Highly efficient blue light complex and preparation method and application thereof

Abstract

The application relates to the technical field of fluorescent material synthesis, and discloses a high-efficiency blue light complex as well as a preparation method and application thereof. The complex has a molecular formula of [(Cu) d (X) e (M) f (N) g ]; d, e, f and g are each 1 or 2; X is halogen, M is an organic phosphorus ligand, and N is 2-methyl imidazole. The high-efficiency blue light complex provided by the application has high luminous efficiency, long service life, strong stability, and the highest quantum efficiency is 71.86%, the CIE coordinate of the complex at room temperature is (0.1602, 0.136), and the complex is close to pure blue light. The high-efficiency blue light complex provided by the application is simple in preparation and purification, has high luminous efficiency, long service life and strong stability.

Description

Technical Field

[0001] This invention relates to the field of fluorescent material synthesis technology, specifically to a high-efficiency blue light-emitting complex, its preparation method, and its applications. Background Technology

[0002] Over the past few decades, research on organometallic complexes for the manufacture of organic light-emitting diodes (OLEDs) has spurred rapid development in the field of organic optoelectronic materials. However, current research largely focuses on noble metal organometallic complexes. Due to the scarcity and high price of noble metal resources, production costs have become a significant constraint on their development. Therefore, copper, with its advantages of high abundance, environmental friendliness, high efficiency, and stability, has become a research target for next-generation OLED luminescent materials.

[0003] Cu(I) complexes occupy an important position in current materials research. For many years, these compounds have been extensively studied in various disciplines such as biology, inorganic chemistry, and materials engineering, revealing their high scientific value and technological application potential. Firstly, due to the rich coordination chemistry of Cu(I) ions, they can form various coordination structures by combining with organic and inorganic ligands, including discrete molecular complexes or extended coordination networks. Furthermore, these structures can exhibit a wide range of physical and chemical properties, such as photoluminescence, electroluminescence, and conductivity, which can be applied in photocatalysis or sensor fields.

[0004] Currently, the reported OLED materials mainly emit green and red light, with fewer high-efficiency blue light materials. Furthermore, the blue light materials for OLEDs that have been reported so far suffer from defects such as short lifespan and low luminous efficiency, which seriously restrict the development of the OLED industry.

[0005] Therefore, synthesizing Cu(I) complexes for OLED blue light materials using a low-cost metal strategy is an urgent problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of scarcity of blue light materials, low luminous efficiency, and short lifespan in the prior art, and to provide a high-efficiency blue light complex, its preparation method, and its application.

[0007] To achieve the above objectives, the present invention provides a highly efficient blue light-emitting complex with the molecular formula [(Cu]). d (X) e (M) f (N) g ]; d, e, f, g are each 1 or 2; X is a halogen, M is an organophosphorus ligand, and N is 2-methylimidazole.

[0008] A second aspect of the present invention provides a method for preparing a highly efficient blue light-emitting complex, the method comprising: carrying out a coordination reaction of an organophosphorus compound, 2-methylimidazole and cuprous halide in a solvent, and then removing the solvent.

[0009] A third aspect of this invention provides the application of the high-efficiency blue light-emitting complex described herein in the field of luminescent materials.

[0010] The high-efficiency blue light complex provided by this invention has high luminous efficiency, long lifespan, and strong stability, and its quantum efficiency is up to 71.86%. The CIE coordinates of the complex at room temperature are (0.1602, 0.136), which is close to pure blue light.

[0011] The high-efficiency blue light complex provided by this invention is a novel and efficient blue photoluminescent material with broad application prospects.

[0012] The method for preparing high-efficiency blue light-emitting complexes provided by this invention is simple to operate, easy to purify, environmentally friendly, uses inexpensive and readily available raw materials, and produces complexes with high yield and stable properties. Attached Figure Description

[0013] Figures 1a-1c This is the crystal structure diagram of the coordination compound, with hydrogen atoms omitted;

[0014] Figures 2a-2c It is the infrared spectrum of the coordination compound;

[0015] Figures 3a-3c This is the powder X-ray diffraction pattern of the complex;

[0016] Figures 4a-4c It is the thermogravimetric diagram of the coordination compound;

[0017] Figures 5a-5c These are the fluorescence excitation and emission spectra of the coordination compounds;

[0018] Figures 6a-6c This is the temperature-dependent fluorescence spectrum of the coordination compound;

[0019] Figures 7a-7c This is a fluorescence lifetime decay curve of the coordination compound;

[0020] Figures 8a-8c This is the photoluminescence quantum efficiency spectrum of the complex at room temperature;

[0021] Figures 9a-9c This is a temperature-dependent integral graph of the fluorescence emission intensity of the complex;

[0022] Figures 10a-10c This is the temperature-dependent CIE diagram of the coordination compound;

[0023] Figures 11a-11c This is a temperature-dependent fluorescence image of the PMMA-doped film of the complex;

[0024] Figures 12a-12c This is a temperature-dependent fluorescence image of the PVA-doped film of the complex;

[0025] Figures 13a-13b This is an integral plot of the temperature-dependent fluorescence emission intensity of the complex-doped film. Detailed Implementation

[0026] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0027] This invention provides a highly efficient blue light-emitting complex with the molecular formula [(Cu]). d (X) e (M) f (N) g ]; d, e, f, and g are each 1 or 2; X is a halogen, M is an organophosphorus ligand, and N is 2-methylimidazole. The high-efficiency blue light complex provided by this invention has the advantages of high luminous efficiency, long service life, and strong stability.

[0028] In this invention, the complex belongs to the triclinic crystal system. Space group, monoclinic P21 / n space group or monoclinic C2 / c space group.

[0029] In this invention, the quantum efficiency of the complex can reach 71.86%, with CIE coordinates of (0.1602, 0.136), which is close to that of pure blue light.

[0030] In this invention, the range of organophosphorus ligands that can be selected is relatively wide. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the organophosphorus ligand is selected from one or more of aromatic phosphorus and aliphatic phosphine-containing organic compounds, preferably triphenylphosphine.

[0031] According to a preferred embodiment of the present invention, the complex has the chemical formula of formula (1) or formula (2) as follows:

[0032] [CuX(PPh3)2(2-Memz)], where X is Cl or Br, equation (1)

[0033] [Cu2I2(PPh3)2(2-Memz)2], Equation (2)

[0034] Among them, PPh3 is triphenylphosphine, and 2-Memz is 2-methylimidazole.

[0035] The quantum efficiency of the aforementioned complex can reach up to 71.86%, with CIE coordinates of (0.1602, 0.136), which is close to that of pure blue light.

[0036] According to a preferred embodiment of the present invention, X of formula (1) is Cl, and complex 1 [CuCl(PPh3)2(2-Memz)] is a mononuclear cuprous complex. The central cuprous metal ion adopts a tetrahedral coordination mode, and coordinates with the N atom in the ligand 2-methylimidazole and the P atom in the two triphenylphosphines and a Cl anion to form a deformed tetrahedral configuration.

[0037] In this invention, coordination compound 1 belongs to the triclinic crystal system. Space group, cell parameters are α=80.836(3)°, β=89.595(2)°, γ=88.882(3)°, Z=2,

[0038] In this invention, complex 1 exhibits a broad excitation band from 400 nm to 450 nm, and a strong emission band centered at 500 nm, with a half-width at half maximum (FWHM) of 89 nm. In the temperature range of 78-500 K, the maximum emission wavelength redshifts by 5 nm with increasing temperature, and the fluorescence emission intensity decreases with increasing temperature.

[0039] According to a preferred embodiment of the present invention, X of formula (1) is Br, and complex 2 [CuBr(PPh3)2(2-Memz)] is a mononuclear cuprous complex. The central cuprous metal ion adopts a tetrahedral coordination mode, and coordinates with the N atom in the ligand 2-methylimidazole and the P atom in the two triphenylphosphines and a Br anion to form a deformed tetrahedral configuration.

[0040] In this invention, coordination compound 2 belongs to the monoclinic crystal system, space group P21 / n, and its cell parameters are as follows: α=90°, β=101.234(3)°, γ=90°, Z=4,

[0041] In this invention, the maximum excitation wavelength of complex 2 is 428 nm, exhibiting a strong emission band centered at 495 nm, with a full width at half maximum (FWHM) of 90 nm. At low temperatures (78-200 K), the fluorescence emission intensity remains stable with increasing temperature, while the maximum emission wavelength exhibits a 40 nm redshift; at high temperatures (200-500 K), the fluorescence emission intensity decreases with increasing temperature, while the maximum emission wavelength exhibits a 10 nm redshift.

[0042] According to a preferred embodiment of the present invention, the complex 3 [Cu2I2(PPh3)2(2-Memz)2] shown in formula (2) is a binuclear cuprous complex, in which the central cuprous metal ion adopts a tetrahedral coordination mode, and coordinates with the N atom in the ligand 2-methylimidazole and the P atom and an I anion in the two triphenylphosphines respectively to form a deformed tetrahedral configuration.

[0043] In this invention, coordination compound 3 belongs to the monoclinic crystal system, space group C2 / c, and its cell parameters are as follows: α=90°, β=93.912(4)°, γ=90°, Z=8,

[0044] In this invention, complex 3 exhibits a broad excitation band from 350 nm to 400 nm, with a strong emission band centered at 450 nm and a full width at half maximum (FWHM) of 77 nm. Within the temperature range of 78-400 K, the fluorescence emission intensity remains almost constant with increasing temperature, while the maximum emission wavelength undergoes a 20 nm blue shift; within the temperature range of 400-500 K, the fluorescence emission intensity decreases with increasing temperature, and the maximum emission wavelength undergoes a 10 nm blue shift.

[0045] The aforementioned preferred high-efficiency blue light complex has the advantages of high luminous efficiency, long service life, and strong stability.

[0046] All highly efficient blue light-emitting complexes possessing the aforementioned characteristics can achieve the objectives of this invention. There are no special requirements for their preparation methods. The following is an illustrative description, but it does not limit the scope of this invention. According to a preferred embodiment of this invention, the preparation method of the highly efficient blue light-emitting complex includes: carrying out a coordination reaction of an organophosphorus compound, 2-methylimidazole and cuprous halide in a solvent, followed by removing the solvent.

[0047] The method for preparing high-efficiency blue light-emitting complexes provided by this invention is simple to operate, environmentally friendly, uses inexpensive and readily available raw materials, and produces complexes with high yield and stable properties.

[0048] In this invention, the range of halogens that can be selected for cuprous halides is relatively wide. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the halogen is selected from Cl, Br and I.

[0049] In this invention, the concentration of cuprous halide in the solvent can be selected within a wide range. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the concentration of cuprous halide in the solvent is 1-10 mmol / L.

[0050] In this invention, there are no special requirements for the type of solvent. The following is an illustrative description, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the solvent is one or more of dichloromethane, methanol and acetonitrile, preferably acetonitrile.

[0051] In this invention, the molar ratio of cuprous halide, organophosphorus ligand, and imidazole ligand can be selected from a wide range. The following is an illustrative example, but it does not limit the scope of the invention. According to a preferred embodiment of the invention, the molar ratio of cuprous halide, organophosphorus compound, and 2-methylimidazole is 1:1-2:1-2.

[0052] In this invention, the coordination reaction is carried out under dynamic conditions, such as under stirring conditions. A wide range of stirring times can be selected, as illustrated below, but this does not limit the scope of the invention. According to a preferred embodiment of the invention, the stirring time is 15-30 min, for example, 16 min, 18 min, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, etc.

[0053] In this invention, there are no special requirements for the solvent removal method after the coordination reaction. Commonly used solvent removal methods are applicable to this invention. For example, the solvent can be removed by evaporating at room temperature for a period of time. There are no special requirements for the evaporation time. For example, it can be evaporated for 1 day, 2 days, 3 days, 4 days, 5 days, etc.

[0054] In this invention, there are no special requirements for the purification of the crystals after solvent removal. Commonly used purification methods can achieve the purpose of this invention. The purification can be carried out according to conventional methods in the field. For example, transparent crystals can be obtained by filtration first, then washed with solvent and distilled water, and finally dried to obtain pure transparent crystals.

[0055] The high-efficiency blue light complex provided by this invention has high luminous efficiency, long service life, and strong stability. It is a new type of high-efficiency blue photoluminescent material with broad application prospects.

[0056] This invention provides the application of the high-efficiency blue light-emitting complex provided by this invention in the field of luminescent materials.

[0057] The reagents used in the experiments of this invention were produced by manufacturers such as Anaiji Chemical and Shanghai Lingfeng Reagent, as detailed in Table 1; the reagents were used directly without further purification.

[0058] Table 1 Reagent List

[0059] reagents Specification Manufacturer <![CDATA[CH3CN]]> Chemically pure Shanghai Lingfeng Reagent Cuprous chloride Chemically pure Anaiji Chemical Reagents Cuprous bromide Chemically pure Anaiji Chemical Reagents Cuprous iodide Chemically pure Anaiji Chemical Reagents Triphenylphosphine Chemically pure Anaiji Chemical Reagents 2-Methylpyridine Chemically pure Anaiji Chemical Reagents polymethyl methacrylate Chemically pure Anaiji Chemical Reagents Polyvinyl alcohol Chemically pure Anaiji Chemical Reagents distilled water Chemically pure Lab-made

[0060] The equipment and instruments used in the experiment are shown in Table 2:

[0061] Table 2 Main Instruments

[0062] instrument Instrument Model Instrument manufacturers Thermostatic heating magnetic stirrer CL-2 Shanghai Leici Xinjing Fourier transform infrared spectrometer IR-50 Thermo Fisher Scientific, USA Elemental analyzer CE-440 (Leemanlabs) EAI (American EAI) X-ray single crystal diffractometer APEX-IIDUO Bruker Germany X-ray powder diffraction D / MAX2500 Japanese Neo-Confucianism Thermogravimetric analyzer Labsys EvoSTA France Seytaram Fluorometer FS5 Edinburgh, UK

[0063] Example 1

[0064] Preparation of complex crystals [CuX(PPh3)2(2-Memz)] (X = Cl, Br) and [Cu2I2(PPh3)2(2-Memz)2]: PPh3 (26.2 mg, 0.1 mmol), 2-Memz (16.4 mg, 0.2 mmol), and cuprous halide (0.1 mmol) were dissolved in 20 mL of acetonitrile according to the required molar ratio. After stirring, the mixture was filtered and allowed to evaporate at room temperature for 3 days. Transparent crystals were obtained by filtration, washed with solvent and distilled water, and dried to obtain pure transparent crystals.

[0065] Complex 1 was obtained: [CuCl(PPh3)2(2-Memz)];

[0066] Complex 2 was obtained: [CuBr(PPh3)2(2-Memz)];

[0067] Complex 3 was obtained: [Cu2I2(PPh3)2(2-Memz)2].

[0068] Test Example 1

[0069] Crystal structure characterization of the coordination compounds: The structure of single-crystal samples of the coordination compounds was characterized using an X-ray single-crystal diffractometer. A Bruker APEX-IICCD instrument was used, with monochromatic radiation of graphite and Mo Kα. Data was collected at the appropriate temperatures. Data collection, data restoration, and cell optimization were performed using two packages: Bruker Instrument Service v4.2.2 and SAINT V8.34A. The coordination compound structure was resolved using the SHELXS package, and the crystal data was optimized using full-matrix least squares with the SHELXL package. Absorption correction was performed using the SADABS multi-scan package. Hydrogen atoms of the organic ligands were analyzed in F-mode using the riding mode on the SHELXTL package. 2 Anisotropy optimization was performed. The final crystal structure of the complex is shown in Figure 1, and the crystallographic data of the complex are shown in Table 3. Some bond lengths of the complex are also shown. The bond angle (°) data are shown in Table 4.

[0070] Table 3 Crystallographic parameters of the coordination compounds

[0071]

[0072]

[0073] a R1=Σ(||F0|-|Fc||) / Σ|F0|; b wR2=[Σw(|F0 2 |-|Fc 2 |) 2 / Σw|F0 2 | 2 ] 1 / 2 ; c GOF=[∑[w(F0 2 -Fc 2 ) 2 ] / (Nobs-Nparams)] 1 / 2 , based on the data I>2σ(I).

[0074] Table 4. Important bond lengths in the crystal structure of coordination compounds Bond angle (°)

[0075]

[0076]

[0077]

[0078] Test Example 2

[0079] Infrared absorption spectroscopy analysis of the complexes: Infrared spectra of the complexes were measured using a Thermo Fisher Scientific IR-50 Fourier transform infrared spectrometer. The obtained infrared spectra are shown below. Figures 2a-2c .like Figures 2a-2c As shown, the black spectral lines are the infrared absorption spectra of ligands PPh3 and 2-Memz, and the red spectral lines are the infrared absorption spectra of the complex. It can be seen from the figure that the absorption spectra of the complex and the absorption spectra of the ligands are in very good agreement, indicating that there are indeed organic ligands in the complex.

[0080] Test Example 3

[0081] X-ray diffraction analysis of the complex powder: X-ray diffraction tests were performed on the complex samples using a Rigaku D / MAX2500 X-ray powder diffractometer (Japan). The obtained powder X-ray diffraction patterns are shown below. Figures 3a-3c .like Figures 3a-3c As shown, the black spectral lines are obtained from experimental data, while the red spectral lines are obtained from computer simulation based on the crystal structure. The figure shows that the experimental and simulated values ​​of the complex are in very good agreement, indicating that the complex is a pure phase.

[0082] Test Example 4

[0083] Thermogravimetric analysis of complexes: Thermogravimetric analysis of the complex samples was performed using a Labsys Evo STA thermogravimetric analyzer (French Seytaram). The obtained thermogravimetric charts are shown below. Figures 4a-4c .

[0084] like Figures 4a-4c As shown, since both complexes 1 and 2 are mononuclear complexes, they exhibit similar structural collapse processes. Below 200°C, complex 1 remains stable; at 200°C, complex 1 begins to collapse, and by 350°C, it has lost approximately 80% of its mass, primarily due to the loss of the halogen atom Cl and the ligand PPh3; within the temperature range of 350-400°C, complex 1 remains stable; above 400°C, complex 1 begins to collapse again, mainly due to the loss of the ligand 2-Memz, and remains stable after 500°C, with a remaining mass of 4%, primarily composed of metal ions.

[0085] Similarly, when the temperature is below 200℃, complex 2 remains stable; when the temperature is 200℃, complex 2 begins to collapse, and by 360℃, complex 2 loses approximately 75% of its mass, mainly due to the loss of halogen atom Br and ligand PPh3; when the temperature is in the range of 360-450℃, complex 2 remains stable; when the temperature is above 450℃, complex 2 begins to collapse again, mainly due to the loss of ligand 2-Memz, and remains stable after 550℃, with a remaining mass of 2%, mainly composed of metal ions.

[0086] Complex 3 is a binuclear complex. It remains stable below 200°C. At 200°C, it begins to collapse, losing approximately 70% of its mass by 350°C, primarily due to the loss of halogen atom I and ligand PPh3. Within the temperature range of 360-550°C, it remains stable. Above 550°C, it begins to collapse again, mainly due to the loss of ligand 2-Memz. It remains stable after 650°C, with a remaining mass of 3%, mainly composed of metal ions. Since there are no guest solvent molecules in the solid samples of complexes 1, 2, and 3, their collapse processes are entirely due to the loss of halogen and ligand mass.

[0087] The thermogravimetric analysis above shows that the decomposition temperature of the copper complex is as high as 200℃, and its thermal stability is relatively high.

[0088] Test Example 5

[0089] Fluorescence assay of the complexes: The fluorescence of the complexes was measured using an Edinburgh FS5 fluorometer (UK). The obtained fluorescence excitation and emission spectra are shown below. Figures 5a-5cThe solid-state photophysical data of the complex at room temperature are summarized in Table 5.

[0090] like Figure 5a As shown, at room temperature, complex 1 exhibits a broad excitation band from 400 nm to 450 nm, with a strong emission band centered at 500 nm, and a full width at half maximum (FWHM) of 89 nm; Figure 7a As shown, the fluorescence lifetime of complex 1 is 1.08 μs; Figure 8a As shown, the photoluminescence quantum yield (PLQY) of complex 1 is 25.44%.

[0091] like Figure 5b As shown, at room temperature, the maximum excitation wavelength of complex 2 is 428 nm, exhibiting a strong emission band centered at 495 nm, with a full width at half maximum (FWHM) of 90 nm. Figure 7b As shown, the fluorescence lifetime of complex 2 is 1.37 μs. Figure 8b As shown, the photoluminescence quantum yield (PLQY) of complex 2 is 5.39%.

[0092] like Figure 5c As shown, at room temperature, complex 3 exhibits a broad excitation band from 350 nm to 400 nm, with a strong emission band centered at 450 nm, and a full width at half maximum (FWHM) of 77 nm. Figure 7c As shown, the fluorescence lifetime of complex 3 is 39.82 μs. Figure 8c As shown, the photoluminescence quantum yield (PLQY) of complex 3 is 71.86%.

[0093] Through equation k r =Φ PL τ -1 The fluorescence decay rates (k) of complexes 1, 2, and 3 were calculated. r The values ​​are 23.6 × 10⁻⁶ respectively. 4 s -1 3.93×10 4 s -1 and 1.80×10 4 s -1 Considering Φ PL =k r / (k r +k nr ), where k nr It is the rate of nonradiative processes including nonradiative singlet decay and ISC, k for complexes 1, 2, and 3. nr The values ​​are 690×10 3 s -1 691×10 3 s -1 and 7.01×103 s -1 Therefore, the increase in quantum yield of complex 3 is related to the combined effect, and its fluorescence lifetime is much greater than that of complexes 1 and 2. Even if both the radiative and nonradiative rates are reduced, complex 3 can still have a high quantum efficiency.

[0094] k of coordination compounds 1 and 2 nr The higher quantum efficiency (k0.05) is due to the strong vibrations of the methyl substituents in its molecule, leading to severe structural distortions during electronic transitions and thus reducing quantum efficiency. However, with the same ligands, the quantum efficiency of complex 3 is higher than that of complexes 1 and 2. This is because complex 3 is a binuclear complex with less molecular vibration, which helps reduce structural distortions and thus lowers k0.05. nr Value, improve quantum efficiency.

[0095] Table 5 Solid-state photophysical data of the complexes at room temperature

[0096]

[0097]

[0098] a Radiative rate constant calculated K r =Φ / τ. b Nonradiative rate constant

[0099] calculatedK nr = (1-Φ) / τ.

[0100] Test Example 6

[0101] Fluorescence quenching properties of the coordination compounds: To investigate the stability of the photoluminescence of the coordination compounds, temperature-dependent fluorescence tests were performed on the coordination compound samples using an Edinburgh FS5 fluorescence spectrometer (UK). The temperature-dependent fluorescence spectra of the obtained coordination compounds are shown below. Figures 6a-6c . Figures 6a-6c The results show that the maximum emission wavelengths of complexes 1, 2 and 3 shift slightly with temperature.

[0102] Specifically, the maximum emission wavelength of complex 1 in the temperature range of 78-500K redshifts by 5 nm with increasing temperature, and the fluorescence emission intensity decreases with increasing temperature.

[0103] At low temperatures (78-200K), the fluorescence emission intensity of complex 2 remained stable with increasing temperature, while the maximum emission wavelength exhibited a redshift of 40nm; at high temperatures (200-500K), the fluorescence emission intensity decreased with increasing temperature, while the maximum emission wavelength exhibited a redshift of 10nm.

[0104] In the temperature range of 78-400K, the fluorescence emission intensity of complex 3 remained almost unchanged with increasing temperature, while the maximum emission wavelength underwent a blue shift of 20nm; in the temperature range of 400-500K, the fluorescence emission intensity decreased with increasing temperature, while the maximum emission wavelength underwent a blue shift of 10nm.

[0105] The results of the maximum emission wavelength of the complex changing with temperature are consistent with the results of the CIE coordinate changes. Figures 10a-10c For the temperature-dependent CIE diagram of the coordination compound, such as Figures 10a-10c As shown, the corresponding CIE coordinates of complex 1 change from (0.1900, 0.4192) at 78K to (0.1975, 0.4285) at 220K, and finally to (0.2085, 0.3982) at 360K. The corresponding CIE coordinates of complex 2 change from (0.1887, 0.2262) at 78K to (0.2463, 0.3784) at 320K, and finally to (0.2600, 0.3469) at 360K. In contrast, complex 3 undergoes only one CIE coordinate transformation, changing from (0.1531, 0.2142) at 78K to (0.1563, 0.1288) at 500K. Therefore, the blue light color of the above copper complexes does not change significantly with temperature, exhibiting high luminescence stability.

[0106] Test Example 7

[0107] Study on the properties of complex-doped films: In order to study the performance of complex-doped films, two types of doped films were prepared and their fluorescence properties were tested under varying temperatures.

[0108] First, the temperature-dependent fluorescence properties of the PMMA-doped film were studied, such as... Figures 11a-11c As shown, the results indicate that the excitation and emission wavelengths of complexes 1@PMMA, 2@PMMA and 3@PMMA are slightly shifted compared to the excitation and emission wavelengths of the pure complexes.

[0109] Through temperature-dependent fluorescence testing of PVA-doped films, we found that they exhibit similar properties to PMMA-doped films, such as... Figures 12a-12c As shown, the results indicate that the excitation and emission wavelengths of complexes 1@PVA, 2@PVA, and 3@PVA are slightly offset compared to the excitation and emission wavelengths of the pure complexes.

[0110] Figures 9a-9c The graphs show the temperature-dependent fluorescence emission intensity integrals of pure complexes 1, 2, and 3. Figures 9a-9cThe results showed that complex 3 exhibited zero thermal quenching (ZTQ) in the temperature range of 78-400 K; while complexes 1 and 2, due to their similar mononuclear structures, exhibited ZTQ in the temperature range of 78-200 K. In the temperature range of 200-500 K, the fluorescence emission intensity of the complexes began to decrease, and the thermal quenching effect of complex 1 was reduced compared to complex 2.

[0111] Figure 13a and Figure 13b The images show the temperature-dependent fluorescence emission intensity integral plots of the PMMA-doped and PVA-doped complex films, respectively. Figures 9a-9c and Figures 13a-13b The comparison shows that although the ZTQ effect of the complex-doped film disappears, its thermal quenching effect is reduced, which may be due to the weakening of the vibration of the complex in the polymer material. Furthermore, it can be seen that the PMMA-doped film is more stable than the PVA-doped film.

[0112] Performance studies of PMMA-doped and PVA-doped films have shown that the complexes 1, 2, and 3 provided in this invention exhibit superior stability, which also demonstrates their potential as membrane devices and suggests broad application prospects.

[0113] The preferred embodiments of the present invention have been described above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various specific technical features in any suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A highly efficient blue light-emitting complex, characterized in that, The molecular formula of this complex is [(Cu]]. d (X) e (M) f (N) g ]; d, e, f, g are each 1 or 2; X is a halogen, M is an organophosphorus compound, and N is 2-methylimidazole.

2. The complex according to claim 1, wherein the complex belongs to the triclinic crystal system. Space group, monoclinic P21 / n space group or monoclinic C2 / c space group.

3. The complex according to claim 1 or 2, wherein, The quantum efficiency of the complex can reach 71.86%, with CIE coordinates of (0.1602, 0.136), which is close to that of pure blue light.

4. The complex according to any one of claims 1-3, wherein, The organophosphorus ligand is selected from one or more of aromatic phosphorus and aliphatic phosphine-containing organic compounds, preferably triphenylphosphine.

5. The complex according to any one of claims 1-4, wherein, The complex has the chemical formula of either formula (1) or formula (2): [CuX(PPh3)2(2-Memz)], where X is Cl or Br, equation (1) [Cu2I2(PPh3)2(2-Memz)2], Equation (2) Among them, PPh3 is triphenylphosphine, and 2-Memz is 2-methylimidazole.

6. The complex according to claim 5, wherein, Formula (1) X is Cl, and complex 1 [CuCl(PPh3)2(2-Memz)] is a mononuclear cuprous complex. The central cuprous metal ion adopts a tetrahedral coordination mode, which coordinates with the N atom in the ligand 2-methylimidazole and the P atom in the two triphenylphosphines and a Cl anion, respectively, to form a deformed tetrahedral configuration. Complex 1 belongs to the triclinic crystal system. Space group, cell parameters are α=80.836(3)°, β=89.595(2)°, γ=88.882(3)°, Z=2, Complex 1 exhibits a broad excitation band from 400 nm to 450 nm, with a strong emission band centered at 500 nm and a full width at half maximum (FWHM) of 89 nm. In the temperature range of 78-500 K, the maximum emission wavelength redshifts by 5 nm with increasing temperature, and the fluorescence emission intensity decreases with increasing temperature.

7. The complex according to claim 5, wherein, Formula (1) X is Br, and complex 2 [CuBr(PPh3)2(2-Memz)] is a mononuclear cuprous complex. The central cuprous metal ion adopts a tetrahedral coordination mode, which coordinates with the N atom in the ligand 2-methylimidazolium and the P atom in the two triphenylphosphines and a Br anion, respectively, to form a deformed tetrahedral configuration. Complex 2 belongs to the monoclinic crystal system, space group P21 / n, with unit cell parameters of... α=90°, β=101.234(3)°, γ=90°, Z=4, Complex 2 has a maximum excitation wavelength of 428 nm and exhibits a strong emission band centered at 495 nm with a full width at half maximum (FWHM) of 90 nm. At low temperatures (78-200 K), the fluorescence emission intensity remains stable with increasing temperature, while the maximum emission wavelength undergoes a redshift of 40 nm. At high temperatures (200-500 K), the fluorescence emission intensity decreases with increasing temperature, while the maximum emission wavelength undergoes a redshift of 10 nm.

8. The complex according to claim 5, wherein, The complex 3[Cu2I2(PPh3)2(2-Memz)2] shown in formula (2) is a binuclear cuprous complex. Its central cuprous metal ion adopts a tetrahedral coordination mode, which coordinates with the N atom in the ligand 2-methylimidazolium and the P atom and an I anion in the two triphenylphosphines, respectively, to form a deformed tetrahedral configuration. Complex 3 belongs to the monoclinic crystal system, space group C2 / c, with cell parameters of... α=90°, β=93.912(4)°, γ=90°, Z=8, Complex 3 exhibits a broad excitation band from 350 nm to 400 nm, with a strong emission band centered at 450 nm and a full width at half maximum (FWHM) of 77 nm. In the temperature range of 78-400 K, the fluorescence emission intensity remains constant with increasing temperature, while the maximum emission wavelength undergoes a blue shift of 20 nm. In the temperature range of 400-500 K, the fluorescence emission intensity decreases with increasing temperature, while the maximum emission wavelength undergoes a blue shift of 10 nm.

9. A method for preparing the high-efficiency blue light-emitting complex according to any one of claims 1-8, characterized in that, The method includes: coordinating an organophosphorus compound, 2-methylimidazole, and cuprous halide in a solvent, followed by solvent removal and purification; Preferably, The halogen of cuprous halides is selected from one of Cl, Br, and I; and / or The concentration of cuprous halide in the solvent is 1-10 mmol / L; and / or The solvent is one or more of dichloromethane, methanol, and acetonitrile, preferably acetonitrile; and / or The molar ratio of cuprous halide, organophosphorus compound and 2-methylimidazole is 1:1-2:1-2.

10. The application of the high-efficiency blue light-emitting complex according to any one of claims 1-8 in the field of luminescent materials.

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