Novel copper halide-based luminescent material as well as preparation method and application thereof

Abstract

The invention relates to a novel copper halide-based luminescent material as well as a preparation method and application thereof. The chemical formula of the copper halide-based luminescent material is [monofunctional group-DABCO] 2Cu4X6, wherein X is at least one of Cl, Br or I; the single functional group comprises at least one of methyl, ethyl, propyl, butyl, amino, carboxyl, hydroxyl, ester group, acylamino, cyano, nitro and sulfonic group; the copper halide-based luminescent material can be excited by near ultraviolet light, purple light or blue light. The crystal lattice stability and the forbidden bandwidth of the copper halide-based luminescent material can be regulated and controlled at the same time through innovation of material components, so that the targets of high water stability, narrow forbidden bandwidth and the like are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of copper halide-based luminescent materials, and particularly relates to a novel copper halide-based luminescent material, a preparation method thereof, and an application thereof. Background Art

[0002] Copper halide-based luminescent materials, such as cesium copper halide, rubidium copper halide, ammonium copper halide and other materials, can simultaneously meet the advantages of non-toxicity and high luminous efficiency, and also have excellent stability in dry air, and are receiving more and more attention and research. However, the characteristics of its ionic crystal make it difficult to maintain the integrity of its crystal structure in water or high-humidity environments, and it is easily damaged by highly polar water molecules to cause lattice damage and luminescence quenching, and this process is irreversible.

[0003] In addition, copper halide-based luminescent materials generally have a large band gap width exceeding 3.5 electron volts, and deep ultraviolet (wavelength less than 350 nanometers) light is required to excite them, and the requirements for the excitation light are relatively harsh. If a copper halide-based luminescent material with high water stability and a narrower band gap width (less than 3.1 electron volts) can be developed, it can work in high-humidity environments or even in water, and can be excited by near-ultraviolet or even violet light, thereby overcoming the above problems and having more advantages in applications. Innovations in material components can simultaneously regulate the lattice stability and band gap width of such materials, which is the key to achieving goals such as high water stability and narrow band gap width, and there is an urgent need for improvement at present. Summary of the Invention

[0004] The present invention provides a novel copper halide-based luminescent material, a preparation method thereof, and an application thereof. Through innovations in material components, the lattice stability and band gap width of copper halide-based luminescent materials can be simultaneously regulated to achieve goals such as high water stability and narrow band gap width.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] A novel copper halide-based luminescent material, the chemical formula of the copper halide-based luminescent material is: [monofunctional group-DABCO] 2 Cu 4 X 6 ;

[0007] Wherein: X is at least one of Cl, Br or I;

[0008] The monofunctional group includes at least one of methyl, ethyl, propyl, butyl, amino, carboxyl, hydroxyl, ester group, amide group, cyano, nitro, sulfonic acid group;

[0009] The copper halide-based luminescent material can be excited by near-ultraviolet light, violet light or blue light.

[0010] Further, the wavelength range of the near-ultraviolet light, violet light or blue light is 360 nm - 480 nm.

[0011] Further, the copper halide-based luminescent material does not undergo fluorescence quenching when immersed in water, and the luminescence intensity of the copper halide-based luminescent material in water is at least maintained at 65% of the luminescence intensity in air.

[0012] A preparation method of a novel copper halide-based luminescent material, which is prepared by a liquid-phase reaction, includes the following steps:

[0013] S1. Provide a mono-functionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as an organic cation source powder;

[0014] Provide one or more of cuprous iodide, cuprous bromide, and cuprous chloride as a copper source powder;

[0015] Provide a polar reaction solvent, which includes one or more of water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), γ-butyrolactone, tetrahydrofuran (THF), ethyl acetate, methyl acetate, methanol, ethanol, and isopropanol;

[0016] S2. Mix the organic cation source powder and the copper source powder, then add the polar reaction solvent, and stir in an inert atmosphere to obtain a suspension; heating may be accompanied during the stirring process;

[0017] As a preferred example: In a glove box under a nitrogen atmosphere, mix the organic cation source and the copper source in a molar ratio of 1:2, add 5 times the mass of DMF solvent, and stir at 60 °C for 24 hours to obtain a suspension.

[0018] S3. Centrifuge the suspension obtained in step S2 to obtain a precipitate, and dry the precipitate to obtain the copper halide-based luminescent material powder.

[0019] As a preferred example: Centrifuge the suspension at a speed of 3000 revolutions per minute for 3 minutes, remove the supernatant to obtain a precipitate, and dry the precipitate in an oven at 60 °C to obtain a water-stable copper halide-based luminescent material powder. The above centrifugation speed, centrifugation time, and drying temperature are all experimental parameters that can be obtained by those skilled in the art through a limited number of experiments. The present invention is only listed for illustration and does not constitute a parameter limitation.

[0020] By adopting the above method: The monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium cation used in the present invention can enhance the stability of the crystal structure of the luminescent material, enabling it to maintain the integrity of the crystal structure without being damaged in strongly polar solvents such as water. Therefore, the prepared copper halide-based luminescent material has excellent water stability and does not undergo luminescence quenching in water. In addition, its band gap is small and can be excited by near-ultraviolet (wavelength greater than 365 nm) and longer-wavelength excitation light.

[0021] Meanwhile, the preparation method of the copper halide-based luminescent material of the present invention is not limited to this, and there are other preparation routes. For example:

[0022] A preparation method of a novel copper halide-based luminescent material, prepared by solid-phase grinding, includes the following steps:

[0023] S1. Provide a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as the organic cation source powder;

[0024] Provide one or more of cuprous iodide, cuprous bromide, and cuprous chloride as the copper source powder;

[0025] S2. Mix the organic cation source powder and the copper source powder, and obtain the copper halide-based luminescent material powder after grinding.

[0026] The preparation method of the copper halide-based luminescent material of the present invention is not limited to this, and there are other preparation routes. For example:

[0027] A preparation method of a novel copper halide-based luminescent material, prepared by solid-phase sintering, includes the following steps:

[0028] S1. Provide a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as the organic cation source powder;

[0029] Provide one or more of cuprous iodide, cuprous bromide, and cuprous chloride as the copper source powder;

[0030] S2. Mix the organic cation source powder and the copper source powder evenly, heat at a temperature above 100 °C for at least half an hour in an inert gas atmosphere, and then cool to room temperature to obtain the copper halide-based luminescent material powder.

[0031] As a preferred example: Mix [methyl DABCO]I and cuprous iodide evenly at a molar ratio of 1:2, load them into a crucible, place them in a tube furnace, heat to 200 °C and keep warm for 1 hour under the condition of continuously introducing nitrogen atmosphere, and then cool to room temperature to obtain the water-stable copper halide-based luminescent material powder.

[0032] The preparation method of the copper halide-based luminescent material of the present invention is not limited to this, and there are other preparation routes. For example:

[0033] A preparation method of a novel copper halide-based luminescent material, wherein the copper halide-based luminescent material is a copper halide-based luminescent colloidal nanocrystal, and the preparation method is room temperature synthesis, including the following steps:

[0034] S1. Provide a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as an organic cation source powder;

[0035] Provide an organic cation source solvent, which includes one or more of water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), γ-butyrolactone, tetrahydrofuran (THF), ethyl acetate, methyl acetate, methanol, ethanol, isopropanol;

[0036] Provide one or more of cuprous iodide, cuprous bromide, and cuprous chloride as a copper source powder;

[0037] Provide a copper source co-solvent, which includes one or more of oleylamine, octylamine, phosphatidylcholine, lecithin, or a tetraalkylammonium hydrohalide with a carbon chain length greater than 6 carbon atoms; for example, oleylamine and octylamine are mixed and added in a volume ratio of 1:1.

[0038] Provide a long-chain organic acid as an organic acid ligand, including but not limited to one or more of oleic acid, caprylic acid, isooctylphosphonic acid, dodecylbenzenesulfonic acid, dodecylphosphonic acid, and tetradecylphosphoric acid; for example, oleic acid and caprylic acid are mixed and added in a volume ratio of 1:1.

[0039] Provide a reaction solvent, which includes one or more of toluene, chlorobenzene, xylene, 1-octadecene, dichloromethane, chloroform, hexane, and octane; for example, toluene and xylene are mixed and added in a volume ratio of 1:1.

[0040] S2. At room temperature, add the organic cation source solvent to the organic cation source and stir to obtain a clear cation source solution; as a further preference: weigh a certain mass of [methyl DABCO]I powder, add a certain volume of DMF, and stir at room temperature until an organic cation source solution with a concentration of 0.05 mol / L is obtained.

[0041] S3. At room temperature, add the reaction solvent to the copper source, and add the copper source co-solvent and the organic acid ligand, and stir to obtain a clear copper source solution; as a further preference: add 5 mL of toluene to 0.05 mmol of cuprous iodide, and add 0.5 mL of oleic acid and 0.1 mL of oleylamine, and stir at room temperature until a clear copper source solution is obtained.

[0042] S4. At room temperature, add the cation source solution to the copper source solution and stir for reaction to obtain the copper halide-based luminescent colloidal nanocrystal dispersion. As a further preference: quickly inject 0.5 mL of the organic cation source solution into the stirring copper source solution.

[0043] S5. It also includes a purification operation: transfer the reaction stock solution to a centrifuge tube for low-speed centrifugation, take the supernatant after centrifugation, add a certain amount of antisolvent to precipitate the nanocrystals and perform high-speed centrifugation treatment; disperse the precipitate in octane or toluene, and filter and collect with a 0.22-μm organic filter head to obtain the colloidal nanocrystal dispersion. According to needs, the above steps can be repeated, and the antisolvent can be continuously added to the dispersion and centrifuged at high speed to purify the product to the required concentration.

[0044] By adopting the above technical solution: in the above reaction, when the copper source meets the organic cation source, a large number of nuclei grow, but due to the presence of the organic acid ligand, the growth is inhibited, and finally colloidal nanocrystals uniformly dispersed in the solvent are formed. The colloidal nanocrystals have the same emission spectrum as the above copper halide-based luminescent material powder on the premise of the same components, and also have good water stability, and can also be excited by near-ultraviolet (wavelength greater than 365 nm) or longer-wavelength excitation light.

[0045] Furthermore, the monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salts include one or more of 1-methyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([methyl DABCO]I), 1-methyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([methyl DABCO]Br), 1-methyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([methyl DABCO]Cl), 1-ethyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([ethyl DABCO]I), 1-ethyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([ethyl DABCO]Br), 1-ethyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([ethyl DABCO]Cl), 1-propyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([propyl DABCO]I), 1-propyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([propyl DABCO]Br), 1-propyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([propyl DABCO]Cl), 1-butyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([butyl DABCO]I), 1-butyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([butyl DABCO]Br), 1-butyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([butyl DABCO]Cl), 1-amino-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([amino DABCO]I), 1-amino-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([amino DABCO]Br), and 1-amino-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([amino DABCO]Cl). For example, [methyl DABCO]I and [methyl DABCO]Cl are mixed and added in a ratio of 1:1.

[0046] Further, the monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salts further include one or more of 1-carboxy-1,4-diazabicyclo[2.2.2]octane-1-ammonium halide ([carboxy-DABCO]X, where: X is one of Cl, Br, or I), 1-hydroxy-1,4-diazabicyclo[2.2.2]octane-1-ammonium halide ([hydroxy-DABCO]X, where: X is one of Cl, Br, or I), 1-ester group-1,4-diazabicyclo[2.2.2]octane-1-ammonium halide ([ester group-DABCO]X, where: X is one of Cl, Br, or I), 1-amide group-1,4-diazabicyclo[2.2.2]octane-1-ammonium halide ([amide group-DABCO]X, where: X is one of Cl, Br, or I), 1-cyano-1,4-diazabicyclo[2.2.2]octane-1-ammonium halide ([cyano-DABCO]X, where: X is one of Cl, Br, or I), 1-nitro-1,4-diazabicyclo[2.2.2]octane-1-ammonium halide ([nitro-DABCO]X, where: X is one of Cl, Br, or I), and 1-sulfonic acid group-1,4-diazabicyclo[2.2.2]octane-1-ammonium halide ([sulfonic acid group-DABCO]X, where: X is one of Cl, Br, or I).

[0047] Further, the organic cation source powder and the copper source powder are mixed in a molar ratio of 1:2.

[0048] Further, cuprous halide includes cuprous iodide, cuprous bromide, cuprous chloride, etc. and their mixtures in different proportions. For example, cuprous iodide and cuprous chloride are mixed and added in a ratio of 1:1.

[0049] Application of a novel cuprous halide-based luminescent material, applying the cuprous halide-based luminescent material as described in any one of claims 1-3 to at least one of the fields of display, lighting, and X-ray technology, specifically including the following forms:

[0050] At least one of a single crystal of a cuprous halide-based luminescent material, a thin film of a cuprous halide-based luminescent material, a colloidal nanocrystal thin film of a cuprous halide-based luminescent material, an X-ray scintillator film, a luminescent material in a down-conversion light-emitting diode, a luminescent material in an electroluminescent diode, and a luminescent material in a light conversion film or a light conversion plate.

[0051] Further, the present invention provides an explanation of the preparation method of the downstream products of the above cuprous halide-based luminescent material:

[0052] A preparation method of a water-stable single crystal of a cuprous halide-based luminescent material, including the following steps:

[0053] Provide a cuprous halide-based luminescent material powder prepared by the above method;

[0054] Provide one or more of water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), γ-butyrolactone, tetrahydrofuran (THF), ethyl acetate, methyl acetate, methanol, ethanol, and isopropanol as solvents;

[0055] Dissolve the copper halide-based luminescent material powder in a solvent under heating to prepare a saturated clear solution; As a preferred example: at 100 °C, add an excessive amount of copper halide-based luminescent material powder to the DMF solvent, stir well to obtain a suspension, and then filter through a needle filter with a pore size of 0.22 microns to obtain a saturated clear solution at 100 °C;

[0056] Slowly cool the above-mentioned saturated clear solution to room temperature under static conditions, and the copper halide-based luminescent material single crystal precipitates from the solution; As a preferred example: place the above-mentioned saturated clear solution on a 100 °C hot stage, and let the hot stage slowly cool to room temperature at a cooling rate of 5 °C / hour, and the copper halide-based luminescent material single crystal precipitates from the solution.

[0057] Remove the supernatant, and after drying, obtain the copper halide-based luminescent material single crystal particles. As a preferred example: remove the supernatant, and thoroughly dry the obtained single crystal in an oven at 60 °C to obtain the single crystal particles.

[0058] An in-situ preparation method of a water-stable copper halide-based luminescent material thin film, comprising the following steps:

[0059] Provide a copper halide-based luminescent material powder prepared by the above method;

[0060] Provide one or more of water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), γ-butyrolactone, tetrahydrofuran (THF), ethyl acetate, methyl acetate, methanol, ethanol, and isopropanol as solvents;

[0061] Put an excessive amount of copper halide-based luminescent material powder into the solvent, stir well, and then filter through a needle filter with a pore size of 0.22 microns to obtain a saturated solution of the luminescent material. Both stirring and filtering can be carried out under heating; As a preferred example: at 60 °C, add an excessive amount of copper halide-based luminescent material powder to the DMSO solvent, stir well to obtain a suspension, and then filter through a needle filter with a pore size of 0.22 microns to obtain a saturated clear solution at 60 °C;

[0062] The above-mentioned saturated solution is spin-coated on the surface of glass, silicon wafers or other common substrates, and then annealed to obtain the water-stable copper halide-based luminescent material film. As a further preference: the above-mentioned saturated clear solution is dropped on the surface of a glass slide at 60 °C, spin-coated at a speed of 4000 revolutions per minute for 120 seconds, and then the glass slide is placed on a hot plate at 100 °C and annealed for 10 minutes to obtain the water-stable copper halide-based luminescent material film.

[0063] A method for preparing a water-stable copper halide-based luminescent material colloidal nanocrystal film, comprising the following steps:

[0064] Provide a water-stable copper halide-based luminescent material colloidal nanocrystal dispersion prepared by the above method;

[0065] The above-mentioned dispersion is spin-coated on the surface of glass, silicon wafers or other common substrates to obtain the water-stable copper halide-based luminescent material colloidal nanocrystal film. As a further preference: the above-mentioned dispersion is dropped on the surface of a glass slide and spin-coated at a speed of 2000 revolutions per minute for 50 seconds to obtain the water-stable copper halide-based luminescent colloidal nanocrystal film.

[0066] A down-conversion light-emitting diode, comprising a near-ultraviolet or violet light-emitting diode and a down-conversion phosphor coated on its surface, wherein the down-conversion phosphor is a copper halide-based luminescent material powder prepared by the above method.

[0067] An electroluminescent diode, comprising an ITO conductive glass, a hole injection layer, a hole transport layer, a copper halide-based luminescent material light-emitting layer, an electron transport layer, and an electrode layer, wherein the copper halide-based luminescent material light-emitting layer is a copper halide-based luminescent material film or a copper halide-based luminescent material colloidal nanocrystal film prepared by the above method. Among the above, except for the copper halide-based luminescent material light-emitting layer, the remaining structures of the electroluminescent diode can all adopt any substance, formulation and process method in the prior art, and those skilled in the art can make arbitrary selections and preparations after seeing the technical concept of the present invention. Therefore, the protection scope of the present invention should all cover and protect.

[0068] In some embodiments, the hole injection layer may include: one or more of poly(3,4-ethylenedioxythiophene) doped with polystyrenesulfonic acid (PEDOT:PSS), nickel oxide, tungsten oxide, vanadium oxide, and molybdenum trioxide.

[0069] In some embodiments, the hole transport layer may include one or more of: poly(9-vinylcarbazole) (PVK), poly[(4,4′-(N-(4-sec-butylphenyl)diphenylamine)] (PolyTPD), poly[9,9-dioctylfluorene-co-N-[4-(3-methylpropyl)]-diphenylamine] (TFB), poly[bis(4-phenyl)(2,4,6-trimethylphenyl)amine] (PTAA), poly[(9,9-dioctylfluorene-2,7-diyl)-alternating-(9-(2-ethylhexyl)-carbazole-3,6-diyl)] (PF8Cz).

[0070] In some embodiments, the electron transport layer may include one or more of: 1,3,5-tris(1-phenyl-1H-benzoimidazol-2-yl)benzene (TPBi), 2,4,6-tris[3-(diphenylphosphoryloxy)phenyl]-1,3,5-triazole (PO-T2T), bis[2-((oxo)diphenylphosphino)phenyl]ether (DPEPO), 3,3'-[5'-[3-(3-pyridyl)phenyl][1,1':3',1”-terphenyl]-3,3”-diyl]dipyridine (TmPyPB), zinc oxide (ZnO).

[0071] A method for preparing a water-stable scintillator film based on a copper halide-based luminescent material, comprising the following steps:

[0072] Providing a copper halide-based luminescent material powder prepared by the above method;

[0073] Providing a polymer matrix, including but not limited to polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyacrylic acid (PAA), polyethylene glycol (PEG), polyethylene oxide (PEO), etc. and mixtures thereof in different proportions, for example, PMMA and PEG are mixed and added in a mass ratio of 1:1;

[0074] Providing one or more of, including but not limited to, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), γ-butyrolactone, tetrahydrofuran (THF), ethyl acetate, methyl acetate, methanol, ethanol, isopropanol, toluene, chlorobenzene, xylene as a dispersant;

[0075] Reducing the particle size of the copper halide-based luminescent material powder by methods such as grinding and ball milling to obtain an ultrafine powder;

[0076] Mix the above ultrafine powder with a polymer matrix, add a dispersant, and stir for several hours to obtain a copper halide-based luminescent material-polymer matrix composite dispersion. The stirring process can be accompanied by heating. As a further preference: Mix the obtained ultrafine powder of copper halide-based luminescent material with PMMA powder at a mass ratio of 1:10, add a DMF dispersant 5 times the solid mass, and stir at 80 °C for 10 hours to obtain a copper halide-based luminescent material-PMMA composite dispersion.

[0077] Coat the above dispersion on the surface of a glass substrate by means of spin coating, blade coating, slot die coating, etc., and anneal at a certain temperature. After the solvent is dried, the water-stable scintillator film based on the copper halide-based luminescent material is obtained and can be peeled off from the surface of the glass substrate. As a further preference: Spin coat the copper halide-based luminescent material-PMMA composite dispersion on the surface of a glass substrate at a speed of 1000 revolutions per minute, and anneal at 80 °C for 30 minutes to obtain the water-stable copper halide-based luminescent material scintillator film, which can be peeled off from the surface of the glass substrate.

[0078] This scintillator film can exhibit bright visible light luminescence under X-ray irradiation, and its luminescence spectrum is basically the same as that under ultraviolet light excitation, and can be used for X-ray imaging applications.

[0079] Advantages of the present invention: The present invention provides a preparation method and application of a water-stable copper halide-based luminescent material, and innovatively develops and uses a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium cation as a copper halide-based luminescent material with an organic cation. This material has excellent water stability and can be excited by near-ultraviolet light (wavelength greater than 365 nm) or light with a longer wavelength, overcoming the disadvantages of other copper halide-based luminescent materials developed in the previous field and having more advantages in applications. The preparation methods of the powder, single crystal, colloidal nanocrystal and thin film forms of this material have been comprehensively developed. Finally, the applications of this material in light-emitting diodes and X-ray imaging are also demonstrated. Description of the Drawings

[0080] Figure 1 For [methyl DABCO] obtained in Example 1 of the present invention 2 Cu 4 I 6 The excitation spectrum and emission spectrum of the powder.

[0081] Figure 2 For [methyl DABCO] obtained in Example 1 of the present invention 2 Cu 4 I 6 Comparison of the luminescence intensities of the powder in air and in water.

[0082] Figure 3 For [amino DABCO] obtained in Example 2 of the present invention2 Cu 4 I 6 The excitation spectrum and emission spectrum of the powder.

[0083] Figure 4 The [amino DABCO] obtained in Example 2 of the present invention 2 Cu 4 I 6 Comparison of the luminescence intensities of the powder in air and in water.

[0084] Figure 5 The [methyl DABCO] obtained in Example 3 of the present invention 2 Cu 4 Cl 6 The excitation spectrum and emission spectrum of the powder.

[0085] Figure 6 The [methyl DABCO] obtained in Example 3 of the present invention 2 Cu 4 Cl 6 Comparison of the luminescence intensities of the powder in air and in water.

[0086] Figure 7 The excitation spectrum and emission spectrum of the powder obtained in Comparative Example 1 of the present invention

[0087] Figure 8 The [methyl DABCO] obtained in Example 4 of the present invention 2 Cu 4 I 6 The excitation spectrum and emission spectrum of the powder.

[0088] Figure 9 The [methyl DABCO] obtained in Example 4 of the present invention 2 Cu 4 I 6 Comparison of the luminescence intensities of the powder in air and in water.

[0089] Figure 10 The [methyl DABCO] obtained in Example 5 of the present invention 2 Cu 4 I 6 The excitation spectrum and emission spectrum of the powder.

[0090] Figure 11 The [methyl DABCO] obtained in Example 5 of the present invention 2 Cu 4 I 6 Comparison of the luminescence intensities of the powder in air and in water.

[0091] Figure 12The [methyl DABCO] obtained in Example 6 of the present invention 2 Cu 4 I 6 The excitation spectrum and emission spectrum of the single crystal

[0092] Figure 13 The [methyl DABCO] obtained in Example 6 of the present invention 2 Cu 4 I 6 Comparison of the luminescence intensities of the single crystal in air and in water

[0093] Figure 14 The [methyl DABCO] obtained in Example 7 of the present invention 2 Cu 4 I 6 The excitation spectrum and emission spectrum of the colloidal nanocrystals

[0094] Figure 15 The [methyl DABCO] obtained in Example 8 of the present invention 2 Cu 4 I 6 The excitation spectrum and emission spectrum of the thin film

[0095] Figure 16 The [methyl DABCO] obtained in Example 9 of the present invention 2 Cu 4 I 6 The excitation spectrum and emission spectrum of the colloidal nanocrystal thin film

[0096] Figure 17 The luminescence spectrum of the down-conversion light-emitting diode obtained in Example 10 of the present invention

[0097] Figure 18 The luminescence spectrum of the down-conversion light-emitting diode obtained in Example 11 of the present invention

[0098] Figure 19 The luminescence spectrum of the scintillator film under X-ray irradiation obtained in Example 12 of the present invention

[0099] Figure 20 The X-ray imaging photograph of a capsule with a spring inside, realized by using the scintillator film prepared in Example 12 of the present invention Detailed implementation manners

[0100] To make the objectives, technical solutions and effects of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific implementation manners described herein are only used to explain the present invention and are not used to limit the present invention

[0101] Example 1: (Preparation of powder by liquid phase of [Methyl DABCO]I and Copper(I) Iodide)

[0102] Weigh 600 mg of [Methyl DABCO]I and 900 mg of Copper(I) Iodide and add them into a 20 mL sample bottle. Then add 8 mL of DMF and stir at room temperature for 5 hours to obtain a white suspension. Centrifuge this suspension at a speed of 3000 revolutions per minute for 3 minutes, remove the supernatant, and place the precipitate in an oven at 60 °C to dry completely to obtain the finished powder, whose composition is [Methyl DABCO] 2 Cu 4 I 6 . This powder emits bright green light under the irradiation of a 400 nm ultraviolet flashlight and does not undergo luminescence quenching when soaked in water. Figure 1 This is the excitation spectrum and emission spectrum of the powder prepared in Example 1. Figure 2 This is the comparison of the luminescence intensities of the powder prepared in Example 1 in air and in water.

[0103] Example 2: (Preparation of powder by liquid phase of [Amino DABCO]I and Copper(I) Iodide)

[0104] Weigh 750 mg of [Amino DABCO]I and 750 mg of Copper(I) Iodide and add them into a 20 mL sample bottle. Then add 8 mL of DMF and stir at room temperature for 5 hours to obtain a white suspension. Centrifuge this suspension at a speed of 3000 revolutions per minute for 3 minutes, remove the supernatant, and place the precipitate in an oven at 60 °C to dry completely to obtain the finished powder, whose composition is [Amino DABCO] 2 Cu 4 I 6 . This powder emits bright green light under the irradiation of a 365 nm ultraviolet flashlight and does not undergo luminescence quenching when soaked in water. Figure 3 This is the excitation spectrum and emission spectrum of the powder prepared in Example 2. Figure 4 This is the comparison of the luminescence intensities of the powder prepared in Example 2 in air and in water.

[0105] Example 3: (Preparation of powder by liquid phase of [Methyl DABCO]Cl and Copper(I) Chloride)

[0106] Weigh 676 mg of [Methyl DABCO]Cl and 824 mg of Copper(I) Chloride and add them into a 20 mL sample bottle. Then add 8 mL of DMF and stir at room temperature for 5 hours to obtain a white suspension. Centrifuge this suspension at a speed of 3000 revolutions per minute for 3 minutes, remove the supernatant, and place the precipitate in an oven at 60 °C to dry completely to obtain the finished powder, whose composition is [Methyl DABCO] 2 Cu 4 Cl 6This powder emits bright orange light under the irradiation of a 400-nm ultraviolet flashlight and does not undergo luminescence quenching when immersed in water. Figure 5 This is the excitation spectrum and emission spectrum of the powder prepared in Example 3. Figure 6 This is the comparison of the luminescence intensities of the powder prepared in Example 3 in air and in water.

[0107] Example 4: (Preparation of powder by solid-phase grinding of [methyl DABCO]I and copper iodide)

[0108] Weigh 600 mg of [methyl DABCO]I and 900 mg of copper iodide and add them to a mortar. Grind for half an hour to obtain the finished powder, with the composition of [methyl DABCO] 2 Cu 4 I 6 This powder emits bright green light under the irradiation of a 400-nm ultraviolet flashlight and does not undergo luminescence quenching when immersed in water. Figure 8 This is the excitation spectrum and emission spectrum of the powder prepared in this example. Figure 9 This is the comparison of the luminescence intensities of the powder prepared in this example in air and in water.

[0109] Example 5: (Preparation of powder by solid-phase sintering of [methyl DABCO]I and copper iodide)

[0110] Weigh 600 mg of [methyl DABCO]I and 900 mg of copper iodide and add them to a sample bottle. Close the lid and shake vigorously to mix the two raw material powders evenly. Then pour them into a boat-shaped crucible, place the crucible in a tube furnace under a nitrogen atmosphere, heat to 200 °C and react for 2 hours, and then cool naturally to room temperature to obtain the finished powder, with the composition of [methyl DABCO] 2 Cu 4 I 6 This powder emits bright green light under the irradiation of a 400-nm ultraviolet flashlight and does not undergo luminescence quenching when immersed in water. Figure 10 This is the excitation spectrum and emission spectrum of the powder prepared in this example. Figure 11 This is the comparison of the luminescence intensities of the powder prepared in this example in air and in water.

[0111] Example 6: (Preparation of luminescent single crystals using the powder prepared in Example 1)

[0112] Weigh 50 mg of the powder prepared in Example 1 and add it to a 4-mL sample bottle. Then add 1 mL of DMSO and stir well at 100 °C. After filtering through a 0.22-μm needle filter while it is hot, a clear hot saturated solution is obtained. Let this solution stand on a hot stage at 100 °C and cool to room temperature at a cooling rate of 5 °C / hour. Remove the supernatant to obtain the luminescent single crystal, with the composition of [methyl DABCO]2 Cu 4 I 6 This single crystal emits bright green light under the irradiation of a 400 nm purple flashlight and does not undergo luminescence quenching when immersed in water. Figure 12 This is the emission spectrum of the single crystal prepared in this example. Figure 13 This is the comparison of the luminescence intensities of the single crystal prepared in this example in air and in water.

[0113] Example 7: (Preparation of Luminescent Colloidal Nanocrystals from [Methyl DABCO]I and Copper(I) Iodide)

[0114] Weigh 0.05 mmol of copper(I) iodide and add it to a 20 mL sample bottle. Then add 5 mL of toluene, 0.5 mL of oleic acid, and 0.1 mL of oleylamine, and stir well at room temperature to obtain a colorless and clear copper source solution. Weigh 0.05 mmol of [Methyl DABCO]I and add it to a 2 mL sample bottle. Then add 1 mL of DMF and stir well at room temperature to obtain a colorless and clear organic cation solution. Rapidly inject 0.5 mL of the organic cation solution into the stirring copper source solution, and stop stirring after waiting for 30 seconds. Add the reaction solution in equal volume to two centrifuge tubes. First, centrifuge at a low speed of 3000 revolutions per minute, take the supernatant, and add twice the volume of ethyl acetate anti-solvent respectively. Then centrifuge at a high speed of 9000 revolutions per minute to remove the supernatant. Add 400 μL of n-octane to each white precipitate, let it stand to completely disperse and dissolve the precipitate, and then centrifuge at 7000 revolutions per minute. Take the supernatant and filter it through a 0.22 μm pore size nylon 66 filter head to obtain 2 Cu 4 I 6 a colloidal nanocrystal dispersion. This dispersion emits bright green light under the irradiation of a 400 nm purple flashlight. Figure 14 This is the excitation spectrum and emission spectrum of the colloidal nanocrystals prepared in this example.

[0115] Example 8: (In-situ Preparation of Thin Films)

[0116] Weigh 50 mg of the powder prepared in Example 1 and add it to a 4 mL sample bottle. Then add 1 mL of DMSO and stir well at 60 °C. Filter while it is hot through a needle filter with a pore size of 0.22 μm to obtain a clear hot saturated solution. Spin-coat this hot saturated solution on a glass slide at 60 °C at a speed of 4000 revolutions per minute, and then anneal it on a hot stage at 100 °C for 10 minutes to obtain a water-stable copper halide-based luminescent thin film with the composition of [Methyl DABCO] 2 Cu 4 I 6 . Figure 15 This is the emission spectrum of this thin film in air and in water.

[0117] Example 9: (Preparation of Colloidal Nanocrystal Film)

[0118] The colloidal nanocrystal dispersion prepared in Example 8 was spin-coated on a glass slide at a speed of 2000 revolutions per minute to obtain a colloidal nanocrystal light-emitting film, with the composition of [methyl DABCO] 2 Cu 4 I 6 . Figure 16 This is the emission spectrum of the film.

[0119] Example 10: (Preparation of Down-conversion Light-emitting Diode)

[0120] The [methyl DABCO] 2 Cu 4 I 6 powder prepared in Example 1 was ground for half an hour to obtain ultrafine powder. 10 times the mass of ultraviolet curable glue was added to the powder, and then stirred thoroughly for 2 hours to uniformly disperse the powder in the glue. The glue was dropped onto the surface of the ultraviolet LED chip, and then irradiated with ultraviolet light to cure the glue, preparing a down-conversion light-emitting diode. When this light-emitting diode works, the ultraviolet light emitted by the ultraviolet LED chip can excite the [methyl DABCO] 2 Cu 4 I 6 powder coated on it, causing it to emit green fluorescence, so that the down-conversion light-emitting diode emits green light outward. Figure 17 This is the emission spectrum of the down-conversion light-emitting diode.

[0121] Example 11: (Preparation of Electroluminescent Diode)

[0122] The ITO conductive glass was ultrasonically cleaned with acetone - water - absolute ethanol for 15 minutes respectively, and then its surface was treated with plasma. A PEDOT:PSS aqueous solution was spin-coated at 4000 revolutions per minute for 45 seconds and annealed at 150 °C for 15 minutes. A PF8Cz chlorobenzene solution was spin-coated at 2000 revolutions per minute for 30 seconds and annealed at 150 °C for 30 minutes. The colloidal nanocrystal dispersion prepared in Example 8 was spin-coated at 2000 revolutions per minute for 30 seconds. The electron transport layer TPBi was prepared by vacuum thermal evaporation, with an evaporation rate of and a thickness of 50 nm. The negative electrode Al was vacuum thermally evaporated, with an evaporation rate of and a thickness of 100 nm. Figure 18 This is the emission spectrum of the electroluminescent diode prepared in this example.

[0123] Example 12: (Preparation of Scintillator Film)

[0124] 4 grams of the [methyl DABCO] 2 Cu 4 I 6Powder, 6 g of PMMA powder and 20 mL of DMF were added, and stirred at 80 °C for 10 hours to obtain a slightly viscous powder-polymer composite dispersion. The dispersion was coated on the surface of a glass slide and then annealed on a hot stage at 80 °C for 30 minutes to obtain a scintillator film. This film can effectively convert X-rays into visible light and thus be used for X-ray imaging. Figure 19 This is the emission spectrum of the scintillator film prepared in this example under X-ray excitation. Figure 20 This is an X-ray imaging photograph of a capsule with a spring inside using the scintillator film prepared in this example.

[0125] Comparative Example 1: (Using non-functionalized 1,4-diazabicyclo[2.2.2]octane ammonium as the organic cation)

[0126] Weighed 580 mg of 1,4-diazabicyclo[2.2.2]octane ammonium iodide ([DABCO]I) and 900 mg of cuprous iodide and added them to a 20 mL sample bottle, and then added 8 mL of DMF. Stirred at room temperature for 5 hours to obtain a white suspension. The suspension was centrifuged at 3000 revolutions per minute for 3 minutes, the supernatant was removed, and the precipitate was placed in an oven at 60 °C and completely dried to obtain the finished powder. This powder does not emit visible fluorescence under 400 nm and 365 nm flashlight irradiation, and the cut-off edge of its excitation spectrum is located at 330 nm, which already belongs to the deep ultraviolet band. In addition, it immediately undergoes irreversible fluorescence quenching when encountering water. This phenomenon indicates that the non-functionalized 1,4-diazabicyclo[2.2.2]octane ammonium cation does not help to increase the excitable wavelength of such luminescent materials and cannot enhance the lattice stability of copper halide-based luminescent materials, resulting in the destruction of the lattice in strongly polar water and causing irreversible luminescence quenching. Figure 7 This is the excitation spectrum and emission spectrum of the powder prepared in this comparative example.

[0127] In summary, the present invention provides a preparation method of a water-stable copper halide-based luminescent material. By using a mono-functionalized 1,4-diazabicyclo[2.2.2]octane ammonium cation, the lattice stability of the material is enhanced, so that it does not undergo luminescence quenching in water; and the band gap is effectively reduced, enabling the copper halide-based luminescent material to be excited by near-ultraviolet light and violet light. The present invention also comprehensively gives the preparation methods of four forms of this material: powder, single crystal, colloidal nanocrystal, and thin film. Finally, the applications of this material in light-emitting diodes and X-ray imaging are also demonstrated. The present invention is expected to further promote the attention and research of the luminescent material field on copper halide-based luminescent materials and make them move towards practical applications earlier.

[0128] The present invention illustrates the detailed preparation method of the present invention through the above embodiments, but the present invention is not limited to the above detailed preparation method, that is, it does not mean that the present invention must rely on the above products and detailed preparation methods to be implemented. Those skilled in the art should understand that any improvement to the present invention, the combination of various raw materials of the products of the present invention or equivalent substitution all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A novel copper halide-based luminescent material, characterized in that: The chemical formula of the copper halide-based luminescent material is: [monofunctional group-DABCO]2Cu4X6; Wherein: X is at least one of Cl, Br or I; The monofunctional group includes at least one of methyl, ethyl, propyl, butyl, amino, carboxyl, hydroxyl, ester, amide, cyano, nitro, and sulfonic acid groups; The copper halide-based luminescent material can be excited by near-ultraviolet light, violet light or blue light.

2. A novel copper halide-based luminescent material according to claim 1, characterized in that: The wavelength range of the near ultraviolet light, purple light or blue light is 360nm-480nm.

3. A novel copper halide-based luminescent material according to claim 1, characterized in that: The copper halide-based luminescent material does not undergo fluorescence quenching when immersed in water, and the luminescence intensity of the copper halide-based luminescent material in water is maintained at least 65% of the luminescence intensity in air.

4. The method for preparing a novel copper halide-based luminescent material according to claim 1, characterized in that: The solid phase grinding method comprises the following steps: S1. Provide a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as an organic cation source powder; Providing one or more of cuprous iodide, cuprous bromide, and cuprous chloride as copper source powder; S2. Mixing the organic cation source powder and the copper source powder, and grinding them to obtain the copper halide-based luminescent material powder.

5. The method for preparing a novel copper halide-based luminescent material according to claim 1, characterized in that: The preparation is carried out by liquid phase reaction, comprising the following steps: S1. Provide a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as an organic cation source powder; Providing one or more of cuprous iodide, cuprous bromide, and cuprous chloride as copper source powder; A polar reaction solvent is provided, wherein the polar reaction solvent comprises one or more of water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), γ-butyrolactone, tetrahydrofuran (THF), ethyl acetate, methyl acetate, methanol, ethanol, and isopropanol; S2, mixing the organic cation source powder and the copper source powder, then adding a polar reaction solvent, and stirring in an inert atmosphere to obtain a suspension; S3, centrifuging the suspension in step S2 to obtain a precipitate, and drying the precipitate to obtain a copper halide-based luminescent material powder.

6. The method for preparing a novel copper halide-based luminescent material according to claim 1, characterized in that: The solid phase sintering method is used for preparation, and the steps include: S1. Provide a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as an organic cation source powder; Providing one or more of cuprous iodide, cuprous bromide, and cuprous chloride as copper source powder; S2. Evenly mix the organic cation source powder and the copper source powder, heat them at a temperature above 100° C. for at least half an hour in an inert gas atmosphere, and then cool them to room temperature to obtain a copper halide-based luminescent material powder.

7. The method for preparing a novel copper halide-based luminescent material according to claim 1, characterized in that: The copper halide-based luminescent material is a copper halide-based luminescent colloidal nanocrystal, and the preparation method is room temperature synthesis, comprising the following steps: S1. Provide a monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salt as an organic cation source powder; An organic cation source solvent is provided, wherein the organic cation source solvent comprises one or more of water, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N-methylpyrrolidone (NMP), γ-butyrolactone, tetrahydrofuran (THF), ethyl acetate, methyl acetate, methanol, ethanol, and isopropanol; Providing one or more of cuprous iodide, cuprous bromide, and cuprous chloride as copper source powder; A copper source cosolvent is provided, wherein the copper source cosolvent comprises at least one of oleylamine, octylamine, phosphatidylcholine, lecithin, or a tetraalkylammonium hydrohalide salt having a chain length greater than 6 carbon atoms; Provide a long-chain organic acid as an organic acid ligand, including but not limited to one or more of oleic acid, octanoic acid, isooctylphosphonic acid, dodecylbenzenesulfonic acid, dodecylphosphonic acid, and tetradecylphosphonic acid; Providing a reaction solvent, the reaction solvent comprising one or more of toluene, chlorobenzene, xylene, octadecene, dichloromethane, chloroform, hexane, and octane; S2. adding the organic cation source solvent to the organic cation source at room temperature, and stirring to obtain a clear cation source solution; S3, adding the reaction solvent to the copper source at room temperature, and adding the copper source co-solvent and the organic acid ligand, and stirring to obtain a clear copper source solution; S4. Add the cation source solution into the copper source solution at room temperature and stir to react, so as to obtain the copper halide-based luminescent colloidal nanocrystal dispersion.

8. A method for preparing a novel copper halide-based luminescent material according to any one of claims 4 to 7, characterized in that: The monofunctionalized 1,4-diazabicyclo[2.2.2]octane ammonium halide salts include 1-methyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([methyl DABCO]I), 1-methyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([methyl DABCO]Br), 1-methyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([methyl DABCO]Cl), 1-ethyl-1,4- Diazabicyclo[2.2.2]octane-1-ammonium iodide ([ethyl DABCO]I), 1-ethyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([ethyl DABCO]Br), 1-ethyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([ethyl DABCO]Cl), 1-propyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([propyl DABCO]I), 1-propyl-1,4- Diazabicyclo[2.2.2]octane-1-ammonium bromide ([propyl DABCO]Br), 1-propyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([propyl DABCO]Cl), 1-butyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([butyl DABCO]I), 1-butyl-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([butyl DABCO]Br), 1-butyl-1,4 -diazabicyclo[2.2.2]octane-1-ammonium chloride ([butylDABCO]Cl), 1-amino-1,4-diazabicyclo[2.2.2]octane-1-ammonium iodide ([aminoDABCO]I), 1-amino-1,4-diazabicyclo[2.2.2]octane-1-ammonium bromide ([aminoDABCO]Br), 1-amino-1,4-diazabicyclo[2.2.2]octane-1-ammonium chloride ([aminoDABCO]Cl) One or more.

9. A method for preparing a novel copper halide-based luminescent material according to any one of claims 4 to 7, characterized in that: The organic cation source powder and the copper source powder are mixed in a molar ratio of 1:

2.

10. Application of a novel copper halide-based luminescent material, characterized in that: The copper halide-based luminescent material according to any one of claims 1 to 3 is applied to at least one of the fields of display, lighting and X-ray technology, specifically including the following forms: Copper halide-based luminescent material single crystal, copper halide-based luminescent material film, copper halide-based luminescent material colloidal nanocrystal film, X-ray scintillator film, as a luminescent material in a down-conversion light-emitting diode, as a luminescent material in an electroluminescent diode, as at least one of the luminescent materials in a light conversion film or a light conversion plate.

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