5, 6-difluorobenzotriazole derivative fluorescent material and application thereof

Abstract

The invention relates to a 5, 6-difluorobenzotriazole derivative fluorescent material, which optimizes the energy band and chemical stability of benzotriazole by introducing fluorine atoms with strong electronegativity, and overcomes the problem of insufficient environmental adaptability of the existing fluorescent material. The fluorescent material provided by the invention can be prepared into liquid ink or solid plastic for preparing fluorescent ink or fluorescent plastic, and has longer service life and better light conversion performance. According to the fluorescent material, the functionality of the material is improved, and the application potential of the fluorescent material in the fields of photoelectric equipment, fluorescent paint, binders and the like is widened.

Description

Technical Field

[0001] The invention belongs to the technical field of fluorescent materials, and specifically relates to a 5,6-difluorobenzotriazole derivative fluorescent material and application thereof. Background Art

[0002] Fluorescent material is a material that can emit light of another wavelength after being excited by absorbed photons, especially absorbing invisible ultraviolet light with a wavelength below 400 nanometers and emitting visible light with a wavelength between 400 and 650 nanometers. Polymer materials containing fluorescent materials are called fluorescent plastics. Fluorescent plastics are not only used for decorative packaging, but also for greenhouse films, converting ultraviolet rays that are harmful to plants into visible light that is beneficial to plant growth, such as Chinese patent CN13854901. In recent years, with the continuous innovation and development of new energy technologies, fluorescent plastics have also begun to be used in fluorescent concentrating solar cells. As described in the scientific review document Appl.Sci.2021,11,1923, fluorescent plastics and wavelength conversion films are used to improve the photoelectric conversion efficiency of solar modules, as well as to increase the service life of photovoltaic modules by absorbing ultraviolet rays, such as International Patent Publication No. WO2015 / 168439A1.

[0003] The performance of fluorescent materials depends on their chemical structure. Currently reported fluorescent materials are divided into organic fluorescent materials, inorganic fluorescent materials and organic-inorganic composite fluorescent materials. The selection of fluorescent materials needs to comprehensively consider their optical properties including absorption wavelength, emission wavelength and light conversion efficiency, production and processing technology including compatibility with plastics, dispersibility and plasticity, and use and environmental adaptability including film-forming properties, weather resistance and environmental friendliness. Organic fluorescent materials have been studied more from the perspective of environmental degradability, diversity of chemical structure and compatibility with organic polymer materials. However, the instability of most organic fluorescent materials to light, heat, water vapor and oxygen limits their market application.

[0004] Among various organic fluorescent materials, as exemplified by International Patent Publication No. WO2015 / 168439A1, benzotriazole derivatives have recently received much attention due to their good UV-to-blue light conversion performance and photostability. However, their chemical stability, especially stability to water and oxygen, is still a limitation, and the main purpose of the present invention is to overcome this limitation. Summary of the invention

[0005] In order to solve the above problems, the present invention discloses a 5,6-difluorobenzotriazole derivative fluorescent material and application thereof, so as to solve the problem of weather resistance of benzotriazole derivative fluorescent materials in the prior art.

[0006] To achieve the above object, the technical solution of the present invention is as follows: A 5,6-difluorobenzotriazole derivative fluorescent material, the general structural formula of the 5,6-difluorobenzotriazole derivative is as follows: ; Wherein, R1, R2, and R3 are each independently selected from substituted or unsubstituted C1-C 30 Alkyl, substituted or unsubstituted C1-C 30 Alkoxy, substituted or unsubstituted C1-C 30 Alkylthio, substituted or unsubstituted C1-C 30 ester group, substituted or unsubstituted C1-C 30 Amine, substituted or unsubstituted C1-C 30 Any one of the aromatic groups.

[0007] Preferably, R1, R2, and R3 are each independently selected from any one or more of methyl, methoxy, ethyl, ethoxy, propyl, propoxy, isopropyl, isopropoxy, butyl, butoxy, isobutyl, isobutoxy, tert-butyl, tert-butoxy, pentyl, pentyloxy, isopentyl, isopentyloxy, hexyl, hexyloxy, heptyl, heptyloxy, octyl, and octyloxy.

[0008] Preferably, R2 and R3 are each independently selected from substituted or unsubstituted C1-C 30 Any one or more of alkylamines and arylamines.

[0009] As an improvement of the present invention, the R1, R2, and R3 are each independently selected from substituted or unsubstituted C1-C 30 of alkyl.

[0010] As an improvement of the present invention, R2 and R3 are tert-butyl groups, and their structural formula is as follows: .

[0011] As an improvement of the present invention, the compound comprising the following structure: , .

[0012] As an improvement of the present invention, the polymer material contains 0.01-10% by weight of the 5,6-difluorobenzotriazole derivative fluorescent material as described in claims 1-4.

[0013] The present invention also provides an application of a 5,6-difluorobenzotriazole derivative fluorescent material in a fluorescent plastic. The fluorescent plastic is obtained by mixing the above-mentioned 5,6-difluorobenzotriazole derivative fluorescent material with a polymer material. In terms of weight percentage, the fluorescent plastic contains 0.01-10% of the 5,6-difluorobenzotriazole derivative fluorescent material.

[0014] As an improvement of the present invention, the polymer material is any one or more of polyethylene (PE), polypropylene (PPE), polyacrylic acid (PMA), polymethyl acrylate (PMMA), polyvinyl alcohol (PVA), polyethylene vinyl acetate (EVA), polyvinyl butyral (PVB), polyolefin elastomer (POE), and polysilicone.

[0015] As an improvement of the present invention, the polymer material is in any physical form of powder, granule or film.

[0016] As an improvement of the present invention, the fluorescent plastic is used in any one of adhesives, fluorescent films, fluorescent concentrated solar energy, packaging materials for photovoltaic modules, and light conversion materials for photovoltaic modules.

[0017] Preferably, the fluorescent plastic is used in the form of a film material for fluorescent concentrating solar panels or an encapsulating film for light conversion to improve the photoelectric conversion efficiency and service life of photovoltaic panels.

[0018] The present invention also provides an application of a 5,6-difluorobenzotriazole derivative fluorescent material in a fluorescent liquid. The fluorescent liquid is prepared by mixing the above-mentioned 5,6-difluorobenzotriazole derivative fluorescent material with a liquid mixture. In terms of weight percentage, the fluorescent liquid contains 0.01-10% of the 5,6-difluorobenzotriazole derivative fluorescent material.

[0019] As an improvement of the present invention, the fluorescent liquid is applied to any one of fluorescent paint, fluorescent adhesive, fluorescent anti-counterfeiting mark and fluorescent ink.

[0020] The beneficial effects of the present invention are: The 5,6-difluorobenzotriazole derivative fluorescent material provided by the present invention optimizes the energy band and chemical stability of the benzotriazole derivative by introducing highly electronegative fluorine atoms to the 5 and 6 positions of benzotriazole. At the same time, alkyl-substituted benzene rings are connected to the 4 and 7 positions and the substituted groups on the 2nd N atom to optimize the interaction between molecules to obtain ideal solubility and compatibility with polymer substrates. The fluorescent material of the present invention can be formulated in liquid ink or solid plastic to prepare fluorescent ink or fluorescent plastic, and has a longer service life and better light conversion performance. Not only does it improve the functionality of the material, but it also broadens its application potential in the fields of optoelectronic equipment, fluorescent coatings, adhesives, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is the NMR spectrum of compound V in Example 1.

[0022] Figure 2 1 is the absorption and emission spectra of compound V in Example 1.

[0023] Figure 3 This is the NMR spectrum of compound VII from Example 2.

[0024] Figure 4 The absorption and emission spectra of compound VII of Example 2 are shown in FIG.

[0025] Figure 5 This is the nuclear magnetic resonance spectrum of compound 4 in comparative example 1.

[0026] Figure 6 The absorption and emission spectra of compound 4 in comparative example 1 are shown in FIG. DETAILED DESCRIPTION

[0027] The present invention will be further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0028] The term "fluorescent dye" as used herein refers to a compound that absorbs photons of a specific wavelength or wavelength range and re-emits photons at a different wavelength or wavelength range. It has the same definition as the "photoconversion material" used herein. "Fluorescent dye" and "photoconversion material" are considered to be equivalent and interchangeable terms in this article.

[0029] The term "photoconversion greenhouse film" used herein refers to a greenhouse film containing photoconversion materials. The film is used in greenhouses, such as plastic greenhouses and green houses, to absorb low-wavelength ultraviolet rays in sunlight, and emit high-wavelength visible light including near-infrared rays after excitation, thereby promoting plant photosynthesis and accelerating plant growth.

[0030] The term "solar cell" as used herein refers to a device that converts photons into electrons through the photovoltaic effect, also known as a photovoltaic device or a solar module, including silicon-based photovoltaic devices, III-V or II-VI PN junction photovoltaic devices, copper-indium-gallium-selenium (CIGS) thin film photovoltaic devices, cadmium sulfide / cadmium telluride (CdS / CdTe) thin film devices, dye-sensitized photovoltaic devices (DSSC), organic thin film photovoltaic devices (OPV) and perovskite photovoltaic devices.

[0031] The term "fluorescent concentrating solar cell" used in this article refers to a small amount of fluorescent material mixed in a transparent organic glass material. Low-wavelength sunlight, mainly ultraviolet light, is absorbed by the fluorescent material in the light guide plate (organic glass) and converted into visible light fluorescence emission with a longer wavelength. Most of this part of fluorescence will be guided to the edge by the light guide plate and converted into electrical energy by the coupled photoelectric converter (solar cell). In this way, the glass (including organic glass or organic film) becomes artistic glass, and the solar cell is hidden in the glass window frame structure, allowing the glass window to generate electricity without feeling. The use of this technology can be used as a solar photovoltaic conversion component for the building facade, beautifying the building facade while maximizing the use of solar energy, providing an effective way for environmental protection, energy saving and zero-energy buildings. In particular, it is beneficial to green agriculture, converting harmful ultraviolet rays to electricity, converting low-wavelength blue light to selective long-wave light to increase plant photosynthesis, promote plant growth, and maintain the greenhouse effect. At the right time and place, according to the application scenario, you can choose a unique functional light wave conversion photosynthesis plastic film, or generate electricity at the same time.

[0032] The term "photoconversion material solar efficiency enhancement film" used in this article refers to a packaging film that adds photoconversion materials to a high-transmittance packaging film to improve the power generation efficiency of photovoltaic modules by absorbing ultraviolet light and converting it into blue light that can be used by photovoltaic modules to generate electricity more efficiently. Commonly used transparent packaging films include polyethylene-vinyl acetate (EVA), polyvinyl butyral (PVB) and polyolefin elastomer (POE).

[0033] The term "liquid mixture" as used herein refers to a mixture that exists in a liquid state at normal temperature and pressure. According to the present invention, the fluorescent liquid mixture is only required to contain 0.01%-10% of fluorescent material by weight, and there is no requirement for other components. The fluorescent mixture may contain solvents, polymer resins, crosslinking agents, bactericides, plasticizers, and other additives according to the purpose, such as fluorescent binders, fluorescent coatings, and fluorescent inks. If the content of fluorescent materials in the liquid mixture is higher than 10%, it will cause fluorescence self-absorption and reduce the luminous quantum efficiency.

[0034] The term "benzotriazole" as used herein and the arrangement of its atoms are shown in the following structure: .

[0035] Example 1 Synthesis of Compound V The overall reaction formula for the synthesis of compound V is as follows:

[0036] Wherein: Mw is the molecular weight.

[0037] (1) Synthesis of intermediate II Compound I (44.8 g, 135.9 mmol) and 1800 mL of ethanol were added to a 3 L reaction bottle and stirred for 5 min to evenly disperse compound I in the reaction system. The reaction bottle was placed in an ice bath, and after the temperature of the reaction liquid dropped to 0 ° C, sodium borohydride (40 g, 1057.4 mmol) was added in batches. After the addition was completed, the temperature was naturally raised to room temperature and the reaction was allowed to proceed overnight. After the reaction, the reaction liquid was poured into 3 L of cold water, extracted with dichloromethane, washed with water 5 times, washed with salt once, dried with countless sodium sulfate, and the solvent was removed to obtain 28 g of intermediate II with a yield of 68.3%.

[0038] (2) Synthesis of intermediate III Take the intermediate II (28 g, 92.7 mmol) obtained in step (1), 180 mL THF and 17.5 mL glacial acetic acid and add them to a 1 L reaction bottle. Place the reaction bottle in an ice bath. When the temperature drops to 0 ° C, add sodium nitrite solution (11.5 g sodium nitrite + 35 mL water) dropwise into the reaction system and react at room temperature overnight. After the reaction, the solvent is removed by rotation, extracted with dichloromethane and washed with water until neutral, dried over anhydrous sodium sulfate and then spin-dried to obtain 28.7 g of intermediate III, with a yield of 98.9%.

[0039] (3) Synthesis of Intermediate IV The intermediate III (28.7 g, 91.7 mmol) obtained in step (2), isobutyl bromide (16.6 g, 121.1 mmol) and 85 mL of N,N-dimethylformamide were added to a 1 L reaction bottle. After stirring for 10 minutes, anhydrous potassium carbonate (50.7 g, 366.9 mmol) and potassium iodide (48.7 g, 293.5 mmol) were added in sequence, and then the temperature was raised to 90 ° C and reacted overnight. After the reaction, the reaction mixture was poured into 2 L of water, and the reaction solution was extracted with ethyl acetate. After washing with water and salt, 30 g of crude product was obtained. The above crude product was separated by silica gel and petroleum ether column chromatography to obtain intermediate IV, with a yield of 50.1%.

[0040] (4) Synthesis of Compound V Take the intermediate IV (7.38 g, 20 mmol) obtained in step (3) and 4-tert-butylphenylboronic acid (10.15 g, 57 mmol) and mix them in 60 mL toluene and 120 mL n-butanol. Purge with argon gas. Add tetrakis(triphenylphosphine)palladium(0) (1.62 g, 1.4 mmol) and an aqueous solution of sodium carbonate (16 g sodium carbonate, 20 mL water) in sequence, and then heat and reflux for 18 hours. After cooling, pour the reaction mixture into water (500 mL) and extract with toluene / ethyl acetate / hexane (4:4:2, 2*300 mL). The extract is washed with water (2*250 mL), and the volatiles are removed under reduced pressure to obtain 16.0 g of white-grey residue. The residue is separated by silica gel and hexane / dichloromethane (2:1) column chromatography to obtain 8.4 g of white solid. The separated product is crystallized from ethanol to obtain 4.3 g of white crystals. Nuclear magnetic resonance spectroscopy confirmed that the chemical structure of the crystal was the target product, namely compound V.

[0041] like Figure 1 and Figure 2 As shown, Figure 1 The compound V 1 H-NMR (400MHz, CDC13); Figure 2 The absorption and emission spectra of compound V are shown: in chloroform solution, the maximum absorption peak is at 326 nm, the maximum emission peak is at 397 nm, and the wavelength difference between the emission peak and the absorption peak is 71 nm.

[0042] Example 2 Synthesis of Compound VII The overall reaction formula for the synthesis of compound VII is as follows:

[0043] Wherein: Mw is the molecular weight.

[0044] (1) Synthesis of intermediate II Same as step (1) of Example 1.

[0045] (2) Synthesis of intermediate III Same as step (2) in Example 1.

[0046] (3) Synthesis of intermediate VI The intermediate III (17.9 g, 64.6 mmol) obtained in step (2), 7-(bromomethyl)pentadecane (26.1 g, 204.3 mmol) and 85 mL of N,N-dimethylformamide were added to a 1 L reaction bottle. After stirring for 10 minutes, anhydrous potassium carbonate (35.9 g, 259.9 mmol) and potassium iodide (33.91 g, 204.3 mmol) were added in sequence, and then the temperature was raised to 90 ° C and reacted overnight. After the reaction, the reaction mixture was poured into 2 L of water, and the reaction solution was extracted with ethyl acetate. After washing with water and salt, 35 g of crude product was obtained. The above crude product was separated by silica gel and petroleum ether column chromatography to obtain 20 g of intermediate VI, with a yield of 57.6%.

[0047] (4) Synthesis of Compound VII Take the intermediate VI (5.37 g, 10 mmol) obtained in step (3) and 4-tert-butylphenylboronic acid (5.07 g, 28.5 mmol) and mix them in 50 mL toluene and 100 mL n-butanol. Purge with argon gas. Add tetrakis(triphenylphosphine)palladium(0) (0.81 g, 0.7 mmol) and an aqueous solution of sodium carbonate (7.9 g sodium carbonate, 10 mL water) in sequence, and then heat and reflux for 16 hours. After cooling, pour the reaction mixture into water (400 mL) and extract with toluene / ethyl acetate / hexane (4:4:2, 2*200 mL). The extract is washed with water (2*200 mL), and the volatiles are removed under reduced pressure to obtain 22 g of brown-gray residue. The residue is separated by silica gel and hexane / dichloromethane (2:1) column chromatography to obtain 6.3 g of white solid. The separated product is recrystallized from ethanol to obtain 5.9 g of white crystals. Nuclear magnetic resonance spectroscopy confirmed that the chemical structure of the crystal was the target product, namely compound VII.

[0048] like Figure 3 and Figure 4 As shown, Figure 3 The compound VII 1 H-NMR (400MHz, CDC13); Figure 4 The absorption and emission spectra of compound VII are shown: in chloroform solution, the maximum absorption peak is at 326 nm, the maximum emission peak is at 395 nm, and the wavelength difference between the emission peak and the absorption peak is 69 nm.

[0049] Comparative Example 1 Synthesis of Compound 4 The overall reaction formula for the synthesis of compound 4 is as follows:

[0050] Wherein: Mw is the molecular weight.

[0051] (1) Synthesis of intermediate 2 A mixture of benzotriazole (35.26 g, 300 mmol), 1-bromo-2-methylpropane (60 g, 440 mmol), potassium carbonate (45.6 g, 330 mmol) and dimethylformamide (300 mL) was stirred under argon and heated at 80°C for 18 hours. The reaction mixture was poured into ice / water (1 L) and extracted with toluene / hexane (2:1, 2×500 mL). The extract was washed with 1N HCl (2×400 mL) and then with brine (200 mL), dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure to obtain 20.68 g of a residue. The residue was mixed and stirred with hexane (600 mL), filtered and discarded, and the obtained hexane was chromatographed on a silica gel (400 g, 15 cm) column, followed by further chromatography with hexane / dichloromethane / ethyl acetate (40:55:5) to collect the slightly yellow component, and the solvent was removed to obtain 9.24 g of an oily liquid. Nuclear magnetic resonance imaging confirmed that the chemical structure of the liquid was intermediate 2 with a purity of 93%.

[0052] (2) Synthesis of intermediate 3 A mixture of intermediate 2 (9.24 g, 52.5 mmol) obtained in step (1), bromine (25.2 g, 157 mmol) and 48% HBr (54 mL) was heated at 130°C for 20 hours under a reflux condenser connected to an HBr trap. The reaction mixture was poured into ice / water (500 mL), neutralized with 5N NaOH (300 mL) and extracted with dichloromethane (2×600 mL). The extract was dried over anhydrous magnesium sulfate and the solvent was removed under reduced pressure. 18.4 g of a light yellow viscous liquid was obtained by column chromatography on silica gel and hexane / dichloromethane (1:1, 200 mL). The chemical structure of the liquid was identified as intermediate 3 by nuclear magnetic resonance, with a purity of 90%.

[0053] (3) Synthesis of compound 4 The intermediate 3 (44.7 g, 90%, 37.38 mmol) obtained in step (2) and 4-tert-butylphenylboronic acid (19 g, 37.38 mmol) were mixed in 100 mL toluene and 200 mL n-butanol, and argon was fully purged. Tetrakis(triphenylphosphine)palladium(0) (3.15 g, 2.73 mmol) and an aqueous solution of sodium carbonate (26.4 g sodium carbonate, 30 ml water) were added in sequence, and then heated at 95°C for 16 hours. After cooling, the reaction mixture was poured into water (800 mL) and extracted with toluene / ethyl acetate / tetrahydrofuran (4:4:2, 2*500 mL). The extract was washed with water (2*200 ml), and the volatiles were removed under reduced pressure to obtain 30.5 g of brown-black residue. The residue was separated by silica gel and hexane / dichloromethane (2:1) column chromatography to obtain 14.5 g of light yellow solid. The separated product was recrystallized from ethanol to obtain 8.9 g of light yellow crystals. Nuclear magnetic resonance analysis showed that the chemical structure of the crystals was the target product, i.e., compound 4.

[0054] like Figure 5 and Figure 6 As shown, Figure 5 The compound 4 1 H-NMR (400MHz, CDC13); Figure 6 The absorption and emission spectra of compound 4 are shown: in chloroform solution, its absorption peak maximum is at 343 nm, its emission peak maximum is at 421 nm, and the wavelength difference between the emission peak and the absorption peak is 78 nm.

[0055] The absorption spectrum peaks and emission spectrum peaks of Examples 1 and 2 and Comparative Example 1 are shown in the following table: Compound Compound V Compound VII Compound 4 Absorption peak(nm) 326 326 343 Emission peak(nm) 397 395 421 In summary, the present invention replaces two active hydrogen atoms on the main structure of benzotriazole with two fluorine atoms, thereby passivating the electronic structure of the main structure of benzotriazole and increasing its energy band gap, which is reflected in the absorption peak value being reduced from 343nm to 326nm. In addition to the alkyl-substituted benzene rings connected to the 4 and 7 positions of the benzotriazole derivative to achieve the molecular light conversion performance, functional substituent groups are also connected to the 5 and / or 6 positions and the No. 2 N atom of the benzotriazole derivative to achieve the multifunctionality of the light conversion agent. Among them, the preferred R, R1, R2 and R3 are conducive to enhancing the solubility of the light conversion agent in the film, which can not only inhibit the migration and agglomeration of the light conversion agent in the film, but also optimize the absorption and emission spectra of the light conversion agent as needed to meet the use requirements of components of different manufacturers in different scenarios. In addition, even when there is a concentration difference in the light conversion agent in the film, the mobility of the light conversion agent at high temperature will be greatly reduced.

[0056] It should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention. For ordinary technicians in this technical field, several improvements and modifications can be made on the basis of the above embodiments without departing from the principles of the present invention. These improvements and modifications all fall within the scope of protection of the claims of the present invention.

Claims

1. A 5,6-difluorobenzotriazole derivative fluorescent material, characterized in that: The general structural formula of the 5,6-difluorobenzotriazole derivatives is as follows: ； Wherein, R1, R2, and R3 are each independently selected from substituted or unsubstituted C1-C 30 Alkyl, substituted or unsubstituted C1-C 30 Alkoxy, substituted or unsubstituted C1-C 30 Alkylthio, substituted or unsubstituted C1-C 30 ester group, substituted or unsubstituted C1-C 30 Amine, substituted or unsubstituted C1-C 30 Any one of the aromatic groups.

2. The 5,6-difluorobenzotriazole derivative fluorescent material according to claim 1, characterized in that: The R1, R2, and R3 are each independently selected from substituted or unsubstituted C1-C 30 of alkyl.

3. The 5,6-difluorobenzotriazole derivative fluorescent material according to claim 2, characterized in that: The R2 and R3 are tert-butyl groups, and their structural formula is as follows: 。 4. The 5,6-difluorobenzotriazole derivative fluorescent material according to claim 3, characterized in that: Includes compounds with the following structures: 、 。 5. Application of a 5,6-difluorobenzotriazole derivative fluorescent material in fluorescent plastics, characterized in that: The fluorescent plastic is prepared by mixing the 5,6-difluorobenzotriazole derivative fluorescent material described in claims 1-4 with a polymer material. In terms of weight percentage, the fluorescent plastic contains 0.01-10% of the 5,6-difluorobenzotriazole derivative fluorescent material.

6. The use of the 5,6-difluorobenzotriazole derivative fluorescent material in fluorescent plastics according to claim 5, characterized in that: The polymer material is any one or more of polyethylene, polypropylene, polyacrylic acid, polymethyl acrylate, polyvinyl alcohol, polyethylene-vinyl acetate, polyvinyl butyral, polyolefin elastomer, and polysilicone.

7. The use of the 5,6-difluorobenzotriazole derivative fluorescent material in fluorescent plastics according to claim 5, characterized in that: The polymer material is in any physical form of powder, granule or film.

8. The use of the 5,6-difluorobenzotriazole derivative fluorescent material in fluorescent plastics according to claim 5, characterized in that: The fluorescent plastic is used in any one of adhesives, fluorescent films, fluorescent concentrated solar energy, packaging materials of photovoltaic modules, and light conversion materials of photovoltaic modules.

9. Application of a 5,6-difluorobenzotriazole derivative fluorescent material in a fluorescent liquid, characterized in that: The fluorescent liquid is prepared by mixing the 5,6-difluorobenzotriazole derivative fluorescent material according to claims 1-4 with a liquid mixture. In terms of weight percentage, the fluorescent liquid contains 0.01-10% of the 5,6-difluorobenzotriazole derivative fluorescent material.

10. Use of the 5,6-difluorobenzotriazole derivative fluorescent material in fluorescent liquid according to claim 9, characterized in that: The fluorescent liquid is applied to any one of fluorescent coatings, fluorescent adhesives, fluorescent anti-counterfeiting labels and fluorescent inks.

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