Preparation method of rapidly-attenuated heat exciton type donor-acceptor complex and application of scintillator of rapidly-attenuated heat exciton type donor-acceptor complex

Abstract

The fast attenuation heat exciton type donor-acceptor complex is characterized by being prepared from a ligand, a connector, metal ions and an organic object in a molar ratio of 1: (1-4): (1-4): (1-10) through coordination and charge transfer. The preparation method comprises the following steps: putting a metal salt, a ligand, a connector and an organic object into a mixed solution of DMF (Dimethyl Formamide), EtOH and H2O; and sealing and heating to form a complex crystalline material. The invention relates to scintillator application. A ligand, a connector and metal ions are coordinated to form a complex acceptor framework, and an organic guest is used as a donor to be filled into pores to form a donor-acceptor configuration heat exciton luminescence mechanism. By replacing ligand acceptor molecules, the photophysical mechanism of the material from delayed fluorescence to fast attenuation heat excitons can be realized, and the regulation and control of emission wavelength and attenuation life can also be realized. The complex disclosed by the invention shows better scintillator properties under ray excitation, including considerable light yield, higher exciton attenuation efficiency and lower radiation detection limit and radiation stability.

Description

(I) Technical Field:

[0001] This invention relates to the field of coordination polymers, and in particular to fast-decaying thermal exciton-type donor-acceptor complexes, their preparation methods and applications, specifically a method for preparing fast-decaying thermal exciton-type donor-acceptor complexes and their scintillator applications. (II) Background Technology:

[0002] With the advancement and development of high-energy physics experiments, and the rapid development of cutting-edge medical imaging technologies (such as time-of-flight positron emission tomography), fields such as space exploration and medical imaging have placed higher demands on the performance optimization of scintillator materials—the core component of radiation detection. Specifically, scintillator materials must not only possess high density and high stopping power to effectively absorb radiation, but the core challenge lies in simultaneously achieving high light yield and ultrafast photon decay efficiency. In traditional scintillator material research, the two key indicators of high light yield and ultrafast photon decay efficiency are mutually restrictive. The former determines the scintillator's sensitivity and energy resolution for radiation detection, while the latter is a prerequisite for achieving ultra-high temporal resolution and reducing signal noise. Although traditional inorganic scintillators have high light yields, their decay times are mostly in the microsecond to millisecond range, essentially due to the parity selection rule of rare-earth ion transitions. Furthermore, while organic scintillators can achieve ultrafast decay at the nanosecond level, their low atomic numbers, weak radiation stopping power, and low exciton utilization efficiency make it difficult to achieve high light yields. Therefore, the mutual constraint between "efficiency and speed" has become a crucial technical bottleneck that scintillator materials urgently need to overcome. The fast-decaying "thermal exciton" mechanism, originating from the field of organic optoelectronics, provides a foundation for solving the aforementioned problem of mutual constraints among performance indicators. The core advantage of thermal exciton materials lies in controlling the excited-state dynamics process to reduce the singlet-triple energy level difference, allowing excitons in the highly excited triplet state (thermal triplet excitons) to return to the singlet state and emit fluorescence via rapid reverse intersystem crossing, with a theoretical exciton utilization rate of 100%. While providing high exciton utilization for scintillator materials to achieve high light yield, the intrinsic decay lifetime can be maintained at the nanosecond level due to the fluorescence transition, achieving high scintillation efficiency and ultrafast response. Thermal exciton materials typically possess rigid and twisted donor-acceptor structural configurations; however, due to the complex synthesis and preparation processes of organic fast-decaying thermal exciton materials, materials with high light yield still require optimization and exploration. (III) Summary of the Invention:

[0003] In view of the shortcomings of the prior art, the present invention aims to provide fast-decaying thermal exciton-type donor-acceptor complexes, their preparation methods, and applications. Firstly, the metal ions / metal clusters of the coordination polymers possess high atomic numbers, enabling effective absorption of radiation. The diversity of building blocks facilitates the realization of delayed fluorescence properties in the materials. Secondly, the composition of the complexes offers diverse options; the donor-acceptor system can be integrated into a ligand via covalent bonds, or constructed through host-guest configurations and supramolecular interactions. Furthermore, crystalline complexes are easy to process and can be mixed with polymer substrates to form films. Combining the above, the aim is to construct novel fast-decaying thermal exciton-type coordination polymers and utilize the multi-level synergistic regulation of the coordination polymer's "composition-structure-properties" to achieve fast-decaying thermal exciton-type scintillator crystalline materials. Finally, non-destructive imaging can be achieved using scintillator films doped with polymer substrates.

[0004] The technical solution of the present invention is a fast-decaying thermal exciton-type donor-acceptor complex, which is prepared by coordination and charge transfer through coordination of a ligand, a linker, a metal ion, and an organic guest in a molar ratio of 1:(1-4):(1-4):(1-10); the ligand acts as an acceptor, and coordinates with the linker and the metal to form a triple-interpenetrating hexagonal nested cage structure; the organic guest acts as a donor.

[0005] The general formula of the complex is [M4(ligand)2(linker)3(H2O)4]·2(guest), where M is a metal ion.

[0006] The ligand is pyridine triazine (TPT), or tripyridylpyrimidine (TPB), or tripyridylpyridine (TPP);

[0007] The linker is selected from one of the following: terephthalic acid (PTA), 1,4-cubicanedicarboxylic acid and its derivatives, 2,5-furandicarboxylic acid and its derivatives, 1,3-bicyclo[1.1.1]pentanedicarboxylic acid and its derivatives, 3,6-thieno[3,2-B]thienodicarboxylic acid and its derivatives, and derivative molecules in which two formic acids are para-substituted by an independent small group in the middle.

[0008] The metal ions are transition metal ions, alkali metal ions, or alkaline earth metal ions.

[0009] The organic guest molecule is selected from one of benzo[B]benzo[4,5]thieno[2,3-D]thiophene (BTP) and its derivatives, or phenyl anthracene and its derivatives.

[0010] A method for preparing rapidly decaying thermal exciton-type donor-acceptor complexes includes the following steps:

[0011] (1) Take metal salt, linker, ligand and organic guest molecule and put them into a mixed solution of DMF, EtOH and H2O; wherein the molar ratio of ligand: linker: metal ion: organic guest molecule is 1:(1-4):(1-4):(1-10);

[0012] (2) After sealing, heating will eventually produce crystals.

[0013] In step (1), the volume ratio of DMF, EtOH and H2O is 1:1:1.

[0014] In step (2), the heating temperature is 90-100℃ and the time is 24-48h.

[0015] In step (2), after sealing, the container is placed in a constant temperature and humidity heating chamber for heating, and finally a complex crystalline material is formed inside the reaction vessel through coordination.

[0016] The preferred molar ratio of ligand:linker:metal ion:organic guest molecule is 1:2:2:2.

[0017] The metal ion is selected as cadmium ion, the ligand is selected as pyridine triazine, the linker is selected as terephthalic acid, and the organic guest molecule is selected as benzo[B]benzo[4,5]thieno[2,3-D]thiophene. The resulting complex is [Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystal.

[0018] Preparation of [Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystals: Cadmium metal salt, terephthalic acid, pyridine triazine, and BTP were taken in proportion and placed in a container containing a mixed solution of DMF, EtOH, and H2O. After sealing, the mixture was heated to finally produce orange-yellow crystals, namely [Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystals.

[0019] The metal ion is selected as cadmium ion, the ligand is selected as tripyridylpyridine, the linker is selected as terephthalic acid, and the organic guest molecule is selected as benzo[B]benzo[4,5]thieno[2,3-D]thiophene. The resulting complex is [Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystal.

[0020] Preparation of [Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystal: Cadmium metal salt, terephthalic acid, tripyridylpyridine, and BTP were taken in proportion and placed in a container containing a mixed solution of DMF, EtOH, and H2O. After sealing, the mixture was heated to finally produce light green crystals, namely [Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystal.

[0021] The fast-decaying thermal exciton-type donor-acceptor complex is used for X-ray detection and non-destructive imaging.

[0022] The fast-decaying thermal exciton-type donor-acceptor complex and its scintillator applications are described. Optionally, to ensure high light yield and fast exciton decay efficiency in X-ray detection, we first conducted photophysical property tests to verify its thermal exciton characteristics; in addition, we characterized the scintillator properties under X-ray irradiation.

[0023] To investigate the photophysical properties of the material, the ultraviolet-visible absorption spectra of a series of complexes and the comparative spectra of the complexes and their components were measured to verify the effective charge transfer between donors and acceptors in the complexes. The room-temperature emission spectra and decay curves of the complexes, as well as the temperature-dependent emission spectra and decay curves of the complexes, were tested to further verify the mechanism. The transient absorption curves of the material were tested to analyze its excited-state dynamics and verify the thermal exciton properties.

[0024] To investigate the scintillator properties of the material, the scintillation performance of a series of coordination polymer materials was systematically characterized. First, the radiative emission intensity under X-rays was measured, and the light yield relative to the BGO standard sample was calculated. The radiation detection limit was then deduced based on the response curves at different dose rates. Simultaneously, the switching stability of the material's light output under constant irradiation was tested. Furthermore, the material was fabricated into a PDMS-based flexible scintillation film, and X-ray imaging verification was successfully achieved.

[0025] A fast-decaying thermal exciton-type donor-acceptor complex is used to prepare a flexible scintillator self-supporting film. The specific method is as follows: high-purity complex crystals are selected, and the crystalline material is first uniformly ground to the micron level. The micron-sized sample powder of the complex is mixed with polydimethylsiloxane (PDMS). The air bubbles are driven to the surface of the mixture by ultrasound and stirring to make the two fully mixed. After heating for 24 hours and standing, a flexible scintillator self-supporting film is finally formed.

[0026] The crystal purity of the complex is greater than 99%, and the micron-sized sample powder of the complex is 0.2-40 microns; the micron-sized sample powder of the complex is mixed with polydimethylsiloxane (PDMS) at a ratio of 2:4 (g:ml).

[0027] The technical effects of this invention are as follows: 1. This invention achieves a photophysical mechanism that transforms materials from delayed fluorescence to rapid decay thermal excitons by changing the ligand-acceptor molecules. When the electron-withdrawing ability of the acceptor molecule decreases from strong to weak, the photophysical mechanism changes from delayed fluorescence to thermal exciton; this ensures efficient utilization of excitons while also achieving rapid exciton decay.

[0028] 2. This invention can not only control the photophysical mechanism and excited state process in systems with different acceptor electron-withdrawing capabilities, but also control the emission wavelength and decay lifetime (emission wavelength: 510-580nm; decay lifetime: 12.72-290ns).

[0029] 3. This invention enables the modulation of the energy level difference between singlet and triplet states in systems with different acceptor electron-withdrawing capabilities, as well as the modulation of excited triplet states with effective kinetic decay.

[0030] 4. The preparation process provided by this invention has the advantages of simple operation, mild conditions and strong controllability. The yield of the prepared material is high and the synthesis route is simple. Unlike the complex preparation method of traditional inorganic crystalline scintillation materials that relies on high temperature and high pressure, it significantly reduces energy consumption and raw material loss. At the same time, the obtained product has good thermal processing performance, thus ensuring that the material has good film-forming stability. It is expected to manufacture a new type of scintillator material based on fast decay thermal exciton type donor-acceptor complex.

[0031] 5. In this invention, a complex acceptor framework is formed by coordination of ligands, linkers and metal ions. The organic guest, as a donor, is encapsulated inside the main framework during the self-assembly process through donor-acceptor charge transfer, thereby forming a fast-decaying thermal exciton emission based on charge transfer across space.

[0032] 6. This invention achieves a series of excited-state energy level modulations for coordination compounds by replacing ligand components in the structure and reducing the conjugation degree of guest molecules or designing them to have bipolar properties. The coordination compounds exhibit fast-decaying thermal exciton fluorescence emission properties. At the same time, by increasing the non-conjugation degree of the guest molecules, the photophysical properties of the thermal exciton coordination compounds are regularly adjusted, enabling X-ray detection and non-destructive imaging applications of flexible thin films of the coordination compounds.

[0033] Advantages of the present invention: 1. The present invention provides a fast decaying thermal exciton-type donor-acceptor complex, which forms a complex acceptor framework by coordination of ligands, linkers and metal ions, and organic guests fill the pores as donors to form a donor-acceptor configuration thermal exciton luminescence mechanism.

[0034] 2. This invention enables the photophysical mechanism of material transitioning from delayed fluorescence to fast decaying thermal excitons by changing the ligand-acceptor molecules, and also enables the modulation of emission wavelength and decay lifetime.

[0035] 3. The complexes of the present invention all exhibit good scintillator properties under radiation excitation, including considerable light yield, fast exciton decay efficiency, and low radiation detection limit and irradiation stability.

[0036] 4. By replacing the acceptor ligand, the energy level difference between singlet and triplet states can be controlled, as well as the excited triplet state with effective kinetic decay can be controlled. (iv) Description of the attached drawings:

[0037] Figure 1 The chemical formulas are for terephthalic acid, pyridine triazine, benzo[B]benzo[4,5]thieno[2,3-D]thiophene, and tripyridylpyridine.

[0038] Figure 2 It is a triple-interpenetrating hexagonal nested cage-like crystal structure of the complex PF1.

[0039] Figure 3 To develop an exciton level transition mechanism for achieving fast decay and high exciton utilization in thermal exciton materials.

[0040] Figure 4 The images show the UV-Vis absorption spectra of the solid states of the complexes PF1 and PPF1 in the examples.

[0041] Figure 5 The emission spectra of complexes PF1 and PPF1 in the solid state in the examples are shown.

[0042] Figure 6-1 , Figure 6-2 The fluorescence emission decay curves of complexes PF1 and PPF1 in the solid state are shown in the examples.

[0043] Figure 7 The images show the radiative emission spectra of the solid states of the complexes PF1 and PPF1 in the examples.

[0044] Figure 8 This study demonstrates the imaging of objects using flexible films containing a series of delayed fluorescence complexes PF1 and PPF1 under X-ray excitation.

[0045] Figure 9 The transient absorption spectrum of the complex PPF1 is shown.

[0046] Figure 10 The temperature-dependent emission spectrum of the complex PPF1.

[0047] Figure 11-1 , Figure 11-2 The temperature decay curve of the complex PPF1. (V) Specific Implementation Methods:

[0048] Example: A fast-decaying thermal exciton-type donor-acceptor complex is prepared from a ligand, a linker, a metal ion, and an organic guest in a molar ratio of 1:2:2:1; the ligand acts as an acceptor, coordinating with the linker and the metal ion to form a triple-interpenetrating hexagonal nested cage structure; the organic guest acts as a donor.

[0049] Crystalline coordination compounds with rapidly decaying thermal exciton properties and their preparation methods:

[0050] Preparation of PF1[Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystals: Take cadmium metal salt Cd(NO3)4… 3)2 0.1 mmol of 4H2O, 0.1 mmol of terephthalic acid (linker), 0.05 mmol of pyridine triazine, and 0.05 mmol of BTP (guest) were placed in a 20 ml vial containing 12 ml of a mixed solution. The mixed solution contained 4 ml of DMF, 4 ml of EtOH, and 4 ml of H2O. The vial was tightly capped and placed in a 100°C oven for 20 hours. Orange-yellow crystals, namely [Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystals, were eventually formed, denoted as PF1.

[0051] Preparation of PPF1[Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystals: According to the above synthesis method, tripyridylpyridine, terephthalic acid, cadmium ions and guest BTP were taken in the same dosage and placed in a 20ml vial containing 12ml of mixed solution. The mixed solution contained 4ml of DMF, 4ml of EtOH, and 4ml of H2O. The vial was tightly capped and placed in a 100℃ oven for 20 hours. Finally, light green crystals were generated, namely [Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystals, denoted as PPF1.

[0052]

[0053] Table 1

[0054] All the above synthetic methods employ quantitative feeding of components, i.e., the optimal feeding amount; the complexes can also be synthesized according to the optimal feeding ratio. In the optimal feeding ratio, the molar ratio between pyridine triazine, the linker (including terephthalic acid; 2-methylterephthalic acid, etc.), cadmium ions (including cadmium nitrate tetrahydrate, cadmium chloride, cadmium oxide), and the guest molecule is: pyridine triazine: linker: cadmium ion: guest molecule = 1:2:2:1. Furthermore, the amount of guest molecule fed into this system can also be changed. In summary, regardless of the optimal feeding ratio, the above complexes can be obtained with a pyridine triazine: linker: cadmium ion: guest molecule ratio of 1:(1-4):(1-4):(1-10), the difference being the purity and yield of the synthesized sample.

[0055] A fast-decaying thermal exciton-type donor-acceptor complex and its scintillator applications. First, the scintillator properties of a series of coordination polymer materials were systematically characterized: their radiative emission intensity under X-rays was measured, and their light yield relative to BGO standard samples was calculated. The radiation detection limit was then deduced based on the response curves at different dose rates. Simultaneously, the switching stability of the material's light output under constant irradiation was tested.

[0056] A fast-decaying thermal exciton-type donor-acceptor complex is used to prepare a flexible scintillator film. The specific method is as follows: high-purity complex crystals are selected, and the crystalline material is first uniformly ground to the micron level. The micron-sized sample powder of the complex is mixed with a polydimethylsiloxane (PDMS) solution at a ratio of 2:4 (g:ml). The air bubbles are driven to the surface of the mixture by ultrasound and stirring to ensure thorough mixing. After heating for 24 hours and allowing it to stand, a flexible scintillator self-supporting film is finally formed.

[0057] The crystal purity of the complex is greater than 99%, and the micron-sized sample powder of the complex is 0.2-40 micrometers.

[0058] like Figure 1 As shown, the chemical structures of some examples of the ligands (pyridine triazine, tripyridylpyridine), linkers (terephthalic acid), and guests (benzo[B]benzo[4,5]thieno[2,3-D]thiophene) are presented.

[0059] like Figure 2 As shown, the crystal hexagonal nested structure of the complex example PF1 is illustrated.

[0060] like Figure 3 As shown, the exciton level transition mechanism that enables thermal exciton materials to achieve fast decay and high exciton utilization is demonstrated.

[0061] like Figure 4 As shown, in the UV-Vis absorption spectroscopy test, the series of complexes all exhibited a broad absorption range from 380 to 550 nm. Unlike the absorption at 300-350 nm, which is attributed to the π→π* absorption transition of the organic components, the absorption at 380-550 nm can be attributed to the charge transfer absorption between the DA components. This also proves that the guest is successfully encapsulated within the framework and generates effective charge transfer interactions between the DA components with the acceptor ligand molecules.

[0062] In the emission spectroscopy test, the excitation wavelength was 370 nm; the test results are as follows: Figure 5 As shown, the emission peak of complex PF1 has a wide full width at half maximum (FWHM), exhibiting typical charge-transfer emission peak characteristics. Its room-temperature emission peak is around 580 nm, and it undergoes a significant redshift with increasing temperature. This redshift can be attributed to the increase in non-radiative transitions in the material caused by atomic thermal vibrations induced by temperature increases. PPF1, on the other hand, exhibits completely different emission spectra at different temperatures. The emission spectrum around 90 K shows three relatively distinct separate emission peaks, with the emission peaks at 500 nm and 525 nm having comparable intensities. At room temperature, however, there is only a charge-transfer emission peak at 510 nm.

[0063] like Figure 6-1 , Figure 6-2The fluorescence emission decay curves shown indicate that PF1 exhibits both transient decay (10.95 ns) and delayed decay (0.29 μs) components, with decay times reaching the microsecond level, clearly representing a thermally activated delayed fluorescence process. In contrast, the decay curve of PPF1 displays both a transient component (3.63 ns) and a delayed component (12.72 ns) under rapid decay. The former can be attributed to the rapid decay of the singlet state (S1), while the latter can be attributed to the exciton transition from S1 to T... n (High triple excited state) → S1 rapid reverse intersystem crossing process, T n →The faster decay rate of S1 is due to T n The energy level is often higher than the S1 energy level, thus it is a thermodynamically spontaneous process. The unique decay curve and emission characteristics of PPF1 suggest that it may possess thermal exciton processes.

[0064] like Figure 7 As shown, the radiation dose rate is 108.1 mGy / s. -1 X-rays were used to irradiate and excite the series of complexes, which exhibited considerable irradiance.

[0065] like Figure 8 As shown, the thin film prepared by mixing the complex and PDMS was subjected to a radiation dose rate of 108.1 mGy / s. -1 Object penetration imaging was performed under X-ray irradiation; from the imaging results, the complex prepared into a thin film still has good light yield and good spatial resolution, and the contrast of the object is relatively clear, demonstrating the potential application of the complex in X-ray imaging.

[0066] like Figure 9 The transient absorption spectrum of the complex PPF1 is shown. The transient absorption spectrum indicates that the energy level states (localized-charge-transfer mixed state, HLCT) initially formed between 0 and 0.8 ns exhibit inter-level absorption followed by decay. Between 0.8 and 1.6 ns, the formation of a second energy level state (cross-space charge transfer, TSCT) and its inter-level absorption are also observed. Because the TSCT state requires excitation of the donor followed by charge transfer to the acceptor, its formation mechanism requires a two-component charge transfer step compared to HLCT, thus taking longer to form.

[0067] like Figure 10 The image shows the temperature-dependent emission spectrum of the complex PPF1. According to the temperature-dependent emission spectrum contour plot of PPF1, the distinct dual emission peaks exhibited at 90 K gradually weaken to no signal at 525 nm as the temperature increases, while the 500 nm emission peak still maintains a significant emission signal intensity, subsequently broadening and redshifting with further temperature increases.

[0068] like Figure 11-1 , Figure 11-2 As shown, the temperature-dependent decay curves of the two emission peaks of PPF1 at 500 nm and 520 nm are characterized. At 500 nm, the transient fast decay component gradually decreases with increasing temperature, while the transient delayed decay component gradually increases with increasing temperature. The emission peak at 525 nm shows the opposite trend. Based on the aforementioned photophysical properties and the several different types of energy levels that may exist in this material, we deduced the luminescence mechanism of PPF1 exhibiting anomalous emission characteristics. First, PPF1 contains localized (LE) energy levels belonging to the monomeric component, a cross-space charge transfer (TSCT) energy level formed under DA interaction, and a hybrid localized-charge transfer (HLCT) energy level formed by the hybridization of the two energy levels. Due to its extremely fast relaxation rate and temperature instability, the LE energy level exhibits a shoulder peak around 460 nm at 90 K, but this gradually disappears with increasing temperature. The HLCT and TSCT states exhibit an energy level order determined by their interactions. The HLCT state, which lies between LE and TSCT, has a slightly higher energy level than the TSCT state. That is, in the emission spectrum, the emission spectrum at 500 nm can be attributed to HLCT emission, while the emission spectrum at 525 nm can be attributed to TSCT emission. At lower temperatures, excitons that have undergone relaxation at higher energy levels are distributed more evenly between the HLCT and TSCT energy levels. Therefore, at 90 K, the two exhibit relatively similar light emission intensities. As the temperature increases, heat helps the excitons in the TSCT energy level overcome the energy level difference with the HLCT state, causing the luminescence at the TSCT level to gradually weaken and eventually disappear, while the emission at the HLCT energy level continues.

Claims

1. A fast-decaying thermal exciton-type donor-acceptor complex, characterized in that... It is prepared by coordination and charge transfer through coordination of ligands, linkers, metal ions and organic guests with a molar ratio of 1:(1-4):(1-4):(1-10); the ligands act as acceptors and coordinate with linkers and metals to form a triple interpenetrating hexagonal nested cage structure; the organic guests act as donors.

2. The fast-decaying thermal exciton-type donor-acceptor complex according to claim 1, characterized in that... The general structural formula of the complex is [M4(ligand)2(linker)3(H2O)4]·2(organic guest), where M is a metal ion.

3. The fast-decaying thermal exciton-type donor-acceptor complex according to claim 1 or 2, characterized in that... The ligand is pyridine triazine (TPT), or tripyridylpyrimidine (TPB), or tripyridylpyridine (TPP); The linker is selected from one of the following: terephthalic acid (PTA), 1,4-cubic alkyldicarboxylic acid and its derivatives, 2,5-furan alkyldicarboxylic acid and its derivatives, 1,3-bicyclo[1.1.1]pentane alkyldicarboxylic acid and its derivatives, 3,6-thieno[3,2-B]thieno alkyldicarboxylic acid and its derivatives, and derivative molecules in which two formic acids are para-substituted by an independent small group in the middle. The metal ions are transition metal ions, alkali metal ions, or alkaline earth metal ions. The organic guest molecule is selected from one of benzo[B]benzo[4,5]thieno[2,3-D]thiophene (BTP) and its derivatives, or phenyl anthracene and its derivatives.

4. The fast-decaying thermal exciton-type donor-acceptor complex according to claim 1 or 2, characterized in that... The metal ion is selected as cadmium ion, the ligand is selected as pyridine triazine, the linker is selected as terephthalic acid, and the organic guest molecule is selected as benzo[B]benzo[4,5]thieno[2,3-D]thiophene. The resulting complex is [Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystal. Preparation of [Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystals: Cadmium metal salt, terephthalic acid, pyridine triazine, and BTP were taken in proportion and placed in a container containing a mixed solution of DMF, EtOH, and H2O. After sealing, the mixture was heated to finally produce orange-yellow crystals, namely [Cd4(TPT)2(PTA)3(H2O)4]·2(BTP) crystals.

5. The fast-decaying thermal exciton-type donor-acceptor complex according to claim 1 or 2, characterized in that... The metal ion is selected as cadmium ion, the ligand is selected as tripyridylpyridine, the linker is selected as terephthalic acid, and the organic guest molecule is selected as benzo[B]benzo[4,5]thieno[2,3-D]thiophene. The resulting complex is [Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystal. Preparation of [Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystals: Cadmium metal salt, terephthalic acid, tripyridylpyridine, and BTP were taken in proportion and placed in a container containing a mixed solution of DMF, EtOH, and H2O. After sealing, the mixture was heated to finally produce light green crystals, namely [Cd4(TPP)2(PTA)3(H2O)4]·2(BTP) crystals.

6. The method for preparing the fast-decaying thermal exciton-type donor-acceptor complex according to claim 1, characterized in that... Includes the following steps: (1) Take metal salts, linkers, ligands and organic guest molecules and put them into a mixed solution of DMF, EtOH and H2O; Among them, ligands: The molar ratio of linker:metal ion:organic guest molecule is 1:(1-4):(1-4):(1-10); (2) After sealing, heat it to eventually generate crystals.

7. The method for preparing the fast-decaying thermal exciton-type donor-acceptor complex according to claim 6, characterized in that... In step (1), the volume ratio of DMF, EtOH and H2O is 1:1:1; In step (2), the heating temperature is 90-100℃ and the time is 24-48h.

8. The application of the fast-decaying thermal exciton-type donor-acceptor complex according to claim 1, characterized in that... It is used for X-ray inspection and non-destructive imaging.

9. The application of the fast-decaying thermal exciton-type donor-acceptor complex according to claim 1, characterized in that... Used to prepare flexible scintillator self-supporting films.

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