Modification method of rare earth superfine nanowire, fluorescent ink, preparation method and application

Abstract

The invention discloses a modification method of rare earth superfine nanowires, fluorescent ink and a preparation method and application of the fluorescent ink. The modification method comprises the steps that the rare earth superfine nanowires are dispersed in an organic solvent to obtain nanowire dispersion liquid, the nanowire dispersion liquid is modified through ligand molecules, and the modified rare earth superfine nanowires are obtained; by modifying the rare earth superfine nanowires, the luminescent property and dispersity of the rare earth superfine nanowires can be remarkably improved, the luminescent property of the fluorescent ink prepared by the invention is remarkably improved, different ligand molecules are selected to treat the rare earth superfine nanowires, the luminescent property of the fluorescent ink can be regulated and controlled, and the fluorescent ink has the advantages of high fluorescence intensity and strong adjustability.

Description

Technical Field

[0001] The invention relates to the technical field of fluorescent inks, and in particular to a modification method of rare earth ultrafine nanowires, fluorescent ink, and a preparation method and application thereof. Background Art

[0002] With the advancement of science and technology, the application demand of fluorescent materials has gradually increased. Fluorescent inks prepared using fluorescent materials have the characteristic of emitting fluorescence under ultraviolet light or visible light, and have wide applications in many fields.

[0003] In the related art, fluorescent ink is prepared using organic fluorescent molecules or inorganic fluorescent powders. However, the luminescence efficiency and stability of organic fluorescent molecules are low, and the adjustability and dispersibility of inorganic fluorescent powders are poor, resulting in low luminescence performance and poor adjustability of fluorescent inks.

[0004] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Summary of the invention

[0005] The technical task of the present invention is to address the above shortcomings and provide a modification method for rare earth ultrafine nanowires, fluorescent ink, preparation method and application. By modifying the rare earth ultrafine nanowires, their luminescence performance and dispersibility can be significantly improved. The luminescence performance of the fluorescent ink prepared in this application is significantly improved. By selecting different ligand molecules to treat the rare earth ultrafine nanowires, the luminescence performance of the fluorescent ink can also be regulated. It has the advantages of high fluorescence intensity and strong adjustable performance.

[0006] To achieve the above object, the present invention provides the following technical solutions: According to one aspect of the present application, a method for modifying rare earth ultrafine nanowires is provided, comprising: dispersing rare earth ultrafine nanowires in an organic solvent to obtain a nanowire dispersion; modifying the nanowire dispersion using ligand molecules to obtain modified rare earth ultrafine nanowires; the method for modifying the nanowire dispersion using ligand molecules comprises: calibrating the concentration of rare earth ions in the nanowire dispersion; adding ligand molecules to the nanowire dispersion according to the concentration of the rare earth ions, stirring at room temperature, adding anhydrous ethanol and then centrifuging, and collecting the precipitate after centrifugation to obtain the modified rare earth ultrafine nanowires.

[0007] In some embodiments, the rare earth ultrafine nanowire is one of a europium ultrafine nanowire, a samarium ultrafine nanowire, and a terbium ultrafine nanowire.

[0008] In some embodiments, the ligand molecule is one or more of acetylacetone, 1-phenyl-1,3-butanedione, thiophenebenzoyltrifluoroacetone, 4,4,4-trifluoro-1-(4-methoxyphenyl)-1,3-butanedione, 3-(4-fluorobenzoyl)-1,1,1 trifluoroacetone, 1,3-bis(4-methoxyphenyl)propane 1,3-dione, 1,3-bis(thiophene)propane 1,3-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, benzoyltrifluoroacetone, 2,6-pyridinedicarboxylic acid, 1-(4-bromophenyl)-1,3-butanedione, and 1-(4-bromophenyl)-4,4,4-trifluoro-butane-1,3-dione; the molar ratio of the ligand molecule to the rare earth ions in the nanowire dispersion is 5:1.

[0009] In some embodiments, the organic solvent is one or more of n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, dodecane, toluene, chloroform, dichloromethane, carbon tetrachloride, octadecene, and N,N-dimethylformamide; the stirring time is 2 hours, the centrifugal speed is 6000-8000 rpm, and the centrifugal time is 3-5 minutes.

[0010] According to another aspect of the present application, a fluorescent ink is provided, comprising the modified rare earth ultrafine nanowires prepared by the method, wherein the concentration of rare earth ions in the fluorescent ink is 0.0015 mmol / mL-0.015 mmol / mL.

[0011] According to another aspect of the present application, a method for preparing fluorescent ink is also provided, comprising: re-dispersing the modified rare earth ultrafine nanowires in an organic solvent, and introducing nitrogen into the dispersed solution in a bubbling manner to obtain fluorescent ink.

[0012] In some embodiments, the dispersion duration is 1 hour, the stirring speed during the dispersion is 500 rpm, the bubbling duration is 0.5 hour, and the organic solvent is one or more of n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, dodecane, toluene, chloroform, dichloromethane, carbon tetrachloride, octadecene, and N,N-dimethylformamide.

[0013] According to another aspect of the present application, the application of the fluorescent ink in packaging printing, anti-counterfeiting labels, and smart sensors is also provided.

[0014] In some embodiments, the smart sensor is a flexible temperature sensor.

[0015] Compared with the prior art, the advantages and positive effects of the present invention are: 1. The present application can significantly improve the luminescence performance of fluorescent ink prepared using the modified rare earth ultrafine nanowires by modifying the rare earth ultrafine nanowires.

[0016] 2. This application can adjust the luminescent properties of fluorescent ink by selecting different ligand molecules to process rare earth ultrafine nanowires, thereby solving the problem that the luminescent properties of traditional fluorescent inks cannot be adjusted, and has the advantage of high adjustability.

[0017] 3. The modified rare earth ultrafine nanowires of the present application have excellent dispersibility and can be dissolved in a variety of organic solvents.

[0018] 4. The ultraviolet light response characteristics of the fluorescent ink prepared in the present application are significantly improved, and it has temperature sensitivity. The temperature rise and fall process can be repeated many times, and the fluorescence intensity after multiple repetitions has a high stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 Shows a schematic diagram of the application process; Figure 2 Digital photos of fluorescent ink in the comparative example of the present application are shown, wherein 2a is under natural light, and 2b is under ultraviolet light; Figure 3 Digital photos of the modified Eu ultrafine nanowire-based fluorescent ink in Example 1 of the present application are shown, wherein 3a is before modification and 3b is after modification; Figure 4 The fluorescence emission spectra of the fluorescent inks in the comparative example and Example 1 of the present application are shown; Figure 5 The absorption spectra of the fluorescent inks in the comparative example and Example 1 of the present application are shown; Figure 6 A schematic diagram of the molecular structure of the ligand used in Example 2 of the present application and a digital photograph of a pattern formed by the fluorescent ink prepared after treatment with the corresponding ligand under ultraviolet light are shown; Figure 7 The fluorescence emission spectra of the fluorescent ink prepared after being treated with different ligands in Example 2 of the present application are shown; Figure 8 The fluorescence emission spectrum of the modified Sm ultrafine nanowire-based fluorescent ink in Example 3 of the present application and its digital photo under ultraviolet light are shown; Fig. 9 The fluorescence emission spectrum of the modified Tb ultrafine nanowire-based fluorescent ink in Example 4 of the present application and its digital photo under ultraviolet light are shown; Fig.10 The temperature-dependent fluorescence emission spectrum of the modified Eu ultrafine nanowire-based fluorescent ink in Example 5 of the present application is shown; Fig.11 The fluorescence emission intensity of the modified Eu ultrafine nanowire-based fluorescent ink in Example 5 of the present application is shown as a cycle curve of temperature change; Fig.12 A digital photograph showing the change in pattern of the modified Eu ultrafine nanowire-based fluorescent ink as a function of temperature in Example 5 of the present application.

[0021] Fig.13 A schematic diagram showing the visible and invisible characteristics of the Eu ultrafine nanowire-based fluorescent ink before modification after spraying the ligand solvent in Example 6 of the present application; Fig.14 A schematic diagram showing the stability of the pattern before and after immersion after the modified Eu ultrafine nanowire-based fluorescent ink is sprayed with a ligand solvent in Example 6 of the present application, wherein 14a is before immersion and 14b is after immersion. DETAILED DESCRIPTION

[0022] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0023] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0024] Comparative Example: Preparation of europium (Eu) ultrafine nanowire-based fluorescent ink before modification.

[0025] The Eu ultrafine nanowires were dispersed in toluene to obtain a high-viscosity pre-modified Eu ultrafine nanowire-based fluorescent ink. The pre-modified Eu ultrafine nanowire-based fluorescent ink was centrifuged at 2000 rpm for 3 min and then kept at 40° C. for 24 h. Figure 2 As shown in a, a gel-like modified Eu ultrafine nanowire-based fluorescent ink is obtained. Figure 2 As shown in b, under ultraviolet light irradiation, the gel-like unmodified Eu ultrafine nanowire-based fluorescent ink emits uniform red fluorescence, indicating that the prepared unmodified Eu ultrafine nanowire-based fluorescent ink has certain luminescence properties, but the luminescence performance is low.

[0026] Example 1: Preparation of modified Eu ultrafine nanowire-based fluorescent ink.

[0027] S1. Dispersing the Eu ultrafine nanowires uniformly in a toluene solvent to obtain a Eu ultrafine nanowire dispersion.

[0028] S2. The actual concentration of Eu ions in the dispersion was determined using inductively coupled plasma optical emission spectroscopy (ICP-OES), and an appropriate amount of FBFA ligand molecules was weighed according to a molar ratio of 3-(4-fluorobenzoyl)-1,1,1 trifluoroacetone (FBFA) to rare earth ions in the Eu ultrafine nanowire dispersion of 5:1.

[0029] S3. Add FBFA to the Eu ultrafine nanowire dispersion and stir at room temperature for two hours. Add anhydrous ethanol and centrifuge at a speed of 6000-8000 rpm for 3-5 minutes. The obtained precipitate is the modified Eu ultrafine nanowire.

[0030] S4. Re-dispersing the modified Eu ultrafine nanowires in toluene to obtain modified Eu ultrafine nanowire-based fluorescent ink.

[0031] Figure 3 Figure 3 shows a digital photo of the fluorescent ink in Example 1 of the present application, wherein 3a is before modification and 3b is after modification. Figure 3 As shown in Figure a, the Eu ultrafine nanowire dispersion will emit red fluorescence under ultraviolet light. Figure 3 As shown in Figure b, the modified Eu ultrafine nanowire-based fluorescent ink emits a more dazzling red fluorescence under ultraviolet light, and its luminous intensity is significantly improved compared with before modification.

[0032] Figure 4 The fluorescence emission spectra of the modified Eu ultrafine nanowire-based fluorescent ink in the comparative example and Example 1 are shown as follows: Figure 4 As shown, the photoluminescence (PL) intensity of the modified Eu ultrafine nanowire-based fluorescent ink in the embodiment is significantly improved.

[0033] Figure 5 The absorption spectra of the modified Eu ultrafine nanowire-based fluorescent ink in the comparative example and Example 1 of the present application are shown as follows: Figure 5 As shown in Figure 2, before modification, there are two obvious absorption peaks in the absorption spectrum of the nanowires, located at 394nm and 465nm, respectively, which represent 7 F0→ 5 L6 and 7 F0→ 5 However, in the absorption spectrum of the ultrafine nanowires after ligand treatment, a strong absorption peak was observed in the range of 320-420 nm, which is the characteristic absorption of FBFA ligand.

[0034] Therefore, the FBFA ligand significantly enhanced the luminescence intensity of Eu-based nanowires through the "antenna effect". In this process, the FBFA ligand acts as an "antenna" to absorb the excitation light and effectively transfer the excitation energy to the higher energy level of Eu ions, thereby filling the excitation energy level of rare earth ions and improving the luminescence efficiency.

[0035] In summary, the luminescence intensity of the fluorescent ink was significantly improved by modifying the ultrafine nanowires through ligand treatment.

[0036] Example 2: Regulation of the luminescent properties of modified Eu ultrafine nanowire-based fluorescent ink.

[0037] The Eu ultrafine nanowires were modified by ligand treatment according to the method in Example 1, and the modified Eu ultrafine nanowires were used to prepare fluorescent ink. The difference from Example 1 is that different ligand molecules are used to modify the Eu ultrafine nanowires, wherein the ligand molecules used are acetylacetone (ACA), 1-phenyl-1,3-butanedione (BA), thiophenebenzoyltrifluoroacetone (TTA), 4,4,4-trifluoro-1-(4-methoxyphenyl)-1,3-butanedione (MBFA), 3-(4-fluorobenzoyl)-1,1,1 trifluoroacetone (FBFA), 1,3-bis(4-methoxyphenyl)-1,3-butanedione (TTA ... The molar ratio of ligand molecules to Eu ions in the nanowire dispersion was 5:1.

[0038] Figure 6 The figure shows the schematic diagram of the molecular structure of the ligand used in Example 2 of the present application and the digital photo of the fluorescent ink prepared after the corresponding ligand treatment under ultraviolet light. Figure 6 As shown, the selected ligand molecules have similar structures with different substituents at both ends. The substituents can be roughly divided into the following categories: electron-withdrawing groups, such as trifluoromethyl and fluorophenyl; electron-donating groups, such as methoxyphenyl, thiophene and furan; neutral conjugated groups, phenyl and inert methyl. Figure 6Digital photos of fluorescent inks prepared after treatment with corresponding ligands under ultraviolet light are also shown. It can be seen that the effects of different ligands on the luminescence of Eu ultrafine nanowires vary significantly, and not all ligands have a promoting effect. The most obvious is that when using the two ligands DMBM and DTM, their substituents are all electron-donating groups, and the fluorescence of the nanowires even disappears completely. However, when using ligands with neutral or inert groups, such as ACA and BA ligand molecules, the brightness of the nanowires is similar to that before treatment. When using ligands containing at least one electron-withdrawing group, including MBFA, HFA, TTA, FFA, BFA and FBFA, the ultrafine nanowires all show significantly enhanced luminescence, emitting dazzling red light.

[0039] Figure 7 , which shows the fluorescence emission spectra of the fluorescent ink prepared after being treated with different ligands in Example 2 of the present application. Figure 7 As shown in the figure, different ligands have significant effects on the luminescence intensity of ultrafine nanowires. Therefore, the luminescence performance of rare earth ultrafine nanowires can be regulated by ligands of different properties. In practical applications, the fluorescence performance of nanowires can be regulated according to the influence of ligand molecules on the fluorescence performance, so as to meet the requirements for luminescence brightness in different application scenarios. Fluorescent ink can also be made into a sensor sensitive to specific molecules based on this characteristic.

[0040] Example 3: Preparation of modified samarium (Sm) ultrafine nanowire-based fluorescent ink.

[0041] The modified Sm ultrafine nanowire-based fluorescent ink was prepared according to the method in Example 1, wherein the difference from Example 1 is that the rare earth ultrafine nanowires used are Sm ultrafine nanowires.

[0042] Figure 8 The fluorescence emission spectrum of the modified Sm ultrafine nanowire-based fluorescent ink in Example 3 of the present application and its digital photo under ultraviolet light are shown. Figure 8 As shown, the modified Sm ultrafine nanowire-based fluorescent ink exhibits the characteristic emission peak of rare earth Sm (III), and the modified Sm ultrafine nanowire-based fluorescent ink exhibits characteristic red fluorescence under ultraviolet light, indicating the successful preparation of the modified Sm ultrafine nanowire-based fluorescent ink.

[0043] Example 4: Preparation of modified terbium (Tb) ultrafine nanowire-based fluorescent ink.

[0044] The modified Tb ultrafine nanowire-based fluorescent ink was prepared according to the method in Example 1, wherein the difference from Example 1 is that the rare earth ultrafine nanowires used are Tb ultrafine nanowires, and the ligand molecules used are 2,6-pyridinedicarboxylic acid.

[0045] Fig. 9 The fluorescence emission spectrum of the modified Tb ultrafine nanowire-based fluorescent ink in Example 4 of the present application and its digital photo under ultraviolet light are shown. Fig. 9 As shown, the modified Tb ultrafine nanowire-based fluorescent ink exhibits the characteristic emission peak of rare earth Tb (III), and the modified Tb ultrafine nanowire-based fluorescent ink exhibits characteristic green fluorescence under ultraviolet light, indicating the successful preparation of the modified Tb ultrafine nanowire-based fluorescent ink.

[0046] Example 5: Detection of temperature sensitivity of modified Eu ultrafine nanowire-based fluorescent ink.

[0047] Fig.10 The temperature-dependent fluorescence emission spectrum of the modified Eu ultrafine nanowire-based fluorescent ink in this embodiment is shown; Fig.11 The cyclic curve of the fluorescence emission intensity of the modified Eu ultrafine nanowire-based fluorescent ink as a function of temperature is shown; Fig.12 Digital photos showing the change of the pattern of the modified Eu ultrafine nanowire-based fluorescent ink with temperature in this embodiment.

[0048] The temperature sensitive property is manifested in that the fluorescence intensity of the fluorescent ink decreases as the ambient temperature increases. When the ambient temperature reaches 135-150°C, the fluorescence intensity of the fluorescent ink is the lowest. When the ambient temperature drops back to room temperature, the fluorescence intensity of the fluorescent ink increases as the ambient temperature decreases and eventually returns to its initial state. The temperature response property can be repeated many times.

[0049] Specifically, the modified Eu ultrafine nanowire-based fluorescent ink prepared in Example 1 was subjected to a temperature-dependent photoluminescence spectrum test. Fig.10 As shown in the figure, with the increase of temperature, the fluorescence intensity of the modified Eu ultrafine nanowire-based fluorescent ink gradually decreases, among which the fluorescence intensity of the main emission peak (615nm) decreases linearly with the increase of temperature, from 100% at room temperature to less than 10% at 150℃.

[0050] like Fig.11 As shown, the change of fluorescence intensity with temperature is reversible, and the emission intensity can still be restored to its original level when the modified Eu ultrafine nanowire-based fluorescent ink undergoes four temperature cycles from room temperature to 100°C.

[0051] like Fig.12 As shown, the seal pattern made of modified Eu ultrafine nanowire-based fluorescent ink also has temperature-dependent fluorescence properties. As the temperature increases, the brightness of the pattern gradually dims and completely disappears at 135-150°C. When the temperature returns to room temperature, the pattern reappears.

[0052] Example 6: Detection of the visibility and stability of Eu ultrafine nanowire-based fluorescent ink before modification by ligand molecules Fig.13 A schematic diagram showing the visible and invisible characteristics of Eu ultrafine nanowire-based fluorescent ink before modification after spraying ligand solvent; Fig.14 A schematic diagram showing the stability of the pattern before and after immersion after the modified Eu ultrafine nanowire-based fluorescent ink is sprayed with a ligand solvent in Example 6 of the present application, wherein 14a is before immersion and 14b is after immersion.

[0053] like Fig.13 As shown, in addition to the above method, the ligand molecules can also be used to improve the luminescent properties of fluorescent inks. The ligand molecules can be dispersed in an organic solvent to obtain a ligand solvent, and the ligand solvent is sprayed on the pattern formed by the rare earth ultrafine nanowire-based fluorescent ink before modification. After the solvent is completely evaporated, the fluorescence intensity of the pattern can be significantly improved.

[0054] Specifically, first, the unmodified Eu ultrafine nanowire-based fluorescent ink is injected into a fountain pen for writing. Since the fluorescence intensity of the unmodified Eu ultrafine nanowire-based fluorescent ink is relatively weak, the written letters cannot be identified at first under ultraviolet light. Next, the ligand molecules used in Example 1 are dispersed in toluene and sprayed on the position just written. At this time, it can be observed that the red fluorescent letters immediately become clearly visible. After the solvent is completely evaporated, a complete and clear red fluorescent letter pattern can be obtained. Therefore, the use of ligand molecules can realize the text display of the unmodified Eu ultrafine nanowire-based fluorescent ink.

[0055] like Fig.14 As shown, after the pattern sprayed with the ligand solvent was immersed in n-hexane, toluene, ethanol and water for half an hour, the pattern remained clearly visible without any blurring or fading. Therefore, this fully proves the stability of the pattern obtained after the Eu ultrafine nanowire-based fluorescent ink was treated with ligand molecules before modification.

[0056] The fluorescent ink prepared above can be used in packaging printing, anti-counterfeiting labels, and smart sensors. For example, in flexible anti-counterfeiting labels, the ultraviolet light response characteristics of fluorescent inks ensure that the authenticity of the product can be verified; in flexible temperature sensors, the temperature sensitivity of fluorescent inks allows the flexible temperature sensors to accurately display the ambient temperature and can also be used in scenarios such as high temperature warnings; in flexible smart packaging printing, fluorescent inks can achieve intelligent tracking and management of goods.

[0057] Through the above specific implementations, those skilled in the art can easily implement the present invention. However, it should be understood that the present invention is not limited to the above specific implementations. On the basis of the disclosed implementations, those skilled in the art can arbitrarily combine different technical features to achieve different technical solutions.

Claims

1. A method for modifying rare earth ultrafine nanowires, characterized in that: include: dispersing rare earth ultrafine nanowires in an organic solvent to obtain a nanowire dispersion; Using ligand molecules to modify the nanowire dispersion to obtain modified rare earth ultrafine nanowires; The method of modifying the nanowire dispersion using ligand molecules comprises: calibrating the concentration of rare earth ions in the nanowire dispersion; According to the concentration of the rare earth ions, ligand molecules are added to the nanowire dispersion, stirred at room temperature, added with anhydrous ethanol and centrifuged, and the precipitate is collected after centrifugation to obtain modified rare earth ultrafine nanowires.

2. The method for modifying rare earth ultrafine nanowires according to claim 1, characterized in that: The rare earth ultrafine nanowire is one of europium ultrafine nanowire, samarium ultrafine nanowire and terbium ultrafine nanowire.

3. The method for modifying rare earth ultrafine nanowires according to claim 1, characterized in that: The ligand molecule is one or more of acetylacetone, 1-phenyl-1,3-butanedione, thiophenebenzoyltrifluoroacetone, 4,4,4-trifluoro-1-(4-methoxyphenyl)-1,3-butanedione, 3-(4-fluorobenzoyl)-1,1,1 trifluoroacetone, 1,3-bis(4-methoxyphenyl)propane 1,3-dione, 1,3-bis(thiophene)propane 1,3-dione, 1,1,1,5,5,5-hexafluoropentane-2,4-dione, benzoyltrifluoroacetone, 2,6-pyridinedicarboxylic acid, 1-(4-bromophenyl)-1,3-butanedione, and 1-(4-bromophenyl)-4,4,4-trifluoro-butane-1,3-dione; the molar ratio of the ligand molecule to the rare earth ions in the nanowire dispersion is 5:

1.

4. The method for modifying rare earth ultrafine nanowires according to claim 1, characterized in that: The organic solvent is one or more of n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, dodecane, toluene, chloroform, dichloromethane, carbon tetrachloride, octadecene, and N,N-dimethylformamide; the stirring time is 2 hours, the centrifugal speed is 6000-8000 rpm, and the centrifugal time is 3-5 minutes.

5. A fluorescent ink, characterized in that: The modified rare earth ultrafine nanowires are prepared by the method according to any one of claims 1 to 4, wherein the concentration of rare earth ions in the fluorescent ink is 0.0015 mmol / mL-0.015 mmol / mL.

6. The method for preparing a fluorescent ink according to claim 5, characterized in that: include: The modified rare earth ultrafine nanowires are redispersed in an organic solvent, and nitrogen is introduced into the dispersed solution in a bubbling manner to obtain fluorescent ink.

7. The method for preparing a fluorescent ink according to claim 6, characterized in that: The dispersion duration is 1 hour, the dispersion stirring speed is 500 rpm, the bubbling duration is 0.5 hour, and the organic solvent is one or more of n-pentane, n-hexane, cyclohexane, n-heptane, n-octane, dodecane, toluene, chloroform, dichloromethane, carbon tetrachloride, octadecene, and N,N-dimethylformamide.

8. Use of the fluorescent ink according to any one of claims 5 to 7 in packaging printing, anti-counterfeiting labels, and smart sensors.

9. The use according to claim 8, characterized in that: The intelligent sensor is a flexible temperature sensor.

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