microwave reaction to obtain a crude product containing fluorescent carbon dots, 15-25 mL of water is added per gram of garlic peel.

[0008] Optionally, in some embodiments of this application, in the step of mixing garlic peel and water and performing a microwave reaction to obtain a crude product containing fluorescent carbon dots, a 0.22 μm aqueous filter membrane is used for filtration.

[0009] Optionally, in some embodiments of this application, in the step of mixing the crude product with water and filtering to obtain a fluorescent carbon dot solution, 70-130 mL of water is added per gram of garlic peel.

[0010] Optionally, in some embodiments of this application, in the step of mixing the fluorescent carbon dot solution with soluble starch, and then freeze-drying and pulverizing to obtain fluorescent powder, the mass ratio of the fluorescent carbon dots in the fluorescent carbon dot solution to the soluble starch is 1:15~35.

[0011] Optionally, in some embodiments of this application, in the step of mixing the fluorescent carbon dot solution with soluble starch, and then freeze-drying and pulverizing to obtain fluorescent powder, the mixing time is 15-30 h.

[0012] Optionally, in some embodiments of this application, in the step of mixing the fluorescent carbon dot solution with soluble starch and then freeze-drying and pulverizing to obtain fluorescent powder, the freeze-drying time is 10-15 h.

[0013] Secondly, this application also proposes an anti-counterfeiting ink, comprising fluorescent powder prepared by the method described above.

[0014] Optionally, in some embodiments of this application, hydroxyethyl cellulose and water are also included.

[0015] Optionally, in some embodiments of this application, the ratio of the mass of the fluorescent powder to the total mass of the hydroxyethyl cellulose and water in the anti-counterfeiting ink is 0.8~1.2:10.

[0016] Optionally, in some embodiments of this application, the mass ratio of hydroxyethyl cellulose to water in the anti-counterfeiting ink is 3~5:100.

[0017] The technical solution provided in this application uses garlic peels, a biomass waste, as raw material, which is low-cost and develops a new use for biomass waste. It is green, environmentally friendly, safe, and reliable. The garlic peels are processed using a microwave method, which is simple to operate and produces carbon dots with uniform particle distribution and good fluorescence properties. The carbon dot aqueous solution is colorless and transparent under sunlight and exhibits obvious green fluorescence under ultraviolet light. Based on these carbon dots, fluorescent inks with consistent fluorescence color can be produced, effectively achieving fluorescence consistency between the solution-state carbon dots and the anti-counterfeiting ink. This serves as an important quality control indicator for evaluating the quality of the final product during production, aiding in quality control, improving yield and product effect, reducing waste, and resulting in an environmentally friendly anti-counterfeiting ink with good color development and excellent screen printing suitability.

[0018] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of this application, the accompanying drawings used in this application will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application. For those skilled in the art, other drawings can be obtained from these drawings without any creative effort.

[0020] Figure 1 TEM image of the G-CDs solution prepared in Example 1; Figure 2 The particle size distribution diagram is shown for the G-CDs solution prepared in Example 1. Figure 3 The images show the G-CDs solution prepared in Example 1 under sunlight and ultraviolet light, respectively. Figure 4 The UV-Vis absorption spectrum of the G-CDs solution prepared in Example 1 is shown below. Figure 5 The fluorescence emission spectra of the G-CDs solution prepared in Example 1 under different excitation light (340 nm ~ 460 nm); Figure 6 These are photographs of the phosphor prepared in Example 1 under sunlight and ultraviolet light, respectively. Figure 7 Here is a photograph of the anti-counterfeiting ink prepared in Example 1 under ultraviolet light; Figure 8 These are photographs of the screen-printed pattern of the anti-counterfeiting ink prepared in Example 1 after undergoing different numbers of rubbings. Figure 9 The screen-printed pattern of the anti-counterfeiting ink prepared in Example 1; Figure 10 The fluorescence emission spectra of the G-CDs solutions prepared in Examples 1 to 4 under 365 nm excitation light are shown. Figure 11 The fluorescence emission spectra of the G-CDs solutions prepared in Examples 1, 5 and 6 under 365 nm excitation light are shown. Detailed Implementation

[0021] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application and are therefore merely examples, and should not be used to limit the scope of protection of this application.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0023] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range, such as 1, 2, 3, 4, 5, and 6, regardless of the range. Furthermore, whenever a numerical range is referred to herein, it means including any referenced number (fraction or integer) within the referred range.

[0024] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0025] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0026] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0027] In the description of the embodiments of this application, the term "at least one" refers to one or more, "more than one" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces). "At least one," "at least one of the following," or similar expressions refer to any combination of these items, including any combination of single or multiple items. For example, "at least one of a, b, or c," or "at least one of a, b, and c," can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0028] This application provides a method for preparing a phosphor based on garlic peel, the method comprising the following steps: S10, garlic peel and water are mixed and subjected to microwave reaction to obtain crude product containing fluorescent carbon dots; S20, the crude product is mixed with water and filtered to obtain a fluorescent carbon dot solution; S30, the fluorescent carbon dot solution is mixed with soluble starch, and then freeze-dried and pulverized to obtain fluorescent powder.

[0029] Garlic peels refer to the outer skin of garlic, which are usually discarded as waste. This application uses garlic peels as a raw material for carbon dots, realizing the reuse of waste biomass materials, developing a new use for biomass waste, and achieving low cost, environmental friendliness, and safety.

[0030] However, garlic peel contains a wide variety of components and many impurities, which inevitably poses a challenge to the preparation of carbon dots with pure fluorescence, obvious effects, and good wavelength stability. To address this, this application employs a microwave method using water as a solvent and precisely controls the reaction conditions, effectively overcoming the aforementioned disadvantages and successfully synthesizing carbon dots. The aqueous solution of these carbon dots is colorless and transparent under sunlight and exhibits green fluorescence under ultraviolet light, with a bright fluorescence color, making it suitable for preparing fluorescent powders and subsequently anti-counterfeiting inks. Furthermore, the carbon dots synthesized in this application have a fluorescence emission wavelength of approximately 505-520 nm, with a narrow fluctuation range, pure fluorescence color, and can emit light under different excitation wavelengths (360-460 nm) with minimal difference in emission wavelength, demonstrating good wavelength stability. In comparison, the carbon dot fluorescence effect based on garlic flesh is poor. Specifically, when carbon dots are synthesized from garlic flesh using the same method, the resulting carbon dot solution can also emit light, but the fluorescence wavelength is approximately in the range of 300~440 nm, and it is greatly affected by the excitation wavelength. The fluorescence generated under different excitation wavelengths (360~460 nm) shows obvious migration, which is not conducive to its use as an anti-counterfeiting material.

[0031] Furthermore, the carbon dots prepared by the method of this application have uniform particle size and good dispersibility, which is beneficial to the subsequent preparation of anti-counterfeiting inks.

[0032] The carbon dots obtained in this application can be combined with soluble starch and then freeze-dried to produce fluorescent powder. The fluorescent powder appears as a white powder under sunlight and exhibits blue-green fluorescence under ultraviolet light, with obvious fluorescence effect. This achieves fluorescence retention of solid carbon dots and develops a new type of fluorescent powder for preparing high-performance anti-counterfeiting inks.

[0033] In step S10: Garlic peels can be used from common white-skinned garlic, which can be collected from supermarkets, farmers' markets, etc., as they are readily available. Deionized water can be used.

[0034] The amount of garlic peel and water added should meet the following conditions: 15-25 mL of water should be added for every gram (g) of garlic peel. For example, you can add 15 mL, 17 mL, 19 mL, 20 mL, 21 mL, 23 mL, 25 mL of water, or any value between two of the above ratios. To improve the extraction rate and carbon point yield, the garlic peel can be chopped before mixing with water.

[0035] In some embodiments of this application, the microwave reaction conditions are as follows: the microwave reaction power is 290~1160 W, for example, it can be 290 W, 300 W, 320 W, 350 W, 400 W, 420 W, 450 W, 480 W, 500 W, 550 W, 580 W, 600 W, 620 W, 650 W, 700 W, 800 W, 830 W, 850 W, 870 W, 900 W, 1000 W, 1100 W, 1150 W, 1160 W, or any value between any two of the above; the time is 3~9 min, for example, it can be 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, or any value between any two of the above. Controlling the reaction conditions within the above range helps to synthesize green fluorescent carbon dots with emission wavelengths of 505 nm~520 nm, improves synthesis efficiency and carbon dot yield, and effectively increases the fluorescence intensity of the carbon dots.

[0036] In step S20, deionized water can be used to disperse and dilute the carbon dots to facilitate filtration and purification.

[0037] In some embodiments of this application, the amount of water added is sufficient to ensure that the carbon dots are adequately diluted to facilitate filtration and purification; this application does not limit the amount added. In specific implementation, the amount can be adjusted according to the amount of garlic peel used as raw material. Specifically, 70-130 mL of water should be added for every gram of garlic peel.

[0038] In some embodiments of this application, a 0.22 μm aqueous filter membrane can be used for filtration to better purify carbon dots.

[0039] In step S30, soluble starch is combined with carbon dots to suppress the fluorescence aggregation quenching of solid carbon dots, thus maintaining their solid fluorescence.

[0040] In some embodiments of this application, the amount of soluble starch can be adjusted according to the mass of fluorescent carbon dots contained in the fluorescent carbon dot solution. Specifically, the mass ratio of fluorescent carbon dots in the fluorescent carbon dot solution to the soluble starch is 1:15 to 35, for example, it can be 1:15, 1:17, 1:20, 1:22, 1:25, 1:28, 1:30, 1:33, 1:35, and any value between any two of the above.

[0041] In some embodiments of this application, in order to ensure that the fluorescent carbon dots and soluble starch are fully compounded, in step S30, when mixing the fluorescent carbon dot solution and soluble starch, the mixing time can be controlled within the range of 15 to 30 hours. For example, it can be 15 h, 18 h, 20 h, 22 h, 23 h, 24 h, 25 h, 26 h, 27 h, 28 h, 29 h, 30 h, and any value between any two of the above.

[0042] In some embodiments of this application, the freeze-drying conditions are as follows: the freeze-drying time is 10-15 hours, for example, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, or any value between the above two. In this application, freeze-drying is used to dry the mixture of fluorescent carbon dot solution and soluble starch. The temperature can be any temperature value less than or equal to 0°C, such as -80°C to -20°C, -20°C to 0°C, etc. Compared with heat treatment, freeze-drying helps to maintain fluorescence and avoid fluorescence quenching. In actual operation, any common freeze dryer on the market can be used, such as the SCIENT2-12 / A type freeze dryer.

[0043] Secondly, this application also proposes an anti-counterfeiting ink, comprising the fluorescent powder prepared by the method described above. Using the aforementioned fluorescent powder, an anti-counterfeiting ink can be formulated that can print clearly visible, glossy, and abrasion-resistant fluorescent patterns on non-fluorescent paper. It exhibits significant fluorescence under ultraviolet light and no fluorescence under sunlight, demonstrating good concealment and reliability, and thus providing a superior anti-counterfeiting effect.

[0044] The anti-counterfeiting ink also emits a green fluorescence, consistent with the fluorescence color of the carbon dot aqueous solution. This effectively achieves consistency between the solution-state carbon dots and the anti-counterfeiting ink. In this way, during industrial production, the quality of the final product can be predicted by detecting the fluorescence of the carbon dots produced in the process. This can serve as an important quality control indicator for evaluating the quality of the final product, which helps in quality control, improves yield and product effect, and reduces waste.

[0045] In some embodiments of this application, the anti-counterfeiting ink further includes hydroxyethyl cellulose and water. Water serves as a dispersing solvent, providing a liquid environment; specifically, it can be deionized water. Hydroxyethyl cellulose is used as an additive; by adding hydroxyethyl cellulose, the rheological properties, viscosity, film-forming properties, and other characteristics of the anti-counterfeiting ink can be controlled. It is understood that in some embodiments, the anti-counterfeiting ink may also include other ink additives, such as diluents, dispersants, smoothing agents, etc.

[0046] In some embodiments of this application, the ratio of the mass of the fluorescent powder to the total mass of the hydroxyethyl cellulose and water in the anti-counterfeiting ink is 0.8 to 1.2:10, for example, it can be 0.8:10, 0.9:10, 1:10, 1.1:10, 1.2:10, or any value between any two of the above.

[0047] In some embodiments of this application, the mass ratio of hydroxyethyl cellulose to water in the anti-counterfeiting ink is 3~5:100, for example, it can be 3:100, 3.5:100, 4:100, 4.5:100, 5:100, or any value between any two of the above.

[0048] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be obtained commercially.

[0049] Example 1 This embodiment proposes a fluorescent powder and an anti-counterfeiting ink, and the preparation method is as follows: (1) Preparation of carbon dots: 0.5 g of garlic peel was chopped and added to 10 mL of deionized water. The mixture was microwaved in a microwave oven (power 870 W, time T = 3 min). After cooling, 50 mL of deionized water was added and ultrasonically dispersed. Finally, the mixture was purified by filtration through a 0.22 μm filter membrane to obtain a G-CDs solution. The G-CDs solution was observed by transmission electron microscopy (TEM), and the results are as follows: Figure 1 and Figure 2 As shown in the figure, the carbon dots are uniformly distributed in the solution system and have good particle size uniformity.

[0050] The G-CDs solution was observed under sunlight and ultraviolet light, respectively. The results are as follows: Figure 3 As shown, the left side represents sunlight, and the right side represents ultraviolet light. The G-CDs solution is a colorless and transparent liquid under sunlight, but exhibits a distinct green fluorescence under ultraviolet light.

[0051] Further observation of the absorption spectrum of the G-CDs solution was performed using a UV spectrophotometer, such as... Figure 4 As shown, the absorption spectrum has two distinct absorption peaks near 285 nm and 310 nm. The absorption peak at 285 nm may be caused by π*π transitions, while the absorption peak at 310 nm is caused by surface state defects of CDs containing a large number of amino and carboxyl groups.

[0052] The G-CDs solution was scanned using an F98 fluorescence spectrophotometer to observe the fluorescence emission spectra of the G-CDs solution under different excitation lights (340 nm ~ 460 nm). Figure 5 As shown in the figure, the G-CDs solution exhibits fluorescence emission properties and produces fluorescence under different excitation light. When the excitation light wavelength is 360nm~460nm, the emission wavelength is in the range of 505~520nm, showing obvious green light characteristics. When the excitation light wavelength is 400nm, the highest fluorescence emission intensity can be obtained, producing strong green fluorescence, and the emission wavelength is 510nm at this time.

[0053] (2) Preparation of phosphor: According to the mass ratio of carbon dots to soluble starch of 1:20, 4 g of soluble starch was dissolved in G-CDs solution, stirred for 24 h and then placed in a freeze dryer and freeze-dried at -18℃ for 12 h to obtain phosphor, which was then taken out and stored for later use.

[0054] The phosphor powder was observed under sunlight and ultraviolet light, respectively. Figure 6 As shown, the left side is under sunlight and the right side is under ultraviolet light. The phosphor shows blue-green fluorescence under ultraviolet light.

[0055] (3) Preparation of anti-counterfeiting ink: Following a mass ratio of hydroxyethyl cellulose to water of 4:100 and a mass ratio of fluorescent powder to the total mass of hydroxyethyl cellulose and water of 1:10, water and hydroxyethyl cellulose are mixed to form a hydroxyethyl cellulose colloid. Then, fluorescent powder is added and stirred until homogeneous to prepare the anti-counterfeiting ink. Figure 7 As shown, the anti-counterfeiting ink exhibits green fluorescence under ultraviolet light.

[0056] The ink underwent performance testing, including tests for viscosity, drying properties, gloss, ink transfer rate, abrasion resistance, and fluorescent anti-counterfeiting performance. The testing methods and results are as follows: The viscosity of the ink was measured using a digital viscometer (SNB-AI), and the measured viscosity was 7600-9400 cP, showing obvious shear thinning.

[0057] The drying properties of the ink were tested by a friction test method using a printed pattern on filter paper. The initial drying time of the ink on non-fluorescent filter paper was 633 s.

[0058] The gloss of the printed material was tested using a gloss meter (test angle 75°). The horizontal gloss was 4.26 GU and the vertical gloss was 5.62 GU.

[0059] The ink transfer rate was calculated by measuring the weight difference of the substrate before and after printing using a weighing method. The ink transfer rate is the ratio of the amount of ink transferred to the substrate surface to the amount of ink applied to the printing plate, expressed by the formula: F = y / x × 100%, where F represents the ink transfer rate, y represents the amount of ink transferred to the substrate surface, and x represents the amount of ink applied to the printing plate. The printing plate used in this experiment to measure the ink transfer rate was 200 mesh. The ink transfer rate of the ink in this embodiment was tested to be 13.58%.

[0060] The abrasion resistance of printed materials is tested using an abrasion resistance testing machine. For example... Figure 8 As shown, after 250 rubs, the fluorescence of the pattern showed no significant change and remained clearly visible, although the fluorescence intensity decreased slightly. This indicates that the ink has good abrasion resistance on the filter paper.

[0061] In summary, it can be seen that the ink prepared in this embodiment has suitable viscosity, initial drying time, printing gloss and ink transfer rate, as well as good abrasion resistance, indicating that the ink proposed in this application has good printing performance.

[0062] Furthermore, fluorescent ink was used for screen printing on non-fluorescent paper (80 mesh, 120 mesh). The fluorescent anti-counterfeiting effect was observed under sunlight and 365nm ultraviolet light, and photographs were taken and saved for comparison and confirmation. Figure 9As shown, the printed matter shows no fluorescence under sunlight, but exhibits a fluorescent pattern under ultraviolet light, with a significant fluorescence effect, indicating that the ink proposed in this application has good screen printing suitability and anti-counterfeiting properties.

[0063] Example 2 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the microwave power of the microwave reaction is changed to 290 W. All other parameters and conditions remain unchanged.

[0064] Example 3 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the microwave power of the microwave reaction is changed to 580 W. All other parameters and conditions remain unchanged.

[0065] Example 4 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the microwave power of the microwave reaction is changed to 1160 W. All other parameters and conditions remain unchanged.

[0066] Example 5 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the microwave reaction time T = 6 min in this embodiment. All other parameters and conditions remain unchanged.

[0067] Example 6 The scheme in this embodiment is basically the same as that in Embodiment 1, except that the microwave reaction time T = 9 min in this embodiment. All other parameters and conditions remain unchanged.

[0068] Comparative Example 1 This comparative example is basically the same as Example 1, except that in step (2) of this comparative example, freeze drying is replaced with drying at 40°C. All other parameters and conditions remain unchanged. Upon observation, the dried product, after 2 hours of drying, was examined under a UV lamp and showed no fluorescence.

[0069] Comparative Example 2 This comparative example is essentially the same as Example 1, except that hydroxyethyl cellulose is replaced with water-based acrylic resin. All other parameters and conditions remain unchanged. The ink prepared in this comparative example shows no obvious fluorescence under ultraviolet light excitation.

[0070] Experimental Example (1) The G-CDs solutions prepared in Examples 1 to 4 were tested for fluorescence emission spectra under 365 nm excitation light. The results are as follows: Figure 10 As shown.

[0071] As can be seen from the figure, the fluorescence emission spectra corresponding to Examples 1 to 4 have strong fluorescence emission intensities, with Example 1 having the highest intensity. This indicates that controlling the microwave power between 290 W and 1160 W, especially 870 W, helps to enhance the fluorescence intensity of the fluorescent carbon dots.

[0072] (2) The G-CDs solutions prepared in Examples 1, 5 and 6 were tested under 365 nm excitation light, and the results are as follows: Figure 11 As shown.

[0073] As can be seen from the figure, the fluorescent carbon dots prepared in each embodiment all have obvious fluorescence emission characteristics, and the emission wavelength does not change significantly. This indicates that controlling the microwave time to 3 to 9 min can prepare fluorescent carbon dots with good fluorescence emission characteristics. In particular, when the microwave time is controlled to 3 min, it helps to significantly enhance the fluorescence intensity of the fluorescent carbon dots.

[0074] It should be noted that this application is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments with the same structure and effect as the technical concept within the scope of this application are included in the technical scope of this application. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of this application, are also included in the scope of this application.

Claims

1. A method for preparing a fluorescent powder based on garlic peel, characterized in that, Includes the following steps: Garlic peels and water were mixed and subjected to a microwave reaction to obtain a crude product containing fluorescent carbon dots. The crude product was mixed with water and filtered to obtain a fluorescent carbon dot solution. The fluorescent carbon dot solution was mixed with soluble starch, then freeze-dried and pulverized to obtain fluorescent powder.

2. The preparation method according to claim 1, characterized in that, In the step of mixing garlic peels and water and subjecting them to a microwave reaction to obtain a crude product containing fluorescent carbon dots, the microwave reaction power is 290~1160 W and the time is 3~9 min.

3. The preparation method according to claim 1, characterized in that, In the step of mixing garlic peel and water and performing a microwave reaction to obtain a crude product containing fluorescent carbon dots, 15-25 mL of water is added for every gram of garlic peel.

4. The preparation method according to claim 1, characterized in that, In the step of mixing the crude product with water and filtering to obtain the fluorescent carbon dot solution, 70-130 mL of water is added for every gram of garlic peel; and / or, A 0.22 μm aqueous filter membrane was used for vacuum filtration.

5. The preparation method according to claim 1, characterized in that, In the step of mixing the fluorescent carbon dot solution with soluble starch, followed by freeze-drying and pulverizing to obtain fluorescent powder, the mass ratio of fluorescent carbon dots in the fluorescent carbon dot solution to the soluble starch is 1:15~35; and / or, The mixing time is 15-30 h.

6. The preparation method according to claim 1, characterized in that, In the step of mixing the fluorescent carbon dot solution with soluble starch, and then freeze-drying and pulverizing it to obtain fluorescent powder, the freeze-drying time is 10-15 h.

7. An anti-counterfeiting ink, characterized in that, The phosphors include those prepared by the method according to any one of claims 1 to 6.

8. The anti-counterfeiting ink according to claim 7, characterized in that, It also includes hydroxyethyl cellulose and water.

9. The anti-counterfeiting ink according to claim 8, characterized in that, In the anti-counterfeiting ink, the ratio of the mass of the fluorescent powder to the total mass of the hydroxyethyl cellulose and water is 0.8~1.2:

10.

10. The anti-counterfeiting ink according to claim 8, characterized in that, In the anti-counterfeiting ink, the mass ratio of hydroxyethyl cellulose to water is 3~5:100.

Images