Quantum dot manufacturing methods, luminescent materials, luminescent components, and display devices

Abstract

This invention provides a method for manufacturing quantum dots, a luminescent material, a luminescent component, and a display device. The method for manufacturing quantum dots includes the following steps: providing a first solution comprising at least one element selected from the group consisting of Group XII and Group XIII elements; providing a second solution comprising at least one element selected from the group consisting of Group XV and Group XVI elements; mixing the first and second solutions; and subjecting the mixed solution to heat treatment. The heating rate of the heat treatment ranges from 2°C / min to 10°C / min.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a luminescent material, and more particularly to a method for manufacturing a luminescent material containing quantum dots, the luminescent material, the luminescent component, and the display device. Background Technology

[0002] Quantum dots are semiconductor light-emitting materials whose band gap can be varied with grain size. This allows the wavelength of emitted light to be adjusted by changing the size of the quantum dots. Quantum dots possess high color purity and saturation, and therefore have been increasingly used in display panel technology in recent years. Quantum yield is one of the important parameters of quantum dots, representing the efficiency with which a quantum dot converts absorbed light into fluorescence. Therefore, improving the quantum yield of quantum dots is one of the important topics in this field. Summary of the Invention

[0003] This invention provides a method for manufacturing quantum dots, which can improve the quantum efficiency of quantum dots.

[0004] The method for manufacturing quantum dots according to the present invention includes the following steps: Providing a first solution comprising at least one element selected from the group consisting of Group XII and Group XIII elements. Providing a second solution comprising at least one element selected from the group consisting of Group XV and Group XVI elements. Mixing the first and second solutions to form a mixed solution. Heat-treating the mixed solution. The heating rate of the heat treatment is in the range of 2°C / min to 10°C / min to form quantum dots.

[0005] In one embodiment of the present invention, the Group XII element in the first solution may include at least one element selected from the group consisting of zinc, cadmium, and mercury. The Group XIII element in the first solution may include at least one element selected from the group consisting of aluminum, gallium, and indium. The Group XV element in the second solution may include at least one element selected from the group consisting of nitrogen, phosphorus, and arsenic. The Group XVI element in the second solution may include at least one element selected from the group consisting of oxygen, sulfur, selenium, and tellurium.

[0006] In one embodiment of the invention, the first solution may further comprise an organic acid. The organic acid may include at least one selected from the group consisting of oleic acid, stearic acid, and lauric acid. The second solution may further comprise an organic solution. The organic solution may include at least one selected from the group consisting of tri-n-octylphosphine, octadecene, tributylphosphine, and dioctylamine.

[0007] In one embodiment of the present invention, the mixing of the first solution and the second solution is carried out at a first temperature of the first solution, and the heat treatment step involves raising the temperature of the mixed solution to a level greater than or equal to the first temperature. In one embodiment of the present invention, the first temperature may be in the range of 230°C to 330°C.

[0008] In one embodiment of the present invention, the mixing of the first solution and the second solution is carried out at a temperature of 20°C to 30°C for the second solution.

[0009] In one embodiment of the invention, heat treatment is performed immediately after the mixed solution is formed.

[0010] In one embodiment of the present invention, the heating rate of the heat treatment can range from 3°C / min to 8°C / min.

[0011] In one embodiment of the present invention, the heating rate of the heat treatment can range from 3.5°C / min to 7.5°C / min.

[0012] In one embodiment of the present invention, the temperature of the mixed solution is raised to a temperature greater than or equal to the first temperature in the heat treatment step, and then the reaction is carried out at the temperature.

[0013] In one embodiment of the present invention, the method for manufacturing quantum dots may further include adding a third solution comprising group XII elements and a fourth solution comprising group XVI elements to the above-mentioned mixed solution. The step of adding the third and fourth solutions to the above-mentioned mixed solution may be performed at a temperature of 230°C to 330°C.

[0014] Based on the above, the method for manufacturing quantum dots of the present invention includes heat treatment of a mixed solution containing a first solution and a second solution, wherein the heating rate of the heat treatment is in the range of 2°C / min to 10°C / min. Therefore, when the cations in the first solution react with the anions in the second solution, the reaction temperature can be prevented from decreasing due to endothermic reactions and the temperature difference between the first and second solutions. This improves the quantum efficiency of the quantum dots.

[0015] The luminescent material of the present invention includes a plurality of quantum dots manufactured by the aforementioned manufacturing method.

[0016] The light-emitting component of the present invention includes a light source and an encapsulation material containing the light-emitting material, the encapsulation material covering the light source.

[0017] The display device of the present invention includes the light-emitting component, and the display device is selected from at least one of the group consisting of televisions, digital cameras, digital video cameras, digital photo frames, mobile phones, notebook personal computers, mobile computers, monitors for computers, portable game consoles, portable information terminals, audio playback devices, game consoles, and automotive displays.

[0018] To make the above features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0019] Figure 1 This is a cross-sectional schematic diagram of a quantum dot according to an embodiment of the present invention.

[0020] Figure 2 This is a cross-sectional schematic diagram of a quantum dot according to another embodiment of the present invention.

[0021] Figure 3 This is a flowchart of a method for manufacturing quantum dots according to an embodiment of the present invention.

[0022] Figure 4 This is a flowchart of a method for manufacturing a luminescent material according to an embodiment of the present invention.

[0023] Explanation of icon numbers

[0024] 100: Quantum dots

[0025] 110: Nucleus

[0026] 120: First shell

[0027] 130: Ligand

[0028] 140: Second shell

[0029] S300, S302, S304, S306, S308, S400, S402, S404, S406, S408: Steps Detailed Implementation

[0030] Figure 1 This is a cross-sectional schematic diagram of a quantum dot according to an embodiment of the present invention.

[0031] Please refer to Figure 1 In this embodiment, the quantum dot 100 may include a core 110, a first shell 120, and a ligand 130. The particle size of the quantum dot 100 may be greater than or equal to 10 nm.

[0032] The nucleus 110 may be located at the center of the quantum dot 100 and may be substantially spherical. The nucleus 110 may include at least one cation and at least one anion. The cation may include a Group XII and / or Group XIII element of the periodic table. For example, the cation of the nucleus 110 may include cadmium (Cd), zinc (Zn), mercury (Hg), aluminum (Al), gallium (Ga), and / or indium (In). The anion of the nucleus 110 may include a Group XV and / or Group XVI element. For example, the anion may include sulfur (S), selenium (Se), tellurium (Te), nitrogen (N), phosphorus (P), and / or arsenic (As). In some embodiments, the core may be a binary core (including, for example, CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, HgS, HgSe, HgTe, GaN, GaP, GaAs, AlN, AlP, AlAs, InN, InP, and InAs, etc.) or a ternary core (including, for example, CdZnS, ZnSeTe, CdSeS, CdZnSe, CdZnTe, CdSeTe, CdSTe, ZnSeS, ZnSTe, HgSeS, HgSeTe, HgSTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnS, HgZnTe, etc.). nSe, HgZnTe, GaNP, GaNAs, GaPAs, AlNP, AlNAs, AlPAs, InNP, InNAs, and InPAs, etc.) or quaternary nuclei (including, for example, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe, GaAlNP, GaAlNAs, GaAlPAs, GaInNP, GaInNAs, GaInPAs, InAlNP, InAlNAs, and InAlPAs, etc.).

[0033] The first shell 120 may substantially cover the surface of the core 110 and may include at least one cation and at least one anion. The cation of the first shell 120 may include a Group XII element, such as zinc and / or cadmium. The anion of the first shell 120 may include a Group XVI element, such as sulfur. In some embodiments, the first shell may be a binary shell (including, for example, ZnS) or a ternary shell (including, for example, ZnCdS).

[0034] In some embodiments, the first shell 120 may have a gradient distribution of components. Different portions of the first shell 120 may have different cationic and / or anionic components. In other words, the cationic and / or anionic components may vary from the innermost part of the first shell 120 to the outermost part of the first shell 120. For example, when the first shell 120 includes zinc (Zn), cadmium (Cd), and sulfur (S), the concentration of zinc may be substantially lowest at the innermost part of the first shell 120 and substantially highest at the outermost part of the first shell 120. That is, the concentration of zinc increases substantially proportionally with increasing distance from the core 110.

[0035] In some embodiments, the first housing 120 may have a substantially homogeneous (or identical) composition. For example, each portion of the first housing 120 may have a substantially homogeneous (or identical) cationic composition and / or a substantially identical (or homogeneous) anionic composition.

[0036] Figure 2 This is a cross-sectional schematic diagram of a quantum dot according to another embodiment of the present invention.

[0037] Please refer to Figure 2 The quantum dot 200 may also include a second shell 140, which essentially covers the surface of the first shell 120. In this way, the particle size of the quantum dot 200 can be increased due to the second shell 140. The second shell 140 may specifically (or additionally) protect the core 110. Therefore, compared to quantum dots without a second shell, the quantum dot 200 can ensure a higher quantum efficiency over a long period of time.

[0038] The second shell 140 may include at least one cation and at least one anion. The cation of the second shell 140 may include a Group XII element (e.g., zinc), and the anion of the second shell 140 may include a Group XVI element (e.g., sulfur). In some embodiments, the second shell 140 may be a binary shell (including, for example, ZnS). The second shell 140 may have a substantially homogeneous (or identical) composition. For example, each portion of the second shell 140 may have a substantially homogeneous (or identical) cationic composition and / or a substantially homogeneous (or identical) anionic composition. The second shell 140 may have a thickness of about 1.6 nm. In some embodiments, the second shell 140 may be substantially different from the first shell 120.

[0039] Ligand 130 may include an organic functional group. Ligand 130 may be provided on the surface of the first shell 120 or the surface of the second shell 140, such that ligand 130 is chemically bonded to the surface of the first shell 120 or the second shell 140. The organic functional group of ligand 130 may include, for example, oleate, stearic acid, lauric acid, trioctylphosphine (TOP), tributylphosphine, triphenylphosphine, octadecene (ODE), or dioctylamine.

[0040] In some embodiments, a ligand 130 comprising oleic acid may be provided on the surface of the first housing 120. In this way, a strong chemical bond can be formed between the first housing 120 and the ligand 130, and the ligand 130 may not detach from the surface of the first housing 120 during repeated cleaning processes in the fabrication of the quantum dot 100.

[0041] In some embodiments, a ligand 130 comprising both oleic acid and trioctylphosphine may be provided on the surface of the second shell 140. In this way, even if the chemical bond between the second shell 140 and the ligand 130 weakens, the quantum dot 200 can maintain a high quantum efficiency over a long period due to the second shell 140. In other embodiments, a ligand 130 comprising only oleic acid may be formed on the surface of the second shell 140, thus the quantum dot 200 can have a higher quantum efficiency due to the stronger chemical bond between the second shell 140 and the ligand 130. The quantum dot 200 may exhibit different colors depending on its composition. Therefore, the quantum dot 200 can emit excitation light of different colors, such as blue, red, and green. In some embodiments, the quantum dot 200 may be a blue quantum dot or a green quantum dot.

[0042] Specifically, when the quantum dot 200 receives incident light with a wavelength greater than 350 nm and less than the emission wavelength, such as incident light with a wavelength of 390 nm to 500 nm, the quantum dot 200 can emit light with a wavelength of 400 nm to 700 nm. Furthermore, the full width at half maximum (FWHM) of the light emitted by the quantum dot 200 is, for example, 20 nm to 60 nm. In some embodiments, the wavelength of light emitted by green quantum dots is, for example, 500 nm to 600 nm, or 510 nm to 560 nm, or 520 nm to 550 nm. In other embodiments, the wavelength of light emitted by red quantum dots is, for example, 600 nm to 700 nm, or 605 nm to 680 nm, or 610 nm to 660 nm. The wavelength of light emitted by blue quantum dots is, for example, 400 nm to 500 nm, or 430 nm to 470 nm, or 440 nm to 460 nm. For example, the wavelength, intensity, and full width at half maximum (FWHM) of the light emitted by quantum dots can be obtained by photoluminescence analysis using a photoluminescence analyzer (manufactured by Horiba, model: FluoroMax-3).

[0043] In some embodiments, the average particle size of red quantum dots is, for example, 3 nm to 25 nm, or 4 nm to 15 nm, or 5 nm to 10 nm. The average particle size of green quantum dots is, for example, 2 nm to 20 nm, or 3 nm to 15 nm, or 4 nm to 9 nm. The average particle size of blue quantum dots is 1 nm to 15 nm, or 2 nm to 10 nm, or 2 nm to 8 nm.

[0044] Figure 3 This is a flowchart of a method for manufacturing quantum dots according to an embodiment of the present invention. Please refer to... Figure 1 and Figure 3 The quantum dot manufacturing method of this embodiment includes the following steps.

[0045] Step S300 involves providing a first solution comprising at least one element selected from the group consisting of Group XII and Group XIII elements. Specifically, the Group XII or Group XIII element is present in the first solution in the form of a cation. For example, the Group XII element in the first solution may include zinc, cadmium, mercury, or combinations thereof. The Group XIII element in the first solution may include aluminum, gallium, indium, or combinations thereof. In some embodiments, the Group XII element (or its precursor) or the Group XIII element (or its precursor) may be mixed with an organic acid to form the first solution. The organic acid may include oleic acid (OA), stearic acid, lauric acid, or combinations thereof. In some embodiments, the first solution has a first temperature. The first temperature may range from 230°C to 330°C. In other embodiments, the first temperature may range from 240°C to 320°C, for example, from 250°C to 320°C.

[0046] Step S302 involves providing a second solution comprising at least one element selected from the group consisting of Group XV and Group XVI elements. Specifically, the Group XV or Group XVI element is present in the second solution in anionic form. For example, the Group XV element in the second solution may include at least one of nitrogen, phosphorus, and arsenic. The Group XVI element in the second solution may include at least one of oxygen, sulfur, selenium, and tellurium. In some embodiments, the Group XV element (or its precursor) or the Group XVI element (or its precursor) may be mixed with an organic solution to form the second solution. The organic solution may include trioctylphosphine (TOP), octadecene (ODE), tributylphosphine, dioctylamine, or combinations thereof. In some embodiments, step S302 may be performed at room temperature. The room temperature range may be 20°C to 30°C.

[0047] In some embodiments, steps S300 and S302 may be performed simultaneously. In other embodiments, step S300 may be performed before or after step S302, and the present invention is not limited to the order of steps S300 and S302.

[0048] In step S304, the first solution and the second solution are mixed. This forms a mixed solution containing the quantum dot core. It should be noted that the quantum dot core described here is... Figure 1 The nucleus 110 of quantum dot 100 or Figure 2The quantum dot 200 has a nucleus 110. Specifically, in step S304, a cation in the first solution reacts with an anion in the second solution to form the nucleus 110. In particular, at least one cation reacts with at least one anion to form the nucleus 110 as a binary, ternary, quaternary, or more nuclei.

[0049] In step S304, the reaction that forms the core 110 is an endothermic reaction. In other words, the temperature of the mixed solution formed by mixing the first solution and the second solution is lower than the temperature of the first solution or the second solution before mixing. In some embodiments, the temperature of the first solution is 230°C to 330°C, while the temperature of the second solution is room temperature. Based on the endothermic reaction and the temperature difference between the first solution and the second solution, the temperature of the mixed solution formed by mixing the first solution and the second solution is lower than the temperature of the first solution. For example, the temperature difference between the mixed solution and the first solution can range from 5°C to 30°C.

[0050] Step S306 involves heat-treating the mixed solution. This raises the temperature of the mixed solution to the higher of the temperatures of the first and second solutions. In some embodiments, the temperature of the heat-treated mixed solution may be higher than both the temperatures of the first and second solutions. The heating rate of the heat treatment ranges from 2°C / min to 10°C / min. In some embodiments, the heating rate ranges from 3°C / min to 8°C / min. In other embodiments, the heating rate ranges from 3.5°C / min to 7.5°C / min. Furthermore, the heat treatment time can range from 1 minute to 15 minutes, or from 1.5 minutes to 10 minutes.

[0051] In some embodiments, the starting point of step S306 may be before the ending point of step S304. In other words, the mixed solution may be heat-treated during the mixing of the first solution and the second solution. In other embodiments, the starting point of step S306 may be after the ending point of step S304. In other words, the mixed solution may be heat-treated only after the mixing of the first solution and the second solution is complete. In some embodiments, the mixed solution may be heat-treated immediately after the mixing of the first solution and the second solution is complete. In other embodiments, the mixed solution may be heat-treated to raise its temperature to a level greater than or equal to the temperature of the first solution, and then the mixed solution may be maintained at this temperature.

[0052] Next, step S308 can be performed, in which a third solution including a Group XII element and a fourth solution including a Group XVI element are added to the above-mentioned mixed solution. In some embodiments, the Group XII element in the third solution and the Group XVI element in the fourth solution exist in the third solution and the fourth solution respectively in the form of cations and anions, and react to generate a first shell 120 of quantum dot 100 (or quantum dot 200). In this way, quantum dot 100 (or quantum dot 200) includes a first shell 120 and a core 110 from the outside to the inside. The first shell 120 and the core 110 can be either single-layer structures or multi-layer structures.

[0053] In some embodiments, the third solution and the fourth solution may be added sequentially to the mixed solution formed in step S306.

[0054] In some embodiments, step S308 may be performed at a second temperature. In some embodiments, the second temperature may range from 230°C to 330°C. In other embodiments, the second temperature may range from 240°C to 320°C, for example, 250°C to 320°C. In some embodiments, the second temperature may be higher than the first temperature. Heating during the formation of the first housing 120 allows the semiconductor material constituting the first housing 120 to be smoothly formed on the surface of the core 110, rather than being dispersed in a solution. This allows the first housing 120 of the quantum dot to better protect the core 110 from damage by external water, oxygen, and blue light. Therefore, the reliability of the quantum dot can be improved.

[0055] Subsequently, the solution obtained in step S308 is precipitated with a polar solvent, such as acetone or ethanol, and then centrifuged and washed to obtain the quantum dots of this embodiment.

[0056] In some embodiments, the organic group of the ligand 130 described above may be referred to as a blocking agent, which can inhibit the aggregation of quantum dots and also moderately isolate the quantum dots from the external environment. In other embodiments, an additional blocking agent may be added to modify the surface of the quantum dots to form the ligand 130 on the surface of the first housing 120. The blocking agent may be composed of a Lewis base compound. In some embodiments, hydrocarbons in an inert solvent may be diluted to form the Lewis base compound described above. The blocking agent may include monodentate or polydentate ligands, such as phosphine, phosphine oxide, alkylphosphonic acid, alkylamine, arylamine, pyridine, long-chain fatty acid, thiophene, or combinations thereof. For example, phosphine may include trioctylphosphine, triphenylphosphine, and tert-butylphosphine, etc. Phosphine oxide may include trioctylphosphine oxide and triphenylphosphine oxide, etc. Alkylamine may include hexadecylamine and octylamine, etc.

[0057] Figure 4This is a flowchart of a method for manufacturing a luminescent material according to an embodiment of the present invention. Please refer to... Figure 4 In some embodiments, the method for manufacturing luminescent materials using the quantum dots described above may include the following steps.

[0058] In step S400, a quantum dot solution and a carrier solution are provided. The quantum dot solution contains the quantum dots formed above and a solvent for dispersing the quantum dots. Similarly, the carrier solution contains a carrier and a solvent for dispersing the carrier. For example, the solvent of the quantum dot solution and the solvent of the carrier solution may each include n-hexane. In some embodiments, the weight percentage of quantum dots in the quantum dot solution is 0.1% to 5%. The weight percentage of the carrier in the carrier solution is 0.5% to 10%.

[0059] In some embodiments, the material of the carrier may be selected from at least one of the group consisting of organic polymers, inorganic polymers, water-soluble polymers, organic solvent-soluble polymers, biopolymers, and synthetic polymers. For example, the carrier material may be at least one from the group consisting of polysiloxane, polyacrylate, polycarbonate, polystyrene, polyethylene, polypropylene, polyketides, polyetheretherketone, polyester, polyamide, polyimide, polyacrylamide, polyolefins, polyacetylene, isoprene, polybutadiene, polyvinylidene difluoride (PVDF), polyvinyl chloride (PVC), ethylene vinyl acetate (EVA), polyethylene terephthalate (PET), polyurethane, and cellulose polymers. In some embodiments, the carrier material may also be an inorganic medium, such as at least one selected from the group consisting of silica gel, bentonite, glass, water glass, quartz, kaolin, silica, alumina and zinc oxide.

[0060] Water glass is a material composed of alkali metal oxides and silicon dioxide. Water glass can be classified into lithium water glass, sodium water glass, and potassium water glass according to the type of alkali metal, with molecular formulas Li₂O·nSiO₂, Na₂O·nSiO₂, and K₂O·nSiO₂, respectively. 'n' represents the water glass modulus, which is the molecular ratio (or molar ratio) of silicon dioxide to alkali metal oxide in the water glass. 'n' can range from 1.5 to 4.0, or from 2.0 to 3.5.

[0061] Polysiloxanes are obtained by hydrolysis-condensation reaction of siloxane compounds represented by the following formula (I):

[0062] R a n Si(OR b ) 4-n n=0~3 formula (I);

[0063] R a R represents an aromatic group having 2 to 15 carbon atoms. b This refers to an alkyl group having 1 to 5 carbon atoms. The aromatic group is, for example (but not limited to), phenyl, tolyl, p-hydroxyphenyl, 1-(p-hydroxyphenyl)ethyl, 2-(p-hydroxyphenyl)ethyl, 4-hydroxy-5-(p-hydroxyphenylcarbonyloxy)pentyl, or naphthyl. The alkyl group is, for example (but not limited to), methyl, ethyl, n-propyl, isopropyl, or n-butyl. In some embodiments, the polysiloxane may be obtained from tetraethoxysilane (TEOS) via a hydrolytic condensation reaction.

[0064] The average particle size of the carrier is, for example, 0.1 μm to 25 μm, or 0.3 μm to 15 μm, or 0.5 μm to 10 μm. In some embodiments, the carrier material is porous. The average surface pore size of the porous carrier is 3 nm to 100 nm. In some embodiments, the quantum dots are green quantum dots, and the average surface pore size of the porous carrier is, for example, 5 nm to 30 nm, or 5 nm to 25 nm, or 5 nm to 20 nm. In other embodiments, the quantum dots are red quantum dots, and the average surface pore size of the porous carrier is, for example, 7 nm to 40 nm, or 7 nm to 35 nm, or 7 nm to 30 nm. Furthermore, when the quantum dots are blue quantum dots, the average surface pore size of the porous carrier is, for example, 3 nm to 25 nm, or 3 nm to 20 nm, or 3 nm to 15 nm. The specific surface area of ​​the porous carrier is, for example, 100 m².2 / g to 1000m 2 / g. In some embodiments, the porous support is porous micron-sized particles. The porous micron-sized particles may be silica particles. The support may be an oleophilic support. For example, the porous micron-sized particles may be oleophilic silica particles. The oleophilic silica particles are obtained by modifying silica particles with a silane compound of the following formula (II):

[0065] R c m Si(OR d ) 4-m m = 1 to 3 (II);

[0066] R c Represents an alkyl group having 3 to 20 carbon atoms, and R d This indicates an alkyl group having 1 to 5 carbon atoms. In some embodiments, R c It is octyl, nonyl, or decyl. R d For example, (but not limited to) methyl, ethyl, n-propyl, isopropyl, or n-butyl.

[0067] Taking a porous carrier made of silica as an example, its particles can have an average diameter of 1 μm to 5 μm, an average surface pore size of 5 nm to 15 nm, and a specific surface area of ​​500 m². 2 / g to 900m 2 / g porous carrier; or particles with an average diameter of 1μm to 5μm, an average surface pore size of 10nm to 30nm, and a specific surface area of ​​250m². 2 / g to 750m 2 / g porous carrier; or particles with an average diameter of 0.5μm to 1.5μm, an average surface pore size of 5nm to 15nm, and a specific surface area of ​​200m². 2 / g to 600m 2 / g porous carrier; or it can be a particle with an average diameter of 0.1μm to 0.5μm, an average surface pore size of 3nm to 12nm, and a specific surface area of ​​100m². 2 / g to 500m 2 / g porous carrier.

[0068] In step S402, the quantum dot solution and the carrier solution are mixed. In step S402, the quantum dots in the quantum dot solution can adhere to the carrier in the carrier solution. In some embodiments, the carrier is a porous carrier, which facilitates the uniform and stable attachment of the quantum dots to the carrier. Subsequently, the solution containing the quantum dots and the carrier can be allowed to stand, and then centrifuged and filtered to obtain the carrier with attached quantum dots.

[0069] Next, step S404 is performed, in which a solution comprising quantum dots and a carrier, and a solution comprising an encapsulating material are mixed. In step S404, the encapsulating material may coat the surface of the carrier to which the quantum dots are attached, to form an encapsulation layer. In some embodiments, the thickness of the encapsulation layer may be from 0.1 nm to 20 nm.

[0070] The encapsulation material can be selected from at least one group consisting of organic polymers, inorganic polymers, water-soluble polymers, organic solvent-soluble polymers, biopolymers, and synthetic polymers. For example, the encapsulation material can be at least one group consisting of polysiloxanes, polyacrylates, polycarbonates, polystyrene, polyethylene, polypropylene, polyketones, polyetheretherketones, polyesters, polyamides, polyimides, polyacrylamide, polyolefins, polyacetylene, polyisoprene, polybutadiene, poly(vinylidene fluoride), poly(vinyl chloride), ethylene vinyl acetate, polyethylene terephthalate, polyurethane, and cellulose polymers. In some embodiments, the encapsulation material can also be an inorganic medium, such as at least one group consisting of silicone, bentonite, glass, quartz, kaolin, silica, alumina, and zinc oxide. In some embodiments, the encapsulation layer and the carrier can be made of the same material. In other embodiments, the encapsulation layer and the carrier can also be made of different materials.

[0071] Subsequently, step S406 is performed, in which the solution comprising the carrier, quantum dots, and encapsulation layer is centrifuged to obtain the luminescent material. In other words, the luminescent material may include a carrier, quantum dots, and an encapsulation layer. The quantum dots are attached to the surface of the carrier, and the encapsulation layer covers both the quantum dots and the carrier.

[0072] In some embodiments, the weight percentage of quantum dots in the luminescent material can be from 0.1% to 20%. In other embodiments, the weight percentage of quantum dots in the luminescent material can be from 0.2% to 15%, or from 0.3% to 10%. When the weight percentage of quantum dots in the luminescent material is less than 0.1%, the concentration of quantum dots in the luminescent material is low, resulting in poor overall luminous efficiency. When the weight percentage of quantum dots in the luminescent material is greater than 20%, the quantum dots are prone to self-absorption, which reduces the overall luminous efficiency of the luminescent material and causes a redshift in the emitted light. For example, the aforementioned weight percentages can be obtained by inductively coupled plasma (ICP) spectroscopy.

[0073] In some embodiments, the luminescent material may be applied within the encapsulation material of the light-emitting component. For example, the encapsulation material of the light-emitting component may include epoxy resin, polysiloxane resin, acrylic resin, or glass. In the light-emitting device, the encapsulation material covers the light source (e.g., an LED, laser source, arc lamp, or blackbody light source), so that the primary light generated by the light source can excite the quantum dots within the encapsulation material to produce secondary light. The wavelength of the primary light may differ from that of the secondary light. In other words, the color of the primary light may differ from that of the secondary light. Furthermore, the intensity and wavelength of the light emitted by the entire light-emitting device can be satisfied by appropriately mixing the colors of the primary and secondary light. It should be noted that the light emitted by the light-emitting device may be solely the light emitted by the quantum dots (i.e., secondary light), or a mixture of light emitted by the light source and light emitted by the quantum dots (i.e., a mixture of primary and secondary light). In some embodiments, the luminescent material may include one or more quantum dots of different colors.

[0074] The light-emitting component (e.g., an LED) using the light-emitting material of this embodiment can serve as a backlight unit or other light-emitting device. Furthermore, a quantum dot light-emitting diode (QLED) display device can be constructed by arranging multiple LEDs using the light-emitting material of this embodiment, where each LED is a pixel.

[0075] In some embodiments, the light-emitting component can be applied to various display devices. Examples of display devices include televisions (also called televisions or television receivers), digital cameras, digital video cameras, digital photo frames, mobile phones, notebook personal computers, mobile computers, monitors for computers, portable game consoles, portable information terminals, audio playback devices, game consoles, and automotive displays.

[0076] It should be noted that the luminescent material in this embodiment is not limited to LED encapsulation materials, but can also be used in optical films, optical sheets, transparent tubes, optical components, color conversion materials, optical materials, inks, labeling agents, etc.

[0077] In summary, the quantum dot manufacturing method of the present invention includes heat treatment of a mixed solution containing a first solution and a second solution, wherein the heating rate of the heat treatment is in the range of 2°C / min to 10°C / min. Therefore, when the cations in the first solution react with the anions in the second solution, the reaction temperature can be prevented from decreasing due to endothermic reactions and the temperature difference between the first and second solutions. This improves the quantum efficiency of the quantum dots.

[0078] The following experimental and comparative examples are provided to verify the effectiveness of the present invention, but the present invention is not limited to the following content.

[0079] Experimental Example

[0080] First, a first solution was prepared. 18 mg of cadmium oxide, 813 mg of zinc acetate, and 7 mL of oleic acid were added to a three-necked flask. Next, 15 mL of octadecene was added to the three-necked flask, and the mixture was heated under vacuum at 120 °C to react and mix. Afterward, the three-necked flask was filled with nitrogen and the temperature was increased to 290 °C.

[0081] A second solution was provided at room temperature, and the first and second solutions were mixed. The mixture of the first and second solutions was then heat-treated. 2.1 mL of 0.001 mol of trioctylphosphine selenide (TOP-Se) and 58 mg of sulfur were injected into the three-necked flask, and the temperature of the solution in the three-necked flask was restored to 290°C at a heating rate of 5.96°C / min, and the reaction was maintained at 290°C.

[0082] The third and fourth solutions were added to the above mixed solution. The third solution consisted of 525 mg of zinc acetate, 1.83 mL of oleic acid, and 4 mL of octadecene. The fourth solution consisted of 309 mg of sulfur and 5 mL of trioctylphosphine. The solution was then stirred to produce a yellow-green suspension, which was cooled and precipitated using 300 mL of ethanol. The precipitate was separated by centrifugation, and the resulting product was green quantum dots. The green quantum dots emitted light with a peak wavelength of 525 nm and a full width at half maximum (FWHM) of 22 nm.

[0083] Quantum dots were mixed with n-hexane to form a quantum dot solution. The weight percentage of quantum dots in the quantum dot solution was 1%. Additionally, porous silica particle carriers were mixed with n-hexane to prepare a carrier solution. The porous silica particles had an average diameter of 3 μm, an average surface pore size of 10 nm, and a specific surface area of ​​700 m². 2 / g. Furthermore, the porous silica particles are modified to possess oleophilic properties. In the carrier solution, the porous silica particles constitute 5% by weight.

[0084] 0.25 g of quantum dot solution was mixed with 5 g of carrier solution and allowed to stand for 10 minutes. The solution, including both quantum dots and carrier, was then centrifuged and filtered to obtain porous silica particles coated with quantum dots, i.e., a carrier coated with quantum dots. Subsequently, the carrier coated with quantum dots was added to 250 g of ethanol and dispersed uniformly.

[0085] A solution comprising an encapsulating material is provided, comprising 0.5 g of tetraethoxysilane (TEOS) and 2.5 g of ammonia (NH4OH) at a weight percentage of 29%. The solution comprising the encapsulating material is added to an ethanol solution comprising a carrier with attached quantum dots, and stirred at room temperature for 4 hours to form an encapsulation layer on the surface of the carrier with attached quantum dots. The pH value of the solution comprising the carrier, quantum dots, and encapsulation layer is in the range of 10 to 11. The solution comprising the carrier, quantum dots, and encapsulation layer is then centrifuged, washed three times with pure water, and dried to obtain 0.2778 g of micron-sized luminescent material.

[0086] Comparative example

[0087] The manufacturing method of the quantum dots in the comparative example is similar to that in the experimental example. The only difference is that the heating rate of the heat treatment in the comparative example is 1.86 °C / min, while the heating rate of the heat treatment in the experimental example is 5.96 °C / min.

[0088] quantum efficiency

[0089] The quantum efficiency of the experimental and comparative examples was measured using the following method: The measurements were performed using the micron-sized luminescent materials of the experimental and comparative examples, respectively, manufactured according to the aforementioned method. The luminescent materials were dispersed in hexane as a solvent to prepare a sample solution with a transmittance (%) ranging from 71% to 79% under blue light (wavelength 450 nm). The solution and solvent (hexane, blank experiment) were analyzed using a photoluminescence analyzer (HORIBA, model: FluoroMax-3) with an integrating sphere (HORIBA). (F-3029) The laser integration area and emission integration area of ​​the sample solution and hexane were measured respectively, and then the following formula was used:

[0090] The quantum efficiency of the sample solution is calculated using (Φ: quantum efficiency, Ec: integral area of ​​light emission from the sample solution, Ea: integral area of ​​light emission from hexane, Lc: integral area of ​​laser emission from the sample solution, La: integral area of ​​laser emission from hexane).

[0091] The quantum efficiency of the quantum dots in the experimental example was calculated to be 51% according to the aforementioned measurements, while the quantum efficiency of the quantum dots in the comparative example was calculated to be 43%. This verifies that increasing the heating rate of the heat treatment to a range of 2℃ / min to 10℃ / min can improve the quantum efficiency of the quantum dots.

[0092] Although the present invention has been disclosed above with reference to embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A method for manufacturing quantum dots, characterized by, include: A first solution is provided comprising at least one element selected from the group consisting of Group XII elements, wherein the Group XII element exists in the first solution in the form of a cation, and the Group XII element in the first solution comprises at least one element selected from the group consisting of zinc, cadmium, and mercury. A second solution is provided comprising at least one element selected from the group consisting of group XVI elements, wherein the group XVI element exists in the second solution in the form of anions, and the group XVI element in the second solution comprises at least one element selected from the group consisting of oxygen, sulfur, selenium, and tellurium; The first solution and the second solution are mixed to form a mixed solution, wherein the mixing of the first solution and the second solution is carried out at a first temperature of 290°C, and the mixing of the first solution and the second solution is carried out at a temperature of 20°C to 30°C for the second solution; and The mixed solution is subjected to heat treatment, and the step of performing the heat treatment is to raise the temperature of the mixed solution to a temperature greater than or equal to the first temperature, wherein the heating rate of the heat treatment is 5.96°C / min to form quantum dots.

2. The method for manufacturing quantum dots according to claim 1, characterized in that, The first solution further includes an organic acid, the organic acid including at least one selected from the group consisting of oleic acid, stearic acid, and lauric acid, and the second solution further includes an organic solution, the organic solution including at least one selected from the group consisting of tri-n-octylphosphine, octadecene, tributylphosphine, and dioctylamine.

3. The method for manufacturing quantum dots according to claim 1, characterized in that, The cations in the first solution react with the anions in the second solution to form a nucleus. The group XII elements in the first solution are selected from zinc and cadmium, and the group XVI elements in the second solution are selected from sulfur and selenium.

4. The method for manufacturing quantum dots according to claim 1, characterized in that, Heat treatment is performed immediately after the mixture is formed.

5. The method for manufacturing quantum dots according to claim 3, characterized in that, In the heat treatment step, the temperature of the mixed solution is raised to a level greater than or equal to the first temperature, and then the reaction is carried out at that temperature.

6. The method for manufacturing quantum dots according to claim 1, characterized in that, Also includes: A third solution comprising a group XII element and a fourth solution comprising a group XVI element are added to the mixed solution, and the reaction is carried out to generate the shell of the quantum dot, wherein the cations of the shell are mainly composed of zinc and / or cadmium, and the anions of the shell are mainly composed of sulfur, and the step of adding the third solution and the fourth solution to the mixed solution is carried out at 230°C to 330°C.

7. A luminescent material, characterized in that, include: carrier; A plurality of quantum dots, wherein the quantum dots are manufactured by the method for manufacturing quantum dots according to any one of claims 1 to 6; and Encapsulation layer The quantum dots are attached to the surface of the carrier, and the encapsulation layer covers the quantum dots and the carrier.

8. A light-emitting component, characterized in that, include: Light source, and An encapsulation material comprising the luminescent material according to claim 7, wherein the encapsulation material covers the light source.

9. A display device, characterized in that, include: The light-emitting component according to claim 8, The display device is selected from at least one of the group consisting of televisions, digital cameras, digital video cameras, digital photo frames, mobile phones, laptop personal computers, mobile computers, monitors for computers, portable game consoles, portable information terminals, audio playback devices, game consoles, and vehicle displays.

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