High-temperature phosphorescent materials, their preparation methods and applications

Abstract

This invention provides a high-temperature resistant phosphorescent material, its preparation method, and its application. The phosphorescent material consists of a dopant and a luminescent guest. The dopant has a chemical structure represented by general formula (I): M₂B₄O₇·nH₂O (I), where M is selected from sodium or potassium, and n is greater than or equal to 0. The luminescent guest is selected from at least one of aromatic carboxylic acids with conjugated structures, potassium aromatic carboxylate, or sodium aromatic carboxylate. The high-temperature resistant phosphorescent material exhibits phosphorescence emission characteristics in a temperature range of -80°C to 300°C. This invention solves the problem that existing organic phosphorescent materials cannot maintain long-lifetime luminescence at extreme high temperatures, such as 200–300°C.

Description

Technical Field

[0001] This invention relates to the field of phosphorescent materials technology, specifically to a high-temperature resistant phosphorescent material, its preparation method, and its application. Background Technology

[0002] Phosphorescent materials, due to their long-lasting luminescence characteristics, i.e., afterglow, play an irreplaceable role in fields such as security indication, anti-counterfeiting, information encryption, and optoelectronic devices. Traditional long-afterglow materials mainly rely on rare earth metals, such as strontium aluminate doped with europium and dysprosium. Although they have good weather resistance, they suffer from problems such as resource scarcity, high cost, complex preparation processes requiring high-temperature sintering at thousands of degrees Celsius, and potential heavy metal toxicity.

[0003] In recent years, pure organic room-temperature phosphorescent (RTP) materials have attracted much attention due to their easy structural modification, low cost, and good flexibility. However, organic RTP materials face a fatal common problem: extremely poor thermal stability and severe temperature quenching effect. Phosphorescence originates from the radiative transition of the excited triplet state of molecules, and triplet excitons are extremely sensitive to thermal perturbations.

[0004] In existing technologies, the following strategies are commonly used to construct organic RTP materials: 1. Crystal engineering, relying on close packing between molecules to restrict movement. However, high temperatures (e.g., >80℃) can cause lattice expansion or melting, leading to rapid quenching of luminescence; 2. Polymer doping: doping phosphorescent molecules into polymer matrices such as PMMA and PVA. However, the glass transition temperature (Tg) of polymer matrices is usually low (around 100℃ or lower). Once the ambient temperature approaches or exceeds Tg, polymer chain segment movement intensifies, the confinement effect on guest molecules fails, leading to the opening of nonradiative transition channels and the disappearance of phosphorescence.

[0005] Although there have been recent reports on the heat resistance of "thermally activated delayed fluorescence (TADF)," it is essentially fluorescence (with a lifetime typically in the microsecond range) and lacks the long afterglow characteristic (milliseconds to seconds) unique to phosphorescence. Currently, there are no reports of pure organic / organic-inorganic hybrid phosphorescent materials maintaining a visible long-lifetime afterglow at extreme high temperatures (such as 200°C or even 300°C). Summary of the Invention

[0006] This invention provides a high-temperature resistant phosphorescent material, its preparation method, and its application, to solve the problem that existing organic phosphorescent materials cannot maintain long-lifetime luminescence at extreme high temperatures such as 200–300°C.

[0007] To achieve the above objectives, the present invention provides the following technical solution: A high-temperature resistant phosphorescent material, wherein the phosphorescent material is composed of a dopant and a luminescent guest; The doped host has the chemical structure shown in general formula (I): M2B4O7·nH2O(I) Where M is selected from sodium or potassium, and n is greater than or equal to 0; The luminescent guest is selected from at least one of aromatic carboxylic acids, potassium aromatic carboxylate, or sodium aromatic carboxylate having a conjugated structure; The high-temperature resistant phosphorescent material exhibits phosphorescence emission characteristics within a temperature range of -80℃ to 300℃.

[0008] To achieve the above-mentioned solution, the present invention also provides the following technical solution: A method for preparing the above-mentioned high-temperature resistant phosphorescent material, the method comprising the following steps: (1) Purification: The luminescent guest and / or doped host are purified by recrystallization; (2) Mixing and dispersing: The purified dopant and luminescent guest are placed in a solvent medium and ultrasonically dispersed to form a mixture; (3) Heating and curing: Heating the mixture to cure it; (4) Drying: Drying removes residual solvent to obtain the high-temperature resistant phosphorescent material.

[0009] To achieve the above-mentioned solution, the present invention also provides the following technical solution: An application of the above-mentioned high-temperature resistant phosphorescent material or the high-temperature resistant phosphorescent material obtained by the above-mentioned preparation method, the application including high-temperature safety indicator, optoelectronic device, display material, information storage material or anti-counterfeiting material.

[0010] Compared with the prior art, the present invention has achieved the following beneficial effects: 1. Traditional RTP materials rely on triplet excitons, which are extremely sensitive to heat. As the temperature rises, nonradiative transitions (thermal vibrations) are rapidly enhanced, leading to rapid quenching of phosphorescence. In contrast, this invention utilizes a rigid inorganic ionic layer formed by the dehydration of tetraborate to achieve an extremely stringent confinement effect on organic aromatic acid guest molecules. This rigid confinement can suppress the thermal vibration of guest molecules even at a high temperature of 300℃, thereby "locking" triplet excitons and achieving high-temperature resistant and long-lifetime luminescence. 2. This invention achieves visible phosphorescence even at 300℃, with a lifespan >10ms, observable afterglow, and stability for at least 2 months. 3. This invention achieves an extremely wide temperature response range of -196℃ to 350℃. For details, please refer to the specific implementation details regarding the data supporting -196℃. Furthermore, the G25-H1 still exhibits afterglow at 350℃, as shown in Figure 13 of the specification with its 77K delayed emission, and the accompanying appendix... Figure 10The 623 K afterglow on the far right proves that the phosphorescent material provided by this invention is not only resistant to high temperatures, but can also work normally over an ultra-wide range from low temperature (-80℃) to high temperature (300℃). 4. This invention achieves an economical and environmentally friendly preparation process, avoiding the use of expensive rare earth metals or complex organic synthetic matrices. It can be prepared simply by aqueous phase mixing and heating dehydration, with extremely low cost, which is conducive to large-scale industrialization. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 These are afterglow images of the high-temperature resistant phosphorescent material G2-H1 obtained in Example 1 of this invention at different temperatures; Figure 2(a) shows the delayed emission spectra of the high-temperature resistant phosphorescent material G2-H1 obtained in Example 2 of the present invention at different temperatures; Figure 2(b) shows the phosphorescence lifetime decay curves of the high-temperature resistant phosphorescent material G2-H1 obtained in Example 2 of the present invention at different temperatures; Figure 3 Phosphorescence photographs of the high-temperature resistant phosphorescent materials G2-H1, G8-H1, G25-H1, and G19-H1 obtained in Examples 1-4 of this invention at different temperatures; Figure 4 The delayed emission spectra of the high-temperature resistant phosphorescent materials G2-H1, G8-H1, G25-H1, and G19-H1 obtained in Examples 1-4 of this invention at 200°C; Figure 5(a) shows the phosphorescence lifetime decay curves of the high-temperature resistant phosphorescent material G25-H1 obtained in Example 2 of the present invention at different temperatures; Figure 5(b) shows the phosphorescence lifetime decay curves of the high-temperature resistant phosphorescent material G8-H1 obtained in Example 3 of the present invention at different temperatures; Figure 5(c) shows the phosphorescence lifetime decay curves of the high-temperature resistant phosphorescent material G19-H1 obtained in Example 4 of the present invention at different temperatures; Figure 6 These are afterglow images of the high-temperature resistant phosphorescent material G25-H1 obtained in Example 3 of the present invention at different temperatures; Figure 7 The delayed emission spectra of the high-temperature resistant phosphorescent material G25-H1 obtained in Example 3 of this invention at 300°C for different storage times are shown. Figure 8Delayed emission photographs of the high-temperature resistant phosphorescent material G25-H1 obtained in Example 3 of this invention, stored at 300°C for different times; Figure 9 This refers to the high-temperature safety indicator in Embodiment 7 of the present invention; Figure 10 This is for storing high-temperature information in Embodiment 8 of the present invention; Figure 11(a) shows the delayed emission spectrum of the main matrix H1 (n=0) of the present invention, where the maximum value of the intensity ordinate is 800; Figure 11(b) shows the delayed emission spectrum of the main matrix H1 (n=0) in Figure 11(a), where the maximum value of the intensity ordinate is 50; Figure 12(a) shows the temperature-delayed emission with G2 (R=COOK) as the main matrix of polyvinyl alcohol. When the matrix is ​​polyvinyl alcohol, there is no high temperature resistance. Figure 12(b) shows the phosphorescence decay curve of polyvinyl alcohol as the main matrix of G2 (R=COOK). When the matrix is ​​polyvinyl alcohol, there is no high temperature resistance. Figure 13(a) shows the delayed emission spectrum of G2-H1 at -196℃; Figure 13(b) shows the phosphorescence decay curve of G2-H1 at -196℃; Figure 14(a) shows the delayed emission spectra of G2-H1 at different doping concentrations; Figure 14(b) shows the phosphorescence decay curves of G2-H1 at different doping concentrations. Detailed Implementation

[0013] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. It should be understood that the specific embodiments described herein are only for illustration and explanation of the present invention and are not intended to limit the present invention.

[0014] Any specific numerical value (including the endpoints of the numerical range) disclosed in this invention is not limited to the exact value, but should be understood to also cover values ​​close to the exact value, such as all possible values ​​within ±5% of the exact value. Furthermore, for the disclosed numerical range, one or more new numerical ranges can be obtained by arbitrarily combining the endpoint values ​​of the range, the endpoint values ​​with specific point values ​​within the range, and the specific point values. These new numerical ranges should also be considered as specifically disclosed in this invention.

[0015] The terminology used in this invention is for the purpose of describing specific exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” as used herein are intended to include the plural forms as well. The terms “comprising,” “including,” “containing,” and “having” are inclusive and thus describe the presence of said features, elements, compositions, steps, integers, operations, and / or components, but do not exclude the presence or inclusion of one or more other features, integers, steps, operations, elements, components, and / or sets thereof. Although the open-ended term “comprising” should be understood as a non-limiting term used to describe and claim the various embodiments described in this invention, in some aspects it may instead be understood as a more restrictive and limiting term, such as “consisting of” or “essentially composed of.” Thus, for any given embodiment describing a composition, material, component, element, feature, integer, operation, and / or process step, the invention also particularly includes embodiments consisting of or substantially consisting of such compositions, materials, components, elements, features, integers, operations, and / or process steps. In the case of “consisting of…”, the alternative embodiments exclude any additional compositions, materials, components, elements, features, integers, operations and / or process steps. In the case of “essentially composed of…”, any additional compositions, materials, components, elements, features, integers, operations and / or process steps that substantially affect the essential and novel characteristics are excluded from such embodiments. However, any compositions, materials, components, elements, features, integers, operations and / or process steps that do not substantially affect the essential and novel characteristics may be included in the embodiments.

[0016] Any method steps, processes, and operations described in this invention should not be construed as necessarily requiring them to be performed in the specific order discussed or shown, unless explicitly specified. It should also be understood that, unless otherwise stated, additional or alternative steps may be used.

[0017] In this invention, except where expressly stated, any matters or issues not mentioned are directly applicable to those known in the art without any modification. Furthermore, any embodiment described in this invention can be freely combined with one or more other embodiments described in this invention, and the resulting technical solutions or concepts are considered part of the original disclosure or original record of this invention, and should not be regarded as new content not disclosed or anticipated by this invention, unless those skilled in the art consider the combination to be clearly unreasonable.

[0018] Unless otherwise stated, the terminology used in this invention has the same meaning as commonly understood by those skilled in the art. If a term is defined in this invention and its definition differs from the common understanding in the art, the definition of this invention shall prevail.

[0019] First aspect This invention provides a high-temperature resistant phosphorescent material, which consists of a dopant host and a luminescent guest. The dopant host has the chemical structure shown in general formula (I): M2B4O7·nH2O (I), where M is selected from sodium or potassium, and n is greater than or equal to 0. The luminescent guest is selected from at least one of aromatic carboxylic acids with conjugated structures, potassium aromatic carboxylate, or sodium aromatic carboxylate. The high-temperature resistant phosphorescent material exhibits phosphorescence emission characteristics in a temperature range of -80℃ to 300℃. By doping a conjugated aromatic carboxylic acid luminescent guest into a specific tetraborate (M2B4O7·nH2O) host, the rigid inorganic ionic layer formed after the dehydration of the tetraborate host exerts a stringent confinement effect on the guest molecules, effectively suppressing the thermal vibration and non-radiative transitions of the guest molecules at high temperatures. This achieves stable phosphorescence emission in a wide temperature range of -80℃ to 300℃, solving the problem of poor thermal stability and easy thermal quenching in existing organic room-temperature phosphorescent materials at high temperatures (e.g., above 100℃).

[0020] In some embodiments of the present invention, the luminescent guest has any structure shown in G1 to G28 of general formula (II), wherein G1 to G28 is selected from any one of benzoic acid, benzene polycarboxylic acid, naphthoic acid, naphthalene polycarboxylic acid, phenanthrene carboxylic acid, phenanthrene polycarboxylic acid, pyrene carboxylic acid, pyrene polycarboxylic acid, biphenyl polycarboxylic acid, benzo[a]phenanthrene polycarboxylic acid, fluorene polycarboxylic acid, and their corresponding sodium or potassium salt derivatives. By selecting carboxylates such as benzene, naphthalene, phenanthrene, and pyrene, which have high-rigidity planar conjugated frameworks, as guests, on the one hand, their high-rigidity structure further reduces the energy loss of the excited state, and on the other hand, provides a rich selection of energy levels. Thus, while ensuring high-temperature resistance, it helps to improve the phosphorescence quantum yield and provides a structural basis for realizing phosphorescence emission of different colors.

[0021] In the above general formula (II), G1 to G28 are: .

[0022] This scheme clarifies the specific chemical structures of the guest molecules, all of which possess excellent planarity and conjugated extensibility, facilitating their insertion into the interstitial lattice of the tetraborate host or their tight encapsulation by the host matrix. This ensures the stability of the doped system in terms of microstructure and further improves the luminescence efficiency of the material.

[0023] In some embodiments of the present invention, the molar ratio of the luminescent guest to the doped host is 0.001 to 10.0 mol. For example, it can be 0.001 mol%, 0.002 mol%, 0.003 mol%, 0.005 mol%, 0.008 mol%, 0.01 mol%, 0.012 mol%, 0.015 mol%, 0.018 mol%, 0.02 mol%, 0.025 mol%, 0.03mol%, 0.035 mol%, 0.04 mol%, 0.05 mol%, 0.06 mol%, 0.07 mol%, 0.08 mol%, 0.1 mol%, 0.15 mol%, 0.2mol%, 0.3mol%, 0.5mol%, 0.8mol%, 1mol%, 1.2mol%, 1.5mol%, 1.8mol%, 2mol%, 2.5mol%, 3mol%, 4mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 The molar ratio of the luminescent guest to the dopant is strictly controlled within the range of 0.1–5.0 mol%, ensuring sufficient luminescent centers to achieve high-brightness phosphorescence while avoiding the aggregation-induced quenching (ACQ) effect caused by excessively high guest concentration. This further optimizes the quantum yield and luminescence performance of the material and solves the problem of weak luminescence or quenching caused by improper doping ratio.

[0024] It is worth noting that the doping system provided by this invention will exhibit phosphorescence even at extremely low concentrations, as shown in Figure 14, which illustrates delayed emission and lifetime at different doping concentrations.

[0025] In some embodiments of the present invention, the high-temperature resistant phosphorescent material exhibits a phosphorescence lifetime ≥100ms and an absolute phosphorescence quantum yield ≥10% at 25°C. This material not only possesses unique high-temperature resistance but also exhibits ultra-long afterglow and high luminous efficiency at room temperature, demonstrating the effective protection of organic guests by the inorganic host and solving the problems of difficult preparation of traditional inorganic long-afterglow materials or low room-temperature phosphorescence efficiency of ordinary organic materials.

[0026] In some embodiments of the present invention, the high-temperature resistant phosphorescent material exhibits a phosphorescence lifetime ≥10ms and an absolute phosphorescence quantum yield ≥0.1% at temperatures <300℃. Within this temperature range, the material maintains a visible millisecond-level phosphorescence lifetime (≥10ms), establishing its position as a practical high-temperature resistant phosphorescent material and solving the problem that existing materials experience rapid afterglow loss with increasing temperature and cannot maintain visual recognition function in high-temperature environments.

[0027] In some embodiments of the present invention, the high-temperature resistant phosphorescent material exhibits a phosphorescence lifetime of ≥10 ms and an absolute phosphorescence quantum yield of ≥0.1% at temperatures ≥300℃. The phosphorescent material provided by the present invention demonstrates superior resistance to thermal quenching at extreme high temperatures (≥300℃). Even under such harsh thermal conditions, the rigid matrix effectively locks in triplet excitons of human molecules, thereby breaking through the thermal resistance limit of existing organic-inorganic hybrid materials and providing possibilities for optical applications in extreme environments.

[0028] In some embodiments of the present invention, the high-temperature resistant phosphorescent material retains its phosphorescence emission activity after continuous operation in a temperature range of -80°C to 300°C for at least two months. The excellent thermal and chemical stability of the phosphorescent material provided by the present invention over a wide temperature range demonstrates the durability of the confined structure, solves the problem of easy oxidation, decomposition, or performance degradation of existing organic phosphorescent materials during long-term high-temperature operation, and significantly extends the lifespan and reliability of the device.

[0029] In some embodiments of the present invention, the high-temperature resistant phosphorescent material retains its phosphorescence emission activity after continuous operation at 300°C for at least two months. The phosphorescent material provided by the present invention exhibits excellent thermal and chemical stability at a high temperature of 300°C, demonstrating the durability of the host confined structure and solving the problems of easy oxidation, decomposition, or performance degradation of existing organic phosphorescent materials during long-term high-temperature operation, thus significantly extending the service life and reliability of the device.

[0030] In some embodiments of the present invention, the phosphorescence emission wavelength of the high-temperature resistant phosphorescent material is in the range of 200–800 nm. Specifically, it can be any value selected from 220 nm, 250 nm, 280 nm, 300 nm, 400 nm, 500 nm, 600 nm, or 700 nm, or a range of values ​​consisting of any two of the above values, or any value within that range. The phosphorescent material provided by the present invention has a broad spectral adjustment range, covering the ultraviolet to visible light region, thereby solving the problem of limited application of single-color phosphorescent materials and enabling it to be used for full-color display, multi-color encoding, or optical anti-counterfeiting in specific wavelength bands.

[0031] In some embodiments of the present invention, the high-temperature resistant phosphorescent material exhibits temperature-responsive properties, with a response temperature range of -196°C to 300°C. Specifically, the response temperature can be any value selected from -190°C, -150°C, -120°C, -100°C, -80°C, -60°C, -40°C, -20°C, 0°C, 10°C, 20°C, 30°C, 50°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 230°C, 250°C, 280°C, or 300°C, or a range of values ​​consisting of any two of the aforementioned values, plus any value within that range. By utilizing the characteristic that the material's luminescent properties (such as intensity, lifetime, and color) change with temperature, an intelligent response to ambient temperature is achieved, thereby endowing the material with application potential in wide-temperature-range temperature sensing, thermal history recording, and other fields, solving the problem of the narrow operating temperature range of existing temperature probes.

[0032] Second aspect This invention provides a method for preparing the high-temperature resistant phosphorescent material described in the first aspect. The preparation method includes the following steps: (1) purification: recrystallizing and purifying the luminescent guest and / or dopant; (2) mixing and dispersing: placing the purified dopant and luminescent guest in a solvent medium and ultrasonically dispersing them to form a mixture; (3) heating and curing: heating the mixture to cure it; (4) drying: drying to remove residual solvent and obtain the high-temperature resistant phosphorescent material. Through simple dissolution, dispersion, heating and curing, and drying steps, the high-temperature resistant confined structure is constructed by inducing the tetraborate host to recrystallize and "capture" guest molecules in situ through the solvent evaporation process. This method is simple, mild, low-cost, and does not require the high-temperature sintering process of traditional inorganic materials, thus solving the problems of high energy consumption, demanding equipment requirements, and complex processes in the preparation of existing heat-resistant phosphorescent materials, which is conducive to large-scale industrial production.

[0033] In some embodiments of the present invention, in step (2), the solvent medium is water, preferably ultrapure water. On the one hand, water is used as a good solvent to ensure the full dissolution of borates and carboxylates; on the other hand, the introduction of impurity ions (such as heavy metal ions or quenchers) is greatly reduced, thereby preventing the quenching effect of impurities on triplet excitons and further improving the phosphorescence quantum yield and purity of the final material.

[0034] In some embodiments of the present invention, in step (2), the mixture is placed in a container of 1-100 mL and 1-100 mL of the solvent medium is added. This limits the matching relationship between the container and the amount of solvent used in laboratory preparation, ensuring a proper match between the solvent evaporation rate and the crystal growth rate, avoiding uneven crystallization due to excessively thick or thin liquid layers, thereby facilitating the formation of a uniformly composed doped system.

[0035] In some embodiments of the present invention, in step (2), the concentration of the dopant in the solvent medium is 10–50 mg / mL. By controlling the concentration of the precursor solution to 10–50 mg / mL, both the solute can be fully dissolved and dispersed, and the crystallization rate during subsequent heating and solidification is controlled. This avoids guest aggregation due to excessively high concentration or increased solvent removal energy consumption and excessively long crystallization time due to excessively low concentration, thus balancing doping uniformity and preparation efficiency.

[0036] In some embodiments of the present invention, in step (2), the temperature of the ultrasonic dispersion is ≥20°C and the duration of the ultrasonic dispersion is ≥5 min. By controlling the temperature and duration of the ultrasonic dispersion, the ultrasonic cavitation effect is used to ensure that the luminescent guest is uniformly dispersed at the molecular level in the host solution, preventing local uneven concentration or precipitation, thereby solving the problem of poor luminescence uniformity of the final solid material.

[0037] In some embodiments of the present invention, in step (2), the dopant added as a raw material is selected from any one of anhydrous sodium tetraborate, sodium tetraborate decahydrate, or potassium tetraborate tetrahydrate. The above scheme clarifies the specific raw material source of the dopant. These raw materials are widely available, inexpensive, and water-soluble, and can be easily converted into the required heat-resistant rigid matrix through subsequent heat treatment, further reducing production costs and ensuring the stability of the raw material supply chain.

[0038] In some embodiments of the present invention, in step (2), the feeding ratio of the luminescent guest to the doped host is a molar percentage calculated based on the molecular weight of the raw materials, and the molar percentage is 0.001 to 10.0 mol. Specifically, it can be any value from 0.002 mol%, 0.003 mol%, 0.005 mol%, 0.008 mol%, 0.01 mol%, 0.012 mol%, 0.015 mol%, 0.018 mol%, 0.02 mol%, 0.025 mol%, 0.03 mol%, 0.035 mol%, 0.04 mol%, 0.05 mol%, 0.06 mol%, 0.07 mol%, 0.08 mol%, 0.1 mol%, 0.15 mol%, 0.2 mol%, 0.3 mol%, 0.5 mol%, 0.8 mol%, 1 mol%, 1.2 mol%, 1.5 mol%, 1.8 mol%, 2 mol%, 2.5 mol%, 3 mol%, 4 mol%, 5 mol%, 6 mol%, 7 mol%, 8 mol%, 9 mol%, 10 mol%, or a range of values ​​consisting of any two of the above values, and any value within that range. By clearly defining the calculation basis for the feed ratio, the actual molar ratio error caused by the different amounts of crystal water in the raw materials (such as anhydrous and decahydrated) is eliminated, ensuring the repeatability of the process and the consistency of product performance between batches.

[0039] In some embodiments of the present invention, in step (3), heating is performed at 30–100°C for 4–12 hours. By controlling the low-temperature, long-duration heating and curing process, the solvent evaporates slowly, inducing the ordered growth of the host lattice and perfectly coating the guest molecules, avoiding lattice defects or guest precipitation caused by rapid drying, thereby further improving the crystal quality of the material and enhancing its heat resistance and luminescence efficiency.

[0040] In some embodiments of the present invention, in step (4), drying is performed at 100–150°C for 20–60 minutes. This subsequent high-temperature drying step thoroughly removes residual solvents and some water of crystallization from the system, not only strengthening the rigid structure of the tetraborate matrix but also minimizing the quenching effect of water molecules (hydroxyl vibrations) on phosphorescence, thereby ensuring the long-term stability of the material in subsequent high-temperature applications.

[0041] It should be noted that the tetraborate used as the dopant in this invention can be anhydrous or hydrates with different water numbers of crystallization (such as anhydrous sodium tetraborate, sodium tetraborate decahydrate, etc.). Although the solubility of raw materials in water varies greatly depending on the hydrate form, they all form the same borate ion environment after dissolving in water, which does not affect the structure and properties of the final material. In particular, for anhydrous sodium tetraborate with low solubility or when preparing precursor solutions with high concentrations (e.g., ≥50 mg / mL), it is recommended to use heating-assisted dissolution (e.g., heating to 50℃~90℃) to ensure that the host and guest molecules achieve uniform mixing at the molecular level in the liquid phase, avoiding uneven doping due to incomplete dissolution, thereby ensuring the consistency of the luminescent properties of the final material. It should be noted that the reason why the phosphorescent material described in this invention can maintain long-lifetime phosphorescent emission at extreme high temperatures of 300°C is due to the following mechanism: during the heating and drying stages of the preparation process, the tetraborate matrix undergoes dehydration and shrinkage, forming a dense and rigid inorganic ionic lattice. This rigid environment formed by dehydration and densification greatly restricts the thermal vibration and rotation of guest molecules, effectively blocking the non-radiative transition channels of triplet excitons at high temperatures. Unlike traditional polymer matrices (limited by low glass transition temperatures Tg), the inorganic matrix of this invention does not soften at high temperatures; instead, due to the tight binding effect of the lattice, the luminescent centers are "locked," thus achieving excellent high-temperature phosphorescent properties.

[0042] Third aspect This invention provides an application of the high-temperature resistant phosphorescent material as described in the first aspect or the high-temperature resistant phosphorescent material prepared by the method described in the second aspect. The applications include high-temperature safety indicators, optoelectronic devices, display materials, information storage materials, or anti-counterfeiting materials. By applying this high-temperature resistant phosphorescent material to fields such as high-temperature safety indicators and anti-counterfeiting, its unique long-lifetime luminescence characteristics at high temperatures fill the application gap of existing materials in high-temperature scenarios (such as fire warning signs and high-temperature equipment operating status markers), thereby improving the safety and functionality of related fields.

[0043] In some embodiments of the present invention, the operating environment temperature of the application is from -80°C to 300°C. Specifically, it can be any value selected from -60°C, -40°C, -20°C, 0°C, 10°C, 20°C, 30°C, 50°C, 80°C, 100°C, 120°C, 150°C, 180°C, 200°C, 230°C, 250°C, 280°C, or 300°C, or a range of any two of the above values ​​plus any value within that range. By specifying a specific application temperature range, covering extremely cold to extremely hot environments, the versatility of the material under extreme conditions is demonstrated. In particular, it provides a reliable optical solution in the high-temperature region (>100°C) where traditional organic materials completely fail, meeting the stringent requirements of special fields such as aerospace and industrial manufacturing.

[0044] In some embodiments of the present invention, the application utilizes the changes in the luminescence color or lifespan of materials at different temperatures to record or encrypt temperature information. By leveraging the reversible or irreversible nature of the material's luminescence properties with temperature changes, it achieves the tracing of temperature history or high-level information encryption (such as high-temperature decryption), thereby solving the problem that single anti-counterfeiting methods are easily copied and improving information security and the concealment of anti-counterfeiting measures.

[0045] Example Unless otherwise stated, all raw materials, equipment, and instruments mentioned in this specification can be obtained through general commercial channels.

[0046] Anhydrous sodium tetraborate was purchased from Adamas-beta, item number: 01018125, specification: 500 g.

[0047] Potassium tetraborate tetrahydrate was purchased from Adamas-beta, item number: 013567187, specification: 2.5 kg.

[0048] Aromatic carboxylic acids were purchased from Shanghai Titan Technology Co., Ltd. and Shanghai Bid Pharmaceutical Co., Ltd.

[0049] Delayed emission and phosphorescence decay curves were obtained in delayed mode on an Agilent Cary Eclipse fluorescence spectrometer.

[0050] The absolute quantum yield was measured using a Hamamatsu Quantaurus-QY C11347-11 quantum yield analyzer.

[0051] Example 1 This embodiment provides a high-temperature resistant phosphorescent material G2-H1 and its preparation method.

[0052] Preparation of the luminescent guest G2 (potassium terephthalate): 1.66 g (10 mmol) of terephthalic acid was added to 50 mL of ethanol, followed by 50 mL of water, and then 1.12 g of potassium hydroxide. The mixture was reacted at 60 °C for 12 hours. After the reaction was complete, the solvent was removed by rotary evaporation. The crude product was purified by recrystallization from ethanol to obtain a white solid, G2.

[0053]

[0054] Preparation of high-temperature resistant phosphorescent material G2-H1: Accurately weigh the prepared luminescent guest G2 (2.42 mg, approximately 1 mol%) and dopant H1 (anhydrous sodium tetraborate, 200 mg), and place them together in a 20 mL screw-top bottle. Add 10 mL of ultrapure water and ultrasonically disperse at 50 °C for 30 minutes to ensure homogeneity. Subsequently, place the mixture in an oven at 80 °C for 6 hours to solidify, and finally dry at 140 °C for 30 minutes to obtain a white to light yellow powdery high-temperature resistant phosphorescent material G2-H1.

[0055]

[0056] Performance test results: At room temperature (25℃), the phosphorescence emission peak of this material is located at around 410nm, the phosphorescence lifetime is 0.322s, the total photoluminescence quantum yield is 96%, and the absolute phosphorescence quantum yield is 81.2%. At a high temperature of 200℃, the phosphorescence emission peak of this material is still maintained at around 410nm, the phosphorescence lifetime is 0.011s (11ms), and afterglow is visible to the naked eye.

[0057] Example 2 This embodiment provides a high-temperature resistant phosphorescent material G8-H1 and its preparation method.

[0058] Preparation of the luminescent guest G8 (potassium 2,3-naphthalenedicarboxylate): 2,3-naphthalenedicarboxylic acid (2.16 g, 10 mmol) was added to 50 mL of ethanol, followed by 50 mL of water, and then 1.12 g of potassium hydroxide. The reaction was carried out at 60 °C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was purified by recrystallization from ethanol to obtain a white solid, G8.

[0059]

[0060] Preparation of high-temperature resistant phosphorescent material G8-H1: Accurately weigh the prepared luminescent guest G8 (2.92 mg, approximately 1 mol%) and dopant H1 (anhydrous sodium tetraborate, 200 mg), and place them together in a 20 mL screw-top bottle. After adding 10 mL of ultrapure water, ultrasonically disperse the mixture at 50 °C for 30 minutes to ensure homogeneity. Subsequently, place the mixture in an oven at 80 °C for 6 hours to solidify it, and finally dry it at 140 °C for 30 minutes to obtain a white to light yellow powder of high-temperature resistant phosphorescent material G8-H1.

[0061]

[0062] Performance test results: At room temperature, the phosphorescence emission peak of this material is located at approximately 510 nm, the phosphorescence lifetime is 1.126 s, the total photoluminescence quantum yield is 16.9%, and the absolute phosphorescence quantum yield is 3.0%. At a high temperature of 300℃, the phosphorescence emission peak of this material is located at approximately 510 nm, and the phosphorescence lifetime is 0.135 s (135 ms).

[0063] Example 3 This embodiment provides a high-temperature resistant phosphorescent material G25-H1 and its preparation method.

[0064] Preparation of the luminescent guest G25 (potassium 3,3',4,4'-biphenyltetracarboxylic acid): 3,3',4,4'-biphenyltetracarboxylic acid (3.31 g, 10 mmol) was added to 50 mL of ethanol, followed by 50 mL of water, and then 2.24 g of potassium hydroxide. The reaction was carried out at 60 °C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was purified by recrystallization from ethanol to obtain a white solid, G25.

[0065]

[0066] Preparation of high-temperature resistant phosphorescent material G25-H1: Accurately weigh the prepared luminescent guest G25 (4.82 mg, approximately 1 mol%) and dopant H1 (anhydrous sodium tetraborate, 200 mg), and place them together in a 20 mL screw-top bottle. Add 10 mL of ultrapure water and ultrasonically disperse at 50 °C for 30 minutes to ensure homogeneity. Subsequently, place the mixture in an oven at 80 °C for 6 hours to solidify, and finally dry at 140 °C for 30 minutes to obtain a white to light yellow powder of the high-temperature resistant phosphorescent material G25-H1.

[0067]

[0068] Performance test results: At room temperature, the phosphorescence emission peak of this material is located at approximately 490 nm, with a phosphorescence lifetime of 1.022 s, a total photoluminescence quantum yield of 42.8%, and an absolute phosphorescence quantum yield of 39.1%. At 300℃, the phosphorescence emission peak is located at approximately 490 nm, with a phosphorescence lifetime of 0.296 s (296 ms). Long-term thermal stability test: The material was continuously stored at 300℃, and tests were conducted every week. The results showed that after 8 weeks (approximately two months) of storage, there was no significant attenuation in the delayed emission spectrum intensity and afterglow brightness, demonstrating its excellent long-term stability at 300℃.

[0069] Example 4 This embodiment provides a high-temperature resistant phosphorescent material G19-H1 and its preparation method.

[0070] Preparation of the luminescent guest G19 (potassium 1,3,6,8-pyrenetetracarboxylate): 1,3,6,8-pyrenetetracarboxylic acid (3.78 g, 10 mmol) was added to 50 mL of ethanol, followed by 50 mL of water, and then 2.24 g of potassium hydroxide. The reaction was carried out at 60 °C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was purified by recrystallization from ethanol to obtain a white solid, G19.

[0071]

[0072] Preparation of high-temperature resistant phosphorescent material G19-H1: Accurately weigh the prepared luminescent guest G19 (5.29 mg, approximately 1 mol%) and dopant H1 (anhydrous sodium tetraborate, 200 mg), and place them together in a 20 mL screw-top bottle. Add 10 mL of ultrapure water and ultrasonically disperse at 50 °C for 30 minutes to ensure homogeneity. Subsequently, place the mixture in an oven at 80 °C for 6 hours to solidify, and finally dry at 140 °C for 30 minutes to obtain a white to light yellow powdery high-temperature resistant phosphorescent material G19-H1.

[0073]

[0074] Performance test results: At room temperature, the phosphorescence emission peak of this material is located at approximately 670 nm, with a phosphorescence lifetime of 0.046 s, a total photoluminescence quantum yield of 31.5%, and an absolute phosphorescence quantum yield of 2.1%. At a high temperature of 300℃, the phosphorescence emission peak of this material is located at approximately 670 nm, with a phosphorescence lifetime of 0.023 s (23 ms), emitting red phosphorescence.

[0075] Example 5 This embodiment provides a high-temperature resistant phosphorescent material G11-H1 and its preparation method.

[0076] Preparation of the luminescent guest G11 (potassium 9-phenanthroline): 2.22 g (10 mmol) of 9-phenanthroline acid was added to 50 mL of ethanol, followed by 50 mL of water, and then 0.56 g of potassium hydroxide. The reaction was carried out at 60 °C for 12 hours. After the reaction was completed, the solvent was removed by rotary evaporation, and the crude product was purified by recrystallization from ethanol to obtain a white solid, G11.

[0077]

[0078] Preparation of high-temperature resistant phosphorescent material G11-H1: Accurately weigh the prepared luminescent guest G11 (2.60 mg, approximately 1 mol%) and dopant H1 (anhydrous sodium tetraborate, 200 mg), and place them together in a 20 mL screw-top bottle. After adding 10 mL of ultrapure water, ultrasonically disperse the mixture at 50 °C for 30 minutes to ensure homogeneity. Subsequently, place the mixture in an oven at 80 °C for 6 hours to solidify it, and finally dry it at 140 °C for 30 minutes to obtain a white to light yellow powder of high-temperature resistant phosphorescent material G11-H1.

[0079]

[0080] Performance test results: At room temperature, the phosphorescence emission peak of this material is located at approximately 520 nm, and the phosphorescence lifetime is 0.962 s. At a high temperature of 300℃, the phosphorescence emission peak of this material is located at approximately 520 nm, and the phosphorescence lifetime is 0.102 s (102 ms).

[0081] Example 6 This embodiment provides a high-temperature resistant phosphorescent material G2-H2 and its preparation method.

[0082] Preparation of luminescent guest G2 (potassium terephthalate): Same as step 1 in Example 1.

[0083]

[0084] Preparation of high-temperature resistant phosphorescent material G2-H2: The luminescent guest G2 (2.42 mg, approximately 1 mol%) and the dopant H2 (potassium tetraborate tetrahydrate, 307 mg) were accurately weighed and placed together in a 20 mL screw-top bottle. After adding 10 mL of ultrapure water, the mixture was ultrasonically dispersed at 50 °C for 30 minutes to ensure homogeneity. Subsequently, the mixture was placed in an oven at 80 °C for 6 hours to solidify, and finally dried at 140 °C for 30 minutes to obtain a white to light yellow powdery high-temperature resistant phosphorescent material G2-H2.

[0085]

[0086] Performance test results: At room temperature, the phosphorescence emission peak of this material is located at approximately 410 nm, and the phosphorescence lifetime is 0.193 s. At a high temperature of 200℃, the phosphorescence emission peak of this material is located at approximately 410 nm, and the phosphorescence lifetime is 0.001 s (1 ms).

[0087] Example 7 This embodiment demonstrates the application of high-temperature resistant phosphorescent materials in high-temperature safety indication.

[0088] Coatings for indicator arrows were fabricated using G2-H1 (blue light) prepared in Example 1, G25-H1 (cyan light) prepared in Example 3, and G19-H1 (red light) prepared in Example 4, respectively. The afterglow of these arrows was observed under different temperature conditions. <100℃: The blue, cyan, and red arrows all show obvious afterglow after the excitation light is turned off, indicating that all three routes are in a safe state; 200℃: Only the cyan and red arrows show afterglow; the blue arrow disappears abruptly, indicating that the route to the left is no longer safe. 300℃: Only the afterglow of the cyan arrow is observable, while the red arrow extinguishes, indicating that both sides are in an extremely unsafe state. This temperature-dependent phosphorescence response enables a visual safety indication in high-temperature environments.

[0089] Example 8 This embodiment demonstrates the application of high-temperature resistant phosphorescent materials in high-temperature information storage and encryption.

[0090] The high-temperature resistant phosphorescent material G25-H1 is combined with another non-high-temperature resistant material (such as ordinary phosphorescent material G22-H1 or other reference materials), and then packaged into a copper tank and arranged according to Morse code rules.

[0091] At room temperature: Since all materials emit light and there are interference terms in the arrangement, the read Morse code is the error message "0?LX"; At high temperatures (e.g., 300℃): the phosphorescence of the interfering material is quenched, and only the high-temperature resistant material G25-H1 continues to emit light. At this point, cracking the Morse code can reveal the hidden and correct information "HZYP". This application utilizes the difference in the high-temperature resistance of materials to successfully achieve high-temperature encrypted storage of information.

[0092] Comparative Example 1 This comparative example provides a performance test for a pure host material H1.

[0093] Preparation method: Weigh 200 mg of main body H1 (anhydrous sodium tetraborate), place it in a 20 mL screw-top bottle, add 10 mL of ultrapure water, ultrasonically disperse at 50 °C for 30 minutes, then heat in an oven at 80 °C for 6 hours, and finally dry at 140 °C for 30 minutes. No luminescent guest is added during this process.

[0094] Test results: As shown in Figure 11, no obvious phosphorescence emission signal was detected in the delayed emission spectrum of the pure host material. This proves that the high-temperature phosphorescence observed in the examples originated from the doped system, rather than from the tetraborate host itself or from impurities.

[0095] Comparative Example 2 This comparative example provides a performance test for G2-PVA, a material based on polyvinyl alcohol (PVA).

[0096] Preparation method: The luminescent guest G2 is dissolved in an aqueous solution of polyvinyl alcohol (PVA), and after being mixed evenly, G2-PVA material is prepared by film formation and drying process.

[0097] Test Results: As shown in Figure 12, the material exhibits significant phosphorescence emission at room temperature (303 K). However, its luminescence intensity rapidly decreases with increasing temperature to 323 K and 343 K; when the temperature reaches 383 K (approximately 110 °C), the phosphorescence completely disappears. This result indicates that when the matrix is ​​polyvinyl alcohol, which lacks high-temperature rigid confinement capability, the material does not possess high-temperature resistance. This conversely demonstrates that the rigid ionic layer structure of the tetraborate matrix in this invention plays a decisive role in achieving phosphorescence emission at 300 °C.

[0098] This invention demonstrates through comparative experiments with Comparative Example 2 and the embodiments that when using traditional polymers (such as PVA) as a matrix, phosphorescence quenching occurs around 110°C due to matrix softening caused by the low glass transition temperature, making high-temperature resistance impossible. In contrast, the tetraborate matrix of this invention forms a dense, rigid inorganic ionic lattice after dehydration, maintaining structural stability even at extreme temperatures of 300°C, thereby effectively suppressing nonradiative transitions of guest molecules. This difference in matrix rigidity is the decisive factor in achieving breakthrough high-temperature phosphorescence resistance in this application.

[0099] Figure 1 It was observed that even at 200℃ (473 K), G2-H1 still exhibited a visible afterglow, proving the high-temperature resistance of its blue light component.

[0100] Figure 2 shows the temperature-dependent (a) delayed emission spectrum and (b) phosphorescence decay spectrum of G2-H1. Figure 1 The observed afterglow phenomenon provides data support.

[0101] Figure 3 The images show the afterglow colors of G2-H1, G25-H1, G8-H1, and G19-H1 after the UV lamps were turned off at different high temperatures, demonstrating that the phosphorescent material provided by this invention can achieve near-full-color high-temperature phosphorescence in various systems.

[0102] Figure 4 The delayed emission spectra of G2-H1, G25-H1, G8-H1, and G19-H1 at 200℃ demonstrate that the phosphorescent materials provided by this invention can exhibit delayed emission characteristics at high temperatures.

[0103] Figure 5(a) shows the temperature-dependent phosphorescence decay curve of G25-H1, indicating that the phosphorescent materials provided by this invention still have a long luminescence lifetime even at 300°C.

[0104] Figure 5(b) shows the temperature-dependent phosphorescence decay curve of G8-H1, indicating that the phosphorescent materials provided by this invention still have a long luminescence lifetime even at 300°C.

[0105] Figure 5(c) shows the temperature-dependent phosphorescence decay curve of G19-H1, indicating that the phosphorescent materials provided by this invention still have a long luminescence lifetime even at 300°C.

[0106] Figure 6 Images of the afterglow of G25-H1 at different temperatures show that even at 300 degrees Celsius, the afterglow is still visible to the naked eye.

[0107] Figure 7 The delayed emission spectra of G25-H1 obtained by storing it at 300℃ for different times and testing it at 300℃ are shown. This indicates that the phosphorescent material provided by this invention maintains almost no change in the peak shape of its delayed emission spectrum even after being stored at high temperature for eight weeks, demonstrating its strong high-temperature resistance.

[0108] Figure 8 The images show the afterglow patterns of G25-H1 obtained at 300°C for different storage times. This demonstrates that the phosphorescent material provided by this invention exhibits almost no change in afterglow even after eight weeks of storage at high temperatures, proving its extremely strong high-temperature resistance.

[0109] Figure 9 This is a multi-color high-temperature safety indicator. At 100℃, there is afterglow; at 200℃, only the upper and right arrows have afterglow; and at 300℃, almost only the middle arrow has afterglow.

[0110] Figure 10 Information is encrypted at high temperatures. Morse code observed at room temperature decodes as "0?LX", while Morse code at 300°C decodes as "HZYP".

[0111] Figure 11(a) shows the delayed emission spectrum of the host matrix H1 (n=0) of this invention, where the maximum value of the intensity ordinate is 800; Figure 11(b) shows the delayed emission spectrum of the host matrix H1 (n=0) in Figure 11(a), where the maximum value of the intensity ordinate is 50. It is worth noting that the delayed emission spectrum of the host matrix H1 (n=0) of this invention shows a clear spectral outline when the maximum value of the intensity ordinate is 40, but the spectral outline is highly compressed when the maximum value of the intensity ordinate is 800. No obvious emission peaks were observed in either spectrum, proving that the host matrix H1 (n=0) provided by this invention exhibits almost no phosphorescence and almost no delayed emission under the same testing conditions, and will not interfere with the judgment of the luminescence of the doped system.

[0112] Figure 12 shows the temperature-dependent (a) delayed emission spectrum and (b) phosphorescence decay curve of G2 incorporated into polyvinyl alcohol, indicating that other matrices cannot effectively withstand high temperatures. It is worth noting that the arrow in Figure 12(b) represents a phosphorescence lifetime decay spectrum that varies with temperature. The sharp decrease in lifetime is due to two main reasons: firstly, as temperature increases, the rigid network vibrations of PVA strengthen, failing to effectively suppress non-radiative transitions; secondly, the increased temperature also enhances the vibrations of the luminescent molecules themselves, leading to enhanced non-radiative transitions, thus weakening phosphorescence and reducing lifetime.

[0113] Figure 13 shows the (a) delayed emission spectrum and (b) phosphorescence decay curve of G2-H1 at -196℃, proving that it can exhibit phosphorescence at extremely low temperatures.

[0114] Figure 14 shows the (a) delayed emission spectrum and (b) phosphorescence decay curve of G2-H1 at different doping concentrations, proving that the phosphorescent material provided by this invention can exhibit phosphorescence in the doping system regardless of whether the concentration is high or extremely low.

[0115] These are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims. Furthermore, specific examples have been used in the specification to illustrate the principles and implementation methods of the present invention. The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention, and the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A high-temperature resistant phosphorescent material, characterized in that, The phosphorescent material is composed of a doped host and a luminescent guest; The doped host has the chemical structure shown in general formula (I): M2B4O7·nH2O(I) Where M is selected from sodium or potassium, and n is greater than or equal to 0; The luminescent guest is selected from at least one of aromatic carboxylic acids, potassium aromatic carboxylate, or sodium aromatic carboxylate having a conjugated structure; The high-temperature resistant phosphorescent material exhibits phosphorescence emission characteristics within a temperature range of -80℃ to 300℃.

2. The high-temperature resistant phosphorescent material as described in claim 1, characterized in that, The luminescent guest has any structure shown in G1 to G28 of general formula (II), wherein G1 to G28 is selected from any one of benzoic acid, benzene polycarboxylic acid, naphthoic acid, naphthalene polycarboxylic acid, phenanthrene polycarboxylic acid, phenanthrene polycarboxylic acid, pyrene polycarboxylic acid, pyrene polycarboxylic acid, biphenyl polycarboxylic acid, benzophenanthrene polycarboxylic acid, fluorene polycarboxylic acid, and their corresponding sodium or potassium salt derivatives.

3. The high-temperature resistant phosphorescent material as described in claim 1, characterized in that, The molar ratio of the luminescent guest to the doped host is 0.001 to 10.0 mol.

4. The high-temperature resistant phosphorescent material as described in claim 1, characterized in that, The properties of the high-temperature resistant phosphorescent material meet at least one of the following conditions: (1) At 25℃, the phosphorescence lifetime is ≥100ms and the absolute phosphorescence quantum yield is ≥10%; (2) At temperatures < 300℃, the phosphorescence lifetime is ≥ 10 ms and the absolute phosphorescence quantum yield is ≥ 0.1%; (3) At a temperature ≥300℃, the phosphorescence lifetime is ≥10ms and the absolute phosphorescence quantum yield is ≥0.1%; (4) It retains phosphorescence emission activity after operating continuously for at least two months in a temperature range of -80℃ to 300℃; (5) It retains phosphorescence emission activity after running continuously at 300°C for at least two months.

5. The high-temperature resistant phosphorescent material as described in claim 1, characterized in that, The phosphorescence emission wavelength of the high-temperature resistant phosphorescent material is in the range of 200–800 nm; Preferably, the high-temperature resistant phosphorescent material has temperature-responsive properties, with a response temperature range of -196°C to 300°C.

6. A method for preparing a high-temperature resistant phosphorescent material as described in any one of claims 1 to 5, characterized in that, The preparation method includes the following steps: (1) Purification: The luminescent guest and / or doped host are purified by recrystallization; (2) Mixing and dispersing: The purified dopant and luminescent guest are placed in a solvent medium and ultrasonically dispersed to form a mixture; (3) Heating and curing: Heating the mixture to cure it; (4) Drying: Drying removes residual solvent to obtain the high-temperature resistant phosphorescent material.

7. The preparation method according to claim 6, characterized in that, Step (2) has at least one of the following characteristics: The solvent medium is water, preferably ultrapure water; Place the mixture in a 1-100 mL container and add 1-100 mL of the solvent medium; The concentration of the dopant in the solvent medium is 10–50 mg / mL; The ultrasonic dispersion temperature is ≥20℃, and the ultrasonic dispersion duration is ≥5min; The dopant added as a raw material is selected from any one of anhydrous sodium tetraborate, sodium tetraborate decahydrate, or potassium tetraborate tetrahydrate. The feeding ratio of the luminescent guest to the doped host is a molar percentage calculated based on the molecular weight of the raw materials, and the molar percentage is 0.001 to 10.0 mol.

8. The preparation method according to claim 6, characterized in that, In step (3), the temperature is increased to 30–100°C for 4–12 hours. And / or, in step (4), drying is carried out at 100-150°C for 20-60 minutes.

9. The application of a high-temperature resistant phosphorescent material as described in any one of claims 1 to 5 or a high-temperature resistant phosphorescent material obtained by the preparation method as described in any one of claims 6 to 8, characterized in that, The applications include high-temperature safety indicators, optoelectronic devices, display materials, information storage materials, or anti-counterfeiting materials.

10. The application as described in claim 9, characterized in that, The operating temperature range of the application is -80℃ to 300℃; And / or, the application utilizes the changes in the material's luminescence color or lifetime at different temperatures to record or encrypt temperature information.

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