Performance-tunable organic afterglow materials, their preparation methods and applications

Abstract

This invention provides a tunable organic afterglow material, its preparation method, and its applications. The organic afterglow material comprises an organic guest luminescent material and a small molecule host material. The organic guest luminescent material is a single compound with an electron donor-electron acceptor structure, consisting of an electron acceptor group and an electron donor group linked by a single bond. This invention provides an organic material system that allows for wide-ranging control of afterglow performance (channels, wavelength, lifetime) using only a single luminescent group without complex molecular structure reconstruction, and can be applied to high-resolution X-ray imaging.

Description

Technical Field

[0001] This invention relates to the field of organic afterglow materials technology, specifically to an organic afterglow material with tunable properties, its preparation method, and its application. Background Technology

[0002] Organic light-emitting materials (OLEDs) have broad application prospects in optoelectronics, anti-counterfeiting encryption, bioimaging, and non-destructive testing. Among these, adjusting the afterglow properties of these materials (including emission wavelength, duration, and even relaxation channels) is crucial for meeting the specific needs of different applications. However, existing organic afterglow materials face significant technical bottlenecks in performance regulation. Current methods for adjusting afterglow performance primarily rely on the material's structure-property relationship. This means that to obtain specific afterglow emission colors, lifetimes, or emission mechanisms, researchers must perform complex molecular design and chemical reconstruction, resynthesizing entirely new molecular frameworks for each specific requirement. This highly complex chemical synthesis-dependent approach not only results in long development cycles and high costs but also severely limits the range of material performance regulation.

[0003] Therefore, how to get rid of the cumbersome molecular reconstruction process and achieve extensive and significant control of afterglow performance using only a single luminescent group system through simple material compounding or physical means, and further successfully apply it to the field of high-resolution X-ray imaging where the luminescence efficiency and stability of materials are extremely important, is an urgent issue to be solved in the field of organic light-emitting materials. Summary of the Invention

[0004] This invention provides a tunable organic afterglow material, its preparation method, and its application. It provides an organic material system that can achieve extensive control of afterglow performance (channel, wavelength, lifetime) using only a single luminescent group system without the need for complex molecular structure reconstruction and can be applied to high-resolution X-ray imaging.

[0005] To achieve the above objectives, the present invention provides the following technical solution: An organic afterglow material with tunable performance, the organic afterglow material comprising an organic guest luminescent material and a small molecule host material; The organic guest luminescent material is a single compound with an electron donor-electron acceptor structure, wherein the compound is composed of an electron acceptor group and an electron donor group connected by a single bond; The electron acceptor group is selected from at least one group having the structure shown in formulas (A-1) to (A-3): ; The electron donor group is selected from at least one group having the structure shown in formulas (D-1) to (D-3): .

[0006] To achieve the above objectives, the present invention also provides the following technical solutions: A method for preparing the above-mentioned organic afterglow material, the method comprising the following steps: The organic guest luminescent material is incorporated into the small molecule host material, and then ground and mixed to obtain an intermediate mixture; The intermediate mixture is heated until completely melted, and then cooled to obtain the organic afterglow material.

[0007] To achieve the above objectives, the present invention also provides the following technical solutions: Application of the above-mentioned organic afterglow material or the organic afterglow material obtained by the above-mentioned preparation method in the preparation of high-resolution X-ray imaging materials, optoelectronic devices, display materials or anti-counterfeiting materials.

[0008] Compared with the prior art, the present invention has achieved the following beneficial effects: This invention achieves significant and multidimensional tunability of the afterglow channel (room temperature phosphorescence / thermally activated delayed fluorescence / long-duration luminescence), emission wavelength, and duration through simple physical doping of specific flexible guest and host materials, and possesses excellent radiative luminescence stability and extremely high X-ray spatial imaging resolution. Attached Figure Description

[0009] To more clearly illustrate the technical solution in one embodiment of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0010] Figure 1 These are the instantaneous and delayed emission spectra of the organic afterglow material prepared in Example 2 of this invention; Figure 2 This is a graph showing the delayed luminescence lifetime decay of the organic afterglow material prepared in Example 2 of this invention; Figure 3 This is a comparison diagram of the luminescence state of the organic afterglow material prepared in Example 2 of the present invention under sunlight and before and after ultraviolet light is turned off; Figure 4 These are the instantaneous and delayed emission spectra of the organic afterglow material prepared in Example 3 of this invention; Figure 5 This is a graph showing the delayed luminescence lifetime decay of the organic afterglow material prepared in Example 3 of this invention; Figure 6 This is a comparison diagram of the luminescence state of the organic afterglow material prepared in Example 3 of the present invention under sunlight and before and after ultraviolet light is turned off; Figure 7 These are the instantaneous and delayed emission spectra of the organic afterglow material prepared in Example 4 of this invention; Figure 8 This is a graph showing the delayed luminescence lifetime decay of the organic afterglow material prepared in Example 4 of this invention. Figure 9 This is a comparison diagram of the luminescence state of the organic afterglow material prepared in Example 4 of the present invention under sunlight and before and after ultraviolet light is turned off; Figure 10 These are the radiation emission spectra of organic afterglow materials with different doping concentrations prepared in Example 5 of this invention under X-ray excitation; Figure 11 This is a graph showing the X-ray radiation luminescence detection limit of the organic afterglow material prepared in Example 5 of this invention. Figure 12 This is a test chart of the X-ray radiation emission cycle stability of the organic afterglow material prepared in Example 5 of the present invention; Figure 13 This is a schematic diagram illustrating the effect of the transparent scintillator film prepared in Example 6 of the present invention on high-resolution X-ray imaging of different objects. Detailed Implementation

[0011] The technical solution of one embodiment 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.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] 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.

[0016] 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.

[0017] As mentioned above, there is an urgent need for an organic material system that can achieve extensive control over afterglow performance (channels, wavelength, lifetime) using only a single luminescent group without requiring complex molecular structure reconstruction, and can be applied to high-resolution X-ray imaging. Therefore, this invention proposes the following technical solution to address the above-mentioned problems.

[0018] First aspect This invention provides a tunable organic afterglow material, comprising an organic guest luminescent material and a small molecule host material; the organic guest luminescent material is a single compound having an electron donor-electron acceptor structure, the compound being composed of an electron acceptor group and an electron donor group connected by a single bond; the electron acceptor group is selected from at least one group having the structure shown in formulas (A-1) to (A-3): ; The electron donor group is selected from at least one group having the structure shown in formulas (D-1) to (D-3): .

[0019] It is understandable that using the aforementioned specific flexible donor-acceptor (DA) molecular framework as the guest luminescence center can construct a highly efficient charge-transfer (CT) state. Specifically, the electron donor and acceptor within the selected structural range have excellent energy level matching and suitable steric hindrance. This special electronic effect not only endows the guest material with abundant exciton relaxation pathways in the excited state, but also enables it to undergo highly sensitive intermolecular interactions with the host matrix during subsequent physical doping. This provides a foundation for completely breaking the limitation of traditional materials where "a single structure corresponds to a single property" and achieving wide-range dynamic control of afterglow luminescence channels and lifetime.

[0020] In some embodiments, the electron donor group may be N,N-dimethylaniline or its derivatives, and the electron acceptor group may be a phosphorescent group.

[0021] In some embodiments of the present invention, the small molecule host material is selected from at least one compound having the structure shown in formulas (H-1) to (H-4): .

[0022] It should be noted that the chemical name of the compound with the structure shown in formula (H-1) is 4-dimethylaminopyridine, and its CAS number is 1122-58-3; the chemical name of the compound with the structure shown in formula (H-2) is benzophenone, and its CAS number is 119-61-9; the chemical name of the compound with the structure shown in formula (H-3) is 1,3,5-tris(1-phenyl-1H-benzo[d]imidazol-2-yl)benzene, and its CAS number is 192198-85-9; and the chemical name of the compound with the structure shown in formula (H-4) is bis(2-diphenylphosphine) ether, and its CAS number is 166330-10-5. It is understood that all of the above compounds can be obtained from Shanghai Bid Pharmaceutical Technology Co., Ltd., and therefore the compounds used in the embodiments of this invention were also obtained by the company through general commercial channels.

[0023] The aforementioned preferred small molecule host not only possesses excellent film-forming properties and optical transparency, but more importantly, its molecular conformation can provide a highly customized rigid microenvironment for the guest luminescent molecules. Through abundant non-covalent interactions between host molecules (such as π-π interactions or strong hydrogen bond networks), the energy loss of non-radiative transitions of guest molecules in excited states can be effectively suppressed, thereby firmly "locking" the exciton energy in the luminescence channel and significantly improving the overall luminescence quantum yield and afterglow stability of the material.

[0024] In some embodiments of the present invention, based on the total mass of the organic afterglow material as 100%, the mass percentage of the organic guest luminescent material is 0.1% to 10%, and the mass percentage of the small molecule host material is 90% to 99.9%. By strictly controlling the host-guest ratio within the above-mentioned specific range, the system can achieve optimal energy transfer and exciton diffusion efficiency. If the guest concentration is too high, it is very easy to induce aggregation-induced quenching (ACQ) effect, resulting in a precipitous drop in luminescence efficiency; while if the concentration is too low, continuous and effective luminescent centers cannot be formed. This ratio range not only ensures that the guest molecules are uniformly dispersed at the monomolecular level in the host matrix, but also endows the material with extremely high luminescence brightness and excellent X-ray radiation resistance.

[0025] In some embodiments of the present invention, with the total mass of the organic afterglow material being 100%, the mass percentage of the organic guest luminescent material is 0.1%, and the mass percentage of the small molecule host material is 99.9%. In this extremely low doping concentration limit state, the guest molecules are almost perfectly "isolated and encapsulated" by the host matrix. This highly isolated microscopic state completely cuts off the energy loss and exciton annihilation pathways between guest molecules, greatly extending the lifetime of triplet excitons. This not only endows the material with the best delayed emission characteristics but also effectively avoids imaging blurring caused by photon scattering, providing a core guarantee for achieving extremely high spatial resolution X-ray imaging.

[0026] In some embodiments of the present invention, when the small molecule host material is a compound having the structure shown in formula (H-1), the organic afterglow material is a thermally activated delayed fluorescence (TADF) afterglow material. When a compound of formula (H-1) is introduced as the matrix, its unique energy level distribution enables extremely precise energy coupling with the guest molecule, effectively compressing the singlet and triplet band gaps (ΔEST) of the system. This microscopic energy level reshaping greatly promotes the occurrence of reverse system-to-system crossing (RISC) processes, thereby successfully exciting highly efficient thermally activated delayed fluorescence (TADF) afterglow, providing a novel pathway for expanding the application of materials in specific photoelectric detection fields.

[0027] In some embodiments of the present invention, when the small molecule host material is a compound having the structure shown in formula (H-2) or formula (H-4), the organic afterglow material is a room-temperature phosphorescent afterglow material. Host materials employing the structure of formula (H-2) or formula (H-4) can, through their more rigid molecular framework or special heavy atom / heteroatom effects, form extremely strong spatial confinement and enhanced spin-orbit coupling to guest molecules at room temperature. This deep physical integration effectively blocks the quenching effect of oxygen molecules and thermal vibrations on triplet excitons in the environment, allowing phosphorescence emission, which is normally extremely difficult to observe at room temperature, to be released stably and continuously, achieving excellent room-temperature phosphorescent (RTP) afterglow.

[0028] In some embodiments of the present invention, when the small molecule host material is a compound having the structure shown in formula (H-3), the organic afterglow material is a long-lasting luminescent afterglow material. The introduction of the compound of formula (H-3) can construct a widely distributed network of "electron traps" with moderate energy levels at the host-guest interface. After the external excitation source is removed, these traps can slowly and continuously release previously stored charge carriers back to the luminescent center, thereby inducing a long-lasting luminescence (LPL) phenomenon lasting for thousands of seconds. This characteristic of achieving a leap in afterglow lifetime by changing only a single host perfectly meets the stringent requirements of advanced anti-counterfeiting and long-term information storage.

[0029] Second aspect This invention provides a method for preparing an organic afterglow material as described in the first aspect, characterized in that the preparation method includes the following steps: incorporating the organic guest luminescent material into the small molecule host material, grinding and mixing to obtain an intermediate mixture; heating the intermediate mixture to complete melting, and then cooling to obtain the organic afterglow material. Unlike traditional preparation routes that require complex chemical reactions or large amounts of toxic solvents, the process provided by this invention employs purely physical grinding and thermal melting methods, which not only fundamentally eliminates the potential interference of solvent residues on luminescence performance, but also utilizes a thermodynamic phase transition process to promote the guest molecules to achieve deep and uniform molecular-level penetration within the host melt. The subsequent cooling and solidification process instantly "freezes" this uniformly dispersed metastable structure, ensuring high uniformity and batch reproducibility of the macroscopic material's optical properties, making it suitable for large-scale industrial mass production.

[0030] In some embodiments of the present invention, the step of heating the intermediate mixture to complete melting is carried out on a heating plate under air conditions. Performing the melting step directly under conventional air conditions fully demonstrates the strong resistance to oxygen and water vapor and the thermodynamic stability of this organic afterglow material system. It also significantly reduces reliance on expensive vacuum equipment or inert gas-protected glove boxes, greatly shortens the preparation cycle, and reduces manufacturing costs, further highlighting the significant commercial advantages of this invention in practical applications.

[0031] Third aspect This invention provides an application of the organic afterglow material as described in the first aspect or the organic afterglow material prepared by the method described in the second aspect in the preparation of high-resolution X-ray imaging materials, optoelectronic devices, display materials, or anti-counterfeiting materials. Benefiting from the comprehensive tunability of the afterglow channel, emission wavelength, and duration of this organic afterglow material, as well as its extremely low detection limit and extremely high spatial resolution under X-ray excitation, its application in the aforementioned high-end optoelectronic and imaging fields can completely overcome the technical bottlenecks of traditional scintillator materials, such as single luminescence, poor flexibility, and the presence of toxic heavy metals. This provides essential core material support for the development of next-generation flexible wearable medical imaging devices, multi-layered dynamic anti-counterfeiting labels, and novel display devices.

[0032] Example The present invention will be further described in detail below with reference to specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0033] Unless otherwise specified, the raw materials, reagents, equipment, materials, instruments, etc. used in the embodiments described in this specification can all be obtained through general commercial channels.

[0034] The raw materials used in this invention specification, including the various compounds described below, were all purchased from Shanghai Titan Technology Co., Ltd. and Shanghai Bid Pharmaceutical Technology Co., Ltd.

[0035] The delayed emission spectra and the lifetime decay curves of the delayed emission spectra were recorded using an Agilent CaryEclipse spectrophotometer.

[0036] The radiation emission spectrum was recorded using an Edinburgh FLS1000 fluorescence spectrophotometer (Edinburgh Instruments Ltd.) equipped with a miniature X-ray source (AMPTEK).

[0037] The photo of the afterglow was taken with a Canon 200D II camera.

[0038] Example 1 This embodiment provides an organic guest luminescent material (taking the synthesis of a single compound composed of an electron acceptor group (A-3) and an electron donor group (D-1) linked by a single bond as an example), and its preparation method is as follows: (1) Add 4-bromo-N-butylnaphthalimide (1.00 g, 3.02 mmol, 1.0 eq), N,N-dimethyl-4-(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)aniline (0.90 g, 3.63 mmol, 1.2 eq), potassium carbonate (1.25 g, 9.06 mmol, 3.0 eq) and tetra(triphenylphosphine)palladium (0.17 g, 0.15 mmol, 0.05 eq) to a mixed solvent of 1,4-dioxane (25 mL) and deionized water (6 mL); (2) Stir the above reaction mixture overnight at 120°C under a nitrogen atmosphere; (3) Quench the reaction with water, extract with dichloromethane, combine the organic phases, dry with magnesium sulfate, filter, and concentrate; (4) Purification by silica gel column chromatography (eluent: dichloromethane: n-propanol = 1:1 volume ratio).

[0039] The organic guest luminescent material obtained in this embodiment is a yellow solid with a mass of 0.84 g and a yield of 74.29%.

[0040] The reaction formula for preparing the organic guest luminescent material is as follows: .

[0041] Example 2 This embodiment provides a performance-tunable organic afterglow material, the formulation and preparation method of which are as follows: (1) Weigh the organic guest luminescent material and the small molecule host material (H-1) prepared in Example 1 in a mass ratio of 0.1:99.9. (2) Grind the above small molecule host material and organic guest luminescent material evenly using a mortar and pestle to obtain an intermediate mixture (mixed powder). (3) The intermediate mixture obtained is placed on a heating plate and heated to 120°C in air until completely melted, and then cooled to obtain the tunable organic afterglow material.

[0042] Example 3 This embodiment provides a performance-tunable organic afterglow material, the formulation and preparation method of which are as follows: The preparation method of this embodiment is basically the same as that of Example 2. The only difference is that the small molecule host material in step (1) is replaced with compound of formula (H-2), and the mass ratio of organic guest luminescent material to small molecule host material (H-2) is 0.1:99.9; in step (3), it is heated to 60°C in air until completely melted.

[0043] Example 4 This embodiment provides a performance-tunable organic afterglow material, the formulation and preparation method of which are as follows: The preparation method of this embodiment is basically the same as that of Example 2. The only difference is that the small molecule host material in step (1) is replaced with compound (H-3), and the mass ratio of organic guest luminescent material to small molecule host material (H-3) is 0.1:99.9; in step (3), it is heated to 280°C in air until it is completely melted.

[0044] Example 5 This embodiment provides a series of tunable organic afterglow materials, the formulations and preparation methods of which are as follows: The preparation method of this embodiment is basically the same as that of Example 2. The only difference is that the small molecule host material in step (1) is replaced with compound of formula (H-4), and three samples with the mass percentage of organic guest luminescent material of 0.1%, 1% and 10% are prepared respectively; in step (3), the material is heated to 200°C in air until it is completely melted.

[0045] Example 6 This embodiment provides a transparent scintillator film for high-resolution X-ray imaging, the formulation and preparation method of which are as follows: (1) Weigh the organic guest luminescent material and the small molecule host material (H-4) prepared in Example 1 in a mass ratio of 1:99. (2) Grind the two together in a mortar and pestle to obtain an intermediate mixture (mixed powder); (3) The intermediate mixture was placed on a square quartz plate with a side length of 3 cm and heated to 200 °C in air until completely melted. Then it was cooled to obtain a transparent scintillator film.

[0046] Test case To verify the beneficial effects of the present invention, the following performance tests were conducted on the products obtained in the above embodiments: 1. Emission spectrum and luminescence lifetime testing: The materials prepared in the examples were tested using an Agilent Cary Eclipse spectrophotometer. At room temperature, the excitation wavelength was set to 360 nm, and the instantaneous maximum emission wavelength and delayed emission spectrum of the materials were recorded. For the luminescence lifetime test, a pulsed xenon lamp was used as the excitation source, and the decay curve of the luminescence intensity over time was recorded. The delayed luminescence lifetime (τ) was then calculated using a fitting method.

[0047] 2. Observation of the afterglow phenomenon: In a dark room at room temperature, the material was continuously irradiated for 5 seconds using a portable UV lamp with a wavelength of 365 nm and a power of 40 W. After the UV lamp was turned off, the afterglow color of the material was observed with the naked eye, and a stopwatch was used to record the duration from when the light source was turned off until the afterglow completely disappeared (becoming invisible to the naked eye).

[0048] 3. X-ray luminescence and limit of detection (LOD) test: The luminescence of the material was tested under X-ray excitation. A miniature X-ray tube was used as the X-ray source, with an operating voltage set between 0 and 50 kV. The radiation dose rate was varied by adjusting the current of the X-ray tube. The luminescence intensity of the material at different dose rates was recorded, and the minimum detection limit of the material for X-rays was calculated based on a signal-to-noise ratio (SNR) of 8.

[0049] Radiation luminescence stability test: Under a set fixed dose rate, the X-ray source was controlled to perform an "on-off" cycle, with each cycle lasting 12.5 seconds on and 12.5 seconds off, for a total of 30 cycles. The rate of change of the material's maximum luminescence intensity was recorded.

[0050] 4. X-ray imaging spatial resolution test: An X-ray imaging system was constructed using the transparent scintillator film prepared in Example 6. A miniature X-ray source (AMPTEK) with a tube voltage of 50 kV was used as the X-ray source. The film was placed in front of a commercial camera (EOS R5) as a scintillator screen.

[0051] Resolution test: A standard JIMA standard X-ray resolution test card is placed tightly against the film, and images are acquired under X-ray irradiation. The spatial resolution (lp mm) is determined by reading the number of the smallest resolvable line pairs in the image. - ¹).

[0052] Physical imaging: Under the same conditions, metal gaskets, integrated circuit chips, shrimp, and springs encapsulated in capsules were placed between an X-ray source and a thin film, and high-resolution X-ray images of their internal structures were acquired.

[0053] The test results are summarized in Table 1 below.

[0054] Table 1 Test results of Examples 2-6

[0055] As shown in Table 1, the organic afterglow materials prepared in the embodiments of the present invention can achieve significant modulation of the afterglow channel, emission wavelength (542~620nm), and duration (0.5s to over 1200s) by simply incorporating the same organic guest luminescent material into different small molecule host materials. Simultaneously, the H-4-based material exhibits excellent film-forming properties and an extremely low X-ray detection limit (22.4 nGy s). - ¹) Excellent resistance to radiation damage and extremely high X-ray imaging spatial resolution (12.5 lp mm) - ¹), which fully demonstrates the great application potential of this flexible donor-acceptor luminescent system in optoelectronic devices and high-resolution X-ray imaging.

[0056] like Figures 1 to 3 As shown, when formula (H-1) is used as the small molecule host material (Example 2), the prepared material exhibits thermally activated delayed fluorescence afterglow characteristics. Figure 1 It can be seen that their maximum emission wavelengths are 548 nm and 558 nm, respectively; from Figure 2 It can be seen that its luminescence lifetime is 81.48 ms; as Figure 3 As shown in the photograph of the actual material, after being excited and then turned off by ultraviolet light, the material produces a bright yellow afterglow that lasts for about 0.5 seconds.

[0057] like Figures 4 to 6 As shown, when formula (H-2) is used as the small molecule host material (Example 3), the prepared material exhibits room-temperature phosphorescent afterglow characteristics. Figure 4 It can be seen that its maximum emission wavelength undergoes a redshift, to 542 nm and 620 nm respectively; from Figure 5 It can be seen that its luminescence lifetime is extended to 101.59 ms; such as Figure 6 As shown, the material produces a red afterglow that lasts for about 1 second after the ultraviolet light is turned off.

[0058] like Figures 7 to 9 As shown, when formula (H-3) is used as the small molecule host material (Example 4), the prepared material exhibits excellent long-lasting luminescence afterglow characteristics. Figure 7 It can be seen that their maximum emission wavelengths are 546 nm and 574 nm, respectively; from Figure 8 The lifetime decay curves show that its luminescence lifetime increases by orders of magnitude, with a decay time exceeding 6000 s; for example... Figure 9 As shown, after the ultraviolet light is turned off, the material can produce a yellow afterglow lasting for about 1200 seconds, making it extremely suitable for long-term anti-counterfeiting and information storage.

[0059] like Figures 10 to 12 As shown, the X-ray radiation luminescence performance of the system using formula (H-4) as the small molecule host material (Example 5) was systematically evaluated. Figure 10 This indicates that the material exhibits bright radiative emission under X-ray excitation at different guest doping concentrations (0.1%, 1%, and 10%). Figure 11 The linear fitting results show that the lowest detection limit for X-rays of this material can reach 22.4 nGy s. - ¹, demonstrating extremely high detection sensitivity; Figure 12 Cyclic tests showed that after 30 cycles of X-ray excitation and de-excitation, the luminescence intensity of the material did not decrease significantly, demonstrating its excellent resistance to photodamage and radiation luminescence stability.

[0060] like Figure 13 As shown, thanks to the excellent film-forming properties and high luminous efficiency of the host material of formula (H-4), the transparent scintillator film prepared in Example 6 achieved a luminous efficiency as high as 12.5 lp mm. - ¹ Spatial resolution. Figure 13 The X-ray imaging results of the thin film on metal gaskets, internal wiring of integrated circuit chips, internal physiological structures of shrimp, and springs encapsulated in opaque capsules are presented intuitively. The images have sharp edges and clear details, which fully demonstrates the outstanding imaging capabilities of the material of this invention in the fields of non-destructive testing and high-resolution medical imaging.

[0061] The above description is merely a specific embodiment 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 performance-tunable organic afterglow material, characterized in that, The organic afterglow material includes organic guest luminescent materials and small molecule host materials; The organic guest luminescent material is a single compound with an electron donor-electron acceptor structure, wherein the compound is composed of an electron acceptor group and an electron donor group connected by a single bond; The electron acceptor group is selected from at least one group having the structure shown in formulas (A-1) to (A-3): ； The electron donor group is selected from at least one group having the structure shown in formulas (D-1) to (D-3): 。 2. The performance-tunable organic afterglow material as described in claim 1, characterized in that, The small molecule host material is selected from at least one compound having the structure shown in formulas (H-1) to (H-4): 。 3. The performance-tunable organic afterglow material as described in claim 1, characterized in that, Based on the total mass of the organic afterglow material being 100%, the mass percentage of the organic guest luminescent material is 0.1% to 10%, and the mass percentage of the small molecule host material is 90% to 99.9%.

4. The performance-tunable organic afterglow material as described in claim 3, characterized in that, Based on the total mass of the organic afterglow material being 100%, the mass percentage of the organic guest luminescent material is 0.1%, and the mass percentage of the small molecule host material is 99.9%.

5. The performance-tunable organic afterglow material as described in claim 2, characterized in that, When the small molecule host material is a compound having the structure shown in formula (H-1), the organic afterglow material is a thermally activated delayed fluorescence afterglow material.

6. The performance-tunable organic afterglow material as described in claim 2, characterized in that, When the small molecule host material is a compound having the structure shown in formula (H-2) or formula (H-4), the organic afterglow material is a room temperature phosphorescent afterglow material.

7. The performance-tunable organic afterglow material as described in claim 2, characterized in that, When the small molecule host material is a compound having the structure shown in formula (H-3), the organic afterglow material is a long-lasting luminescent afterglow material.

8. A method for preparing an organic afterglow material as described in any one of claims 1 to 7, characterized in that, The preparation method includes the following steps: The organic guest luminescent material is incorporated into the small molecule host material, and then ground and mixed to obtain an intermediate mixture; The intermediate mixture is heated until completely melted, and then cooled to obtain the organic afterglow material.

9. The preparation method according to claim 8, characterized in that, The step of heating the intermediate mixture to complete melting is carried out on a heating plate under air conditions.

10. The application of an organic afterglow material as described in any one of claims 1 to 7, or an organic afterglow material obtained by the preparation method as described in claim 8 or 9, in the preparation of high-resolution X-ray imaging materials, optoelectronic devices, display materials, or anti-counterfeiting materials.

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