Preparation method and application of green light-emitting hybrid manganese halide crystal

Abstract

The application belongs to the technical field of luminescent materials, and specifically discloses a preparation method of a green luminescent hybrid manganese halide crystal. Zero-dimensional hybrid manganese-based halides with excellent luminescent performance are prepared by means of ingenious design of organic cations and a simple volatilization method. The zero-dimensional hybrid manganese-based halides have high quantum yield and negligible self-absorption, have extraordinary radiation luminescent performance, and have light yields of 61809 ph / MeV and 55569 ph / MeV, respectively, which are far higher than 25000 ph / MeV of commercial LuAG:Ce, and the zero-dimensional hybrid manganese-based halides are applied to X-ray imaging.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of luminescent materials, and particularly relates to a preparation method and application of a green luminescent hybrid manganese halide crystal. BACKGROUND

[0002] X-ray scintillators are an important component of medical imaging, non-destructive testing, environmental monitoring, and security screening. The scintillator absorbs X-rays and converts them into visible light radiation, and then a projection image of the object can be obtained using a visible light camera. The most widely used commercial scintillator is NaI(Tl), CsI(Na), LYSO, and PbWO4. Despite decades of intensive research, scintillators are still imperfect. First, the conversion efficiency of light is still very limited, and in addition, almost all commercial scintillators are prepared at high temperature and high pressure, which increases their cost and preparation difficulty, and the inherent rigidity cannot meet the growing demand for flexible electronic products.

[0003] In recent years, metal halide perovskites have been widely used in X-ray sensors due to their high photoluminescence quantum yield (PLQY), strong absorption, long carrier diffusion length, high defect tolerance, and environmentally friendly processing. In addition, the soft nature of perovskites makes them potential candidates for flexible integration of imaging sensors. To date, many new technologies have been developed for the preparation of perovskite X-ray detectors. Henning et al. used inkjet printing technology to prepare a flexible perovskite X-ray detector. The advantages of this technology are high reproducibility and strong stability. Huang et al. reported that the good connectivity and crystallinity of perovskite crystals in the perovskite-filled film created a smooth surface, resulting in good imaging quality. Polymer encapsulation can also be used to prepare flexible thin films of X-ray detectors, achieving stable and efficient X-ray detection. Lead-free perovskite single crystals, such as Cs2AgBiBr6, Cs3Bi2I9, and Cs3Cu2I5, have also been applied to X-ray detection. However, the fabrication process of high-quality scintillator thin films is often complex, which may hinder their large-scale production.

[0004] Flexible scintillators are usually prepared by combining perovskite nanocrystal powders with polymers. For example, Zeng et al. prepared a large-area thin film by adding CsPbBr3@Cs4PbBr6 powder to a polystyrene / toluene solution; Liang et al. introduced BA2PbBr4:Mn(II) solid powder into polymethyl methacrylate / dichloromethane to achieve a scintillator with high-resolution X-ray imaging.

[0005] In recent years, manganese-based metal halides have shown high emission performance and good stability, making them the most advanced scintillating materials. Tao and colleagues prepared a Mn 2+A temperature-dependent tunable dual emission, i.e. an additional emission center from STEs, was found in the 0D hybrid (C4H9NH3)2MnI4, which is a 0D Mn 2+ The first example in the metal halide. Unfortunately, most of the manganese halide complexes are not ideal for X-ray imaging applications, and the irradiance luminescence intensity is weak under X-ray irradiation compared with commercial scintillators, and the imaging effect is poor.

[0006] Therefore, it is an urgent problem to be solved in the prior art to provide an organic-inorganic hybrid manganese metal halide which can be used as an X-ray scintillator material, has high fluorescence quantum yield and good air stability. SUMMARY

[0007] To solve the above technical problems, the present application provides a preparation method of a green light-emitting hybrid manganese halide crystal, which ingeniously designs organic cations and uses a simple volatilization method to prepare a zero-dimensional hybrid manganese-based halide with excellent luminescent performance, high quantum yield and negligible self-absorption, extraordinary radiation luminescent performance, and light yields of 61809 ph / MeV and 55569 ph / MeV, far exceeding the 25000 ph / MeV of commercial LuAG:Ce, and applies it to X-ray imaging.

[0008] To achieve the above purpose, the present application is realized by the following technical scheme:

[0009] On the one hand, the present application provides a preparation method of a green light-emitting hybrid manganese halide crystal, comprising the following steps:

[0010] S1: Dissolve 1,4-diazabicyclo[2,2,2]octane in an organic solvent, then add 2-bromoethylbenzene, stir to form a white precipitate, and then treat to obtain ethylphenyltrivinyldiamine bromide organic ligand;

[0011] S2: Add manganese halide and ethylphenyltrivinyldiamine bromide organic ligand to an organic solvent, mix thoroughly, and heat and volatilize to obtain a manganese halide organic-inorganic hybrid crystal.

[0012] Preferably, the molar ratio of 1,4-diazabicyclo[2,2,2]octane to 2-bromoethylbenzene in S1 is 1:1.

[0013] Preferably, the concentration of 1,4-diazabicyclo[2,2,2]octane in the organic solvent in S1 is 1 mmol / (1-2) mL.

[0014] Preferably, in the step S1, the 1,4-diazabicyclo[2,2,2]octane is dissolved in the organic solvent, the 2-bromoethylbenzene is added under stirring, and the ethylphenyltrivinyldiamine bromide organic ligand is prepared by stirring for 3h, centrifuging, washing and drying after forming a white precipitate.

[0015] Preferably, in the step S2, the molar ratio of the manganese halide and the ethylphenyltrivinyldiamine bromide organic ligand is 1:(2-2.2).

[0016] Preferably, in the step S2, the concentration of the manganese halide in the organic solvent is 1mmol / (10-15)mL, and the concentration of the ethylphenyltrivinyldiamine bromide organic ligand in the organic solvent is 2mmol / (20-25)mL.

[0017] Preferably, in the step S2, the manganese halide and the ethylphenyltrivinyldiamine bromide organic ligand are added to the organic solvent respectively, filtered respectively, mixed thoroughly, and heated and volatilized to obtain the manganese halide organic-inorganic hybrid crystal.

[0018] Preferably, in the step S2, the heating treatment is performed at a temperature of 55-75℃ for 6-10h.

[0019] In another aspect, the application provides an application of the manganese halide organic-inorganic hybrid crystal prepared by the above method to preparation of an X-ray scintillator.

[0020] Preferably, the method for preparing the X-ray scintillator from the manganese halide organic-inorganic hybrid crystal comprises the following steps:

[0021] S1: first, the manganese halide organic-inorganic hybrid crystal is ground into powder, and then the powder is ultrasonically dispersed in a dichloromethane solution to obtain a mixture containing a manganese-based metal organic-inorganic hybrid halide;

[0022] S2: the solution containing the manganese-based metal organic-inorganic hybrid halide is mixed with polydimethylsiloxane PDMS, wherein the mass ratio of the manganese halide powder and the polydimethylsiloxane PDMS is 1:(1-2), and then ultrasonic stirring is performed to obtain a colloidal solution;

[0023] S3: the obtained colloidal solution is dropped on a glass sheet by using a spin coating method, heated at 120℃ for 12h, and finally a scintillator thin film is obtained.

[0024] The application has the following beneficial effects:

[0025] The manganese halide organic-inorganic hybrid crystal provided by the application has a molecular formula of (pe-ted)2MnX4; pe-ted +The ethylphenyltriethylenediamine cation; X is at least one of Cl and Br, belonging to ethylphenyltriethylenediammonium salt. The benzene ring connected by N on the ethylphenyltriethylenediammonium salt cation in the structure enhances the interaction between atoms within the material and reduces the defect state density, thereby improving the overall stability and luminescence efficiency of the manganese-based metal organic-inorganic hybrid metal halide crystal. It exhibits excellent crystallinity, high quantum yield and negligible self-absorption, and has extraordinary radioluminescence performance. The light yield is 61809ph / MeV and 55569ph / MeV, respectively, far exceeding the 25000ph / MeV of commercial LuAG:Ce, which is conducive to its application in high-quality X-ray imaging. In addition, due to the pe-ted + The highly hydrophobic manganese-based metal organic-inorganic hybrid crystals show good air stability and can maintain stable luminescence and radiation properties after storage in ambient air for more than 1 month, which is much better than the recently reported all-inorganic compound Cs3MnI. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0027] Figure 1 is the mass spectrum of the organic ligand pet-ted ligand;

[0028] Figure 2 is the NMR image of the organic ligand PET-TED ligand;

[0029] Figure 3 Schematic diagram of the structure of the organic ligand pet-ted ligand;

[0030] Figure 4 Schematic diagram of the unit cell structure of the compound (pe-ted)2MnBr4;

[0031] Figure 5 For the compound (pe-ted)2MnCl 2.06 Br 1.94 Schematic diagram of the unit cell structure;

[0032] Figure 6 For the compound (pe-ted) 2MnBr4 and the compound (pe-ted) 2MnCl 2.06 Br 1.94 Powder diffraction pattern and single crystal structure simulated X-ray diffraction pattern;

[0033] Figure 7Thermogravimetric and microcalorimetric thermogravimetric plot for compound (pe-ted)2MnBr4;

[0034] Figure 8 Thermogravimetric and microcalorimetric thermogravimetric plot for compound (pe-ted)2MnCl 2.06 Br 1.94 ;

[0035] Figure 9 Excitation emission spectrum for compound (pe-ted)2MnBr4 and compound (pe-ted)2MnCl 2.06 Br 1.94 ;

[0036] Figure 10 Quantum yield plot for compound (pe-ted)2MnBr4;

[0037] Figure 11 Quantum yield plot for compound (pe-ted)2MnCl 2.06 Br 1.94 ;

[0038] Figure 12 Radioluminescence intensity plot for compound (pe-ted)2MnBr4 versus compound (pe-ted)2MnCl 2.06 Br 1.94 and scintillator LuAG:Ce;

[0039] Figure 13 Radioluminescence intensity plot for compound (pe-ted)2MnBr4 versus compound (pe-ted)2MnCl 2.06 Br 1.94 under two hours high dose rate irradiation;

[0040] Figure 14 Radioluminescence intensity plot for compound (pe-ted)2MnBr4 switching five hundred cycles;

[0041] Figure 15 Radioluminescence intensity plot for compound (pe-ted)2MnCl 2.06 Br 1.94 switching five hundred cycles;

[0042] Figure 16 Signal to noise ratio versus dose rate plot for compound (pe-ted)2MnBr4 versus compound (pe-ted)2MnCl 2.06 Br 1.94 and scintillator LuAG:Ce;

[0043] Figure 17 Radioluminescence intensity plot for flexible film under two hours high dose rate irradiation;

[0044] Figure 18 Intensity plot for flexible film switch for five hundred cycles of irradiation;

[0045] Figure 19 Figure for the linear dependence of the signal-to-noise ratio on the dose rate for flexible film and scintillator LuAG:Ce. DETAILED DESCRIPTION

[0046] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, not all the embodiments.

[0047] I. The materials used in the following examples are as follows:

[0048] The raw materials used in the embodiments of the present application are provided by the Maclin Reagent Company: manganese bromide hydrate (purity: 98%), manganese chloride (purity: 99.0%), 1,4-diazabicyclo[2,2,2]octane (purity: 98%), 2-bromoethylbenzene (purity: 98%), acetone (Xilong, purity: 99.5%).

[0049] II. Instruments and detection methods:

[0050] The crystal structure is tested by an X-ray single crystal diffractometer (Rigaku, XtaLAB Synergy Custom);

[0051] The powder diffraction is tested by an X-ray powder diffractometer (Bruker D8 ADVANCE);

[0052] The ultraviolet-visible light absorption spectrum is tested by an ultraviolet-visible spectrophotometer (PerkinElmer Lambda 900);

[0053] The PL spectrum and lifetime decay curve are tested by an Edinburgh FLS1000 fluorescence spectrometer;

[0054] A commercially available X-ray tube (TUB00154-9I-W06, MOXTEK, tungsten target, maximum power 12W) is used as an X-ray source. An Edinburgh FLS1000 and a PMT900 photomultiplier tube are used to collect spectral signals;

[0055] A commercial camera (Canon EOS M50 Mark II M50) is used to take images for a flexible large-area X-ray imaging screen;

[0056] Thermal stability is tested by thermogravimetric analysis (TGA) by a Netzsch TG 209F1 Libra.

[0057] Example 1

[0058] Preparation of pe-ted

[0059] S1: Synthesis of 2-ethylbenzene-1,4-diazabicyclo[2,2,2]octane-1-ium (pe-ted ligand):

[0060] Dissolve 2.24 g of 1,4-diazabicyclo[2,2,2]octane (Ted) (20 mmol) in 25 mL of acetone, add 3.70 g of 2-bromoethylbenzene (20 mmol) under magnetic stirring, continue to stir for two hours, a large amount of white precipitate is generated, the precipitate is collected by centrifugation, and washed with acetonitrile three times, and finally dried under vacuum to obtain the product pe-ted ligand 4.98 g, Figure 1 and Figure 2 The mass spectrum and nuclear magnetic resonance spectrum of the organic ligand pe-ted ligand successfully prove the purity of the synthesized organic ligand; Figure 3 The structural diagram of the organic ligand (red ball: manganese; purple ball: nitrogen; gray ball: carbon);

[0061] S2: Synthesis of (pe-ted)2MnBr4 crystal:

[0062] Dissolve 0.28 g of manganese bromide hydrate (1 mmol) in 10 mL of N,N-dimethylformamide, dissolve 0.59 g of pe-ted ligand (1 mmol) in 20 mL of methanol, filter the two solutions into a clear beaker respectively, heat at 55°C for 8 hours, and transparent block-shaped crystals are precipitated, obtaining the crystal product with a mass of 0.81 g; the cell structure diagram of the compound (pe-ted)2MnBr4 crystal is shown in Figure 4 .

[0063] Example 2

[0064] Preparation of (pe-ted)2MnCl 2.06 Br 1.94

[0065] S1: Synthesis of 2-ethylbenzene-1,4-diazabicyclo[2,2,2]octane-1-ium (pe-ted ligand):

[0066] Dissolve 2.24 g of 1,4-diazabicyclo[2,2,2]octane (Ted) (20 mmol) in 25 mL of acetone, add 3.70 g of 2-bromoethylbenzene (20 mmol) under magnetic stirring, continue to stir for two hours, a large amount of white precipitate is generated, the precipitate is collected by centrifugation, and washed with acetonitrile three times, and finally dried under vacuum to obtain the product pe-ted ligand 4.98 g;

[0067] S2: (pe-ted)2MnCl​2.06 Br 1.94 Synthesis of the crystal:

[0068] 0.16 g of manganese chloride (1 mmol) was dissolved in 10 mL of N,N- dimethylformamide, 0.59 g of pe-ted ligand (1 mmol) was dissolved in 20 mL of methanol, the two solutions were filtered into a clear beaker respectively, heated at 65 °C for 6 hours, transparent block crystals precipitated, the crystal product mass was 0.63 g. (pe-ted)2MnCl 2.06 Br 1.94 The schematic diagram of the unit cell structure of the crystal is shown in Figure 5 .

[0069] Comparative Example 1

[0070] In contrast to Example 1, the preparation of (pe-ted)2MnBr4

[0071] S1: Synthesis of 2-ethylbenzene-1,4-diazabicyclo[2,2,2]octane-1-ium (pe-ted ligand):

[0072] 1.12 g of 1,4-diazabicyclo[2,2,2]octane (Ted) (10 mmol) was dissolved in 10 mL of acetonitrile, 1.85 g of 2-bromoethylbenzene (10 mmol) was added under magnetic stirring, and the stirring was continued for two hours, a large amount of white precipitate was generated, the precipitate was collected by centrifugation and washed with acetone three times, and finally dried under vacuum to obtain the product pe-ted ligand 2.63 g;

[0073] S2: Synthesis of (pe-ted)2MnBr4 crystal:

[0074] 0.28 g of manganese bromide hydrate (1 mmol) was dissolved in 10 mL of N,N- dimethylformamide, 0.59 g of pe-ted ligand (1 mmol) was dissolved in 20 mL of ethanol, the two solutions were filtered into a clear beaker respectively, heated at 65 °C for 6 hours, transparent block crystals precipitated, the crystal product mass was 0.78 g. Compared with Example 1, the solvents used for pe-ted ligand and (pe-ted)2MnBr4 crystal are different, but the corresponding products can be obtained.

[0075] Based on the above examples and comparative examples, the results show that:

[0076] Figure 6 The compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl 2.06 Br 1.94The powder diffraction pattern of the compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl 2.06 Br 1.94 The crystal has high purity and component uniformity.

[0077] Figure 7 The compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl Figure 8 Br 2.06 Br 1.94 The thermogravimetric and microcalorimetric thermogravimetric diagrams of the synthesized manganese-based metal halides are stable before 265℃, and the organic cations are lost first as the temperature rises.

[0078] Figure 9 The compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl 2.06 Br 1.94 The excitation emission spectra of the compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl 2+ The asymmetric absorption can be attributed to the odd-parity forbidden d→d transition of Mn 2+ The compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl 4 T1→ 6 A1 transition. The half-peak width is about 50 nm, and the Stokes shift is about 70 nm.

[0079] Figure 10 The compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl Figure 11 Br 2.06 Br 1.94 The quantum yield diagram of the compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl 2.06 Br 1.94 The quantum yield of the compound (pe-ted)2MnBr4 is as high as 95.29%, and the quantum yield of the compound (pe-ted)2MnCl

[0080] Figure 12 The compound (pe-ted)2MnBr4 and the compound (pe-ted)2MnCl 2.06 Br 1.94radioluminescence intensity plot. Under the same X-ray dose rate (3.6 mGy / s) irradiation, all the radioluminescence emission spectra are the same as the photoluminescence emission, indicating that the radioluminescence emission and photoluminescence emission have the same radiative recombination path under UV excitation, blue light excitation and X-ray excitation. Because LuAG:Ce (25000 ph / MeV) exhibits similar PL emission peak at ~520 nm as the compounds, the influence of the detection response difference can be minimized, based on the integrated radioluminescence emission spectrum area and the light yield of LuAG:Ce (25000 ph / MeV), the light yield of compound (pe-ted)2MnBr4 and compound (pe-ted)2MnCl 2.06 Br 1.94 are about 61809 ph / MeV, 55569 ph / MeV, respectively.

[0081] Figure 13 compound (pe-ted)2MnBr4 and compound (pe-ted)2MnCl 2.06 Br 1.94 Stability of long-time irradiation under high dose rate, indicating the radiation stability of the synthesized compounds, which is expected to be made into flexible film and applied to medical detection.

[0082] Figure 14 and Figure 15 compound (pe-ted)2MnBr4 and compound (pe-ted)2MnCl 2.06 Br 1.94 Cyclic radiation intensity plot of 500 cycles of on-off switching, the response under x-ray irradiation has good repeatability and stability.

[0083] The detection limit is also another key parameter for evaluating the performance of X-ray scintillators, Figure 16 compound (pe-ted)2MnBr4 and compound (pe-ted)2MnCl 2.06 Br 1.94 and the linear relationship of the signal-to-noise ratio of the scintillator LuAG:Ce with the dose rate, the response radioluminescence emission spectrum under X-ray dose rate ranging from 200-700 μGy / s was carried out, showing the linear RL response of luminescence intensity to dose rate. When the signal-to-noise ratio is 3, the X-ray detection limit of compound (pe-ted)2MnBr4 is calculated as 1.376 μGy / s, and the X-ray detection limit of compound (pe-ted)2MnCl 2.06 Br 1.94 corresponding to 1.440 μGy / s, both of which are lower than the dose rate required for medical X-ray diagnosis (5.5 μGy / s) and the commercial scintillator LuAG:Ce (8.583 μGy / s).

[0084] By spin coating a colloidal solution of PDMS containing metal halides, a flexible film is obtained. Figure 17 The flexible film was irradiated with radiation at a high dose rate for two hours, and the radiation intensity remained stable.

[0085] Figure 18 This is a radiation intensity diagram of the flexible membrane switch after 500 cycles, indicating that the membrane has good durability and stability in practical applications.

[0086] Figure 19 The linear relationship between the signal-to-noise ratio of the flexible film and the scintillator LuAG:Ce and the dose rate is shown. Through linear fitting, the detection limit of the film is 5.173μGy / s, which is better than the 8.583μGy / s of the commercial scintillator LuAG:Ce.

[0087] The (pe-ted)2MnX4 (X=Cl, Br) single crystal materials prepared in the embodiment and the comparative example both achieved a fluorescence yield of more than 80%; (pe-ted)2MnBr4, as an X-ray scintillator, has a high quantum yield of 95.29% and high crystal stability, and has broad application prospects; (pe-ted)2MnBr4 has efficient X-ray imaging capabilities, with a light yield of up to 61809ph / MeV and a detection limit as low as 1.376μGy / s, both of which are superior to commercial LuGG:Ce scintillator materials; and the (pe-ted)2MnBr4 crystal has good solution processability and film-forming properties, and a uniform and dense luminescent thin film can be obtained by a simple spin coating method while maintaining the excellent luminescence properties of the crystal.

[0088] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. The preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification.

Claims

1. A method for preparing a green light emitting hybrid manganese halide crystal, characterized in that, The method comprises the following steps: S1: dissolving 1,4-diazabicyclo[2,2,2]octane in an organic solvent, then adding 2-bromoethyl benzene, stirring to form a white precipitate, and then treating to obtain ethyl phenyl trivinyl diamine bromide organic ligand; S2: adding manganese halide and ethyl phenyl trivinyl diamine bromide organic ligand into an organic solvent, mixing thoroughly, and heating and evaporating to obtain manganese halide organic-inorganic hybrid crystal.

2. The method of claim 1, wherein the method is characterized by: In S1, the molar ratio of 1,4-diazabicyclo[2,2,2]octane to 2-bromoethyl benzene is 1:

1.

3. The method of claim 1, wherein the method is characterized by: In S1, the concentration of 1,4-diazabicyclo[2,2,2]octane in the organic solvent is 1 mmol / (1-2) mL.

4. The method for preparing the green luminescent hybrid manganese halide crystal according to claim 1, wherein: In S1, 1,4-diazabicyclo[2,2,2]octane is dissolved in an organic solvent, 2-bromoethyl benzene is added under stirring, stirring is performed for 3 h, a white precipitate is formed, and then centrifugation, washing and drying are performed to obtain ethyl phenyl trivinyl diamine bromide organic ligand.

5. The method for preparing the green luminescent hybrid manganese halide crystal according to claim 1, wherein: In S2, the mass ratio of manganese halide to ethyl phenyl trivinyl diamine bromide organic ligand is 1:(2-2.2).

6. The method for preparing the green luminescent hybrid manganese halide crystal according to claim 1, wherein: In S2, the concentration of manganese halide in the organic solvent is 1 mmol / (10-15) mL, and the concentration of ethyl phenyl trivinyl diamine bromide organic ligand in the organic solvent is 2 mmol / (20-25) mL.

7. The method of claim 1, wherein the method is characterized by: In S2, manganese halide and ethyl phenyl trivinyl diamine bromide organic ligand are respectively added into an organic solvent, respectively filtered, mixed thoroughly, and heated and evaporated to obtain manganese halide organic-inorganic hybrid crystal.

8. The method of claim 7, wherein the method is characterized by: In S2, the heating treatment temperature is 55-75 ℃, and the heating treatment time is 6-10 h.

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