A quantum dot-based lens material and its preparation method and application

Abstract

The present invention relates to the field of quantum dot materials, and in particular to a lens material based on quantum dots, and a preparation method and application thereof. The present application discloses a lens material based on quantum dots, and the raw materials for preparation include: a quantum dot precursor, an acrylic compound, an initiator, and a quantum dot stabilizer. The raw materials for preparing the quantum dot precursor include: a cadmium source solution, a sulfur source solution, an oxysilane substance, and a sulfonate substance. The cadmium source is selected from at least one of cadmium oxide, cadmium nitrate, and cadmium chloride; the sulfur source is selected from at least one of sulfur powder, sodium sulfide, cysteine, and thioacetamide. The polymer coating can effectively isolate oxygen, moisture, etc., avoid quantum dot fluorescence quenching and inactivation, and improve the stability of the quantum dot lens material. Moreover, the luminous efficiency is high, the photoluminescence quantum yield (PLQY) is greater than 60%, the brightness decay after photothermal aging is less than 15%, and the transmittance is greater than 90%.

Description

Technical Field

[0001] The present invention relates to the field of quantum dot materials, and in particular to a quantum dot-based lens material and a preparation method and application thereof. Background Art

[0002] Quantum dots (QDs), as a new type of luminescent material, have the advantages of narrow luminescence spectrum, wide excitation spectrum, high quantum yield, and solution preparation. Light-emitting diodes (LEDs) made from them can achieve narrow emission half-wave peaks (<20nm) in the red, blue, and green bands through a color conversion process, with a color gamut exceeding 120% NTSC.

[0003] According to the different positions of quantum dots in the backlight structure, quantum dot backlight technology is mainly divided into three types: the first is to replace the phosphor material with quantum dots and directly package it with the LED chip; the second is to sandwich the quantum dots between two layers of water-proof and oxygen-proof films to form a "sandwich" quantum dot film, and attach it directly above the light guide plate; the third is to encapsulate the quantum dots in a special glass tube in a water-proof and oxygen-proof environment and install it at the incident point of the backlight LED. All three technologies have their own advantages and disadvantages.

[0004] However, in the prior art, the dispersibility and stability of quantum dots are the main issues that limit their application in LED backlight modules. Summary of the Invention

[0005] In order to solve the above problems, the first aspect of the present invention provides a quantum dot-based lens material, the preparation raw materials including: quantum dot precursor, acrylic compound, initiator, quantum dot stabilizer.

[0006] The raw materials for preparing the quantum dot precursor include: a cadmium source solution, a sulfur source solution, an oxysilane substance, and a sulfonate substance.

[0007] The cadmium source is selected from at least one of cadmium oxide, cadmium nitrate, and cadmium chloride; and the sulfur source is selected from at least one of sulfur powder, sodium sulfide, cysteine, and thioacetamide.

[0008] The cadmium source or sulfur source in the raw materials for preparing the quantum dot precursor can be replaced by, but not limited to, phosphides (such as boron phosphide, aluminum phosphide, copper phosphide, gallium phosphide, indium phosphide), nitrides (such as aluminum nitride, gallium nitride, indium nitride, silicon nitride, germanium nitride), sulfides (such as cadmium sulfide, mercury sulfide, beryllium sulfide, magnesium sulfide, germanium sulfide, tin sulfide, lead sulfide, zinc sulfide), selenides (such as lead selenide, cadmium selenide, mercury selenide, beryllium selenide, magnesium selenide, germanium selenide, tin selenide, zinc selenide), tellurides (such as lead telluride, cadmium telluride, germanium telluride, mercury telluride, beryllium telluride, tin telluride, zinc telluride), halides (copper bromide, copper iodide), metal oxides (such as aluminum oxide, lead oxide, zinc oxide), and other raw materials for preparing other quantum dots.

[0009] The oxysilane substance is selected from at least one of propyltrimethoxysilane, butyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, and N,N-diethyl-3-aminopropylmethyldimethoxysilane.

[0010] The sulfonate substance is selected from at least one of 1,4-dioctadecyl sodium sulfosuccinate, sodium dodecylbenzenesulfonate, sodium 4-tetradecylbenzenesulfonate, and sodium 2-(trimethylsilyl)ethanesulfonate.

[0011] The initiator is selected from persulfates, azo compounds or peroxides.

[0012] The quantum dot stabilizer is selected from at least one of n-hexane, dimethyl sulfoxide, oleic acid, oleylamine, chloroform, and isobornyl acrylate.

[0013] The method for preparing the quantum dot-based lens material comprises the following steps:

[0014] S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 1-5%;

[0015] S2. Mixing the mixture with an acrylic compound and stirring at 500-1000 r / min to form an emulsion;

[0016] S3, adding an initiator to the emulsion for microwave polymerization;

[0017] S4. After the polymerization is completed, the product is filtered, dried, and a quantum dot stabilizer is added to obtain a quantum dot-based lens material.

[0018] In step S1, the quantum dot precursor is prepared by mixing a cadmium source solution and a sulfur source solution, ultrasonicating for 10-30 minutes, and then adding an oxysilane substance and a sulfonate substance, wherein the total concentration of the added oxysilane substance and the sulfonate substance is 0.5-2 g / L.

[0019] Preferably, in step S1, the preparation method of the quantum dot precursor is: 100 mL of cadmium source solution and 100 mL of sulfur source solution are mixed and ultrasonicated for 10-30 minutes, and then 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate are added. Wherein: the total concentration of the added 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate is 1 g / L, and the weight ratio of 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate solution is 1:1:2.

[0020] The cadmium source solution is an ethanol solution of cadmium chloride and / or cadmium nitrate with a concentration of 1 g / mL; the sulfur source solution is an aqueous solution of cysteine.

[0021] In step S2, the acrylic compound includes methyl methacrylate and tert-butyl methacrylate; wherein the weight ratio of the mixture to the acrylic compound is 5:1, and the weight ratio of methyl methacrylate to tert-butyl methacrylate is 1:1.

[0022] In step S3, the initiator is selected from persulfates, azo compounds or peroxides, such as potassium persulfate, sodium bisulfate, sodium azide, oxybenzoyl, azobisisobutyronitrile, dimethyl azobisisobutyrate, etc. The weight of the initiator accounts for 1-8‰ of the weight of the acrylic compound.

[0023] The microwave power is 100-480W, and the time is 1-20min.

[0024] This application combines microwave technology with dimethyl azobisisobutyrate as an initiator to enable faster polymerization of methyl methacrylate, tert-butyl methacrylate, etc., accelerating the reaction rate. It also allows the prepared quantum dots to be well coated in the polymer, improving the stability of the quantum dots.

[0025] Beneficial effects: The preparation method of the present application is simple and low-cost. Through the interaction of 3-acryloxypropyltriethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate, sodium dodecylbenzenesulfonate and cadmium source and sulfur source, 3-acryloxypropyltriethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and acrylic compound are polymerized to prepare a polymer-coated quantum dot lens material. The polymer coating can effectively isolate oxygen and moisture, avoid quantum dot fluorescence quenching and inactivation, and improve the stability of the quantum dot lens material. In addition, the luminous efficiency is high, the photoluminescence quantum yield (PLQY) is greater than 60%, the brightness decay is less than 15% after photothermal aging, and the transmittance is still greater than 90%. DETAILED DESCRIPTION

[0026] The present invention will be specifically described below through examples.

[0027] Unless otherwise stated, all raw materials used were commercially available.

[0028] Example

[0029] Example 1

[0030] The method for preparing a lens material based on quantum dots comprises the following steps:

[0031] S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 3%;

[0032] S2. Mixing the mixture with an acrylic compound and stirring at 800 r / min to form an emulsion;

[0033] S3, adding an initiator to the emulsion for microwave polymerization;

[0034] S4. After the polymerization is completed, the product is filtered, dried, and a quantum dot stabilizer is added to obtain a quantum dot-based lens material.

[0035] In step S1, the preparation method of the quantum dot precursor is as follows: 100 mL of cadmium source solution and 100 mL of sulfur source solution are mixed and ultrasonicated for 20 minutes, and then 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate are added. The total concentration of the added 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate is 1 g / L, and the weight ratio of 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate solution is 1:1:2.

[0036] The cadmium source solution was an ethanol solution of cadmium chloride at a concentration of 1 g / mL; the sulfur source solution was an aqueous solution of cysteine at a molar ratio of cadmium chloride to cysteine of 0.5:1.

[0037] In step S2, the acrylic compound includes methyl methacrylate and tert-butyl methacrylate; wherein the weight ratio of the mixture to the acrylic compound is 5:1, and the weight ratio of methyl methacrylate to tert-butyl methacrylate is 1:1.

[0038] In step S3, the initiator is dimethyl azobisisobutyrate, and the weight of the initiator accounts for 5‰ of the weight of the acrylic compound.

[0039] The microwave power is 240W, and the time is 10 minutes.

[0040] Example 2

[0041] The method for preparing a lens material based on quantum dots comprises the following steps:

[0042] S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 1%;

[0043] S2. Mix the mixture with an acrylic compound and stir at 500 r / min to form an emulsion;

[0044] S3, adding an initiator to the emulsion for microwave polymerization;

[0045] S4. After the polymerization is completed, the product is filtered, dried, and a quantum dot stabilizer is added to obtain a quantum dot-based lens material.

[0046] In step S1, the preparation method of the quantum dot precursor is as follows: 100 mL of cadmium source solution and 100 mL of sulfur source solution are mixed and ultrasonicated for 10 minutes, and then 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate are added. The total concentration of the added 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate is 1 g / L, and the weight ratio of 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate solution is 1:1:2.

[0047] The cadmium source solution is an ethanol solution of cadmium chloride and / or cadmium nitrate at a concentration of 1 g / mL; the sulfur source solution is an aqueous solution of cysteine at a molar ratio of cadmium chloride to cysteine of 0.5:1.

[0048] In step S2, the acrylic compound includes methyl methacrylate and tert-butyl methacrylate; wherein the weight ratio of the mixture to the acrylic compound is 5:1, and the weight ratio of methyl methacrylate to tert-butyl methacrylate is 1:1.

[0049] In step S3, the initiator is dimethyl azobisisobutyrate, etc. The weight of the initiator accounts for 5‰ of the weight of the acrylic compound.

[0050] The microwave power is 100 W, and the time is 20 min.

[0051] Example 3

[0052] The method for preparing a lens material based on quantum dots comprises the following steps:

[0053] S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 5%;

[0054] S2. mixing the mixture with an acrylic compound and stirring at 1000 r / min to form an emulsion;

[0055] S3, adding an initiator to the emulsion for microwave polymerization;

[0056] S4. After the polymerization is completed, the product is filtered, dried, and a quantum dot stabilizer is added to obtain a quantum dot-based lens material.

[0057] In step S1, the preparation method of the quantum dot precursor is as follows: 100 mL of cadmium source solution and 100 mL of sulfur source solution are mixed and ultrasonicated for 30 minutes, and then 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate are added. The total concentration of the added 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate is 1 g / L, and the weight ratio of 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate solution is 1:1:2.

[0058] The cadmium source solution is an ethanol solution of cadmium chloride and / or cadmium nitrate at a concentration of 1 g / mL; the sulfur source solution is an aqueous solution of cysteine at a molar ratio of cadmium chloride to cysteine of 0.5:1.

[0059] In step S2, the acrylic compound includes methyl methacrylate and tert-butyl methacrylate; wherein the weight ratio of the mixture to the acrylic compound is 5:1, and the weight ratio of methyl methacrylate to tert-butyl methacrylate is 1:1.

[0060] In step S3, the initiator is selected from persulfates, azo compounds or peroxides, such as potassium persulfate, sodium bisulfate, sodium azide, benzoyl peroxide, azobisisobutyronitrile, dimethyl azobisisobutyrate, etc. The weight of the initiator accounts for 8‰ of the weight of the acrylic compound.

[0061] The microwave power is 480W, and the time is 5 minutes.

[0062] Comparative Example 1

[0063] The method for preparing a lens material based on quantum dots comprises the following steps:

[0064] S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 3%;

[0065] S2. Mixing the mixture with an acrylic compound and stirring at 800 r / min to form an emulsion;

[0066] S3, adding an initiator to the emulsion for microwave polymerization;

[0067] S4. After the polymerization is completed, the product is filtered, dried, and a quantum dot stabilizer is added to obtain a quantum dot-based lens material.

[0068] In step S1, the quantum dot precursor is prepared by mixing 100 mL of a cadmium source solution and 100 mL of a sulfur source solution, ultrasonicating the mixture for 20 minutes, and then adding sodium dodecylbenzenesulfonate, wherein the total concentration of the sodium dodecylbenzenesulfonate after addition is 1 g / L.

[0069] The cadmium source solution was an ethanol solution of cadmium chloride at a concentration of 1 g / mL; the sulfur source solution was an aqueous solution of cysteine at a molar ratio of cadmium chloride to cysteine of 0.5:1.

[0070] In step S2, the acrylic compound includes methyl methacrylate and tert-butyl methacrylate; wherein the weight ratio of the mixture to the acrylic compound is 5:1, and the weight ratio of methyl methacrylate to tert-butyl methacrylate is 1:1.

[0071] In step S3, the initiator is dimethyl azobisisobutyrate, and the weight of the initiator accounts for 5‰ of the weight of the acrylic compound.

[0072] The microwave power is 240W, and the time is 10 minutes.

[0073] Comparative Example 2

[0074] The method for preparing a lens material based on quantum dots comprises the following steps:

[0075] S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 3%;

[0076] S2. Mixing the mixture with an acrylic compound and stirring at 800 r / min to form an emulsion;

[0077] S3, adding an initiator to the emulsion for microwave polymerization;

[0078] S4. After the polymerization is completed, the product is filtered, dried, and a quantum dot stabilizer is added to obtain a quantum dot-based lens material.

[0079] In step S1, the quantum dot precursor is prepared by mixing 100 mL of a cadmium source solution and 100 mL of a sulfur source solution, ultrasonically mixing for 20 minutes, and then adding 3-acryloxypropyltriethoxysilane and sodium dodecylbenzenesulfonate. The total concentration of 3-acryloxypropyltriethoxysilane and sodium dodecylbenzenesulfonate after addition is 1 g / L, and the weight ratio of 3-acryloxypropyltriethoxysilane to sodium dodecylbenzenesulfonate solution is 1:2.

[0080] The cadmium source solution was an ethanol solution of cadmium chloride at a concentration of 1 g / mL; the sulfur source solution was an aqueous solution of cysteine at a molar ratio of cadmium chloride to cysteine of 0.5:1.

[0081] In step S2, the acrylic compound includes methyl methacrylate and tert-butyl methacrylate; wherein the weight ratio of the mixture to the acrylic compound is 5:1, and the weight ratio of methyl methacrylate to tert-butyl methacrylate is 1:1.

[0082] In step S3, the initiator is dimethyl azobisisobutyrate, and the weight of the initiator accounts for 5‰ of the weight of the acrylic compound.

[0083] The microwave power is 240W, and the time is 10 minutes.

[0084] Comparative Example 3

[0085] The method for preparing a lens material based on quantum dots comprises the following steps:

[0086] S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 3%;

[0087] S2. mixing the mixture with an acrylic compound and stirring at 800 r / min to form an emulsion;

[0088] S3, adding an initiator to the emulsion for microwave polymerization;

[0089] S4. After the polymerization is completed, the product is filtered, dried, and a quantum dot stabilizer is added to obtain a quantum dot-based lens material.

[0090] In step S1, the preparation method of the quantum dot precursor is as follows: 100 mL of cadmium source solution and 100 mL of sulfur source solution are mixed and ultrasonicated for 20 minutes, and then 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate, and sodium dodecylbenzenesulfonate are added. The total concentration of 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate, and sodium dodecylbenzenesulfonate after addition is 1 g / L, and the weight ratio of 3-acryloxypropyl triethoxysilane, sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate, and sodium dodecylbenzenesulfonate solution is 1:1:2.

[0091] The cadmium source solution was an ethanol solution of cadmium chloride at a concentration of 1 g / mL; the sulfur source solution was an aqueous solution of cysteine at a molar ratio of cadmium chloride to cysteine of 0.5:1.

[0092] In step S2, the acrylic compound is methyl methacrylate, tert-butyl methacrylate, and 2-butyloctyl methacrylate; wherein the weight ratio of the mixture to the acrylic compound is 5:1, and the weight ratio of methyl methacrylate, tert-butyl methacrylate, and 2-butyloctyl methacrylate is 1:1:1.

[0093] In step S3, the initiator is dimethyl azobisisobutyrate, and the weight of the initiator accounts for 5‰ of the weight of the acrylic compound.

[0094] The microwave power is 240W, and the time is 10 minutes.

[0095] Performance Testing

[0096] The lens material prepared in Examples 1-3 or Comparative Examples 1-3 was added to toluene, followed by the PMMA solution, and heated and stirred until uniformly mixed to obtain a quantum dot colloidal material, wherein the mass fraction of the material prepared in Examples 1-3 or Comparative Examples 1-3 was 5%, the mass fraction of the resin material was 85%, and the mass fraction of the solvent was 10%. The quantum dot colloidal material was then injected into a lens mold and cured to obtain a QD lens. The QD lens was placed between a conventional expansion board and an LED lamp bead, fixed, and then performance tested.

[0097] The photoluminescence quantum yield (PLQY) of Examples 1-3 was tested to be greater than 60%. The photoluminescence quantum yield (PLQY) refers to the ratio of the number of emitted photons to the number of absorbed photons.

[0098] The prepared OD lens was placed under 60°C and 90% RH conditions for 1000 hours, and its brightness decay was tested. The test results are shown in the table below. It can be seen that the brightness decay of the QD lens is minimal after aging. Furthermore, the transmittance of the QD lens remains greater than 90% after aging.

[0099]

[0100]

[0101] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A quantum dot-based lens material, characterized by: The preparation raw materials include: quantum dot precursor, acrylic compound, initiator, quantum dot stabilizer; The raw materials for preparing the quantum dot precursor include: cadmium source solution, sulfur source solution, oxysilane substances, and sulfonate substances; The cadmium source solution is an ethanol solution of cadmium chloride and / or cadmium nitrate with a concentration of 1 g / mL; the sulfur source solution is an aqueous solution of cysteine; The acrylic compound includes methyl methacrylate and tert-butyl methacrylate; the weight ratio of methyl methacrylate to tert-butyl methacrylate is 1:1; The oxysilane substance is selected from 3-acryloxypropyltriethoxysilane; The sulfonate substance is selected from sodium 4-(2-methylprop-2-enyloxy)benzenesulfonate and sodium dodecylbenzenesulfonate; The initiator is selected from persulfate, azo compound or peroxide; The quantum dot stabilizer is selected from at least one of n-hexane, dimethyl sulfoxide, oleic acid, oleylamine, chloroform, and isobornyl acrylate; The method for preparing the quantum dot-based lens material comprises the following steps: S1. The quantum dot precursor is mixed with water and wet-grinded to obtain a mixture, wherein the weight ratio of the quantum dot precursor to water is 1-5%; S2. Mixing the mixture with an acrylic compound and stirring at 500-1000 r / min to form an emulsion; S3, adding an initiator to the emulsion for microwave polymerization; S4, filtering after polymerization, drying, and adding a quantum dot stabilizer to obtain a quantum dot-based lens material; In step S1, the preparation method of the quantum dot precursor is: mixing the cadmium source solution and the sulfur source solution, ultrasonicating for 10-30 minutes, and then adding the oxysilane substance and the sulfonate substance, wherein the total concentration of the added oxysilane substance and the sulfonate substance is 0.5-2g / L; The weight ratio of the mixture to the acrylic acid compound is 5:

1.

2. An application of the quantum dot-based lens material according to claim 1 in an LED backlight module.

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