Quantum dot-multielement composite particle, quantum dot diffusion plate and preparation method

Abstract

This invention relates to the field of nano-optical materials technology, and particularly to a quantum dot-multi-component composite particle, a quantum dot diffuser plate, and a preparation method thereof. The quantum dot-multi-component composite particle includes a core of original quantum dot particles, an antioxidant ligand layer coated on the surface of the original quantum dot particles, and a ternary polymer barrier layer coated on the surface of the antioxidant ligand layer. The ternary polymer barrier layer contains ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene. By directly coordinating the antioxidant to the surface of the quantum dots to form an antioxidant ligand layer, targeted protection of the quantum dots is achieved. By using a ternary polymer barrier layer to coat the original quantum dot particles coated with the antioxidant ligand layer, the ethylene-vinyl alcohol copolymer can act as an oxygen barrier, the polyvinylidene chloride can act as a water barrier, and the polystyrene can improve compatibility, thereby improving the water and oxygen resistance of the quantum dot-multi-component composite particle, while also improving the compatibility between the nanoparticles and polystyrene.

Description

Technical Field

[0001] This invention relates to the field of nano-optical materials technology, and in particular to a quantum dot-multi-component composite particle, a quantum dot diffuser plate, and a preparation method thereof. Background Technology

[0002] Quantum dots, as novel zero-dimensional nanomaterials, possess characteristics such as high fluorescence quantum yield, narrow emission spectrum, and good photostability. Compared with quantum dot diffusion plates prepared in combination with polystyrene, quantum dot films have a significant cost advantage. However, existing quantum dot diffusion plates do not achieve the desired water and oxygen barrier effects, and their protective ability for quantum dots is still somewhat inferior to that of quantum dot films. Furthermore, high-concentration diffusion plates face stability bottlenecks. Therefore, improving the protective ability of quantum dot materials and enhancing the compatibility between nanoparticles and the substrate have become key technical issues in the preparation of quantum dot diffusion plates.

[0003] In addition, existing quantum dots using coating processes have drawbacks such as limited coating layer functionality, failure of antioxidant protection, and poor matrix compatibility.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a quantum dot-multi-component composite particle, a quantum dot diffusion plate and a preparation method, which aims to solve the problems of single function of the coating layer, failure of antioxidant protection and poor matrix compatibility of quantum dots using the existing coating process.

[0006] The technical solution of the present invention is as follows:

[0007] A quantum dot-multi-component composite particle includes a primary quantum dot particle as the core, an antioxidant ligand layer coated on the surface of the primary quantum dot particle, and a ternary polymer barrier layer coated on the surface of the antioxidant ligand layer; the ternary polymer barrier layer contains ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene.

[0008] The quantum dot-multi-component composite particle, wherein the antioxidant ligand layer contains a first antioxidant; the first antioxidant contains one or more of amino, carboxyl, and thiol groups.

[0009] The quantum dot-multi-component composite particles, wherein the mass ratio of the original quantum dot particles to the ternary polymer barrier layer is (5-30):(60-95);

[0010] The mass ratio of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene is 1:(0.5-1):(2-5).

[0011] The quantum dot-multi-component composite particles, wherein the ternary polymer barrier layer further contains a second antioxidant; the second antioxidant is a hindered phenolic antioxidant;

[0012] The second antioxidant accounts for 2-4% of the total mass of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene.

[0013] A method for preparing quantum dot-multi-component composite particles, comprising the following steps:

[0014] The original quantum dots, the first antioxidant, and the organic solvent were mixed and subjected to a coordination reaction to obtain a quantum dot-antioxidant pre-conjugate.

[0015] Ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polystyrene and dimethyl sulfoxide were heated and mixed to obtain a ternary polymer coating solution;

[0016] The quantum dot-antioxidant preconjugate is mixed with the ternary polymer coating liquid, and after the coating reaction, an initiator is added to carry out a crosslinking reaction to obtain quantum dot-multi-component composite particles.

[0017] The method for preparing quantum dot-multi-component composite particles, wherein the temperature of the coordination reaction is 40℃-60℃ and the time of the coordination reaction is 0.5h-3h;

[0018] The temperature of the heating and mixing treatment is 100℃-140℃, and the time of the heating and mixing treatment is 0.5h-1.5h.

[0019] The method for preparing quantum dot-multi-component composite particles, wherein the mass ratio of the quantum dot-antioxidant pre-conjugate to the total mass of the ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene is 1:(2-10).

[0020] The method for preparing quantum dot-multi-component composite particles, wherein the coating reaction temperature is 100℃-150℃ and the coating reaction time is 1h-6h;

[0021] The cross-linking reaction is carried out at a temperature of 70℃-85℃ for 1h-6h.

[0022] A quantum dot diffusion plate, comprising, by mass parts:

[0023] Quantum dot-multi-component composite particles, 5-20 parts;

[0024] 65-80 parts of polystyrene;

[0025] 1-5 parts of diffused particles;

[0026] 1-5 parts of compound additive;

[0027] Third antioxidant 1-5 parts;

[0028] The quantum dots in the quantum dot-multi-component composite particle include red quantum dots and green quantum dots.

[0029] A method for preparing a quantum dot diffusion plate includes the following steps:

[0030] A mixture is obtained by mixing quantum dot-multi-component composite particles, polystyrene, diffusion particles, composite additives, and a third antioxidant.

[0031] The mixture is extruded by a twin-screw extruder and then subjected to flat vulcanization molding to obtain a quantum dot diffusion plate.

[0032] Beneficial effects: This invention provides a quantum dot-multi-component composite particle, a quantum dot diffusion plate, and a preparation method. The quantum dot-multi-component composite particle includes a core of original quantum dot particles, an antioxidant ligand layer coated on the surface of the original quantum dot particles, and a ternary polymer barrier layer coated on the surface of the antioxidant ligand layer. The ternary polymer barrier layer contains ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene. This invention solves the problem of antioxidant migration by directly coordinating antioxidants onto the surface of quantum dots to form an antioxidant ligand layer, thus achieving targeted protection of quantum dots. Simultaneously, a ternary polymer barrier layer containing ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene is used to coat the original quantum dot particles coated with the antioxidant ligand layer. This allows the ethylene-vinyl alcohol copolymer to act as an oxygen barrier, the polyvinylidene chloride to act as a water barrier, and the polystyrene to improve compatibility, thereby enhancing the water and oxygen resistance of the quantum dot-multi-component composite particles. It also improves the compatibility between the nanoparticles and polystyrene. Furthermore, the quantum dot diffusion plate made using this quantum dot-multi-component composite particle exhibits excellent optical properties and high stability. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of a quantum dot-multi-component composite particle according to the present invention;

[0034] Figure 2 This is a schematic diagram of the process flow for a quantum dot-multi-component composite particle preparation method according to the present invention;

[0035] Figure 3 This is a schematic diagram of the quantum dot-multi-component composite particles and quantum dot diffusion plate prepared in Example 1;

[0036] Figure 4 This is a graph showing the brightness decay of a quantum dot diffuser during the aging process. Detailed Implementation

[0037] This invention provides a quantum dot-multi-component composite particle, a quantum dot diffusion plate, and a preparation method thereof. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0038] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.

[0039] like Figure 1 As shown, the present invention provides a quantum dot-multi-component composite particle, comprising a primary quantum dot particle 10 as the core, an antioxidant ligand layer 20 coated on the surface of the primary quantum dot particle 10, and a ternary polymer barrier layer 30 coated on the surface of the antioxidant ligand layer 20; the ternary polymer barrier layer 30 contains ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene.

[0040] In this embodiment, by directly coordinating antioxidants onto the surface of quantum dots to form an antioxidant ligand layer, the problem of antioxidant migration is solved, achieving targeted protection of quantum dots. Simultaneously, a ternary polymer barrier layer containing ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene is used to coat the original quantum dot particles coated with the antioxidant ligand layer. This allows the ethylene-vinyl alcohol copolymer to act as an oxygen barrier, the polyvinylidene chloride to act as a water barrier, and the polystyrene to improve compatibility, thereby enhancing the water and oxygen resistance of the quantum dot-multi-component composite particles. It also improves the compatibility between the nanoparticles and polystyrene. Furthermore, the quantum dot diffusion plate made using this quantum dot-multi-component composite particle exhibits excellent optical properties and high stability.

[0041] Specifically, this invention utilizes a mixture of ethylene-vinyl alcohol copolymer (with oxygen-barrier function), polyvinylidene chloride (PVDC) (with water-blocking function), and polystyrene (which enhances the compatibility between quantum dot-multi-component composite particles and polystyrene) as a ternary polymer barrier layer. This enhances the water and oxygen resistance of the quantum dot-multi-component composite particles and improves the compatibility between the quantum dot-multi-component composite particles and polystyrene during the preparation of the quantum dot diffusion plate, which is beneficial for subsequent preparation of the quantum dot diffusion plate. Through the synergistic effect of the ethylene-vinyl alcohol copolymer, PVDC, and polystyrene, the water and oxygen resistance of the quantum dot-multi-component composite particles is improved. Furthermore, antioxidants are directly coordinated on the surface of the original quantum dots, forming an antioxidant ligand layer, which solves the problem of antioxidant migration and achieves targeted protection of the quantum dots.

[0042] In some embodiments, the original quantum dot particles are oil-soluble core-shell structured quantum dots composed of group II-VI or group III-V elements, including but not limited to CdSe, CdSe / ZnSe / ZnS, CdSe / ZnS, CdSe / CdS, CdZnSe / ZnS, CdSZnSeS / ZnS, and InP / ZnSe / ZnS.

[0043] In some embodiments, the antioxidant ligand layer contains a first antioxidant; the first antioxidant has active functional groups that can coordinate with the metal elements in the original quantum dots; the first antioxidant contains one or more of amino, carboxyl, and thiol groups; by directly coordinating a first antioxidant containing one or more of amino, carboxyl, and thiol groups onto the surface of the original quantum dots, the problem of antioxidant migration is solved, and targeted protection of the quantum dots is achieved.

[0044] In some embodiments, the first antioxidant is selected from one or more of N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, tris[2,4-di-tert-butylphenyl]phosphite, and 4,4'-thiobis(6-tert-butyl-3-methylphenol). The first antioxidant contains amino, carboxyl, or thiol groups, which can coordinate with the metal elements in the original quantum dot particles to achieve the coating of the antioxidant ligand layer.

[0045] In some embodiments, the mass ratio of the original quantum dot particles to the ternary polymer barrier layer is (5-30):(60-95); preferably, the mass fraction of the original quantum dots in the quantum dot-multi-component composite particles is about 5%-30%, and the mass fraction of the ternary polymer barrier layer is 60%-95%.

[0046] In some embodiments, the mass ratio of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene is 1:(0.5-1):(2-5). Forming a ternary polymer barrier layer from the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene in the above mass ratio allows the quantum dot-multi-component composite particles to possess better resistance to water and oxygen.

[0047] In a preferred embodiment, the mass ratio of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene is 1:0.8:3.2, 1:1:3.5, or 1:1:5.

[0048] In some embodiments, the ternary polymer barrier layer further contains a second antioxidant; the second antioxidant is a hindered phenolic antioxidant; by adding a hindered phenolic antioxidant to the ternary polymer barrier layer, the problem of antioxidant migration can be further solved, and the targeted protection of quantum dots can be better achieved.

[0049] In some embodiments, the hindered phenolic antioxidant is selected from, but not limited to, one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and tris(2,4-di-tert-butylphenyl)phosphite. These hindered phenolic antioxidants can neutralize oxygen molecules, ozone, or photogenerated free radicals that the shell cannot block before they reach the quantum dot surface, thereby significantly extending fluorescence lifetime and device stability.

[0050] In some embodiments, the second antioxidant accounts for 2-4% of the total mass of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene. Controlling the proportion of the second antioxidant within this range is sufficient to rapidly consume any infiltrated residual oxygen without affecting the water and oxygen resistance of the ternary polymer barrier layer. Preferably, the second antioxidant accounts for 2% of the total mass of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene.

[0051] In addition, such as Figure 2 As shown, the present invention also provides a method for preparing quantum dot-multi-component composite particles, comprising the following steps:

[0052] Step S10: Mix the original quantum dots, the first antioxidant, and the organic solvent, and obtain a quantum dot-antioxidant pre-conjugate through a coordination reaction;

[0053] Step S20: The ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polystyrene and dimethyl sulfoxide are heated and mixed to obtain a ternary polymer coating solution;

[0054] Step S30: Mix the quantum dot-antioxidant preconjugate with the ternary polymer coating liquid, and after the coating reaction, add an initiator to carry out a crosslinking reaction to obtain quantum dot-multi-component composite particles.

[0055] In this embodiment, the antioxidant can be directly coordinated onto the surface of the quantum dots to form an antioxidant ligand layer through the above preparation method, which solves the problem of antioxidant migration and achieves targeted protection of the quantum dots. At the same time, the original quantum dot particles coated with the antioxidant ligand layer are coated with a ternary polymer barrier layer containing ethylene-vinyl alcohol copolymer, polyvinylidene chloride and polystyrene. This allows the ethylene-vinyl alcohol copolymer to act as an oxygen barrier, the polyvinylidene chloride to act as a water barrier, and the polystyrene to improve compatibility, thereby improving the water and oxygen resistance of the quantum dot-multi-component composite particles. At the same time, the compatibility between the nanoparticles and polystyrene is improved when preparing the quantum dot diffusion plate. Furthermore, the quantum dot diffusion plate made using this quantum dot-multi-component composite particle has excellent optical properties and high stability.

[0056] In some embodiments, the mass ratio of the original quantum dot to the first antioxidant is (0.1-10):1. At this mass ratio, the first antioxidant can be directly coordinated on the surface of the quantum dot to form an antioxidant ligand layer, thereby achieving targeted protection of the quantum dot.

[0057] In a preferred embodiment, the mass ratio of the original quantum dot to the first antioxidant is 2:1 or 1:0.6.

[0058] In some embodiments, the coordination reaction temperature is 40℃-60℃, and the coordination reaction time is 0.5h-3h; through the coordination reaction, the first antioxidant can be directly coordinated on the surface of the quantum dot to form an antioxidant ligand layer, thereby achieving targeted protection of the quantum dot.

[0059] In a preferred embodiment, the coordination reaction is carried out at a temperature of 50°C for 2 hours; or, the coordination reaction is carried out at a temperature of 55°C for 1.5 hours.

[0060] In some embodiments, in step S10, the organic solvent includes, but is not limited to, one or more of xylene, toluene, n-hexane, cyclohexane, octane, and chloroform. These organic solvents facilitate the dissolution of atomic quantum dots and provide a reaction environment for coordination reactions. Preferably, the mass ratio of the original quantum dots to the organic solvent is 1:(8-100).

[0061] In some embodiments, in step S10, after the coordination reaction is completed, ethanol is added to the product, and the product is washed by centrifugation to obtain a quantum dot-antioxidant pre-conjugate; preferably, the volume ratio of ethanol to organic solvent is 1:1.

[0062] In some embodiments, the heating and mixing treatment is performed at a temperature of 100°C-140°C for a duration of 0.5h-1.5h. This heating and mixing treatment allows the ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene to dissolve better in dimethyl sulfoxide, forming a uniformly dispersed mixed solution.

[0063] In a preferred embodiment, the heating and mixing treatment is performed at a temperature of 120°C for 1 hour; or, the heating and mixing treatment is performed at a temperature of 135°C for 1.5 hours.

[0064] In some embodiments, the total mass ratio of the ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene to the mass ratio of the dimethyl sulfoxide is 1:(6-30). Controlling the mass ratio within this range can better form a uniform ternary polymer coating solution.

[0065] In some embodiments, in step S20, after heating and mixing the ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polystyrene and dimethyl sulfoxide, a second antioxidant is added to obtain a ternary polymer coating liquid containing the second antioxidant.

[0066] In some embodiments, the second antioxidant accounts for 2-4% of the total mass of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene.

[0067] In some embodiments, the mass ratio of the quantum dot-antioxidant preconjugate to the total mass of the ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene is 1:(2-10). At this mass ratio, the ternary polymer coating liquid can better coat the quantum dot-antioxidant preconjugate, resulting in quantum dot-multi-component composite particles with water and oxygen resistance.

[0068] In some embodiments, the coating reaction temperature is 100℃-150℃, and the coating reaction time is 1h-6h; the crosslinking reaction temperature is 70℃-85℃, and the crosslinking reaction time is 1h-6h. By controlling the temperature and time of the coating and crosslinking reactions, the coating of the quantum dot-antioxidant preconjugate by the ternary polymer barrier layer can be improved.

[0069] In a preferred embodiment, the coating reaction temperature is 150°C and the coating reaction time is 1 hour; the crosslinking reaction temperature is 75°C and the crosslinking reaction time is 3 hours; or, the coating reaction temperature is 140°C and the coating reaction time is 3 hours; the crosslinking reaction temperature is 70°C and the crosslinking reaction time is 4 hours; or, the coating reaction temperature is 125°C and the coating reaction time is 5 hours; the crosslinking reaction temperature is 85°C and the crosslinking reaction time is 1 hour.

[0070] In some embodiments, the initiator includes, but is not limited to, one or more of azobisisobutyronitrile, azobisisoheptanenitrile, and ammonium persulfate, used to promote further cross-linking reactions of the various polymer materials.

[0071] In addition, the present invention also provides a quantum dot diffusion plate, comprising, by mass parts:

[0072] Quantum dot-multi-component composite particles, 5-20 parts;

[0073] 65-80 parts of polystyrene;

[0074] 1-5 parts of diffused particles;

[0075] 1-5 parts of compound additive;

[0076] Third antioxidant 1-5 parts;

[0077] The quantum dots in the quantum dot-multi-component composite particle include red quantum dots and green quantum dots.

[0078] In this embodiment, the quantum dot diffusion plate prepared by mixing according to the specified mass fraction has high resistance to water and oxygen. Furthermore, since the quantum dot-multi-component composite particles adopt a ternary polymer barrier layer containing ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene, the compatibility between the quantum dot-multi-component composite particles and polystyrene can be improved. This allows for more efficient conversion of the blue light portion of the LED into narrow half-peak and wide green / red light, which is then mixed with the remaining blue light to form high color gamut, high brightness, and low energy consumption white light, while simultaneously achieving uniform light diffusion.

[0079] In some embodiments, the diffused particles are inorganic nano-oxides or organic polymer nanoparticles; the inorganic nano-oxides include, but are not limited to, one or more of nano-silica, nano-titanium dioxide, and nano-zirconia; the organic polymer nanoparticles include, but are not limited to, polymethyl methacrylate nanoparticles. These diffused particles can form a refractive index gradient within the quantum dot diffuser plate, causing multiple scattering of the LED point light source and "dispersing" the strong light spot; simultaneously, they increase the optical path and improve the absorption rate of the quantum dots for excitation blue light, thereby enhancing color conversion efficiency.

[0080] In some embodiments, the third oxidant is a hindered phenolic antioxidant, including but not limited to one or more of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate], octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate, bis(2,4-di-tert-butylphenyl)pentaerythritol diphosphite, and tris(2,4-di-tert-butylphenyl)phosphite.

[0081] In some embodiments, the composite additives include, but are not limited to, dodecyl mercaptan, octadecyl mercaptan, zinc stearate, etc.

[0082] Finally, the present invention also provides a method for preparing a quantum dot diffusion plate, comprising the following steps:

[0083] Step S100: Mix quantum dot-multi-component composite particles, polystyrene, diffusion particles, composite additives, and third antioxidant to obtain a mixture;

[0084] Step S200: The mixture is extruded by a twin-screw extruder and then subjected to flat vulcanization molding to obtain a quantum dot diffusion plate.

[0085] In some embodiments, the temperature for the flat vulcanization molding is 180°C-230°C.

[0086] In some embodiments, the thickness of the quantum dot diffusion plate is 1 mm to 2.5 mm.

[0087] The following examples further illustrate the present invention in detail. It should also be understood that the following examples are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of the present invention are within the scope of protection of the present invention.

[0088] The original quantum dots used in the following examples and comparative examples are CdSe core-shell structured quantum dots, and the preparation method is briefly described below:

[0089] Se source was rapidly injected into a solution containing Cd and Zn precursors to form CdZnSe quantum dot nuclei. Then, an equimolar solution of zinc oleate-octadecene was added, and S source was slowly added dropwise to form a ZnS protective layer. After the reaction was completed, the original red CdSe quantum dot powder was obtained by centrifugation, purification and drying.

[0090] A mixture of Se and S sources was rapidly injected into a solution containing Cd and Zn precursors to form CdZnSeS quantum dot nuclei. Then, an equimolar solution of zinc oleate-octadecene was added, and the S source was slowly added dropwise to form a ZnS protective layer. After the reaction was completed, the original green CdSe quantum dot powder was obtained by centrifugation, purification and drying.

[0091] Example 1

[0092] This embodiment provides a quantum dot-multi-component composite particle, and the specific steps of its preparation method are as follows:

[0093] Weigh 1g of original green CdSe quantum dots and place them in a three-necked flask. Add 25mL of xylene and stir until completely dissolved. Add 0.5g of antioxidant N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine. Purge with nitrogen gas and stir under nitrogen protection. Heat to 50°C and react for 2 hours. Cool to room temperature and add 25mL of anhydrous ethanol. Centrifuge to collect the precipitate and dry to obtain the green quantum dot-antioxidant pre-conjugate.

[0094] 1 g of ethylene-vinyl alcohol copolymer, 0.8 g of polyvinylidene chloride and 3.2 g of polystyrene were placed in a three-necked flask, 50 mL of dimethyl sulfoxide was added, and the mixture was heated to 120 °C for 1 h under nitrogen protection. After adding 0.1 g of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], the mixture was cooled to room temperature to obtain a multi-component polymer coating solution.

[0095] 1g of green quantum dot-antioxidant pre-conjugate was added to the above-mentioned multi-component polymer coating liquid. The mixture was heated to 150℃ and reacted for 1h under nitrogen protection. The mixture was then cooled to 75℃ and 0.05g of azobisisobutyronitrile was added. After reacting at this temperature for 3h, the mixture was cooled to room temperature and then dried and pulverized by rotary evaporation to obtain green CdSe quantum dot-multi-component composite particles.

[0096] Using the same method, the original green CdSe quantum dots were replaced with the original red CdSe quantum dots to obtain red CdSe quantum dot-multi-component composite particles.

[0097] This embodiment also provides a quantum dot diffusion plate, the specific steps of which are as follows:

[0098] Take 4g of green CdSe quantum dot-multi-component composite particles, 1g of red CdSe quantum dot-multi-component composite particles, 80g of polystyrene, 5g of diffusion particles, 5g of octadecyl mercaptan, and 5g of antioxidant prepared above, add them to a high-speed mixer, granulate by twin-screw extrusion, vulcanize in a flat plate at 200℃, cool and demold to obtain diffusion plate QDDP-S1.

[0099] The schematic diagram of the quantum dot-multi-component composite particle and quantum dot diffuser plate prepared in this embodiment is shown below. Figure 3 As shown.

[0100] Example 2

[0101] This embodiment provides a quantum dot-multi-component composite particle, and the specific steps of its preparation method are as follows:

[0102] Weigh 1g of original green CdSe quantum dots and place them in a three-necked flask. Add 25mL of xylene and stir until completely dissolved. Add 0.6g of antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol), purge with nitrogen, stir and heat to 50℃ under nitrogen protection, react for 2h, cool to room temperature, add 25mL of anhydrous ethanol, centrifuge to collect the precipitate, and dry to obtain the green quantum dot-antioxidant pre-conjugate.

[0103] 1g of ethylene-vinyl alcohol copolymer, 1g of polyvinylidene chloride and 3.5g of polystyrene were placed in a three-necked flask, 60mL of dimethyl sulfoxide was added, and the mixture was heated to 120℃ and reacted for 1h under nitrogen protection. After adding 0.11g of antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol) and cooling to room temperature, a multi-component polymer coating solution was obtained.

[0104] 1g of green quantum dot-antioxidant pre-conjugate was added to the above-mentioned multi-component polymer coating liquid. The mixture was heated to 140℃ and reacted for 3h under nitrogen protection. The mixture was then cooled to 70℃ and 0.055g of azobisisobutyronitrile was added. After reacting at this temperature for 4h, the mixture was cooled to room temperature and then dried and pulverized by rotary evaporation to obtain green CdSe quantum dot-multi-component composite particles.

[0105] Using the same method, the original green CdSe quantum dots were replaced with the original red CdSe quantum dots to obtain red CdSe quantum dot-multi-component composite particles.

[0106] This embodiment also provides a quantum dot diffusion plate, the specific steps of which are as follows:

[0107] Take 4g of green CdSe quantum dot-multi-component composite particles, 1g of red CdSe quantum dot-multi-component composite particles, 80g of polystyrene, 5g of diffusion particles, 5g of octadecyl mercaptan, and 5g of antioxidant prepared above, add them to a high-speed mixer, granulate by twin-screw extrusion, vulcanize in a flat plate at 200℃, cool and demold to obtain diffusion plate QDDP-S2.

[0108] Example 3

[0109] This embodiment provides a quantum dot-multi-component composite particle, and the specific steps of its preparation method are as follows:

[0110] Weigh 1g of original green CdSe quantum dots and place them in a three-necked flask. Add 25mL of xylene and stir until completely dissolved. Add 0.6g of antioxidant 4,4'-thiobis(6-tert-butyl-3-methylphenol), purge with nitrogen, and stir and heat to 55℃ under nitrogen protection. React for 1.5h, then cool to room temperature. Add 25mL of anhydrous ethanol, centrifuge to collect the precipitate, and dry to obtain the green quantum dot-antioxidant pre-conjugate.

[0111] Take 1g of ethylene-vinyl alcohol copolymer, 1g of polyvinylidene chloride and 5g of polystyrene into a three-necked flask, add 60mL of dimethyl sulfoxide, heat to 135℃ under nitrogen protection and react for 1.5h, add 0.14g of antioxidant tris(2,4-di-tert-butylphenyl) phosphite and cool to room temperature to obtain a multi-component polymer coating solution;

[0112] 1g of green quantum dot-antioxidant pre-conjugate was added to the above-mentioned multi-component polymer coating liquid, and the mixture was heated to 125℃ and reacted for 5h under nitrogen protection. The mixture was then cooled to 85℃ and 0.055g of azobisisobutyronitrile was added. After reacting at this temperature for 1h, the mixture was cooled to room temperature and then dried and pulverized by rotary evaporation to obtain green CdSe quantum dot-multi-component composite particles.

[0113] Using the same method, the original green CdSe quantum dots were replaced with the original red CdSe quantum dots to obtain red CdSe quantum dot-multi-component composite particles.

[0114] This embodiment also provides a quantum dot diffusion plate, the specific steps of which are as follows:

[0115] Take 4g of green CdSe quantum dot-multi-component composite particles, 1g of red CdSe quantum dot-multi-component composite particles, 80g of polystyrene, 5g of diffusion particles, 5g of octadecyl mercaptan, and 5g of antioxidant prepared above, add them to a high-speed mixer, granulate by twin-screw extrusion, vulcanize in a flat plate at 200℃, cool and demold to obtain diffusion plate QDDP-S3.

[0116] Comparative Example 1

[0117] This comparative example provides a quantum dot-multi-component composite particle, and the specific steps of its preparation method are as follows:

[0118] 1 g of ethylene-vinyl alcohol copolymer, 0.8 g of polyvinylidene chloride and 3.2 g of polystyrene were placed in a three-necked flask, 50 mL of dimethyl sulfoxide was added, and the mixture was heated to 120 °C for 1 h under nitrogen protection. After adding 0.1 g of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], the mixture was cooled to room temperature to obtain a multi-component polymer coating solution.

[0119] 1g of original green CdSe quantum dots and 0.5g of antioxidant N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine were added to the above-mentioned multi-component polymer coating solution. The mixture was heated to 150℃ and reacted for 1h under nitrogen protection. The temperature was then lowered to 75℃ and 0.05g of azobisisobutyronitrile was added. The mixture was kept at this temperature for 3h and then cooled to room temperature. The mixture was then dried by rotary evaporation and pulverized to obtain green CdSe quantum dot-multi-component composite particles.

[0120] Using the same method, the original green CdSe quantum dots were replaced with the original red CdSe quantum dots to obtain red CdSe quantum dot-multi-component composite particles.

[0121] This comparative example also provides a quantum dot diffusion plate, the specific steps of which are as follows:

[0122] Take 4g of green CdSe quantum dot-multi-component composite particles, 1g of red CdSe quantum dot-multi-component composite particles, 80g of polystyrene, 5g of diffusion particles, 5g of octadecyl mercaptan, and 5g of antioxidant prepared above, add them to a high-speed mixer, granulate by twin-screw extrusion, vulcanize in a flat plate at 200℃, cool and demold to obtain diffusion plate QDDP-D1.

[0123] Comparative Example 2

[0124] This comparative example provides a quantum dot-unit composite particle, the specific steps of which are as follows:

[0125] Weigh 1g of original green CdSe quantum dots and place them in a three-necked flask. Add 25mL of xylene and stir until completely dissolved. Add 0.5g of antioxidant N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine. Purge with nitrogen gas and stir under nitrogen protection. Heat to 50°C and react for 2 hours. Cool to room temperature and add 25mL of anhydrous ethanol. Centrifuge to collect the precipitate and dry to obtain the green quantum dot-antioxidant pre-conjugate.

[0126] Take 5g of ethylene-vinyl alcohol copolymer into a three-necked flask, add 50mL of dimethyl sulfoxide, heat to 120℃ under nitrogen protection and react for 1h, add 0.1g of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid] and cool to room temperature to obtain a unit polymer coating solution;

[0127] 1g of green quantum dot-antioxidant pre-conjugate was added to the above unit polymer coating liquid, and the mixture was heated to 150℃ and reacted for 1h under nitrogen protection. The mixture was then cooled to 75℃ and 0.05g of azobisisobutyronitrile was added. After reacting at this temperature for 3h, the mixture was cooled to room temperature and then dried and pulverized by rotary evaporation to obtain green CdSe quantum dot-unit composite particles.

[0128] Using the same method, the original green CdSe quantum dots were replaced with the original red CdSe quantum dots to obtain red CdSe quantum dot-multi-component composite particles.

[0129] This comparative example also provides a quantum dot diffusion plate, the specific steps of which are as follows:

[0130] Take 4g of green CdSe quantum dot-multi-component composite particles, 1g of red CdSe quantum dot-multi-component composite particles, 80g of polystyrene, 5g of diffusion particles, 5g of octadecyl mercaptan, and 5g of antioxidant prepared above, add them to a high-speed mixer, granulate by twin-screw extrusion, vulcanize in a flat plate at 200℃, cool and demold to obtain diffusion plate QDDP-D2.

[0131] Comparative Example 3

[0132] This comparative example provides a quantum dot-multi-component composite particle, and the specific steps of its preparation method are as follows:

[0133] Weigh 1g of original green CdSe quantum dots and place them in a three-necked flask. Add 25mL of xylene and stir until completely dissolved. Add 0.5g of antioxidant N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine. Purge with nitrogen gas and stir under nitrogen protection. Heat to 50°C and react for 2 hours. Cool to room temperature and add 25mL of anhydrous ethanol. Centrifuge to collect the precipitate and dry to obtain the green quantum dot-antioxidant pre-conjugate.

[0134] 1 g of ethylene-vinyl alcohol copolymer, 0.8 g of polyvinylidene chloride and 3.2 g of polystyrene were placed in a three-necked flask, 50 mL of dimethyl sulfoxide was added, and the mixture was heated to 120 °C and reacted for 1 h under nitrogen protection. After adding 0.1 g of antioxidant pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic acid], the mixture was cooled to room temperature to obtain a multi-component polymer coating solution.

[0135] Add 1g of green quantum dot-antioxidant preconjugate and 0.05g of azobisisobutyronitrile to the above-mentioned multi-component polymer coating solution, and directly obtain green CdSe quantum dot-multi-component composite particles by rotary evaporation drying and pulverization without coating and cross-linking reaction.

[0136] Using the same method, the original green CdSe quantum dots were replaced with the original red CdSe quantum dots to obtain red CdSe quantum dot-multi-component composite particles.

[0137] This comparative example also provides a quantum dot diffusion plate, the specific steps of which are as follows:

[0138] Take 4g of green CdSe quantum dot-multi-component composite particles, 1g of red CdSe quantum dot-multi-component composite particles, 80g of polystyrene, 5g of diffusion particles, 5g of octadecyl mercaptan, and 5g of antioxidant prepared above, add them to a high-speed mixer, granulate by twin-screw extrusion, vulcanize in a flat plate at 200℃, cool and demold to obtain diffusion plate QDDP-D3.

[0139] The quantum dot diffusion plates prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to high-temperature and high-humidity blue light aging experiments at a temperature of 45°C, a humidity of 75% RH, an emission wavelength of 450 nm, and an energy of 300 mW / cm². 2 The brightness decay curve of the quantum dot diffuser plate after aging under blue light for 1000 hours is shown below. Figure 4 As shown in the table below, the performance of the quantum dot diffuser plate after aging is as follows:

[0140]

[0141] Normalized to a brightness of 100 for QDDP-S1 before aging, the performance verification results of Examples 1-3 show that the preparation method has excellent process stability and performance controllability. In Examples 2 and 3, the amount of quantum dots gradually decreased compared to Example 1. Although the initial brightness of the quantum dot diffuser plate decreased slightly, the brightness retention rate of all sample examples remained stable at over 95%. Furthermore, optical characterization confirmed that no quantum dot aggregation occurred, proving that the "antioxidant coordination-multi-component coating" system constructed in this invention can effectively ensure the dispersion and long-term optical stability of quantum dots.

[0142] The comparative experiments of Comparative Examples 1-3 further revealed the necessity of the "antioxidant coordination-multi-component coating" system of the present invention: Comparative Example 1 did not use active functional group antioxidants to modify the quantum dots with ligands. The antioxidants existed in a free state. Under the high temperature environment of multi-component coating and subsequent molding, the fluorescence efficiency of the quantum dots was damaged, resulting in low initial brightness. Furthermore, due to the lack of targeted protection on the surface of the quantum dots, the brightness retention rate was only 77% after 1000h aging. This confirms that the coordination and binding of antioxidants with quantum dots is the key to achieving long-term protection.

[0143] Comparative Example 2 uses a single polymer coating scheme. On the one hand, due to the lack of a highly efficient water-blocking layer of polyvinylidene chloride and a compatibility adjustment layer of polystyrene, the water-blocking and oxygen-barrier performance is insufficient. On the other hand, the interfacial bonding force with the matrix polystyrene is weak, which eventually leads to local quantum dot agglomeration. Comparative Example 3 completely omits the coating process. The quantum dot-antioxidant pre-combination is directly blended with the matrix. It neither forms an effective barrier layer nor has the cross-linking anchoring effect induced by the initiator, resulting in severe agglomeration of quantum dots and a significant decrease in stability after aging.

[0144] In summary, the present invention provides a quantum dot-multi-component composite particle, a quantum dot diffusion plate, and a preparation method thereof. The quantum dot-multi-component composite particle includes a core of original quantum dot particles, an antioxidant ligand layer coated on the surface of the original quantum dot particles, and a ternary polymer barrier layer coated on the surface of the antioxidant ligand layer; the ternary polymer barrier layer contains ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene. This invention solves the problem of antioxidant migration by directly coordinating antioxidants onto the surface of quantum dots to form an antioxidant ligand layer, thus achieving targeted protection of quantum dots. Simultaneously, a ternary polymer barrier layer containing ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene is used to coat the original quantum dot particles coated with the antioxidant ligand layer. This allows the ethylene-vinyl alcohol copolymer to act as an oxygen barrier, the polyvinylidene chloride to act as a water barrier, and the polystyrene to improve compatibility, thereby enhancing the water and oxygen resistance of the quantum dot-multi-component composite particles. It also improves the compatibility between the nanoparticles and polystyrene. Furthermore, the quantum dot diffusion plate made using this quantum dot-multi-component composite particle exhibits excellent optical properties and high stability.

[0145] Specifically, this invention solves three major technical bottlenecks simultaneously—quantum dot agglomeration, insufficient long-term protection, and poor matrix compatibility—through the core technology of "quantum dot-antioxidant pre-conjugate + multi-component synergistic coating," significantly improving the optical uniformity and environmental stability of the diffuser plate, and possessing clear inventiveness and industrial application value.

[0146] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A quantum dot-multi-component composite particle, characterized in that, The system comprises original quantum dot particles as the core, an antioxidant ligand layer coating the surface of the original quantum dot particles, and a ternary polymer barrier layer coating the surface of the antioxidant ligand layer; the ternary polymer barrier layer contains ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene; the antioxidant ligand layer contains a first antioxidant; the first antioxidant contains one or more of amino, carboxyl, and thiol groups; The preparation method of the quantum dot-multi-component composite particles includes the following steps: The original quantum dots, the first antioxidant, and the organic solvent were mixed and subjected to a coordination reaction to obtain a quantum dot-antioxidant pre-conjugate. Ethylene-vinyl alcohol copolymer, polyvinylidene chloride, polystyrene and dimethyl sulfoxide were heated and mixed to obtain a ternary polymer coating solution; The quantum dot-antioxidant preconjugate is mixed with the ternary polymer coating liquid, and after the coating reaction, an initiator is added to carry out a crosslinking reaction to obtain quantum dot-multi-component composite particles.

2. The quantum dot-multi-component composite particle according to claim 1, characterized in that, The mass ratio of the original quantum dot particles to the ternary polymer barrier layer is (5-30):(60-95); The mass ratio of the ethylene-vinyl alcohol copolymer, the polyvinylidene chloride, and the polystyrene is 1:(0.5-1):(2-5).

3. The quantum dot-multi-component composite particle according to claim 1, characterized in that, The coordination reaction is carried out at a temperature of 40℃-60℃ for a duration of 0.5h-3h. The temperature of the heating and mixing treatment is 100℃-140℃, and the time of the heating and mixing treatment is 0.5h-1.5h.

4. The quantum dot-multi-component composite particle according to claim 1, characterized in that, The mass ratio of the quantum dot-antioxidant preconjugate to the total mass of the ethylene-vinyl alcohol copolymer, polyvinylidene chloride, and polystyrene is 1:(2-10).

5. The quantum dot-multi-component composite particle according to claim 1, characterized in that, The coating reaction is carried out at a temperature of 100℃-150℃ for 1h-6h. The cross-linking reaction is carried out at a temperature of 70℃-85℃ for 1h-6h.

6. A quantum dot diffusion plate, characterized in that, By weight, including: 5-20 parts of the quantum dot-multi-component composite particles as described in any one of claims 1-5; 65-80 parts of polystyrene; 1-5 parts of diffused particles; 1-5 parts of compound additive; Third antioxidant 1-5 parts; The quantum dots in the quantum dot-multi-component composite particle include red quantum dots and green quantum dots.

7. A method for preparing a quantum dot diffusion plate as described in claim 6, characterized in that, Including the following steps: A mixture is obtained by mixing quantum dot-multi-component composite particles, polystyrene, diffusion particles, composite additives, and a third antioxidant. The mixture is extruded by a twin-screw extruder and then subjected to flat vulcanization molding to obtain a quantum dot diffusion plate.

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