A quantum dot-based material and preparation method thereof

Abstract

The present invention relates to the field of quantum dot materials, and in particular to a quantum dot-based material and a preparation method thereof. The raw materials for preparation include: PMMA, polymer-modified carbon quantum dots, and ABCD-type quantum dots; wherein element A is at least one of Na, Fe, Cd, and Zn; element B is at least one of Fe, Cd, Ga, Mg, Pb, Cs, and Cu; element C is In; and element D is at least one of S, Br, and I, and the four elements A, B, C, and D are different. The present invention uses polymer-modified carbon quantum dots to improve the stability and uniform distribution of the carbon quantum dots; the prepared polymer-modified carbon quantum dots and ABCD-type quantum dots of a specific diameter are dispersed in PMMA to further prepare a material with high stability, good temperature and humidity resistance, and a long service life.

Description

Technical Field

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

[0002] Quantum dots are "quasi-zero-dimensional" nanomaterials with nanometer-scale dimensions in all three dimensions. Due to the quantum size effect, their electrons and holes are quantum confined in three dimensions, transforming the continuous energy bands in the bulk material into discrete energy levels. Semiconductor quantum dots have broad application prospects in single-electron devices, memories, and various optoelectronic devices for spectral and photoelectric conversion.

[0003] However, in the existing technology, the dispersion and stability of quantum dots are the main problems that limit their application. Summary of the Invention

[0004] In order to solve the above problems, the first aspect of the present invention provides a quantum dot-based material, the preparation raw materials include: PMMA, polymer-modified carbon quantum dots, ABCD type quantum dots;

[0005] Among them, element A is at least one of Na, Fe, Cd, and Zn; element B is at least one of Fe, Cd, Ga, Mg, Pb, Cs, and Cu; element C is In; and element D is at least one of S, Br, and I, and the four elements A, B, C, and D are different.

[0006] Preferably, element A is Zn; element B is Cu; element C is In; and element D is S.

[0007] In one embodiment, the weight ratio of polymer-modified carbon quantum dots to ABCD quantum dots is 1:1.5-3.

[0008] Preferably, the weight ratio of polymer-modified carbon quantum dots to ABCD quantum dots is 1:2.

[0009] In one embodiment, a method for preparing polymer-modified carbon quantum dots comprises the following steps: adding an amine substance and methyl methacrylate to a non-polar solvent, reacting at 250°C for 15-20 hours, cooling to below 80°C, adding methyl methacrylate and benzoyl peroxide, stirring evenly, maintaining the temperature at 50-60°C and continuing the reaction for 24-36 hours, washing and purifying, and then drying to obtain polymer-modified carbon quantum dots.

[0010] In one embodiment, a method for preparing polymer-modified carbon quantum dots comprises the following steps: adding 1-methylundecylamine, N-dodecyl-2-acrylamide and methyl methacrylate to a non-polar solvent, reacting at 250°C for 15-20 hours, cooling to below 80°C, adding methyl methacrylate and benzoyl peroxide, stirring evenly, maintaining the temperature at 50-60°C and continuing the reaction for 24-36 hours, washing and purifying, and then drying to obtain polymer-modified carbon quantum dots.

[0011] Preferably, the preparation method of polymer-modified carbon quantum dots comprises the following steps: adding 1 mol of 1-methylundecylamine, 0.5-2 mol of N-dodecyl-2-acrylamide and 3-6 mol of methyl methacrylate to a non-polar solvent, reacting at 250° C. for 15-20 hours, cooling to below 80° C., adding 5-10 mol of methyl methacrylate and benzoyl peroxide (benzoyl peroxide is 1-3% of the total mass of methyl methacrylate), stirring evenly, maintaining the temperature at 50-60° C. and continuing the reaction for 24-36 hours, washing and purifying, and then drying to obtain polymer-modified carbon quantum dots.

[0012] Preferably, the ABCD quantum dots are ZnCuInS / ZnS quantum dots; the diameter of the ZnCuInS / ZnS quantum dots is 1-10 nm.

[0013] Preferably, the diameter of the ZnCuInS / ZnS quantum dots is 4-5 nm. There is no particular restriction on the manufacturer of the ZnCuInS / ZnS quantum dots. The ZnCuInS / ZnS quantum dots described in the present disclosure were purchased from Xi'an Qiyue Biotechnology.

[0014] The preparation method of the material comprises the following steps:

[0015] S1: Add PMMA to chloroform and stir evenly;

[0016] S2: Add polymer-modified carbon quantum dots to the solution obtained in step S1 and stir evenly;

[0017] S3: Add ABCD quantum dots to the solution obtained in step S2 and stir evenly;

[0018] S4: ultrasonically disperse the solution obtained in step S3, and place the solution in a vacuum drying oven to dry at room temperature.

[0019] The material of the present invention is prepared by mixing quantum dot powder with PMMA in a specific ratio and adopting high-speed stirring and ultrasonic dispersion technology to ensure uniform dispersion of the quantum dots.

[0020] The quantum dot-based material can be used to prepare a ratio fluorescence sensor for detecting heavy metal ions in water, such as mercury, cadmium, lead, etc., and is particularly suitable for detecting mercury ions.

[0021] The preparation method of the ratiometric fluorescence sensor is a commonly used preparation method in the art and is not particularly limited.

[0022] Preferably, the preparation method of the ratiometric fluorescence sensor in the present application comprises the following steps:

[0023] Step 1: Pre-prepare quantum dot-based materials;

[0024] Step 2: 1.0 g of the material prepared in step 1 was ultrasonically dispersed in toluene and then refluxed with 0.2 g of 3-(aminopropyl)dimethylethoxysilane for 0.5-3 hours to obtain modified particles; the modified particles were dispersed in dichloromethane, 80 mg of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin was added, and refluxed for 2-5 hours to obtain an intermediate product;

[0025] Step 3: The intermediate product obtained in step 2 is dispersed in ethanol at a concentration of 0.5 wt %, and then a crystal film with a thickness of 1 μm is obtained on a polydimethylsiloxane substrate by spin coating to obtain a fluorescence ratio sensor.

[0026] Beneficial effects:

[0027] The present invention uses polymer-modified carbon quantum dots to improve the stability and uniform distribution of the carbon quantum dots; the prepared polymer-modified carbon quantum dots and ABCD-type quantum dots of a specific diameter are dispersed in PMMA to further prepare a material with high stability, good temperature and humidity resistance, and long service life.

[0028] The carbon quantum dot-based materials prepared in the present disclosure have better stability and can be well used in electrodes, heavy metal detection, etc. DETAILED DESCRIPTION

[0029] The present invention will be specifically described below through examples.

[0030] Unless otherwise stated, all raw materials used were commercially available.

[0031] Example

[0032] Example 1

[0033] Example 1 provides a quantum dot-based material, and the raw materials for preparation include: PMMA, polymer-modified carbon quantum dots, and ZnCuInS / ZnS quantum dots; the diameter of the ZnCuInS / ZnS quantum dots is 4-5 nm and is purchased from Xi'an Qiyue Biological.

[0034] The preparation method of polymer-modified carbon quantum dots comprises the following steps: adding 1 mol of 1-methylundecylamine, 1 mol of N-dodecyl-2-acrylamide and 4 mol of methyl methacrylate to toluene, reacting at 250° C. for 16 hours, cooling to below 80° C., adding 6 mol of methyl methacrylate and benzoyl peroxide (benzoyl peroxide is 1% of the total mass of methyl methacrylate), stirring evenly, maintaining the temperature at 50-60° C. and continuing the reaction for 30 hours, washing, purifying and drying to obtain polymer-modified carbon quantum dots.

[0035] The preparation method of the material comprises the following steps:

[0036] S1: Add 10 g of PMMA to 300 mL of chloroform and stir well.

[0037] S2: Add 1 g of polymer-modified carbon quantum dots to the solution obtained in step S1 and stir evenly;

[0038] S3: Add ABCD quantum dots to the solution obtained in step S2 and stir evenly;

[0039] S4: The solution obtained in step S3 is ultrasonically dispersed for 8 hours, and then placed in a vacuum drying oven for drying at room temperature.

[0040] The weight ratio of polymer-modified carbon quantum dots to ABCD-type quantum dots is 1:2.

[0041] Example 2

[0042] Example 2 provides a quantum dot-based material, the preparation raw materials include: PMMA, polymer-modified carbon quantum dots, ZnCuInS / ZnS quantum dots; the diameter of the ZnCuInS / ZnS quantum dots is 4-5nm, purchased from Xi'an Qiyue Biological.

[0043] The preparation method of polymer-modified carbon quantum dots comprises the following steps: adding 1 mol of 1-methylundecylamine, 0.5 mol of N-dodecyl-2-acrylamide and 5 mol of methyl methacrylate to toluene, reacting at 250° C. for 16 hours, cooling to below 80° C., adding 6 mol of methyl methacrylate and benzoyl peroxide (benzoyl peroxide is 1% of the total mass of methyl methacrylate), stirring evenly, maintaining the temperature at 50-60° C. and continuing the reaction for 30 hours, washing, purifying and drying to obtain polymer-modified carbon quantum dots.

[0044] The preparation method of the material comprises the following steps:

[0045] S1: Add 10 g of PMMA to 300 mL of chloroform and stir well.

[0046] S2: Add 1 g of polymer-modified carbon quantum dots to the solution obtained in step S1 and stir evenly;

[0047] S3: Add ABCD quantum dots to the solution obtained in step S2 and stir evenly;

[0048] S4: The solution obtained in step S3 is ultrasonically dispersed for 8 hours, and then placed in a vacuum drying oven for drying at room temperature.

[0049] The weight ratio of polymer-modified carbon quantum dots to ABCD quantum dots is 1:1.5.

[0050] Example 3

[0051] Example 3 provides a quantum dot-based material, the preparation raw materials include: PMMA, polymer-modified carbon quantum dots, ZnCuInS / ZnS quantum dots; the diameter of the ZnCuInS / ZnS quantum dots is 4-5nm, purchased from Xi'an Qiyue Biological.

[0052] The preparation method of polymer-modified carbon quantum dots comprises the following steps: adding 1 mol of 1-methylundecylamine, 2 mol of N-dodecyl-2-acrylamide and 6 mol of methyl methacrylate to toluene, reacting at 250° C. for 16 hours, cooling to below 80° C., adding 6 mol of methyl methacrylate and benzoyl peroxide (benzoyl peroxide is 1% of the total mass of methyl methacrylate), stirring evenly, maintaining the temperature at 50-60° C. and continuing the reaction for 30 hours, washing, purifying and drying to obtain polymer-modified carbon quantum dots.

[0053] The preparation method of the material comprises the following steps:

[0054] S1: Add 10 g of PMMA to 300 mL of chloroform and stir well.

[0055] S2: Add 1 g of polymer-modified carbon quantum dots to the solution obtained in step S1 and stir evenly;

[0056] S3: Add ABCD quantum dots to the solution obtained in step S2 and stir evenly;

[0057] S4: The solution obtained in step S3 is ultrasonically dispersed for 8 hours, and then placed in a vacuum drying oven for drying at room temperature.

[0058] The weight ratio of polymer-modified carbon quantum dots to ABCD-type quantum dots is 1:3.

[0059] Comparative Example 1

[0060] A quantum dot-based material, the specific implementation method is the same as that of Example 1, except that: a method for preparing polymer-modified carbon quantum dots comprises the following steps: adding 2 mol of 1-methylundecylamine and 4 mol of methyl methacrylate to toluene, reacting at 250° C. for 16 hours, cooling to below 80° C., adding 6 mol of methyl methacrylate and benzoyl peroxide (benzoyl peroxide is 1% of the total mass of methyl methacrylate), stirring evenly, maintaining the temperature at 50-60° C. and continuing the reaction for 30 hours, washing and purifying, and then drying to obtain polymer-modified carbon quantum dots.

[0061] Comparative Example 2

[0062] A quantum dot-based material, the specific implementation method is the same as that of Example 1, except that: a method for preparing polymer-modified carbon quantum dots comprises the following steps: adding 2 mol of N-dodecyl-2-acrylamide and 4 mol of methyl methacrylate to toluene, reacting at 250°C for 16 hours, cooling to below 80°C, adding 6 mol of methyl methacrylate and 0.5 mol of benzoyl peroxide, stirring evenly, maintaining the temperature at 50-60°C and continuing the reaction for 30 hours, washing and purifying, and then drying to obtain polymer-modified carbon quantum dots.

[0063] Comparative Example 3

[0064] A quantum dot-based material, the specific implementation method is the same as that of Example 1, except that: a method for preparing polymer-modified carbon quantum dots comprises the following steps: adding 1 mol of 1-methylundecylamine, 1 mol of N-(N-octadecyl)acrylamide and 4 mol of methyl methacrylate to toluene, reacting at 250°C for 16 hours, cooling to below 80°C, adding 6 mol of methyl methacrylate and benzoyl peroxide (benzoyl peroxide is 1% of the total mass of methyl methacrylate), stirring evenly, maintaining the temperature at 50-60°C and continuing the reaction for 30 hours, washing and purifying, and then drying to obtain polymer-modified carbon quantum dots.

[0065] Performance Testing

[0066] (1) The quantum dot-based material prepared in the present application was placed at 85% humidity and 85°C for 48 hours and then the emission spectrum was tested. It was found that the half-peak widths of the transparent materials of Examples 1-3 did not increase, but the half-peak widths of Comparative Example 1, Comparative Example 2, and Comparative Example 3 increased by 17%, 21%, and 34%, respectively, indicating that the quantum dot material prepared by this method has high stability.

[0067] (2) The quantum dot-based materials prepared in different examples and comparative examples were prepared into ratiometric fluorescence sensors according to the following steps:

[0068] Step 1: Prepare quantum dot-based materials according to Examples 1-3 and Comparative Examples 1-3 respectively;

[0069] Step 2: 1.0 g of the material prepared in step 1 was ultrasonically dispersed in toluene and then refluxed with 0.2 g of 3-(aminopropyl)dimethylethoxysilane for 2 hours to obtain modified particles; the modified particles were dissolved in dichloromethane, 80 mg of 5-(4-aminophenyl)-10,15,20-triphenylporphyrin was added, and refluxed for 3 hours to obtain an intermediate product;

[0070] Step 3: The intermediate product obtained in step 2 is dispersed in ethanol at a concentration of 0.5 wt %, and then a crystal film with a thickness of 1 μm is obtained on a polydimethylsiloxane substrate by spin coating to obtain a fluorescence ratio sensor.

[0071] The detection limit of the sensor was tested by preparing mercury ions with different concentration gradients. It was found that the sensors prepared in Examples 1-3 of the present invention had a low detection limit for Hg. 2+ The detection limit of the sensor prepared in Comparative Example 1 was 0.85-0.91 pM for Hg 2+ The detection limit of the sensor prepared in Comparative Example 2 was 10.2 pM for Hg 2+ The detection limit of the sensor prepared in Comparative Example 3 was 10.5 pM for Hg 2+ The detection limit was 10.67 pM.

[0072] Due to the coordination reaction between mercury and porphyrin, the fluorescence of porphyrin decreases, while the fluorescence of the quantum dot-based materials prepared in Examples 1-3 of the present application remains basically unchanged. As the ratio of the two peak intensities changes, the sensing system increases, and Hg can be sensitively detected. 2+ .

[0073] 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 material, characterized in that: The raw materials for preparation include: PMMA, polymer-modified carbon quantum dots, and ABCD-type quantum dots; the ABCD-type quantum dots are ZnCuInS / ZnS quantum dots with a diameter of 4-5nm. The preparation method of polymer-modified carbon quantum dots comprises the following steps: adding 1 mol of 1-methylundecylamine, 1 mol of N-dodecyl-2-acrylamide, and 4 mol of methyl methacrylate to toluene, reacting at 250° C. for 16 hours, cooling to below 80° C., adding 6 mol of methyl methacrylate and benzoyl peroxide in an amount of 1% by weight of the total weight of the methyl methacrylate, stirring evenly, maintaining the temperature at 50-60° C. and continuing the reaction for 30 hours, washing, purifying, and drying to obtain polymer-modified carbon quantum dots; The preparation method of the material comprises the following steps: S1: Add 10 g of PMMA to 300 mL of chloroform and stir well. S2: Add 1 g of polymer-modified carbon quantum dots to the solution obtained in step S1 and stir evenly; S3: Add ABCD quantum dots to the solution obtained in step S2 and stir evenly; S4: ultrasonically disperse the solution obtained in step S3 for 8 hours, and then place it in a vacuum drying oven and dry it at room temperature; The weight ratio of polymer-modified carbon quantum dots to ABCD-type quantum dots is 1:2.