Thin film phosphor material, method of making and use in electromagnetic wave detection

Abstract

The application relates to the technical field of electromagnetic wave detection, in particular to a thin film phosphorescent material, a preparation method thereof and application of the thin film phosphorescent material in electromagnetic wave detection. The thin film phosphorescent material comprises polyvinylidene fluoride and 4-biphenyl boronic acid doped in the polyvinylidene fluoride; and the mass ratio of the 4-biphenyl boronic acid to the polyvinylidene fluoride is (0.005-3):100. The thin film material obtained through mutual doping of small molecules and polymers has excellent room-temperature phosphorescent light emitting performance; the thin film phosphorescent material can be used for detecting electromagnetic waves, and can be especially used for detecting long-wave electromagnetic waves.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electromagnetic wave detection, in particular to a thin film phosphor material, a preparation method thereof and application thereof in electromagnetic wave detection. BACKGROUND

[0002] Electromagnetic waves are also called electromagnetic radiation (most frequencies are 10 21 ~ 10 3 Hz), which exist in microwave ovens, mobile phones, televisions and other electronic products. Electromagnetic wave energy is generally generated by objects above absolute zero, and cannot be identified by the naked eye. According to GB9715-88 “Environmental Electromagnetic Wave Health Standards”, the electromagnetic radiation intensity in the area where people live should be no more than 10 μw / cm 2 , and the electromagnetic radiation power of the mobile phone when working close to the ear is 120-1100 μw / cm 2 , and the electromagnetic radiation intensity of other electronic devices is even higher. These “electromagnetic pollution” can greatly harm human health. Therefore, the detection of electromagnetic waves is very important.

[0003] The patent application with publication number CN111286332A describes a rare earth-based multimodal luminescent perovskite material and its preparation method and application, which describes a rare earth-based perovskite material with a chemical composition of A2A’ 1-a A” a B 1-b-c-d B’ b R c R’ d X6, which can be used for naked-eye detection of electromagnetic waves that cannot be perceived by humans. The patent application with publication number CN102174390A describes a method for real-time detection of electromagnetic radiation bioluminescence effect, which uses a kind of bioluminescent macrophages, and uses electromagnetic radiation energy to act on biological samples to detect the change information of bioluminescence in real time, and indirectly detects electromagnetic waves according to the luminescence of cells.

[0004] However, the existing above-mentioned technologies have the following problems: (1) The preparation of rare earth-based perovskite materials requires high temperature and high pressure conditions, and the process is complex, and rare earth metal resources are limited and expensive; (2) The electromagnetic waves detected by the rare earth-based perovskite material belong to the short wave range, and the long wave range electromagnetic waves cannot be excited, and thus cannot be detected; (3) The biological sample must have cell activity, and the cell must be kept active for a long time under extremely harsh conditions; (4) The biological tissue cannot be conveniently carried, and cannot be used in large areas.

[0005] Therefore, the present application is proposed. SUMMARY

[0006] An object of the present application is to provide a thin film phosphor material, which can be used for real-time monitoring of electromagnetic waves.

[0007] Another object of the present application is to provide a preparation method of the thin film phosphorescent material.

[0008] Still another object of the present application is to provide an application of the thin film phosphorescent material in electromagnetic wave detection.

[0009] To achieve the above object, the present application provides a thin film phosphorescent material comprising polyvinylidene fluoride and 4-biphenylboronic acid doped in the polyvinylidene fluoride.

[0010] The mass ratio of the 4-biphenylboronic acid to the polyvinylidene fluoride is (0.005-3) : 100.

[0011] In the specific embodiment of the present application, the mass ratio of the 4-biphenylboronic acid to the polyvinylidene fluoride is (0.03-0.5) : 100.

[0012] In the specific embodiment of the present application, the mass ratio of the 4-biphenylboronic acid to the polyvinylidene fluoride is (0.05-0.3) : 100.

[0013] In the specific embodiment of the present application, the weight average molecular weight of the polyvinylidene fluoride is 100,000-1,000,000.

[0014] In the specific embodiment of the present application, the thin film phosphorescent material does not contain oxygen molecules inside.

[0015] The present application also provides a preparation method of the thin film phosphorescent material, comprising the following steps:

[0016] drying the solution containing the polyvinylidene fluoride and the 4-biphenylboronic acid to obtain the thin film phosphorescent material;

[0017] In the solution, the mass ratio of the 4-biphenylboronic acid to the polyvinylidene fluoride is (0.005-3) : 100.

[0018] In the specific embodiment of the present application, the mass fraction of the polyvinylidene fluoride in the solution is 5%-15%.

[0019] In the specific embodiment of the present application, the preparation of the solution containing the polyvinylidene fluoride and the 4-biphenylboronic acid comprises: dissolving the polyvinylidene fluoride in a solvent to obtain a solution of the polyvinylidene fluoride; and then dissolving the 4-biphenylboronic acid in the solution of the polyvinylidene fluoride to obtain the solution containing the polyvinylidene fluoride and the 4-biphenylboronic acid. Further, the solvent comprises at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide, dimethyl sulfoxide, triethyl phosphate and N-methyl pyrrolidone.

[0020] In the detailed description of the present application, the film-forming method comprises any one of dipping, coating, spraying, spin coating and drop coating.

[0021] In the detailed description of the present application, the drying comprises treating at 60-140℃ for 4-10h.

[0022] In the detailed description of the present application, further comprising: irradiating the thin film phosphorescent material with 240-300nm ultraviolet light. Further, the irradiation time is ≥0.5min, preferably ≥5min.

[0023] In another aspect of the present application, the thin film phosphorescent material is applied in electromagnetic wave detection.

[0024] In the detailed description of the present application, the electromagnetic wave has a frequency of 2-10GHz. Further, the electromagnetic wave has a power of 100-1000W.

[0025] In the detailed description of the present application, the detection method comprises placing the thin film phosphorescent material in a test environment or test system, and detecting the phosphorescent light intensity, phosphorescent lifetime and / or afterglow duration before and after placing the thin film phosphorescent material in the test environment or test system.

[0026] In the detailed description of the present application, the time for placing the thin film phosphorescent material in the test environment or test system is ≥60s, preferably ≥120s.

[0027] Compared with the prior art, the present application has the following advantages:

[0028] (1) The thin film material obtained by the present application through the mutual doping of small molecules and polymers has excellent room-temperature phosphorescent light emitting performance; and the thin film material obtained by the present application does not affect the mechanical properties of the polyvinylidene fluoride polymer itself;

[0029] (2) The thin film phosphorescent material of the present application has a simple preparation process and low cost; and the prepared thin film phosphorescent material can be carried in a portable manner and has stable phosphorescent light emitting performance;

[0030] (3) The thin film phosphorescent material of the present application can be used for detecting electromagnetic waves, especially long-wave electromagnetic waves. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions in the specific embodiments of the present application or the prior art, the drawings needed in the description of the specific embodiments or the prior art will be briefly introduced. Obviously, the drawings described below are some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative effort.

[0032] Figure 1 A schematic diagram of doping of small molecules and polymers in the thin film phosphorescent material provided in the embodiments of the present application;

[0033] Figure 2 Fluorescent emission photos and afterglow decay photos of different thin film phosphorescent materials provided in embodiments 1-6 under irradiation of a 254 nm ultraviolet lamp;

[0034] Figure 3 A phosphorescent intensity comparison line graph of the thin film phosphorescent material provided in embodiments 4 and 7 after irradiation of different electromagnetic waves for different times;

[0035] Figure 4 Fluorescent emission spectrum and phosphorescent spectrum of the thin film phosphorescent material provided in the embodiments of the present application;

[0036] Figure 5 Phosphorescent lifetime of the thin film phosphorescent material provided in the embodiments of the present application before and after irradiation of a 254 nm ultraviolet lamp;

[0037] Figure 6 Afterglow decay photo of the thin film phosphorescent material provided in embodiment 7 after irradiation of a 254 nm ultraviolet lamp;

[0038] Figure 7 Mechanism diagram of the long lifetime afterglow generated by the thin film phosphorescent material provided in the present application after irradiation of a 254 nm ultraviolet lamp;

[0039] Figure 8 High resolution scanning electron microscope photo of the thin film phosphorescent material provided in embodiment 4;

[0040] Figure 9 Phosphorescent spectrum of the thin film phosphorescent material provided in embodiment 4 before and after irradiation of electromagnetic waves;

[0041] Figure 10 Phosphorescent spectrum of the thin film phosphorescent material provided in embodiment 7 before and after irradiation of electromagnetic waves;

[0042] Figure 11 Phosphorescent spectrum of the thin film phosphorescent material provided in embodiment 7 after heating treatment at 60.7°C;

[0043] Figure 12A schematic diagram of molecular chain rearrangement and crystal phase transition of the thin film phosphorescent material provided by the present application after 2.45GHz electromagnetic wave treatment is shown in FIG. 1.

[0044] Figure 13 The crystallinity and the proportion of each before and after electromagnetic wave irradiation of the thin film phosphorescent material provided by the present application for Example 7 are shown in FIG. 2. DETAILED DESCRIPTION

[0045] The technical solutions of the present application will be described clearly and completely in combination with the drawings and specific embodiments, but those skilled in the art will understand that the following described embodiments are part of the embodiments of the present application, not all the embodiments, and are only used to illustrate the present application, and should not be regarded as limiting the scope of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application. The specific conditions are not specified in the examples, and the conventional conditions or the conditions recommended by the manufacturer are used. The reagents or instruments used are not specified by the manufacturer, and are conventional products that can be purchased on the market.

[0046] In one aspect, the present application provides a thin film phosphorescent material, comprising polyvinylidene fluoride and 4-biphenylboronic acid doped in the polyvinylidene fluoride.

[0047] The mass ratio of 4-biphenylboronic acid to polyvinylidene fluoride is (0.005-3):100.

[0048] The material obtained by doping small molecule 4-biphenylboronic acid (BPBA) and polyvinylidene fluoride (PVDF) with each other not only does not affect the mechanical properties of PVDF itself, but also endows the material with excellent room-temperature phosphorescent luminescence performance.

[0049] The thin film phosphorescent material of the present application can continuously emit green long-life phosphorescence for 15s when continuously irradiated with 240-300nm ultraviolet light for more than 1min, such as 5min, and the phosphorescence wavelength is about 488nm.

[0050] In different embodiments, the mass ratio of BPBA to PVDF can be 0.005:100, 0.01:100, 0.03:100, 0.05:100, 0.08:100, 0.1:100, 0.12:100, 0.15:100, 0.18:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, 1.5:100, 2:100, 2.5:100, 3:100, or a range consisting of any two of them.

[0051] The mass ratio of BPBA to PVDF is within the above range, and the corresponding material has room temperature phosphorescence characteristics, and the afterglow can be observed by naked eye or the corresponding phosphorescence spectrum can be detected by instrument.

[0052] The BPBA can be directly purchased, and the structural formula is as follows:

[0053]

[0054] The PVDF can be directly purchased, and the structural formula is as follows:

[0055]

[0056] In the specific embodiment of the present application, the mass ratio of BPBA to PVDF is (0.03-0.5):100. When the mass ratio of BPBA to PVDF is within the range of (0.03-0.5):100, the corresponding thin film phosphorescent material can be observed by naked eye.

[0057] In the specific embodiment of the present application, the mass ratio of BPBA to PVDF is (0.05-0.3):100.

[0058] In the preferred embodiment of the present application, the mass ratio of BPBA to PVDF is 0.1:100.

[0059] When the mass ratio of BPBA to PVDF is 0.1:100, the corresponding thin film phosphorescent material has the best phosphorescent light emitting performance.

[0060] In the specific embodiment of the present application, the weight average molecular weight of polyvinylidene fluoride is 100,000-1,000,000.

[0061] As in different embodiments, the weight average molecular weight of polyvinylidene fluoride can be 100,000, 200,000, 300,000, 400,000, 500,000, 600,000, 700,000, 800,000, 900,000, 1,000,000 or a range composed of any two of them.

[0062] In the specific embodiment of the present application, the crystallinity of polyvinylidene fluoride is 30%-60%. As in different embodiments, the crystallinity of polyvinylidene fluoride can be 30%, 40%, 50%, 60% or a range composed of any two of them. Polyvinylidene fluoride belongs to a semi-crystalline polymer, wherein the crystalline part of polyvinylidene fluoride includes various crystal phases, such as α, β, γ, ε, δ five crystal phases, wherein the content of ε, δ crystal direction is low, close to 0 (<5%).

[0063] In the specific embodiment of the present application, the thin film phosphorescent material does not contain oxygen molecules inside.

[0064] The present application adopts 240-300nm ultraviolet light to irradiate the thin film phosphor material, and the oxygen removal time of the continuous irradiation is at least 0.5min, and the effect is best when reaching 5min; the triplet exciton of the BPBA consumes the oxygen in the PVDF, so that the thin film phosphor material after treatment has longer afterglow.

[0065] The present application also provides a preparation method of the thin film phosphor material.

[0066] The solution containing the polyvinylidene fluoride and the 4-biphenyl boronic acid is dried to form a film to obtain the thin film phosphor material.

[0067] In the solution, the mass ratio of the 4-biphenyl boronic acid to the polyvinylidene fluoride is (0.005-3):100.

[0068] As in different embodiments, the mass ratio of the BPBA to the PVDF in the solution can be 0.005:100, 0.01:100, 0.03:100, 0.05:100, 0.08:100, 0.1:100, 0.12:100, 0.15:100, 0.18:100, 0.2:100, 0.3:100, 0.4:100, 0.5:100, 0.6:100, 0.7:100, 0.8:100, 0.9:100, 1:100, 1.5:100, 2:100, 2.5:100, 3:100, or a range consisting of any two of them.

[0069] In the specific embodiment of the present application, the mass fraction of the polyvinylidene fluoride in the solution is 5%-15%.

[0070] As in different embodiments, the mass fraction of the PVDF in the solution can be 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, or a range consisting of any two of them.

[0071] In the specific embodiment of the present application, the preparation of the solution containing the polyvinylidene fluoride and the 4-biphenyl boronic acid includes: dissolving the polyvinylidene fluoride in a solvent to obtain a solution of the polyvinylidene fluoride; and then dissolving the 4-biphenyl boronic acid in the solution of the polyvinylidene fluoride to obtain the solution containing the polyvinylidene fluoride and the 4-biphenyl boronic acid. Further, the solvent includes at least one of N,N-dimethylformamide (DMF), N,N-dimethylacetamide, dimethyl sulfoxide, triethyl phosphate, and N-methyl pyrrolidone.

[0072] In actual operation, when preparing the solution of polyvinylidene fluoride, the polyvinylidene fluoride can be dissolved in the solvent at room temperature by conventional magnetic stirring, etc., to form a uniform solution. When preparing the solution of polyvinylidene fluoride and 4-biphenylboronic acid, the 4-biphenylboronic acid is added to the solution of polyvinylidene fluoride, and the 4-biphenylboronic acid can be dissolved in the solvent at room temperature by conventional magnetic stirring to form a uniform solution.

[0073] The time of magnetic stirring can be adjusted according to actual needs, such as 1-48h, to ensure that the formed solution is uniform and stable.

[0074] In the specific embodiments of the present application, the film-forming method includes any one of immersion, coating, spraying, drop coating and spin coating.

[0075] In the specific embodiments of the present application, drying includes treatment at 60-140℃ for 4-10h.

[0076] As in different embodiments, the temperature of drying can be 60℃, 65℃, 70℃, 75℃, 80℃, 85℃, 90℃, 95℃, 100℃, 105℃, 110℃, 115℃, 120℃, 125℃, 130℃, 135℃, 140℃ or a range consisting of any two of them; the time of drying treatment can be 4h, 5h, 6h, 7h, 8h, 9h, 10h or a range consisting of any two of them, and the time of drying treatment can be appropriately adjusted according to actual conditions to ensure drying.

[0077] The film-forming drying method can use conventional operations. Taking drop coating as an example, the drop coating method can include: drop coating the solution of polyvinylidene fluoride and 4-biphenylboronic acid on a substrate, and then placing it in an oven at a certain temperature for drying treatment to obtain the corresponding thin film material.

[0078] The substrate can use a quartz sheet or other inert substrate that does not interact with the components of the drop-coated solution.

[0079] In the specific embodiments of the present application, it also includes: using 240-300nm ultraviolet light to irradiate the thin film phosphor material. Further, the irradiation treatment time is ≥0.5min, preferably ≥2min, such as ≥5min.

[0080] After irradiating the thin film phosphor material under 240-300nm ultraviolet light, the treated thin film phosphor material has a long-life afterglow, because the triplet exciton of BPBA consumes the oxygen in PVDF.

[0081] As in different embodiments, the wavelength of the ultraviolet light can be 240 nm, 245 nm, 250 nm, 255 nm, 260 nm, 265 nm, 270 nm, 275 nm, 280 nm, 285 nm, 290 nm, 295 nm, 300 nm, or a range consisting of any two of them; the irradiation treatment time can be 0.5 min, 1 min, 2 min, 3 min, 4 min, 5 min, 6 min, 7 min, 8 min, 9 min, 10 min, or a range consisting of any two of them. Among them, the longer the irradiation treatment time, the more complete the consumption of oxygen in PVDF, but in order to balance the efficiency, usually 5-10 min of irradiation treatment time is enough to consume the oxygen in PVDF.

[0082] In another aspect of the present application, the application of any one of the above-mentioned thin film phosphor materials in electromagnetic wave detection is provided.

[0083] In a specific embodiment of the present application, the frequency of the electromagnetic wave is 2-10 GHz. Further, the power of the electromagnetic wave is 100-1000 W.

[0084] As in different embodiments, the frequency of the electromagnetic wave can be 2 GHz, 3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, 9 GHz, 10 GHz, or a range consisting of any two of them. The power of the electromagnetic wave can be 100 W, 200 W, 300 W, 400 W, 500 W, 600 W, 700 W, 800 W, 900 W, 1000 W, or a range consisting of any two of them.

[0085] In a specific embodiment of the present application, the detection method comprises: placing the thin film phosphor material in the environment to be tested or the system to be tested, and detecting the phosphorescent light intensity, phosphorescent lifetime and / or afterglow duration before and after the thin film phosphor material is placed in the environment to be tested or the system to be tested.

[0086] Among them, whether there is an electromagnetic wave in the environment or system can be distinguished by observing the afterglow situation with the naked eye or by detecting the phosphorescent light intensity with an instrument. When the thin film phosphor material used has not been pre-irradiated with 240-300 nm ultraviolet light to consume oxygen, the phosphorescent emission spectrum can be tested by an instrument, and the change in phosphorescent light intensity before and after is used for discrimination; when the thin film phosphor material used has been pre-irradiated with 240-300 nm ultraviolet light to consume oxygen, the afterglow intensity situation can be observed with the naked eye for discrimination. If the phosphorescent intensity or the afterglow intensity is enhanced, it indicates that there is a corresponding electromagnetic wave in the environment to be tested or the system to be tested.

[0087] The thin film phosphor material of the present application has significantly enhanced phosphorescent light emitting performance after being continuously irradiated by electromagnetic waves with a frequency of 2-10 GHz and a power of 100-1000 W for a period of time. When the thin film phosphor material is subjected to oxygen consumption under irradiation by ultraviolet light with a wavelength of 240-300 nm, the phosphorescent light emitting performance is enhanced more significantly after being continuously irradiated by electromagnetic waves with a frequency of 2-10 GHz and a power of 100-1000 W for a period of time.

[0088] It is found through research that, after being irradiated by electromagnetic waves with a frequency of 2-10 GHz and a power of 100-1000 W for a period of time, the C-F dipole of PVDF is polarized, accompanied by obvious dielectric relaxation, and electromagnetic energy is converted into internal energy, so that the molecular chains in the PVDF polymer are rearranged, the crystallinity is reduced, the alpha phase is increased, and the phosphorescence is enhanced.

[0089] In the specific embodiments of the present application, the time of being placed in the environment to be tested or the system to be tested is ≥60 s, preferably ≥120 s.

[0090] As in different embodiments, the time of being placed in the environment to be tested or the system to be tested can be 60 s, 80 s, 100 s, 120 s, 140 s, 150 s, 160 s, 180 s, 200 s, or a range formed by any two of them.

[0091] Among them, the longer the time of being placed in the environment to be tested or the system to be tested, the more significant the influence on the thin film phosphor material.

[0092] Examples 1-6

[0093] The present embodiment provides a thin film phosphor material and a preparation method thereof, wherein the preparation method of the thin film phosphor material comprises the following steps:

[0094] (1) 10 g of PVDF polymer with a weight average molecular weight of 530000 (Anjie Chemical, Shanghai Sain Chemical Technology Co., Ltd.) is dissolved in 90 g of N,N-dimethylformamide (DMF), and magnetically stirred at room temperature for 24 h to obtain a 10% mass fraction of PVDF DMF uniform solution.

[0095] (2) 0.005-1 mg of BPBA is doped into 1 g of the PVDF DMF uniform solution obtained in step (1), and magnetically stirred at room temperature for 10 h to obtain a uniform DMF solution containing BPBA and PVDF.

[0096] (3) 200 μL of the DMF solution containing BPBA and PVDF obtained in step (2) is drop-coated on a 1.5 cm x 1.5 cm quartz sheet, and then placed in an oven at 80°C for 5 h to obtain a thin film phosphor material.

[0097] The mass of BPBA used in the thin film phosphorescent material of examples 1-6 is shown in Table 1.

[0098] Table 1 Mass of BPBA used in the thin film phosphorescent material of different examples

[0099] No. Amount of BPBA added in Step (2) / mg Example 1 0.005 Example 2 0.01 Example 3 0.05 Example 4 0.1 Example 5 0.5 Example 6 1

[0100] Figure 1 The schematic diagram of the doping between small molecule BPBA and polymer PVDF in the thin film phosphorescent material provided by the examples of the present application is shown in the figure, and the small molecule BPBA is incorporated between adjacent PVDF polymer segments.

[0101] Figure 2 The fluorescence emission photos under 254 nm ultraviolet lamp irradiation and the afterglow decay photos after 5 min irradiation of different thin film phosphorescent materials provided by examples 1-6 are shown in the figure. As can be seen from the figure, the thin film phosphorescent materials of examples 1-2 and 6 have no afterglow, and the corresponding spectrum can be detected by the instrument; the thin film phosphorescent materials of examples 3-4 have visible afterglow with naked eyes.

[0102] Example 7

[0103] This example refers to example 4, and the only difference is that the obtained thin film phosphorescent material is further irradiated under 254 nm ultraviolet light for 5 min.

[0104] Example 8

[0105] The present example provides an application of a thin film phosphorescent material in electromagnetic wave detection, which comprises the following steps:

[0106] The thin film phosphorescent materials prepared in examples 1-7 are continuously irradiated for 120 s by electromagnetic waves with a frequency of 2.45 GHz and a power of 600 W, and the phosphorescent emission intensity of the thin film phosphorescent materials before and after electromagnetic wave treatment is detected.

[0107] Among them, the above detection can be carried out by observing the afterglow with naked eyes or detecting the phosphorescent emission intensity by an instrument.

[0108] Example 9

[0109] The present example provides an application of a thin film phosphorescent material in electromagnetic wave detection, which comprises the following steps:

[0110] The thin film phosphorescent materials prepared in examples 4 and 7 are continuously irradiated by electromagnetic waves with a frequency of 2.45 GHz and a power of 200-1000 W for 30-240 s, and the phosphorescent emission spectrum of the thin film phosphorescent materials before and after electromagnetic wave treatment is detected.

[0111] The phosphorescence intensity under different conditions is shown in the following comparative line graph. Figure 3 Figure 3 In Fig. a is the phosphorescence intensity before (Example 4) and after (Example 7) irradiation with 254 nm UV light. The microwave treatment conditions are: electromagnetic waves with a frequency of 2.45 GHz, different power irradiation for 120 s. Figure 3 In Fig. b is the phosphorescence intensity before (Example 4) and after (Example 7) irradiation with 254 nm UV light. The microwave treatment conditions are: electromagnetic waves with a frequency of 2.45 GHz, 600 W power irradiation for different times. In this case, Figure 3 In Fig. a and Figure 3 In Fig. b, the phosphorescent material of the thin film is obtained from different batches prepared in parallel.

[0112] Experimental Example 1

[0113] Figure 4 The fluorescence and phosphorescence spectra of the thin film phosphorescent material provided in Example 4 or Example 7 of the present application are shown in the following figures, in which the purple dotted line represents the fluorescence spectrum of the thin film phosphorescent material of Example 4, the green dotted line represents the phosphorescence spectrum of the thin film phosphorescent material of Example 4, the purple solid line represents the fluorescence spectrum of the thin film phosphorescent material of Example 7, and the green solid line represents the phosphorescence spectrum of the thin film phosphorescent material of Example 7. The inset represents the initial afterglow photo of the thin film phosphorescent material of Example 7 after the irradiation of UV light is turned off. As can be seen from the figures, the thin film phosphorescent material of the present application has fluorescence and phosphorescence emission characteristics, and after pre-irradiation treatment with UV light, the fluorescence and phosphorescence emission performance of the corresponding thin film phosphorescent material is significantly enhanced.

[0114] Figure 5 The phosphorescence lifetime of the thin film phosphorescent material provided in Example 4 and Example 7 of the present application is shown in the following figure, in which blue represents the phosphorescence lifetime of the thin film phosphorescent material of Example 4, which is 1.21 ms, and red represents the phosphorescence lifetime of the thin film phosphorescent material of Example 7 after irradiation treatment, which is 1208.3 ms. As can be seen from the figure, after pre-irradiation treatment with UV light, the phosphorescence lifetime of the corresponding thin film phosphorescent material is significantly prolonged.

[0115] Figure 6 The afterglow decay photo of the thin film phosphorescent material provided in Example 7 of the present application after irradiation with 254 nm UV light for 5 min is shown in the following figure. As can be seen from the figure, the afterglow of the thin film phosphorescent material of the present application is visible to the naked eye for up to 15 s after irradiation treatment.

[0116] Figure 7 ​The mechanism diagram of the long-life afterglow of the thin film phosphorescent material provided by the present application after irradiation of a 254 nm ultraviolet lamp is shown in the figure. The triplet excitons generated by BPBA of the thin film phosphorescent material of the present application under irradiation of a 254 nm ultraviolet lamp can undergo energy transfer with oxygen in PVDF, consume the oxygen in the thin film, and thus realize long-life afterglow.

[0117] Experimental Example 2

[0118] Figure 8 The high-resolution scanning electron microscope image of the thin film phosphorescent material provided by the present application in Example 4. As can be seen from the figure, a plurality of crystal phases coexist in the thin film phosphorescent material of the present application.

[0119] Figure 9 and Figure 10 The phosphorescence spectra of the thin film phosphorescent materials of Example 4 and Example 7 before and after electromagnetic wave irradiation, respectively, in Example 8 of the present application. As can be seen from the figure, the phosphorescence spectrum of the thin film phosphorescent material of Example 4 (not subjected to 254 nm ultraviolet light irradiation) changes significantly after electromagnetic wave irradiation, and the phosphorescence intensity is significantly enhanced, but no afterglow is visible to the naked eye. The phosphorescence spectrum of the thin film phosphorescent material of Example 7 (subjected to 254 nm ultraviolet light irradiation) changes significantly after electromagnetic wave irradiation, and the phosphorescence intensity is significantly enhanced, and obvious afterglow is visible to the naked eye.

[0120] Figure 11 The phosphorescence spectrum of the thin film phosphorescent material provided by the present application in Example 7 after heating treatment at 60.7℃ for 120s. As can be seen from the figure, the phosphorescence spectrum of the thin film phosphorescent material does not change significantly after heating treatment, which indicates that the increase in phosphorescence intensity of the thin film phosphorescent material by electromagnetic wave treatment of the present application is not caused by temperature rise due to electromagnetic waves.

[0121] Figure 12 The schematic diagram of the rearrangement of molecular chains and crystal phases of the thin film phosphorescent material after electromagnetic wave treatment in Example 8 of the present application. In order to further verify the mechanism shown in the figure, the crystallinity and the proportion of each crystal phase of the thin film phosphorescent material of Example 7 before and after electromagnetic wave irradiation are characterized in Example 8, and the crystallinity and the proportion of each crystal phase before and after electromagnetic wave irradiation are shown in Table 2 and Figure 11 Figure 13 .

[0122] Table 2 Crystallinity and proportion of each crystal phase before and after electromagnetic wave irradiation

[0123] Crystallinity (%) α(％) β(％) γ (%) Before electromagnetic wave irradiation 42.50 44 48 8 After electromagnetic wave irradiation 34.04 58 35 7

[0124] ​From the test results, by electromagnetic wave irradiation, the molecular chain and crystal phase of PVDF polymer are rearranged, the crystallinity is reduced, the proportion of alpha phase is increased, and the proportion of beta phase is reduced, so that the phosphorescent light condition is significantly changed, and the detection of electromagnetic wave is realized.

[0125] The thin film material obtained by the mutual doping of small molecules and polymers has excellent room temperature phosphorescent light performance; the preparation process of the thin film phosphorescent material is simple, and the cost is low; the prepared thin film phosphorescent material can be carried in a portable manner, and the corresponding phosphorescent light performance is stable. In addition, the thin film phosphorescent material can be used for detecting electromagnetic waves, and especially can be used for detecting long wave electromagnetic waves.

[0126] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and not to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that: it can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. The application of thin-film phosphorescent materials in electromagnetic wave detection, characterized in that, The thin-film phosphorescent material includes polyvinylidene fluoride and 4-biphenylboronic acid doped in the polyvinylidene fluoride; The mass ratio of the 4-biphenylboronic acid to the polyvinylidene fluoride is (0.005~3):100; The frequency of the electromagnetic waves is 2 to 10 GHz.

2. The application according to claim 1, characterized in that, The mass ratio of 4-biphenylboronic acid to polyvinylidene fluoride is (0.03~0.5):

100.

3. The application according to claim 1, characterized in that, The mass ratio of 4-biphenylboronic acid to polyvinylidene fluoride is (0.05~0.3):

100.

4. The application according to claim 1, characterized in that, The polyvinylidene fluoride has a weight-average molecular weight of 100,000 to 1,000,000.

5. The application according to claim 1, characterized in that, The thin-film phosphorescent material does not contain oxygen molecules.

6. The application according to any one of claims 1 to 5, characterized in that, The preparation method of the thin-film phosphorescent material includes the following steps: The solution containing polyvinylidene fluoride and 4-biphenylboronic acid was dried to form a film, thus obtaining the thin film phosphorescent material. In the solution, the mass ratio of 4-biphenylboronic acid to polyvinylidene fluoride is (0.005~3):

100.

7. The application according to claim 6, characterized in that, The polyvinylidene fluoride in the solution has a mass fraction of 5% to 15%.

8. The application according to claim 6, characterized in that, The preparation of the solution containing polyvinylidene fluoride and 4-biphenylboronic acid comprises: dissolving the polyvinylidene fluoride in a solvent to obtain a polyvinylidene fluoride solution; and then dissolving the 4-biphenylboronic acid in the polyvinylidene fluoride solution to obtain the solution containing polyvinylidene fluoride and 4-biphenylboronic acid.

9. The application according to claim 8, characterized in that, The solvent includes at least one of N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, triethyl phosphate, and N-methylpyrrolidone.

10. The application according to claim 6, characterized in that, The film-forming method includes any one of: dipping, coating, spraying, spin coating and drop coating; And / or, the drying includes: treating at 60~140°C for 4~10 h.

11. The application according to claim 6, characterized in that, The preparation method of the thin film phosphorescent material further includes: irradiating the thin film phosphorescent material with 240-300 nm ultraviolet light.

12. The application according to claim 11, characterized in that, The irradiation treatment time is ≥0.5 min.

13. The application according to claim 11, characterized in that, The irradiation treatment time is ≥5 min.

14. The application according to claim 1, characterized in that, The power of the electromagnetic wave is 100 to 1000 W.

15. The application according to claim 1, characterized in that, The detection method includes: placing the thin film phosphorescent material in a test environment or test system, and detecting the phosphorescence intensity, phosphorescence lifetime, and / or afterglow duration of the thin film phosphorescent material before and after being placed in the test environment or test system.

16. The application according to claim 15, characterized in that, The time spent in the test environment or test system is ≥60 s.

17. The application according to claim 15, characterized in that, The time spent in the test environment or test system is ≥120 s.

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