Preparation method and application of efficient blue light emission hybrid material

Abstract

The invention belongs to the technical field of light-emitting hybrid materials, and particularly discloses a preparation method and application of an efficient blue light emitting hybrid material. The preparation method comprises the following steps: dispersing cuprous halide, triphenylphosphine (tpp) and tetraethylammonium halide in N, N-dimethylformamide (DMF) according to a molar ratio of 1: 1: 1 to form a uniform solution, and performing ultrasonic treatment at room temperature to generate luminescent powder; and washing, centrifuging and drying in vacuum to obtain the hybrid material. The highest photoluminescence quantum yield is up to 70%, and the luminescence mechanism is thermally activated delayed fluorescence. The material can be used for a white light LED (CIE coordinate (0.33, 0.33)) and an X-ray scintillator (the light yield is 32537 photons / MeV, and the spatial resolution is 20lpmm <-1 >), and has the characteristics of simple preparation and excellent performance.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent hybrid materials, and in particular relates to a preparation method and application of a high-efficiency blue light emitting hybrid material. Background Art

[0002] Organic-inorganic hybrid semiconductors are a class of materials of great interest to researchers. They combine the unique properties of inorganic and organic components while exhibiting novel properties not achievable by a single component. To address the uncontrollable structure and poor thermal stability of hybrid semiconductor materials based on Group I-VII binary metal halides, a design strategy centered on coordinated anion modules has been proposed, resulting in the successful synthesis of a series of highly efficient blue-light-emitting materials. These structures consist of neutral organic ligands forming coordinated anion clusters with discrete inorganic modules. These coordinated anion cluster modules then form ion pairs with organic ligand cations, further assembling into ionic hybrid structures. The ionic bonds in these materials enhance their thermal stability, while the coordination of the neutral organic ligands with Cu atoms preserves their excellent photoluminescence properties. In this structural control strategy, triphenylphosphine (TPP) serves as a neutral organic ligand, a commonly used steric modulator, to prevent uncontrolled aggregation into extended inorganic structures (chains / layers), thereby enforcing the formation of discrete anionic coordination modules.

[0003] While these materials have shown promising potential for white light LED applications, their synthesis involves time-consuming volatilization and crystallization steps, and impurities may be introduced during the preparation process, which may hinder subsequent applications. In addition, the ligands required for synthesis must be obtained through organic reactions and separation and purification, which increases experimental complexity and reduces the feasibility of commercial applications of the materials. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention proposes a preparation method and application of a high-efficiency blue light emitting hybrid material.

[0005] The method for preparing the high-efficiency blue light emitting hybrid material of the present invention comprises the following steps:

[0006] Cuprous halide, triphenylphosphine (TPP) and tetraethylammonium halide are dispersed in N,N-dimethylformamide (DMF) in a molar ratio of 1:1:1 to form a uniform solution, which is then ultrasonically treated at room temperature to generate a luminescent powder; and the hybrid material is obtained after washing, centrifugation and vacuum drying.

[0007] The cuprous halide is CuCl, CuBr or CuI; the tetraethylammonium halide is tetraethylammonium chloride (TEACl), tetraethylammonium bromide (TEABr) or tetraethylammonium iodide (TEAI).

[0008] The power of the ultrasonic treatment is 200-500W, and the ultrasonic treatment is carried out for 10 minutes, and then the powder is washed with ethyl acetate or ethanol.

[0009] The present invention also provides a high-efficiency blue light emitting hybrid material prepared by the above method, the general structural formula of the hybrid material is:

[0010] When the cuprous halide is CuCl, the structure is CuCl2(tpp)(TEA);

[0011] When the cuprous halide is CuBr, the structure is Cu2Br3(tpp)2(TEA);

[0012] When the cuprous halide is CuI, the structure is Cu2I4(tpp)2(TEA)2;

[0013] Wherein, TEA is a tetraethylammonium cation.

[0014] The hybrid material of the present invention is used in white light LEDs. The hybrid material is mixed with yellow light phosphor to prepare white light emitting phosphor. The white light phosphor has CIE coordinates of (0.33, 0.33) and a color temperature of 5603K.

[0015] The yellow phosphor is (Cu4I8)(CuI4)3(C 12 H 26 N2)6, the mass ratio of the hybrid material to the yellow phosphor is 1:150.

[0016] The hybrid material of the present invention is used in X-ray imaging, and the hybrid material is used to prepare an X-ray scintillator.

[0017] The beneficial effects of the present invention are:

[0018] Compared with existing technologies, this invention utilizes a simple solution ultrasonic treatment method and inexpensive tetraethylammonium ligand to rapidly prepare a highly efficient blue-light-emitting hybrid material. This method significantly shortens preparation time, achieves a yield of 88%-98%, and eliminates the need for complex purification steps, significantly reducing preparation costs and experimental complexity. The prepared hybrid material exhibits excellent photophysical properties, with a photoluminescence quantum yield of up to 70%, an emission wavelength concentrated in the blue region of 440-467nm, and CIE chromaticity coordinates close to pure blue light. Its luminescence mechanism is thermally activated delayed fluorescence, with an energy difference of only 0.06941 eV between the lowest excited singlet and triplet states. The material also exhibits a thermal decomposition onset temperature exceeding 190°C and remains stable in air for 25 days. In terms of application, this material can be combined with yellow phosphor to prepare a white light emitting phosphor with CIE coordinates of (0.33, 0.33), which has excellent color rendering properties when used in white light LEDs; when used as an X-ray scintillator, the light yield reaches 32537 photons / MeV, and the detection limit is as low as 0.186μGyairs. -1 The spatial resolution of the flexible film composited with TPU reaches 20lpmm -1 , and has good stability under continuous irradiation, providing a new way for the application of blue light materials in lighting and medical imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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.

[0020] Figure 1 These are photos of the solution after mixing the raw material and DMF (ab), the mixed solution after ultrasound (cd), and the powder after drying (ef) under natural light and 365nm ultraviolet light in the examples.

[0021] Figure 2 The following are the following: (ac) microscope images of the crystals of Compound -Cl, -Br and -I under 365 nm ultraviolet light (the inset shows the corresponding image under transmitted white light), (df) schematic diagrams of the crystal structure, (gi) structural view of the inorganic module, and (jl) simulated SXRD and experimental PXRD patterns.

[0022] Figure 3 In the embodiments (ac) are the photoluminescence excitation spectra (dashed line) and emission spectra (solid line) of Compound-Cl, -Br and -I at room temperature, the photoluminescence quantum yield analysis curves (df) of Compound-Cl, -Br and -I, and the emission spectra (gi) under light excitation of different energies.

[0023] Figure 4are the CIE color coordinates of Compound -Cl, -Br and -I in the examples.

[0024] Figure 5 : The fluorescence lifetime decay curves of Compound-Cl, -Br and -I in the examples and their corresponding single exponential fitting curves (ac).

[0025] Figure 6 The figures are the temperature-dependent fluorescence lifetime decay curves (ab) of Compound-I at 80-460K in the embodiment; (c) the decay lifetimes at different temperatures (discrete points) and their fitting curves (solid lines); and (de) the energy level diagrams representing the photophysical processes of Compound-I at low and high temperatures, respectively, where τ(S1), τ(DF), τ(T1), ISC, RISC and ΔE(S1-T1) represent the fluorescence decay lifetime, delayed fluorescence decay lifetime, phosphorescence decay lifetime, intersystem crossing, reverse intersystem crossing and the energy gap between the S1 and T1 states, respectively.

[0026] Figure 7 TG and DTG curves (ac) of Compound-Cl, -Br and -I in the examples, (d) fluorescence spectra and (e) powder XRD patterns of fresh samples and samples after being placed in air for 25 days.

[0027] Figure 8 is the PL emission spectrum (λ ex =365nm) (a), CIE coordinate diagram, the inset is the CIE coordinates and correlated color temperature (CCT) value of the white light phosphor (b), and photos of colored pencils under the illumination of white light LED lamp beads (ce).

[0028] Figure 9 Figures 1 and 2 show the relationship between (a) absorption coefficient and photon energy, (b) X-ray attenuation efficiency as a function of scintillator thickness, and (c) RL spectra for Compound-Cl, -Br, -I, CWO, and YAG(Ce) in the examples. Comparison of light yields for Compound-Cl, -Br, and -I, (d) CWO, and (e) YAG(Ce).

[0029] Figure 10 In the embodiment, Compound-Cl, -Br and -I are at 220~705μGy air s -1 Radioluminescence spectra (RL) (ac) within the dose rate range, signal-to-noise ratios of Compound-Cl, -Br, and -I as a function of dose rate (df), Compound-I at a dose rate of 705 μGy air s -1The variation of RL intensity under continuous X-ray excitation (g) and the tolerance to X-ray cyclic irradiation (h) (dose rate: 705 μGy air s -1 , interval 30s).

[0030] Figure 11 Photographs of the transparent and flexible Compound-I@TPU scintillator film (a, b) under natural light and 365nm UV light, an image of a standard X-ray test chart (left), and X-ray imaging of the Compound-I@TPU scintillator (right) (c). X-ray images of the Compound-I@TPU flexible scintillator film with attached spring capsules (d) and chips (e). The inset is an optical image before X-ray exposure. DETAILED DESCRIPTION

[0031] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. In addition, the technical features involved in the various embodiments described below can be combined with each other as long as they do not conflict with each other.

[0032] Example 1

[0033] The reagents used were: CuI (>99.5%, Aladdin), CuBr (99%, Aladdin), CuCl (97%, Maclean), tetraethylammonium iodide (TEAI, 98%, Maclean), tetraethylammonium bromide (TEABr, 98%, Maclean), tetraethylammonium chloride (TEACl, 98%, Maclean), and N,N-dimethylformamide (DMF, 99.9%, Maclean). All reagents were used without further purification.

[0034] Preparation of high-efficiency blue-light-emitting hybrid materials: 2 mmol each of the corresponding cuprous halide (CuCl, CuBr, CuI), triphenylphosphine, and tetraethylammonium halide (TEACl, TEABr, TEAI) were added to a glass vial, followed by 1 mL of DMF. After capping, the mixture was sonicated at room temperature for approximately ten minutes. Illumination with a UV lamp revealed a large amount of blue-emitting powder, designated Compound-Cl, Compound-Br, and Compound-I. The solution containing Compound-Cl was washed with 20 mL of ethyl acetate, while the solution containing Compound-Br and Compound-I was washed with 20 mL of ethanol. The powders were then centrifuged and vacuum-dried to obtain dry powders. The yields of Compound-Cl, Compound-Br, and Compound-I were 93%, 88%, and 98%, respectively.

[0035] Single crystal preparation: Add 2 mmol each of cuprous halide, triphenylphosphine, and tetraethylammonium halide to a glass vial, followed by 1 mL of DMF. Tighten the lid and heat in an oven at 100°C for 10 hours. After cooling to room temperature, transparent crystals will be visible within the vial, emitting blue light under 365 nm UV light.

[0036] Synthesis method and structure analysis of the compound:

[0037] Taking Compound-I as an example, cuprous iodide (CuI), triphenylphosphine (tpp) and tetrabutylammonium iodide (TEAI) were dispersed in anhydrous N,N-dimethylformamide (DMF) at a molar ratio of 1:1:1 to form a uniform solution ( Figure 1 ab), after ten minutes of ultrasonic treatment, a large amount of luminescent powder was generated from the solution ( Figure 1 cd), add ethanol to the solution to wash the powder, centrifuge and vacuum dry to obtain a clean white powder ( Figure 1 e), the powder emits blue light under 365nm ultraviolet light ( Figure 1 f) The same is true for the synthesis of Compound-Cl and Compound-Br.

[0038] The synthesis method of single crystals of these compounds is also very simple. The crystalline products can be synthesized by dissolving the raw materials in DMF in a stoichiometric ratio and then performing a hydrothermal treatment at 100 ° C for 10 hours. Figure 2 As shown in Figures ac, the synthesized crystal emits bright blue light under 365nm ultraviolet (UV) light. The crystal also has ideal single crystal X-ray diffraction (SCXRD) analysis characteristics, and its crystal structure has been successfully resolved. Figure 2 df are shown, and the key crystallographic data are summarized in Table 1.

[0039] Table 1 Crystal analysis data of three compounds

[0040]

[0041]

[0042] In Compound-Cl( Figure 2 In d), a single Cu atom is trigonal planarly coordinated and connected to two Cl atoms and one P atom in the tpp ligand, forming [CuCl2(tpp)] - Coordinate anion clusters and then combine with tetraethylammonium to form CuCl2(tpp)(TEA). As for Compound-Br( Figure 2e), each Cu atom is tetrahedrally coordinated and connected to three Br atoms and one P atom, forming a trigonal bipyramidal arrangement. These units assemble into a negatively charged dimer structure [Cu2Br3(tpp)2] - , and then combined with tetraethylammonium to form Cu2Br3(tpp)2(TEA). As for Compound-I ( Figure 2 f), each Cu atom is tetrahedrally coordinated with three I atoms and one P atom in the tpp ligand in a trigonal bipyramid to form a negatively charged dimer Cu2I4(tpp) 2- Then it combines with tetraethylammonium to form Cu2I4(tpp)2(TEA)2. CuCl2 in Compound-Cl, -Br and -I - 、Cu2Br3 - and Cu2I4 2- The single crystal structure views of the inorganic module are as follows Figure 2 The crystal phase and purity of the synthesized powder were confirmed by X-ray diffraction (XRD), as shown in Figure 2 As shown in Figure 1, the peak positions in the PXRD pattern are very consistent with the peak positions simulated from the SXRD data, confirming the successful preparation of pure phase samples, which were then used for further characterization.

[0043] Photophysical properties of the compound:

[0044] The room temperature PL and PLE spectra of the compounds are shown in Figure 2. Figure 3 ac. All compounds exhibited similar spectra, with excitation maxima at 370-385 nm and emission maxima at 440-467 nm. It is worth noting that this deep blue luminescence is relatively rare in copper halide hybrid systems, and its wide excitation range covers most of the ultraviolet spectrum. The wide excitation range covers most of the ultraviolet spectrum. The small Stokes shift observed between the PLE and PL peaks indicates minimal energy loss and high efficiency in ultraviolet photon energy utilization, highlighting its potential application value in energy-saving optoelectronic devices. In addition, all PL spectra exhibited single-band emission with a full width at half maximum (FWHM) value of 70-90 nm (see Table 2 for details), indicating its high color purity in the blue light region.

[0045] Table 2 Some optical properties of the three compounds

[0046]

[0047] In addition, if Figure 3As shown in df, the PLQY of Compound-Cl, -Br and -I are 26%, 41% and 70% respectively. It can be observed that the quantum yield increases gradually from Compound-Cl to Compound-Br and then to Compound-I, showing a certain regularity. The excitation-dependent PL spectra of the compounds, such as Figure 3 As shown in gi, the 3D continuous PL color mapping produces a single emission center, which indicates that the emission originates from a single radiative transition mechanism. The International Commission on Illumination (CIE) chromaticity coordinates of the compound are calculated and plotted on Figure 4 All coordinates are in the blue light region and are close to the pure blue chromaticity coordinates (0.15, 0.06) defined in the standard RGB (sRGB) color gamut, indicating that it is suitable as a high-efficiency blue light-emitting material.

[0048] Luminescence mechanism of the compound:

[0049] The room temperature PL lifetime decay curve of the compound is as follows Figure 5 By fitting the decay curves with a single exponential, the lifetimes (τ) were found to be in the range of 9–22 μs (see Table 2). These long lifetimes suggest the possibility of phosphorescence emission or thermally activated delayed fluorescence (TADF) mechanisms.

[0050] In order to further study its luminescence mechanism, the temperature-dependent lifetime decay curves of Compound-I were measured in the temperature range of 80K to 460K (specifically 80, 100, 120, 140, 160, 180, 200, 220, 240, 260, 280, 300, 320, 340, 360, 380, 400, 420, 440 and 460K), as shown in Figure 2. Figure 6 ab. The corresponding observed lifetimes from these measurements are plotted on Figure 6 c. As the temperature decreases, the lifetime of Compound-I gradually increases above 200K, and rises sharply below 200K to 80K. This trend is consistent with the mechanism proposed by Yersin et al., that is, delayed fluorescence originates from thermally activated reverse intersystem crossing (RISC) from the lowest excited triplet state (T1) to the lowest excited singlet state (S1). From 460K to 80K, the fluorescence lifetime of Compound-I increases by about 56 times, from 2.6μs at 460K to 146.0μs at 80K. Figure 6As shown in Figure d, the excitons on the S1 excited state are transferred to the T1 excited state through intersystem crossing (ISC), and are mainly frozen in the T1 state at low temperatures (such as 80K), so the luminescence can be attributed to the pure T1 state. As the temperature increases, the hot excitons are transferred to the S1 state through anti-intersystem crossing. Through continuous anti-intersystem crossing (RISC) from the T1 state, the excitons in the S1 state increase significantly, thereby realizing an efficient thermally activated delayed fluorescence (TADF) process ( Figure 6 e).

[0051] According to the literature, the observed decay time (τ obs ) and absolute temperature (T) have the following relationship:

[0052]

[0053] Among them, k B represents the Boltzmann constant, τ(S1) and τ(T1) represent the luminescence decay time of the S1 and T1 excited states respectively, and ΔE(S1-T1) is the energy gap difference between the two states. Figure 6 As shown in c, the τ of Compound-I obs -T data were well fitted. The fitting results are shown in Figure 5 As shown in ab, the fitted τ(T1) value of Compound-I (147.6μs) is very close to the observed value (146.0μs) at 80K, and the fitted ΔE(S1-T1) is 0.06941eV. The small energy gap between the S1 and T1 excited states is crucial for promoting antisystem crossing and achieving dominance of the TADF process at ambient temperature. Currently, TADF has been observed primarily in copper complexes and pure organic molecules with small energy gaps. These TADF materials are considered promising candidates for optoelectronic devices.

[0054] Application performance of compounds in white light LEDs:

[0055] In cuprous halide organic-inorganic hybrid structures, strong blue light emission usually originates from neutral molecular clusters. Although these structures exhibit high photoluminescence quantum yields, the decomposition temperature of these clusters is usually below 130°C, and their poor stability hinders their potential for practical applications. Figure 7Figures ac show the thermogravimetric (TG) curves of Compound-Cl, -Br, and -I, respectively (the inset is the differential thermogravimetric (DTG) curve). As can be seen from the figure, these crystals exhibit good thermal stability, and their decomposition onset temperatures are determined by thermogravimetric analysis to be over 190°C. Among them, Compound-Br has the highest stability, with a decomposition onset temperature of 230°C. These compounds undergo a similar decomposition process, characterized by the first loss of TPP and TEA ligands in the temperature range of 200-350°C, followed by a gradual loss of copper halide above 350°C.

[0056] The enhanced thermal stability of Compound-Cl, -Br and -I can be attributed to the synergistic effect of ionic and covalent bonds in their hybrid structures. With its excellent photoluminescence quantum yield and good stability in air (it can maintain its luminescence and structural stability for 25 days) ( Figure 7 e), Compound-I is very suitable for the preparation of lighting devices. In order to prepare white light LEDs, a yellow light emitting phosphor Y1, namely (Cu4I8)(CuI4)3(C 12 H 26 N2)6, and mixed it with Compound-I to prepare white light emitting phosphor. em =592nm) powders were mixed and ground uniformly at a mass ratio of 1:50, 1:100 and 1:150 to obtain white light emitting phosphors. Figure 8 As shown in the PL emission spectrum in a, the yellow light emission intensity increases with the increase of the mass ratio of Y1. The CIE coordinates calculated from the spectrum are listed in the inset table and plotted in Figure 8 In b, the light emitted by the mixed phosphor is mainly in the white light region. It is worth noting that the mixed powder with a mass ratio of 1:150 exhibits pure white light emission with CIE coordinates of (0.33, 0.33) and a color temperature of 5603K, which is close to the international artificial daylight standard (6500K). In order to demonstrate its practical applicability, different proportions of phosphors were dispersed in UV-curing adhesive and evenly coated on UV LED lamp beads (365nm, 3V, 0.06W) to prepare white light LED lamp beads. When the lamp beads are powered on, bright white light is emitted, clearly showing the bright colors of colored pencils ( Figure 8 ce), which indicates excellent color rendering properties of white light and highlights the application potential of the synthesized compounds in white light LEDs.

[0057] Application performance of compounds in X-ray imaging:

[0058] In addition to being used in white light LEDs, these compounds can also be used in X-ray imaging. Using the XCOM photon cross-section database (https: / / www.nist.gov / pml / xcom-photon-cross-sections-database), the photon cross-sections of Compound -Cl, -Br and -I as well as commercial scintillators CWO (CdWO4) and YAG (Ce) [Y3Al5O 12 :Ce 3+ ]X-ray absorption coefficient in a wide range of photon energies, such as Figure 9 As shown in a. Figure 9 b shows the variation of the attenuation efficiency of Compound-Cl, -Br, -I, CWO and YAG(Ce) with thickness at an X-ray photon energy of 8 keV. It is noteworthy that at a thickness of 1 mm, the attenuation efficiency of the three compounds is close to 100%. In addition, their radioluminescence (RL) performance was evaluated and compared with that of CWO and YAG(Ce). Figure 9 As shown in c, the emission intensity of Compound-Br and -I exceeds that of CWO and YAG(Ce). Based on the reference value of CWO (13000 photons / MeV), the conversion efficiency of X-rays to visible light (i.e., X-ray light yield) was calculated by the integral area of ​​the RL spectrum and the X-ray attenuation efficiency. The light yields of Compound-Cl, -Br, and -I were 5280, 16120, and 32537 photons / MeV, respectively. Figure 9 d). In order to verify the accuracy of the light yield measurement, another commercial scintillator YAG (Ce) was used as a reference to calculate the light yield of Compound -Cl, -Br and -I, as shown in Figure 2. Figure 9 The results are highly consistent with those calculated using CWO, with the difference within 100 photons / MeV, confirming the reliability of the light yield calculation. In addition to light yield, the detection limit is another key parameter for evaluating X-ray scintillator performance. It is defined as the X-ray dose rate corresponding to a signal-to-noise ratio (SNR) of 3. Figure 10 ac show the RL spectra of the three compounds under different X-ray dose rates, indicating that the RL intensity increases with the increase of X-ray dose. Figure 10 df shows the relationship between their RL intensity and X-ray dose rate, which can be between 220 and 705 μGy air s -1 The detection limits of Compound-Cl, -Br and -I were calculated to be 0.596, 0.694 and 0.186 μGy, respectively. air s -1 These values ​​are significantly lower than the standard dose rate of 5.5 μGy required for medical X-ray diagnosisair s -1 Such a low detection limit can effectively reduce the risk of radiation exposure to patients during medical diagnosis.

[0059] Among the three compounds, Compound-I has the highest light yield and the lowest detection limit, so it was selected to prepare the flexible scintillator film. In order to further evaluate the feasibility of Compound-I in commercial scintillator applications, its X-ray irradiation stability and cyclic stability were investigated.

[88] .like Figure 10 As shown in g, after 150 minutes of continuous X-ray irradiation, the radiation luminescence intensity remains almost unchanged. Figure 10 h shows the RL intensity of Compound-I under 100 cycles of on-off X-ray excitation. It can be seen that the intensity remains almost unchanged, which demonstrates its excellent long-term operational stability and highlights its potential for practical applications.

[0060] In order to prepare a transparent and flexible scintillator film, TPU (thermoplastic polyurethane elastomer rubber) was selected as the film-forming material. Specifically, after mixing DMF and TPU, they were heated at 50°C for 10 hours to fully dissolve TPU in DMF. Subsequently, the synthesized Compound-I-DMF suspension was directly added to the TPU-DMF solution and stirred evenly, and then it was dropped onto a glass substrate. A film of uniform thickness was prepared by spin coating. The spin-coated film was naturally solidified after standing at room temperature for five hours and could be peeled off from the glass substrate. Figure 11 ab shows images of the scintillator film composed of Compound-I and TPU under natural light and 365nm UV excitation, demonstrating its transparency and excellent flexibility. In addition, the spatial resolution of the flexible film was evaluated using an X-ray standard test pattern. Figure 11 As shown in c, in the X-ray image, 20lp mm -1 The line spacing of the spatial resolution is still clearly discernible. To illustrate the potential application of the prepared Compound-I@TPU flexible film in X-ray imaging, a capsule containing a spring and a bank card were placed in front of the film. Under X-ray irradiation, the metal patterns on the spring and the bank card were clearly visible ( Figure 11 de), demonstrating its broad prospects in X-ray imaging applications.

[0061] Summary: Highly efficient blue-light emitting powders were synthesized by a simple solution sonication method using inexpensive tetraethylammonium ligands. These materials, especially Compound-I, exhibited excellent photoluminescence properties with a PLQY of up to 70%. Through systematic characterization and theoretical calculations, their structure-property relationship was revealed, and their luminescence mechanism was determined to be thermally activated delayed fluorescence (TADF). When applied to white light LED devices and X-ray imaging, these materials showed excellent performance: pure white light emission with CIE coordinates of (0.33, 0.33) was achieved in white light LED devices, and 20lp mm was achieved in X-ray imaging. -1 This provides a new approach to advance the design and application of blue light emitting materials.

[0062] 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 high-efficiency blue light emitting hybrid material, characterized in that: The following steps are involved: Cuprous halide, triphenylphosphine and tetraethylammonium halide are dispersed in N,N-dimethylformamide in a molar ratio of 1:1:1 to form a uniform solution, which is then ultrasonically treated at room temperature to generate luminescent powder; and the hybrid material is obtained after washing, centrifugation and vacuum drying.

2. The method for preparing a high-efficiency blue light emitting hybrid material according to claim 1, characterized in that: The cuprous halide is CuCl, CuBr or CuI; the tetraethylammonium halide is TEACl, TEABr or TEAI.

3. The method for preparing a high-efficiency blue light emitting hybrid material according to claim 1, characterized in that: The power of the ultrasonic treatment is 200-500W, and the ultrasonic treatment is carried out for 10 minutes, and then the powder is washed with ethyl acetate or ethanol.

4. The high-efficiency blue light emitting hybrid material prepared by the preparation method according to claim 1, characterized in that: The general structural formula of the hybrid material is: When the cuprous halide is CuCl, the structure is CuCl2(tpp)(TEA); When the cuprous halide is CuBr, the structure is Cu2Br3(tpp)2(TEA); When the cuprous halide is CuI, the structure is Cu2I4(tpp)2(TEA)2; Wherein, TEA is a tetraethylammonium cation.

5. Use of the high-efficiency blue-light-emitting hybrid material prepared by the preparation method according to claim 1 in a white light LED, wherein the hybrid material is mixed with a yellow light phosphor to prepare a white light-emitting phosphor; the white light phosphor has CIE coordinates of (0.33, 0.33) and a color temperature of 5603K.

6. The use according to claim 5, characterized in that The yellow phosphor is (Cu4I8)(CuI4)3(C 12 H 26 N2)6, the mass ratio of the hybrid material to the yellow phosphor is 1:

150.

7. Use of the high-efficiency blue light emitting hybrid material prepared by the preparation method according to claim 1 in X-ray imaging, wherein the hybrid material is used to prepare an X-ray scintillator.

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