Organic long-afterglow material as well as preparation method and application thereof

Abstract

The invention discloses an organic long-afterglow material as well as a preparation method and application thereof, and the organic long-afterglow material comprises donor molecules, acceptor molecules and multiple resonance molecules, the multi-resonance molecule is N7, N7, N13, N13, 5, 9, 11, 1-octaphenyl-5H, 9H, 11H, 15H-[1, 4] benzaza-boron [2, 3, 4-kl] [1, 4] benzaza-boron [4 ', 3', 2 ': 4, 5] [1, 4] benzaza-boron [3, 2-b] dibenzaza-borane-7, 13-diamine. According to the organic long afterglow material, multiple resonance molecules serve as a light collector, the coulomb interaction force needing to be overcome by charge separation is reduced by means of visible light effective excitation and excited state intrinsic charge separation characteristics of the multiple resonance molecules, and the coulomb interaction force needs to be overcome by means of gradual charge transfer. Electrons and holes are respectively transmitted to acceptor molecules and donor molecules, so that effective light storage is realized, and finally, the organic long afterglow material presents green ultra-long afterglow luminescence under the excitation of visible light.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic afterglow luminescent materials, and in particular relates to an organic long afterglow material and a preparation method and application thereof. Background Art

[0002] Organic long-lasting glow materials, due to their flexible design, easy processing, and good biocompatibility, have shown great application value in optical recording, information encryption, and bioimaging. These materials typically consist of a binary system: a donor molecule and an acceptor molecule. By varying the molar ratio of the donor to the acceptor molecule, they achieve the slow release of photogenerated excitons.

[0003] The luminescence process of organic long afterglow materials includes the charge transfer state under illumination, the charge separation state of optical storage, and the afterglow luminescence produced by the slow recombination of charges. Among them, charge separation is the key step that determines the afterglow performance. This process needs to overcome the large Coulomb interaction force to decompose the photogenerated excitons into electrons and holes to achieve optical storage. Therefore, ultraviolet light excitation is often required to provide sufficient driving force for charge separation. In contrast, visible light-activated organic long afterglow materials can more effectively utilize common light sources for operation and can be used in practical applications such as emergency lighting and information encryption. To date, only a few organic long afterglow systems can work under visible light excitation, but they all have the problems of red shift of afterglow spectrum and short afterglow duration. Summary of the Invention

[0004] To address the shortcomings of the prior art, the present invention provides an organic long-afterglow material, its preparation method, and its application. By introducing multi-resonant molecules as light collectors into a binary organic long-afterglow system, the organic long-afterglow material exhibits green, long-lasting luminescence under visible light excitation, with the afterglow duration lasting up to four hours under visible light excitation. Furthermore, the present invention utilizes the effective visible light excitation of the multi-resonant molecules and the intrinsic charge separation properties of the excited state to effectively reduce the magnitude of the Coulomb interaction forces required for charge separation in the system. Furthermore, through stepwise charge transfer, electrons and holes are transferred to acceptor and donor molecules, respectively, achieving effective light storage, ultimately resulting in the organic long-afterglow material exhibiting green, ultra-long-lasting luminescence under visible light excitation.

[0005] The technical solutions of the present invention are as follows:

[0006] An organic long afterglow material comprising a donor molecule, an acceptor molecule and a multi-resonance molecule;

[0007] The multi-resonance molecule is N 7 ,N 7 ,N 13 ,N 13,5,9,11,1-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]dibenzazaborolane-7,13-diamine (v-DABNA).

[0008] According to an embodiment of the present invention, the molar ratio of the donor molecule to the acceptor molecule is 1-10:99, preferably 1-3:99, for example, the molar ratio of the donor molecule to the acceptor molecule is 1:99, 1.5:99, 2:99, 3:99, 4:99, 5:99, 6:99, 7:99, 8:99, 9:99, or 10:99.

[0009] According to an embodiment of the present invention, the molar ratio of the multiple resonance molecules to the total amount of the donor molecules and the acceptor molecules is 0.1-5:100, preferably (0.5-1.5):100, for example, the molar ratio of the multiple resonance molecules to the total amount of the donor molecules and the acceptor molecules is 0.5:100, 1:100, 1.5:100, 2:100 or 3:100.

[0010] According to an embodiment of the present invention, the donor molecule is 4,4',4"-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), and the structure of m-MTDATA is shown in Formula 1:

[0011]

[0012] According to an embodiment of the present invention, the receptor molecule is tris[2,4,6-trimethyl-3-(3-pyridyl)phenyl]borane (3TPYMB) or cyanuric acid.

[0013] For example, the structure of the Cyanuric acid is shown in Formula 2, and the structure of the 3TPYMB is shown in Formula 3.

[0014]

[0015]

[0016] According to an embodiment of the present invention, the structure of the v-DABNA is shown in Formula 4:

[0017]

[0018] According to an embodiment of the present invention, the organic long afterglow material has a homogeneous structure, and the donor molecules, the acceptor molecules and the multi-resonance molecules are evenly distributed in the organic long afterglow material.

[0019] According to an embodiment of the present invention, the organic long afterglow material is a light yellow film or light yellow powder.

[0020] According to an embodiment of the present invention, the effective absorption wavelength of the organic long afterglow material reaches 550 nm.

[0021] The present invention also provides a method for preparing the above-mentioned organic long afterglow material, which comprises:

[0022] (1a) mixing the acceptor molecule, the donor molecule and the multi-resonance molecule, heating and melting, and obtaining the organic long afterglow material;

[0023] Alternatively, when the receptor molecule is cyanuric acid, the preparation method of the organic long afterglow material is:

[0024] (1b) Urea, donor molecules and multi-resonance molecules are mixed and subjected to a hydrothermal reaction to prepare the organic long afterglow material.

[0025] According to an embodiment of the present invention, step (1a) or (1b) is performed under an inert atmosphere, for example, under a nitrogen atmosphere.

[0026] According to an embodiment of the present invention, in step (1b), the method is carried out in a solvent, and the solvent is at least one of water and an organic solvent, and the organic solvent is selected from at least one of tetrahydrofuran, acetonitrile, chlorobenzene, dichlorotoluene, etc. For example, the method is carried out in a mixed solvent of water and an organic solvent.

[0027] According to an embodiment of the present invention, in step (1b), the concentration of urea in the solvent is 300-800 mg / ml, preferably 400-600 mg / ml.

[0028] According to an embodiment of the present invention, in step (1b), the concentration of the donor molecule in the solvent is 1-10 mg / ml, preferably 1-6 mg / ml.

[0029] According to an embodiment of the present invention, in step (1b), the concentration of the multi-resonance molecule in the solvent is 1-10 mg / ml, preferably 1-6 mg / ml.

[0030] According to an embodiment of the present invention, in step (1b), the temperature of the hydrothermal reaction is 200-250°C, for example, 200°C, 210°C, 215°C, 220°C, 230°C, 240°C or 250°C, and the time of the hydrothermal reaction is 30-90 minutes, for example, 60 minutes.

[0031] According to an embodiment of the present invention, step (1b) further comprises post-treatment, such as drying and grinding the prepared product into powder.

[0032] According to an embodiment of the present invention, the organic long afterglow material prepared in step (1b) is in powder form.

[0033] According to an embodiment of the present invention, in step (1a), the melting and casting temperature is 200-260°C, and the melting and casting time is 5-60s; preferably, the melting and casting temperature is 225-240°C, and the melting and casting time is 20-25s.

[0034] According to an embodiment of the present invention, step (1a) further comprises post-treatment, wherein the prepared product is rapidly cooled, for example, by rapidly cooling on a steel plate.

[0035] Preferably, the organic long afterglow material in step (1a) is in the form of a film.

[0036] As an exemplary embodiment of the present invention, the method for preparing the organic long afterglow material specifically includes the following steps:

[0037] 1) Weigh the donor molecule, acceptor molecule and multi-resonance molecule powders respectively;

[0038] 2) Transfer the weighed powder mixture into a glove box and grind it to mix thoroughly;

[0039] 3) Spread the mixed powder obtained in step 2) on a 10*10*0.5mm 3 in a quartz tank;

[0040] 4) Place the quartz tank on a preheated hot plate to rapidly melt the powder using heat conduction;

[0041] 5) placing the sample after the casting process on a steel plate surface and allowing it to cool rapidly to obtain an organic long afterglow material, i.e., an organic long afterglow film;

[0042] 6) Encapsulating the afterglow film obtained in step 5).

[0043] Preferably, in step 2), the grinding process is carried out in an agate mortar to improve the powder mixing degree and reduce the powder loss caused by the roughness of the mortar. The grinding time is 1 to 10 minutes, preferably 5 minutes.

[0044] Preferably, in step 2), the size of the quartz substrate is 20*20*3mm 3 .

[0045] Preferably, in step 5), the temperature of the steel plate is 10-20°C.

[0046] Preferably, in step 6), the packaging method is to cover 20*20mm 2The quartz cover glass is pressed to expel the gas in the groove and then sealed with UV-curing adhesive.

[0047] As an exemplary embodiment of the present invention, the method for preparing the organic long afterglow material comprises the following steps:

[0048] S1) mixing a urea solution, a donor molecule solution, and a multi-resonance molecule solution to obtain a mixed solution;

[0049] S2) subjecting the mixed solution obtained in step S1) to a hydrothermal reaction;

[0050] S3) drying the solid obtained in step S2) in a vacuum oven;

[0051] S4) Grinding the solid obtained in step S3) into powder in a mortar.

[0052] According to an embodiment of the present invention, in step S1), preferably, the urea solution is a urea aqueous solution, and the concentration of the urea solution is 500 mg / ml. Preferably, the urea solution can be ultrasonicated for 20 minutes to ensure complete dissolution.

[0053] Preferably, in step S1), the donor molecule solution is an organic solvent of the donor molecule, such as tetrahydrofuran, and the concentration of the donor molecule solution is 1 mg / ml. Preferably, the donor molecule solution can be sonicated for 20 minutes.

[0054] Preferably, in step S1), the multiple resonance molecular solution is an organic solvent for multiple resonance molecules; the organic solvent is, for example, acetonitrile, and the concentration of the multiple resonance molecular solution is 1 mg / ml. Preferably, the multiple resonance molecular solution can be sonicated for 20 minutes.

[0055] Preferably, in step S3), the vacuum oven temperature is 40-80° C., such as 60° C.; and the drying time is 8-12 hours, such as 11 hours.

[0056] The present invention also provides applications of the organic long afterglow material in the fields of optical recording materials, information encryption materials, lighting materials, etc.

[0057] Beneficial effects of the present invention:

[0058] The organic long afterglow material of the present invention introduces multiple resonance molecules as light collectors, so that the organic long afterglow material exhibits green ultra-long afterglow luminescence under visible light excitation; specifically, it has the following advantages:

[0059] 1. In the organic long afterglow material of the present invention, by using multiple resonant molecules as light collectors and utilizing the effective visible light excitation of the multiple resonant molecules and the intrinsic charge separation characteristics of the excited state, the magnitude of the Coulomb interaction force required to overcome charge separation is reduced, and electrons and holes are transferred to the acceptor molecules and donor molecules respectively through stepwise charge transfer, thereby achieving effective light storage, and ultimately causing the organic long afterglow material to exhibit green ultra-long afterglow luminescence under visible light excitation. . The present invention successfully broadens the effective excitation wavelength of the organic long afterglow material from the ultraviolet band to the visible band, achieving the purpose of multiple resonant molecular light collection and donor and acceptor molecular light storage, and provides a new development idea for the realization of organic long afterglow materials excited by visible light;

[0060] 2. The donor molecules, acceptor molecules, and multi-resonance molecules provided by the present invention are all soluble in solvents and have excellent solution processability. Large-scale preparation of organic long-lasting glow materials can be achieved through spin coating. For example, patterned construction can be achieved through screen printing. For organic afterglow patterns with high precision requirements, large-scale preparation and processing can be achieved through ternary co-evaporation of the three molecules.

[0061] 3. The organic long-afterglow material of the present invention can be used as an emergency lighting material. After being excited by visible light, it can maintain visible luminescence for several hours without the need for external energy storage devices. For example, the organic long-afterglow material can be used as an emergency exit in a fire. Due to its excellent thermoluminescent properties, even after the luminescence is invisible in a dark environment after four hours, it can still accelerate the recombination of residual charges under thermal stimulation, and then emit emergency luminescence for channel identification.

[0062] 4. The organic long-afterglow material of the present invention can be used as an encrypted information carrier. Since the duration of the afterglow of the organic long-afterglow material is controllable, it can realize diverse information carrying under the same material system. In addition, the organic long-afterglow material has the ability to identify wavelengths. Therefore, the encrypted information material using this material can use the excitation light source and the reading time as keys. Only under the correct light source and reading time can the true information be obtained. Incorrect conditions will obscure the information. The present invention can achieve multiple throws of the encryption key by adjusting the ratio and materials, increasing the difficulty of cracking and improving the security of the information.

[0063] 5. The introduction of multiple resonance molecules in the organic long afterglow material of the present invention deepens the defect state in the system, reduces the charge recombination rate, and further increases the duration of the afterglow. By adding multiple resonance molecules at different contents, the afterglow duration of the organic long afterglow material can be increased by 10 times compared with the binary organic long afterglow film (i.e., a binary system of donor molecules and acceptor molecules) under the same excitation light source and the same excitation time. After visible light excitation, the afterglow duration can be as long as 4 hours.

[0064] 6. In the hydrothermal preparation of the organic long-afterglow material, cyanuric acid, obtained by hydrothermal condensation of urea, is used as the acceptor molecule in the organic long-afterglow material. Since the acceptor molecule is the main material in the organic long-afterglow material (molar proportion >99%), the use of low-cost urea raw material greatly reduces the manufacturing cost of the organic long-afterglow material. At the same time, the organic long-afterglow material can also be excited by visible light.

[0065] 7. In the present invention, whether or not the multi-resonance molecules are introduced has almost no effect on the afterglow luminescence peak position and peak broadening of the organic long afterglow material. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] Figure 1 This is a diagram of the melt-casting preparation process of the organic long afterglow material described in Example 1.

[0067] Figure 2 The multi-resonance molecules in Example 1, the organic long afterglow film in Example 1 (ie Figure 1 UV-visible absorption diagram of the ternary system in (Comparative Example 1) and the binary system film in Comparative Example 1.

[0068] Figure 3 These are fluorescence spectra of the afterglow film of Comparative Example 3, the afterglow film of Comparative Example 4, the multi-resonance molecule, the donor molecule m-MTDATA, and the acceptor molecule 3TPYMB.

[0069] Figure 4 1 and 2 are fluorescence lifetime diagrams of the thin film in comparative example 1, the thin film in comparative example 3, and the multi-resonance molecule.

[0070] Figure 5 This is a time-resolved spectrum of the afterglow process of the organic long afterglow material in Example 1 and Comparative Example 1; wherein,

[0071] a is the time-resolved spectrum of the organic long afterglow material in Example 1.

[0072] b is the time-resolved spectrum of the organic long afterglow material in Comparative Example 1.

[0073] Figure 6 In FIG. 1 , a is a graph showing the afterglow duration of the organic long afterglow material in Example 1 and Comparative Example 1 as the wavelength changes.

[0074] b is a graph showing the variation of the afterglow duration of the organic long afterglow materials in Examples 1, 8-10 and Comparative Example 1 with the doping concentration of the multi-resonance molecules at different excitation wavelengths.

[0075] Figure 7 This is a graph showing the afterglow performance of the organic long afterglow material in Example 1 and the afterglow material in the prior art.

[0076] Figure 8 This is a comparison chart of the afterglow duration of the organic long afterglow powder prepared in Example 2 and Comparative Example 2.

[0077] Figure 9 In the figure, a is a display diagram of the afterglow duration of the organic long afterglow film in Example 1 and Comparative Example 1; b is a display diagram of the organic long afterglow material in Example 1 and Comparative Example 1 in information encryption applications; c is a display diagram of the organic long afterglow material in Example 1 in emergency exit applications.

[0078] Figure 10 This is a comparative diagram showing the afterglow duration of the organic long afterglow material (ternary system) of Example 1 and the binary system of Comparative Example 1 under visible light excitation. DETAILED DESCRIPTION

[0079] The technical solutions of the present invention will be described in further detail below with reference to specific embodiments. It should be understood that the following embodiments are merely illustrative and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are encompassed within the scope of protection that the present invention is intended to protect.

[0080] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0081] Example 1 Preparation of organic long afterglow film

[0082] Weigh 1 mg of the donor molecule 4,4',4"-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA), 76 mg of the acceptor molecule tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane (3TPYMB), 0.7 mg of the multi-resonance molecule N 7 ,N 7 ,N 13 ,N 13 ,5,9,11,1-octaphenyl-5H,9H,11H,15H-[1,4]benzazaborino[2,3,4-kl][1,4]benzazaborino[4',3',2':4,5][1,4]benzazaborino[3,2-b]dibenzoazaborane-7,13-diamine (v-DABNA), prepare a mixed powder with a molar ratio of 1.5:99:0.5. Transfer the weighed powder mixture to the glove box and grind it in an agate mortar for five minutes. After fully mixing, spread the powder on a 10*10*0.5mm 3The sample was placed in a quartz tank and preheated on a constant temperature hot plate set to 230°C. The quartz tank was then placed on a preheated hot plate, where heat conduction was used to rapidly melt the powder for 20 seconds. The melted sample was then placed on a steel plate at 10°C for rapid cooling, yielding a translucent, pale yellow, long-lasting film. This organic long-lasting material, known as a ternary system, was then covered with a quartz cover glass, which was then pressed to expel the gas from the tank and sealed with UV-curable adhesive.

[0083] Comparative Example 1

[0084] Weigh 1 mg of the donor molecule 4,4',4"-tris(N-3-methylphenyl-N-phenylamino)triphenylamine (m-MTDATA) and 76 mg of the acceptor molecule tris(2,4,6-trimethyl-3-(pyridin-3-yl)phenyl)borane (3TPYMB) to prepare a mixed powder with an appropriate molar ratio. The weighed powder mixture was transferred to a glove box and ground in an agate mortar for five minutes. After thorough mixing, the powder was spread evenly on a 10*10*0.5mm 3 The sample was placed in a quartz tank and preheated on a constant temperature hot plate set to 230°C. The quartz tank was then placed on the preheated hot plate, where heat conduction was used to rapidly melt the powder for 20 seconds. The melted sample was then placed on a steel plate at 10°C for rapid cooling, resulting in a transparent afterglow film, representing the binary system. The sample was then covered with a quartz cover glass, which was then pressed to expel the gas from the tank and sealed with UV-curable adhesive.

[0085] Example 2 Preparation of organic long afterglow powder

[0086] 5 mg of the donor molecule (m-MTDATA), 10 g of urea, and 5 mg of the multi-resonance molecule (v-DABNA) were fully dissolved in 5 ml of tetrahydrofuran, 20 ml of water, and 5 ml of acetonitrile, respectively. The solution was sonicated for 20 minutes to obtain a clear solution. The solutions were then mixed to prepare a mixture with a molar ratio of 1.5:99:0.5. The resulting mixture was hydrothermally reacted in a preheated oven at 215°C for one hour, causing the urea to deaminize and condense into cyanuric acid, which then mixed uniformly with the remaining molecules in the liquid phase. The resulting solid was dried in a vacuum oven at 60°C for 11 hours to ensure complete evaporation of the solvent. After drying, the solid was ground to yield a pale yellow powder with afterglow properties, representing an organic long-afterglow material, a ternary system.

[0087] Comparative Example 2

[0088] Dissolve 10g of urea molecules and 5mg of donor molecules (m-MTDATA) in 20ml of water and 5ml of tetrahydrofuran, respectively, and ultrasonicate for 20 minutes to obtain a clear solution. Mix the solutions to prepare a mixture with a suitable molar ratio. The resulting mixture is hydrothermally reacted in a preheated 215°C oven for 1 hour to deaminize and condense the urea into cyanuric acid and uniformly mix with the donor molecules in the liquid phase. The resulting solid is placed in a 60°C vacuum oven and dried for 11 hours to ensure complete volatilization of the solvent. After drying, the solid is ground to obtain a white powder, i.e., a binary system, i.e. Figure 4 donor / acceptor in .

[0089] Comparative Example 3

[0090] The difference between Comparative Example 3 and Example 1 is that no donor molecule is used, and a long afterglow material is obtained.

[0091] The specific afterglow material preparation process is as follows: 1 mg of the multi-resonance molecule (v-DABNA) and 76 mg of the receptor molecule (3TPYMB) are weighed separately to prepare a mixed powder with an appropriate molar ratio. The weighed powder mixture is transferred to a glove box and ground in an agate mortar for five minutes. After thorough mixing, the powder is spread evenly on a 10*10*0.5mm 3 The quartz tank is placed on a hot plate with a constant temperature of 230°C for preheating. The quartz tank is placed on a hot plate after preheating, and the powder is rapidly melted by heat conduction. The melting process lasts for 20 seconds. The melted sample is placed on a steel plate at 10°C for rapid cooling to obtain a transparent afterglow film. Figure 3 The sample is covered with a quartz cover glass, which is then pressed to expel the gas from the tank and sealed with UV-curable adhesive.

[0092] Comparative Example 4

[0093] The difference between Comparative Example 4 and Example 1 is that no acceptor molecule is used, and a long afterglow material is obtained.

[0094] The specific afterglow material preparation process is as follows: 1 mg of the multi-resonance molecule (v-DABNA) and 71 mg of the donor molecule (m-MTDATA) are weighed separately to prepare a mixed powder with an appropriate molar ratio. The weighed powder mixture is transferred to a glove box and ground in an agate mortar for five minutes. After thorough mixing, the powder is spread evenly on a 10*10*0.5mm 3 The quartz tank is placed on a hot plate with a constant temperature of 230°C for preheating. The quartz tank is placed on a hot plate after preheating, and the powder is rapidly melted by heat conduction. The melting process lasts for 20 seconds. The melted sample is placed on a steel plate at 10°C for rapid cooling to obtain a transparent afterglow film. Figure 3The sample is covered with a quartz cover glass, which is then pressed to expel the gas from the tank and then sealed with UV-curable adhesive.

[0095] Example 3 Characterization of the Fluorescence Optical Properties of Organic Long Afterglow Films

[0096] The multi-resonance molecules in Example 1 and the organic long afterglow film in Example 1 (i.e. Figure 2 The ternary system in Example 1) and the binary system film in Comparative Example 1 (ie Figure 2 The optical properties of the binary system in the test are characterized, and the test results are as follows Figure 2 ,Depend on Figure 2 It can be seen that compared with the binary system film (i.e., the organic long afterglow film of Comparative Example 1), the absorption spectrum of the ternary system film (i.e., the organic long afterglow film of Example 1) after the introduction of the multiple resonance molecules has an absorption peak value near 447nm that is significantly increased, and the absorption curve has a tailing until near 550nm, while the binary system film and the multiple resonance molecules themselves have no obvious absorption in this band, indicating that the change in the absorption spectrum is not caused by the simple superposition of the absorption spectra of the binary system film and the multiple resonance molecules, and there is an interaction between the multiple resonance molecules and the donor molecules and the acceptor molecules.

[0097] The afterglow film of Comparative Example 3 (ie Figure 3 Acceptor / multiple resonance molecules), afterglow film of comparative example 4 (ie Figure 3 The fluorescence spectra of the donor / multiple resonance molecule), the multiple resonance molecule, the donor molecule m-MTDATA and the acceptor molecule 3TPYMB were studied and characterized using a fluorescence spectrometer Spectrascan PR650. Figure 3 It can be seen that the mixture of receptor molecules and multi-resonance molecules (i.e. Figure 3 The luminescence peak of the acceptor / multiple resonance molecule is centered at the luminescence peak of the multiple resonance molecule, showing a broadening of the peak, which further proves that an excimer complex can be formed between the acceptor molecule and the multiple resonance molecule, and charge transfer occurs under light excitation. Figure 3 The same phenomenon is also seen with the donor / multiple resonance molecules in the present invention. It can be seen that the present invention provides a possibility for stepwise charge transfer between the multiple resonance molecules and the donor and acceptor molecules.

[0098] Figure 4 For the film in Comparative Example 1 (i.e. Figure 4 donor / acceptor), the film in Comparative Example 3 (i.e. Figure 4 The fluorescence lifetime diagram of the receptor / multiple resonance molecule) and the multiple resonance molecule, such as Figure 4As shown, the extension of fluorescence lifetime brought by the multi-resonance molecule further proves the existence of interaction between the multi-resonance molecule and the receptor molecule.

[0099] Example 4 Characterization of the Afterglow Optical Properties of Organic Long Afterglow Films

[0100] The time-resolved spectra of the afterglow process of the organic long afterglow materials in Example 1 and Comparative Example 1 were characterized using an FLS1000 steady-state transient fluorescence spectrometer. Figure 5 It can be seen that after visible light excitation, the luminescence of the ternary system (ie, Example 1) is first dominated by the luminescence peak of the multiple resonance molecules at 490nm, and gradually moves to the afterglow luminescence peak between the donor and the acceptor at 550nm over time, and finally becomes luminescence at the same position as the afterglow luminescence peak of the binary system. At the same time, compared with the binary system at the same collection time, the luminescence intensity of the ternary system is significantly stronger than that of the binary system. This phenomenon further proves the existence of a charge transfer process from multiple resonance molecules to donor and acceptor molecules in the organic long afterglow material, indicating that the multiple resonance molecules can effectively act as a light collector to transfer the collected excitons in the form of electron holes to the donor and acceptor molecules as the main material.

[0101] Example 5 Characterization of the Afterglow Duration of Organic Long Afterglow Films

[0102] The optical signal emitted by the long afterglow film of Example 1 or Comparative Example 1 was converted into an electrical signal using a photomultiplier (Thorlab PDA200C), and then collected using a Keithley 2400. The afterglow performance of the organic long afterglow film of Example 1 or Comparative Example 1 was characterized at an ambient temperature of 40°C. The excitation wavelengths used were 375nm, 405nm, 447nm, 488nm, or 532nm. The test results are shown in FIG. Figure 6 As shown in a. Figure 6 It can be seen that the ternary system has almost no effect on the afterglow duration in the ultraviolet band; the afterglow duration of the film is slightly improved under 405nm excitation in the near-ultraviolet band; at 447nm corresponding to the main blue range of white light LEDs, the afterglow duration is 10 times longer than that of the binary system; the afterglow duration is still 10 times longer when excited at 488nm; for 532nm excitation light close to its emission wavelength, due to the existence of tail absorption, the ternary component (ie, Example 1) still exhibits an organic long afterglow of nearly 100s, while the binary system (ie, Comparative Example 1) cannot be excited in this band.

[0103] Figure 7 The afterglow performance diagram of the organic long afterglow material in Example 1 and the afterglow material in the prior art is shown in FIG. Figure 7 It can be seen that the long afterglow material of the present invention can emit organic long afterglow light for up to 4 hours under visible light.

[0104] Example 8

[0105] The difference between Example 8 and Example 1 is that the content of the multiple resonance molecule is 1.4 mg, so that the molar amount of the multiple resonance molecule is 1 mol% of the total molar amount of the acceptor molecule and the donor molecule.

[0106] Example 9

[0107] The difference between Example 9 and Example 1 is that the content of the multiple resonance molecule is 2.1 mg, so that the molar amount of the multiple resonance molecule is 1.5 mol% of the total molar amount of the acceptor molecule and the donor molecule.

[0108] Example 10

[0109] The difference between Example 10 and Example 1 is that the content of the multiple resonance molecule is 2.8 mg, so that the molar amount of the multiple resonance molecule is 2 mol% of the total molar amount of the acceptor molecule and the donor molecule.

[0110] The afterglow duration of organic long afterglow materials prepared by doping with multiple resonance molecules at different contents was studied, wherein the doping ratios of the multiple resonance molecules were 0 (i.e., Comparative Example 1), 0.5 mol% (i.e., Example 1), 1 mol% (i.e., Example 8), 1.5 mol% (i.e., Example 9), and 2 mol% (i.e., Example 10), and the excitation wavelengths were 375 nm, 405 nm, 447 nm, 488 nm, or 532 nm, respectively. The test results are shown in FIG. Figure 6 As shown in b, Figure 6 As shown in Figure b, the afterglow duration of the long-afterglow material within the visible light range first increases and then decreases with the doping concentration of the multi-resonance molecules, indicating that the collection of visible light by the multi-resonance molecules indeed plays a positive role in achieving long-lasting visible-light organic afterglow. At high doping concentrations, an excess of multi-resonance molecules increases the rate of charge recombination within the system, resulting in a reduction in afterglow duration. Therefore, the materials of the present invention can achieve diverse information carrying capabilities within the same material system.

[0111] Example 6 Characterization of Afterglow Performance of Organic Long Afterglow Powder

[0112] The light signals emitted by the organic long afterglow powders prepared in Example 2 and Comparative Example 2 were converted into electrical signals using a photomultiplier (Thorlab PDA200C) and then collected using a Keithley 2400. The afterglow properties of the organic long afterglow powders in Example 2 and Comparative Example 2 were characterized. The test results are shown in FIG. Figure 8 As shown by Figure 8It can be seen that the afterglow duration of the organic long afterglow powder (ie, Example 2) after the introduction of the multi-resonance molecules under 447nm excitation is increased by 10 times compared with that of Comparative Example 2, showing an organic long afterglow luminescence of more than 100s.

[0113] Example 7: Application of organic long afterglow materials in information encryption and emergency exits

[0114] Figure 9 a is a graph showing the afterglow duration of the organic long afterglow film in Example 1 and Comparative Example 1. Figure 9 It can be seen from a that the afterglow duration of the film is significantly increased after the introduction of multi-resonance molecules, from only 1200s in the binary system to 12000s in the ternary system.

[0115] The afterglow materials of Example 1 and Comparative Example 1 were encoded. The "ICCAS" portion of the groove "88888" was filled with the ternary system of Example 1. The difference between "76089" and "ICCAS" was filled with the binary system of Comparative Example 1. The remaining portion of "88888" was filled with a mixture that does not have afterglow properties, such as a molar ratio of donor molecules, acceptor molecules, and multi-resonance molecules of 1:3:0.5 or 1:1:0.5. A diagram showing the application of organic long afterglow materials in information encryption was obtained, as shown in FIG. Figure 9 The encrypted information shown in b shows the surface information "88888" under both ultraviolet and visible light. When using an incorrect UV excitation light source, only the masked information "76089" is obtained, and this masked information remains unchanged over time. When the correct light source is used for excitation, the information still displays the masked information "76089" at the incorrect read time. When the read time is also correct, such as after 0.5 hours, the true information "ICCAS" is obtained. This shows that the encrypted information using the organic long-afterglow material of the present invention can use both the excitation light source and the read time as keys. Only under the correct light source and read time can the true information be obtained; incorrect conditions display the masked information.

[0116] Figure 9c is a display diagram of the organic long afterglow material in Example 1 in emergency exit applications. The specific test process in the figure is: the film in Example 1 is excited under visible light, and after the light source is powered off, the film is subjected to afterglow illumination for up to 4 hours, until the afterglow is invisible to the naked eye. At this time, the charge recombination luminescence in the film is still ongoing, but due to the continuous consumption of charge separation states in the afterglow process, the number of charge recombination per unit time is reduced, and the luminescence intensity is lower than the visible range of the human eye. At this time, the afterglow film is placed on a hot plate at 50°C for heating, which promotes the escape of charges in the film defects and causes the remaining charge separation states in the film to recombine rapidly, which greatly increases the number of charge recombination per unit time. It shows that as the ambient temperature rises, the film re-luminesces. By Figure 9 c It can be seen that this organic long afterglow material can be used as emergency lighting, such as fire emergency exit lighting. Due to the excellent thermoluminescent properties of the material, after being excited by visible light, no external energy storage equipment is required. Even after the afterglow is invisible in a dark environment for 4 hours, it can still accelerate the recombination of residual charges under thermal stimulation and perform emergency luminescence for channel identification.

[0117] The above is an exemplary description of the embodiments of the present invention. However, the scope of protection of the present invention is not limited to the above embodiments. Any modifications, equivalent substitutions, improvements, etc. made by those skilled in the art within the spirit and principles of the present invention shall be included in the scope of protection of the present invention.

Claims

1. An organic long afterglow material, characterized in that: It includes donor molecules, acceptor molecules and multi-resonance molecules; The multi-resonance molecule is N 7 ,N 7 ,N 13 ,N 13 ,5,9,11,1-Octaphenyl-5H,9H,11H,15H-[1,4]benzazaboro[2,3,4-kl][1,4]benzazaboro[4',3',2':4,5][1,4]benzazaboro[3,2-b]dibenzazaborolane-7,13-diamine.

2. The organic long afterglow material according to claim 1, characterized in that The molar ratio of the donor molecule to the acceptor molecule is 1-10:99; Preferably, the molar ratio of the multi-resonance molecules to the total amount of the donor molecules and the acceptor molecules is 0.1-5:

100.

3. The organic long afterglow material according to claim 1 or 2, characterized in that: The organic long afterglow material has a homogeneous structure, and the donor molecules, the acceptor molecules and the multi-resonance molecules are evenly distributed in the organic long afterglow material.

4. The organic long afterglow material according to claim 1 or 2, characterized in that: The organic long afterglow material is a light yellow film or light yellow powder. Preferably, the effective absorption wavelength of the organic long afterglow material reaches 550 nm.

5. The method for preparing the organic long afterglow material according to any one of claims 1 to 4, characterized in that: The method is: (1a) mixing the acceptor molecule, the donor molecule and the multi-resonance molecule, heating and melting, and obtaining the organic long afterglow material; Alternatively, when the receptor molecule is cyanuric acid, the preparation method of the organic long afterglow material is: (1b) Urea, donor molecules and multi-resonance molecules are mixed and subjected to a hydrothermal reaction to prepare the organic long afterglow material.

6. The method according to claim 5, characterized in that In step (1b), the method is carried out in a solvent, the solvent is a mixture of water and an organic solvent, and the organic solvent is selected from at least one of tetrahydrofuran, acetonitrile, chlorobenzene, and dichlorotoluene. For example, the method is carried out in a mixed solvent of water and a solvent.

7. The method according to claim 5 or 6, characterized in that In step (1b), the concentration of urea in the solvent is 300-800 mg / ml; Preferably, in step (1b), the concentration of the donor molecule in the solvent is 1-10 mg / ml; Preferably, in step (1b), the concentration of the multi-resonance molecule in the solvent is 1-10 mg / ml.

8. The method according to any one of claims 5 to 7, characterized in that: In step (1b), the temperature of the hydrothermal reaction is 200-250° C., and the time of the hydrothermal reaction is 30-90 minutes.

9. The method according to any one of claims 5 to 8, characterized in that: In step (1a), the melting and casting temperature is 200-260° C., and the melting and casting time is 5-60 seconds.

10. Use of the organic long afterglow material according to any one of claims 1 to 4 in the fields of optical recording materials, information encryption materials or lighting materials.

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