CN112210365B - Method for preparing nano zirconium dioxide carbon quantum dot composite material by one-pot method - Google Patents

Abstract

The invention discloses a one-pot method for preparing nano-zirconia-carbon quantum dot composite materials. The zirconium oxychloride octahydrate is added to deionized water, the pH is adjusted to 1.5-2.5 with an aqueous sodium hydroxide solution, and the reaction is carried out by heating and dripping. Add an aqueous solution containing an aminosilane coupling agent, continue stirring, and then add citric acid, stir evenly, transfer to a high-temperature reaction kettle for reaction, cool to room temperature, and freeze-dry. The present invention prepares solid-state stable zirconium dioxide carbon quantum dot composite material by one-step hydrothermal method, and prepares carbon quantum dot by amino-containing alkoxysilane compound, which can improve the compatibility between composite material and LED packaging material, To reduce light scattering, the high refractive index of the composite material can increase the refractive index of the packaging material, thereby improving the light extraction efficiency of the LED. The composite material has stable fluorescent properties, and the fluorescent properties are basically unchanged after one month of ultraviolet or high temperature treatment, and it is resistant to acid and alkali corrosion.

Description

One-pot method for preparing nano-zirconia carbon quantum dot composites

technical field

The invention belongs to the technical field of composite materials, and more particularly relates to a composite material of carbon quantum dots and a high-fold inorganic metal oxide, a preparation method and an application in the field of LED packaging.

Background technique

Due to their excellent optical properties, tunable fluorescence properties, and environmental friendliness, carbon quantum dots are widely used in optoelectronic devices, biological research, optical catalysis and other fields. Among them, carbon quantum dots have broad research prospects for white light LEDs, which can replace heavy metal quantum dots and reduce the cost of LED packaging. However, carbon quantum dots have properties such as low light efficiency, poor optical properties, low luminous efficiency, low fluorescence quantum yield, and aggregation-induced quenching, which limit their application in optoelectronic devices. From the perspective of carbon quantum dots replacing phosphors in white LEDs, the problems that need to be solved to obtain higher light-emitting efficiency and stable light-emitting color are (1) to obtain solid-state stable fluorescent carbon quantum dots (2) to improve carbon quantum dots Compatibility with encapsulation material.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the deficiencies of the prior art, and to provide a one-pot method for preparing nano-zirconia carbon quantum dot composite materials. The carbon quantum dots are prepared by an amino-containing alkoxysilane compound, which can improve the performance of composite materials and LED packaging. The compatibility between materials reduces light scattering, and the high refractive index of the composite material can increase the refractive index of the packaging material, thereby improving the light extraction efficiency of the LED. The composite material has stable fluorescent properties, and the fluorescent properties are basically unchanged after one month of ultraviolet or high temperature treatment, and it is resistant to acid and alkali corrosion.

The technical purpose of the present invention is achieved through the following technical solutions.

The one-pot method for preparing nano-zirconia carbon quantum dot composite materials is to disperse the soluble zirconium source compound evenly in deionized water, adjust the pH to 1-3 with alkaline solution, and heat to 60-80 degrees Celsius for the reaction; the reaction is over. Then, dropwise add the aqueous solution of the amino group-containing silane coupling agent to the system, and then add citric acid and disperse it evenly, then transfer it to a high-temperature reaction kettle and seal it, and heat it up to 170-210 °C for a hydrothermal reaction. Cool to room temperature at 20-25 degrees Celsius, freeze-dry the product to obtain a zirconium dioxide carbon quantum dot composite material; the mass (parts) ratio of the soluble zirconium source compound, the amino-containing silane coupling agent and the citric acid is (1-10) : (1-10): (0.1-1), namely 1-10 parts by mass of soluble zirconium source compound, 1-10 parts by mass of amino-containing silane coupling agent, 0.1-1 part by mass of citric acid, each part by mass is 1g.

In the above technical solution, the soluble zirconium source compound is zirconium oxychloride octahydrate, zirconium nitrate (zirconium nitrate pentahydrate) or zirconium sulfate (zirconium sulfate pentahydrate).

In the above technical solution, the alkali solution is an aqueous solution of sodium hydroxide or potassium hydroxide, and the concentration is 0.1-0.3 mol/L.

In the above technical solution, the pH is adjusted to 1.5-2.5 by using the alkaline solution.

In the above technical scheme, a water bath is selected, and the temperature is raised from a room temperature of 20-25 degrees Celsius to 60-80 degrees Celsius at a rate of 1-5 degrees Celsius per minute to carry out the insulation reaction, the reaction temperature is preferably 70-80 degrees Celsius, and the reaction time is 1-5 hours, Preferably 3-5 hours.

In the above technical scheme, the amino-containing alkoxysilane coupling agent is N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(β-aminoethyl)- γ-Aminopropylmethyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropyl Methyldiethoxysilane or gamma-aminopropyltrimethoxysilane.

In the above technical scheme, the soluble zirconium source compound in deionized water is naturally cooled to room temperature of 20-25 degrees Celsius after the heat preservation reaction is completed at 60-80 degrees Celsius, and an aqueous solution of the silane coupling agent containing amino groups is uniformly dispersed dropwise. The acceleration is 0.1-0.5ml per minute. After the dripping is completed, use mechanical or ultrasonic stirring to disperse evenly. The stirring time is 30 to 120 minutes; then add citric acid and use mechanical or ultrasonic stirring to disperse uniformly and stir. The time is 30 to 120 minutes.

In the above technical solution, the high temperature reaction kettle is a high temperature reaction kettle lined with polytetrafluoroethylene.

In the above technical scheme, the temperature is raised from 20-25 degrees Celsius at room temperature to 170-210 degrees Celsius at a rate of 1-5 degrees Celsius per minute for hydrothermal reaction, and the reaction time is 3-12 hours; the reaction temperature is 180-200 degrees Celsius, and the reaction The time is 6-10 hours.

The invention discloses a zirconium dioxide carbon quantum dot composite material prepared according to the above-mentioned one-pot method and its application as an LED packaging material (ie, a fluorescent filler), especially its application in white light LEDs.

The fluorescence quantum yield of the ZrO2/CD powder prepared by the one-pot method of the present invention can reach 23-25%.

In the present invention, the solid-state stable zirconium dioxide-carbon quantum dot composite material is prepared by a simple one-step hydrothermal method, and the carbon quantum dot is prepared by an amino group-containing alkoxysilane compound, which can improve the gap between the composite material and the LED packaging material. The compatibility of the composite material can reduce light scattering, and the high refractive index of the composite material can improve the refractive index of the packaging material, thereby improving the light extraction efficiency of the LED. The composite material has stable fluorescent properties, and the fluorescent properties are basically unchanged after one month of ultraviolet or high temperature treatment, and it is resistant to acid and alkali corrosion.

Description of drawings

Fig. 1 is the scanning electron microscope photograph of the nanometer zirconium dioxide carbon quantum dot composite material prepared by the present invention.

2 is a photo of the nano-zirconia carbon quantum dot composite prepared by the present invention under sunlight and ultraviolet light (365 nm), wherein the yellow on the left is the photo under sunlight, and the blue on the right is the photo under ultraviolet light.

3 is a photo of the resin obtained by compounding the nano zirconium dioxide carbon quantum dot composite material prepared by the present invention and epoxy resin under sunlight and ultraviolet light (365nm), wherein the yellow on the left is the photo under sunlight, and the blue on the right Colors are photos under UV light.

Fig. 4 is the fluorescence emission spectrum of the ZrO2/CD powder prepared by the present invention under different excitation light (the excitation light wavelength is 320-440 nm).

Fig. 5 is a temperature-dependent curve diagram of the emission fluorescence intensity (relative fluorescence intensity) of the ZrO2/CD powder prepared by the present invention under excitation light of 380 nm.

Fig. 6 is a fluorescence spectrum diagram of the pH-dependent fluorescence intensity of the ZrO2/CD powder prepared by the present invention under excitation light of 380 nm.

FIG. 7 is a transmission electron microscope photograph of the nano-zirconia carbon quantum dot composite material prepared by the present invention.

Fig. 8 is the fluorescence emission spectrum diagram of the resin obtained by compounding the nano-zirconia carbon quantum dot composite material prepared by the present invention and epoxy resin (excitation light wavelength is 340-400 nm).

Fig. 9 is the test chart of the resin obtained by compounding the nano-zirconia carbon quantum dot composite material and epoxy resin prepared by the present invention on a 460nm white light LED chip, wherein (a) is a photo of the chip package, the light is bluish, 0.5g Epoxy resin, 0.1g curing agent triethylenetetramine and 0.5g nano-zirconia carbon quantum dot composite material; (b) is the chip package photo, the light is yellowish, 0.5g epoxy resin, 0.1g curing agent triethylenetetramine CIE chromaticity coordinates of amine and 1.0 g nano-zirconia-carbon quantum dot composites (c) after chip packaging, a and b correspond to two kinds of chip packaging, respectively.

Detailed ways

The technical solutions of the present invention are further described below in conjunction with specific embodiments.

Example 1

One-pot preparation of zirconia-carbon quantum dot composites

Add 4g of zirconium oxychloride octahydrate into 50ml of deionized water, stir well, take 0.1mol/l sodium hydroxide aqueous solution to adjust the pH of the above solution to 2, heat to 50°C, react for 3h, add 30ml dropwise to a concentration of 0.1 g/ml N-(β-aminoethyl)-γ-aminopropylmethyldimethoxysilane aqueous solution, continue to stir for 60 minutes, then add 0.3 g of citric acid, stir evenly, and transfer to the polytetrafluoroethylene lining In the high-temperature reaction kettle of 180°C, the reaction was carried out at 180° C. for 6 h, cooled to room temperature, and the product was freeze-dried to obtain a zirconia carbon quantum dot composite material.

Example 2

One-pot preparation of zirconia-carbon quantum dot composites

Add 6g of zirconium oxychloride octahydrate into 100ml of deionized water, stir evenly, take 0.1mol/l sodium hydroxide aqueous solution to adjust the pH of the above solution to 1.5, heat to 70°C, react for 2h, add 60ml dropwise to a concentration of 0.1 g/ml N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane aqueous solution, continue to stir for 80 minutes, then add 0.6g of citric acid, stir evenly, and transfer to the polytetrafluoroethylene lining In the high temperature reaction kettle of 200°C, the reaction was carried out at 200 °C for 5 h, cooled to room temperature, and the product was freeze-dried to obtain a zirconia carbon quantum dot composite material.

Example 3

One-pot preparation of zirconia-carbon quantum dot composites

Add 1g of zirconium oxychloride octahydrate into 30ml of deionized water, stir evenly, take 0.1mol/l sodium hydroxide aqueous solution to adjust the pH of the above solution to 2.5, heat to 80 °C and react for 1h, add 80ml dropwise to a concentration of 0.1g /ml γ-aminopropylmethyldimethoxysilane aqueous solution, continue to stir for 120 minutes, then add 0.8g of citric acid, stir evenly, and transfer to a high-temperature reaction kettle lined with PTFE, and react at 210 ° C for 10 hours , cooled to room temperature, and the product was freeze-dried to obtain a zirconium dioxide carbon quantum dot composite material.

Example 4

One-pot preparation of zirconia-carbon quantum dot composites

Add 10g of zirconium oxychloride octahydrate into 300ml of deionized water, stir well, take 0.1mol/l sodium hydroxide aqueous solution to adjust the pH of the above solution to 2, heat to 60 °C for 4h reaction, add 100ml dropwise to a concentration of 0.1g /ml γ-aminopropyltrimethoxysilane aqueous solution, continue to stir for 30 to 120 minutes, then add 1 g of citric acid, stir evenly, and transfer to a high-temperature reaction kettle lined with PTFE, react at 170 ° C for 12 h, and cool At room temperature, the product was freeze-dried to obtain a zirconium dioxide carbon quantum dot composite material.

Example 5

Application of a zirconium dioxide carbon quantum dot composite material

Take 0.5g of zirconium dioxide carbon quantum dot composite material, add it into 0.5ml of methanol, stir evenly, then add the above suspension to the mixture of 1g of epoxy resin and 0.2g of triethylenetetramine, continue to stir and remove in vacuo The bubbles were added into a polytetrafluoroethylene mold, and cured at room temperature for 12 hours to obtain a solid fluorescent resin.

Characterize the zirconium dioxide carbon quantum dot composite material obtained by using the technical solution of the present invention. As shown in Figures 1-2 and 7, the nanometer zirconium dioxide carbon quantum dot composite material under sunlight and ultraviolet light (365nm) respectively behave as: Yellow and blue, judging from the lattice and size, a large number of carbon quantum dots (4–5 nm) are present in the composite.

It can be seen from Figure 4-6 that the zirconium dioxide carbon quantum dot composite material exhibits different fluorescence properties under different wavelengths of excitation light, and under the excitation light of 380nm, the fluorescence emission intensity is the largest, so the excitation light of 380nm is selected. From room temperature of 20 degrees Celsius to 100 degrees Celsius, the fluorescence emission intensity of the composite material gradually decreased; different pH environments were selected for detection, and at pH 6-7, the fluorescence emission intensity was better, which was significantly higher than that of alkaline environment and strong acidity. surroundings. Therefore, when selecting the applicable environment, it can be adjusted according to the temperature and pH. It should be noted that the composite material of the present invention has stable fluorescence properties, and the fluorescence properties can be retained even under high temperature, acid-base conditions (up to 1 month). .

In Example 5, after the zirconium dioxide carbon quantum dot composite material was selected to be mixed with epoxy resin and curing agent (triethylenetetramine), solid fluorescent resin was obtained, as shown in accompanying drawing 3, under sunlight and ultraviolet light ( 365nm), respectively appear yellow and blue, which is basically consistent with the performance of the zirconium dioxide carbon quantum dot composite material of the present invention. It can be seen from Figure 8 that the solid fluorescent resin exhibits different fluorescence properties under excitation light of different wavelengths, and under excitation light of 380 nm, the fluorescence emission intensity is the highest, which is consistent with the performance of the zirconium dioxide carbon quantum dot composite material of the present invention. Use a 460nm white light LED chip as a detection device to package and detect the solid fluorescent resin. As shown in Figure 9, the bottom part of (a) is the package sample, and the yellow substance in the center is the solid fluorescent resin (0.5g epoxy resin, 0.1g Curing agent triethylenetetramine and 0.5g nano-zirconia carbon quantum dot composite material), the top is the fluorescent detection state, and the solid fluorescent resin in the center can be seen to emit blue light; in the same way (b), the yellow substance in the center is Solid fluorescent resin (0.5g epoxy resin, 0.1g curing agent triethylenetetramine and 1.0g nano zirconium dioxide carbon quantum dot composite material), the light is yellowish, and the following table shows the test data.

The zirconium dioxide carbon quantum dot composite material of the present invention is compounded with epoxy resin, and the purpose of adjusting the luminous color in the white LED can be realized by adjusting the ratio of the two. For example, the dosage of epoxy resin is 0.5-1 mass part, the dosage of zirconium dioxide carbon quantum dot composite material is 0.5-1 mass part, and the dosage of curing agent is 0.1-0.3 mass part.

By adjusting the process parameters according to the content of the present invention, the preparation of the composite material can be realized, and the performance is basically consistent with that of the present invention. The present invention has been exemplarily described above. It should be noted that, without departing from the core of the present invention, any simple deformation, modification, or other equivalent replacements that can be performed by those skilled in the art without any creative effort fall into the scope of the present invention. the scope of protection of the invention.

Claims (10)

1. the method for preparing nanometer zirconium dioxide carbon quantum dot composite material by one-pot method, it is characterized in that, disperse soluble zirconium source compound evenly in deionized water and adjust pH to 1～3 using lye, heat to 60-80 degrees Celsius Incubate the reaction; after the reaction, add dropwise an aqueous solution of the alkoxysilane coupling agent containing amino groups uniformly dispersed in the system, then add citric acid and disperse evenly, then transfer to a high-temperature reaction kettle to seal, and heat up to 170-210 After the hydrothermal reaction is carried out at ℃, it is naturally cooled to 20-25 degrees Celsius, and the product is freeze-dried to obtain a zirconium dioxide carbon quantum dot composite material; The mass ratio is (1-10):(1-10):(0.1-1). 2. the method for preparing nano-zirconia carbon quantum dot composite material by one-pot method according to claim 1, is characterized in that, soluble zirconium source compound is zirconium oxychloride octahydrate, zirconium nitrate pentahydrate or zirconium sulfate pentahydrate . 3. the method for preparing nano-zirconia carbon quantum dot composite material by one-pot method according to claim 1, is characterized in that, the alkoxysilane coupling agent containing amino group is N-(β-aminoethyl)- γ-Aminopropylmethyldimethoxysilane, N-(β-aminoethyl)-γ-aminopropylmethyldiethoxysilane, N-(β-aminoethyl)-γ-aminopropyl Trimethoxysilane, γ-aminopropylmethyldimethoxysilane, γ-aminopropylmethyldiethoxysilane or γ-aminopropyltrimethoxysilane. 4. the method for preparing nanometer zirconium dioxide carbon quantum dot composite material by one-pot method according to claim 1, is characterized in that, lye is the aqueous solution of sodium hydroxide or potassium hydroxide, and concentration is 0.1-0.3mol/L ; Use lye to adjust pH to 1.5～2.5. 5. the method for preparing nano-zirconia carbon quantum dot composite material by one-pot method according to claim 1, is characterized in that, selecting water bath from 20-25 degrees Celsius to be warmed up to 60-80 degrees Celsius at a speed of 1-5 degrees Celsius per minute The reaction is carried out at a temperature of 100 degrees Celsius, and the reaction time is 1-5 hours. 6. the method for preparing nano-zirconia carbon quantum dot composite material by one-pot method according to claim 1, is characterized in that, the soluble zirconium source compound in deionized water is naturally cooled to 60-80 degrees Celsius after the thermal insulation reaction finishes. 20-25 degrees Celsius, dropwise add the aqueous solution of the alkoxysilane coupling agent containing amino group to it, the dropping rate is 0.1-0.5ml per minute, after the dropping is completed, use mechanical or ultrasonic stirring to disperse evenly, The stirring time is 30-120 minutes; then citric acid is added, and mechanical or ultrasonic stirring is used to disperse uniformly, and the stirring time is 30-120 minutes. 7. The method for preparing nano-zirconia carbon quantum dot composites by one-pot method according to claim 1, wherein the temperature is increased to 170-210°C at a rate of 1-5°C per minute from 20-25°C. The hydrothermal reaction is carried out, and the reaction time is 3-12 hours. 8 . The zirconium dioxide carbon quantum dot composite material prepared by the method according to claim 1 , wherein the fluorescence quantum yield can reach 23-25%. 9 . 9. Application of the zirconium dioxide carbon quantum dot composite material prepared by the method according to any one of claims 1 to 7 as an LED packaging material or a fluorescent filler. 10. The application according to claim 9, wherein the zirconium dioxide carbon quantum dot composite material is compounded with the epoxy resin, and the ratio of the two is adjusted to realize the purpose of adjusting the luminous color in the white LED, and the amount of the epoxy resin is: 0.5-1 part by mass, the amount of zirconia carbon quantum dot composite material is 0.5-1 part by mass, and the amount of curing agent is 0.1-0.3 part by mass.

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