Preparation method and application of quantum dots coated with multiple layers of silicon dioxide

Abstract

The invention discloses a preparation method and application of multi-layer silicon dioxide coated quantum dots, and the preparation method comprises the following steps: controlling the aperture and concentration of SiO2 porous microspheres, adjusting the mixing rate and time of a SiO2 porous microsphere solution and a quantum dot solution, and preparing the multi-layer silicon dioxide coated quantum dots. According to the preparation method, the quantum dots are firstly coated with silicon dioxide through the SiO2 porous microspheres, then secondary coating is conducted through the silane coupling agent, the quantum dot optical film is prepared, the stability of the quantum dot optical film under the conditions of 60 DEG C and 90% RH is obviously improved, and the quantum dots are effectively protected.

Description

Technical Field

[0001] The invention belongs to the technical field of quantum dot optical film stability, and specifically relates to a preparation method and application of multi-layer silica-coated quantum dots. Background Art

[0002] Quantum dots are widely used in information display, optoelectronic devices, and bioimaging due to their excellent optical properties and adjustable emission wavelength. However, quantum dots themselves are sensitive to water and oxygen, and their optical properties will decrease when exposed to water and oxygen. Therefore, in order to reduce or isolate the impact of water and oxygen on quantum dot materials, research on the encapsulation of quantum dots has gradually increased in recent years. At present, quantum dots have been embedded in SiO2 porous microspheres, or quantum dot precursors have been mixed with SiO2 porous microspheres to synthesize corresponding quantum dot composite materials in situ. The composite materials obtained effectively improve the ability of quantum dots to resist water and oxygen, thereby improving the stability of quantum dots. However, the embedding rate of quantum dot materials prepared in this way is low, and there is a problem that many quantum dots cannot be embedded in SiO2 porous microspheres. This problem causes the quantum dots to be made into optical films. The stability is poor under high temperature and high humidity conditions. Therefore, it is necessary to find a quantum dot processing solution to improve the stability of quantum dot optical films.

[0003] In view of the above problems, the present invention proposes a preparation method and application of multi-layer silica-coated quantum dots. Summary of the invention

[0004] Technical problems solved: In response to the above technical problems, the present invention provides a method for preparing and applying multi-layer silica-coated quantum dots, which can effectively solve the shortcomings of the prior art quantum dot optical films, that is, poor stability under high temperature and high humidity conditions.

[0005] Technical solution: In the first aspect, the present invention provides a method for preparing multi-layer silica-coated quantum dots, comprising the following steps: controlling the pore size and concentration of SiO2 porous microspheres, adjusting the mixing rate and time of the SiO2 porous microsphere solution and the quantum dot solution, and obtaining silica-coated quantum dots.

[0006] Preferably, the pore size of the SiO2 porous microspheres is 50-150 nm.

[0007] Preferably, the solvent of the SiO2 porous microsphere solution is one or a mixture of n-hexane, n-heptane, toluene, xylene, dichloromethane, chloroform, and ethanol, and the concentration of the SiO2 porous microspheres is 1% to 10%.

[0008] Preferably, the quantum dot solution is a CdSe quantum dot solution or an InP quantum dot solution.

[0009] Preferably, the injection rate of the SiO2 porous microsphere solution is 10 to 50 mL / h, the injection rate of the quantum dot solution is 2 to 30 mL / h, and the injection rate ratio of the SiO2 porous microsphere solution to the quantum dot solution is 1:1 to 5:1; the mixing time of the SiO2 porous microsphere solution and the quantum dot solution is 30 to 60 min.

[0010] In the second aspect, the present invention provides an application of multi-layer silica-coated quantum dots prepared by the preparation method described in the first aspect in the preparation of optical films. Specifically, a silane coupling agent and an acrylic resin are mixed and stirred, and after stirring evenly, multi-layer silica-coated quantum dots are added for secondary coating. After sufficient stirring, a quantum dot optical film is prepared by a high-precision roll-to-roll coating process, and the stability of the quantum dot optical film is improved under the conditions of 60°C and 90%RH.

[0011] Preferably, the silane coupling agent is one or more of tetramethoxysilane, tetraethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

[0012] Preferably, the acrylic resin is a light-curing resin, which undergoes a polymerization reaction under ultraviolet light to cure the glue.

[0013] Preferably, the silane coupling agent and the acrylic resin are mixed in a mass ratio of 1:50 to 1:10, with a stirring speed of 500-2000 rpm / min and a stirring time of 30-90 min.

[0014] Preferably, the mass ratio of the multilayer silica-coated quantum dots to the acrylic resin is 1:20-1:5, the stirring speed is 500-2000 rpm / min, and the stirring time is 30-90 min.

[0015] Preferably, the quantum dot optical film has a thickness of 300-350 μm.

[0016] Beneficial effect: The present invention firstly coats quantum dots with silicon dioxide through SiO2 porous microspheres, and then uses a silane coupling agent for secondary coating to prepare a quantum dot optical film. The stability of the quantum dot optical film under the conditions of 60°C and 90% RH is significantly improved, and the quantum dots are effectively protected. DETAILED DESCRIPTION

[0017] The present invention is described in detail below in conjunction with specific embodiments: Comparative Example 1 600 mg of SiO2 porous microspheres with a pore size of 75 nm were dissolved in 30 g of toluene solution. After ultrasonic dissolution, the SiO2 porous microsphere solution was injected into the rubber tube at 25 mL / h using microfluidic technology, and the CdSe quantum dot solution was injected into the pipeline at 10 mL / h. The green CdSe quantum dot solution and the red CdSe quantum dot solution were mixed with the SiO2 porous microsphere solution in the pipeline for 45 min, respectively, to obtain the SiO2 coated red and green CdSe quantum dot solutions. 20 g of the coated green CdSe quantum dots and 10 g of the coated red CdSe quantum dots were added to 500 g of acrylic resin, stirred at 1000 rpm / min for 60 min, and a quantum dot optical film with a thickness of 300 μm was prepared by high-precision roll-to-roll coating process, and the stability test was carried out under high temperature and high humidity conditions of 60 ℃ and 90% RH. Example 1

[0018] 600 mg of SiO2 porous microspheres with a pore size of 75 nm were dissolved in 30 g of toluene solution. After ultrasonic dissolution, the SiO2 porous microsphere solution was injected into the rubber tube at 25 mL / h using microfluidic technology, and the CdSe quantum dot solution was injected into the pipeline at 10 mL / h. The green CdSe quantum dot solution and the red CdSe quantum dot solution were mixed with the SiO2 porous microsphere solution in the pipeline for 45 min, respectively, to obtain the SiO2-coated red and green CdSe quantum dot solutions. 10 g of tetraethoxysilane was added to 500 g of acrylic resin and stirred at 1000 rpm / min for 30 min. After sufficient stirring, 20 g of coated green CdSe quantum dots and 10 g of coated red CdSe quantum dots were added and stirred at 1000 rpm / min for 60 min. A quantum dot optical film with a thickness of 300 μm was prepared by a high-precision roll-to-roll coating process and subjected to a stability test under high temperature and high humidity conditions of 60 ℃ and 90% RH. Example 2

[0019] 600 mg of SiO2 porous microspheres with a pore size of 75 nm were dissolved in 30 g of toluene solution. After ultrasonic dissolution, the SiO2 porous microsphere solution was injected into the rubber tube at 25 mL / h using microfluidic technology, and the CdSe quantum dot solution was injected into the pipeline at 10 mL / h. The green CdSe quantum dot solution and the red CdSe quantum dot solution were mixed with the SiO2 porous microsphere solution in the pipeline for 45 minutes, respectively, to obtain the SiO2-coated red and green CdSe quantum dot solutions. 10 g of 3-mercaptopropyltrimethoxysilane was added to 500 g of acrylic resin and stirred at 1000 rpm / min for 30 min. After sufficient stirring, 20 g of coated green CdSe quantum dots and 10 g of coated red CdSe quantum dots were added and stirred at 1000 rpm / min for 60 min. A quantum dot optical film with a thickness of 300 μm was prepared by a high-precision roll-to-roll coating process and subjected to a stability test under high temperature and high humidity conditions of 60 ℃ and 90% RH. Example 3

[0020] 600 mg of SiO2 porous microspheres with a pore size of 75 nm were dissolved in 30 g of toluene solution. After ultrasonic dissolution, the SiO2 porous microsphere solution was injected into the rubber tube at 25 mL / h using microfluidic technology, and the CdSe quantum dot solution was injected into the pipeline at 10 mL / h. The green CdSe quantum dot solution and the red CdSe quantum dot solution were mixed with the SiO2 porous microsphere solution in the pipeline for 45 min, respectively, to obtain the SiO2-coated red and green CdSe quantum dot solutions. 10 g of 3-aminopropyltriethoxysilane was added to 500 g of acrylic resin and stirred at 1000 rpm / min for 30 min. After sufficient stirring, 20 g of coated green CdSe quantum dots and 10 g of coated red CdSe quantum dots were added and stirred at 1000 rpm / min for 60 min. A quantum dot optical film with a thickness of 300 μm was prepared by a high-precision roll-to-roll coating process and subjected to a stability test under high temperature and high humidity conditions of 60 ℃ and 90% RH.

[0021] The stability test results of the quantum dot optical films prepared in the comparative examples and the examples under high temperature and high humidity conditions of 60°C and 90% RH are shown in Table 1 below: Table 1 Changes in optical data of quantum dot optical films after storage at 60 ℃ and 90% RH , Table 1 shows the optical data changes of the quantum dot optical films prepared in the comparative examples and the examples after being stored at 60°C and 90% RH for 1000 hours, wherein △x is the value of the color coordinate x minus the initial color coordinate x after 1000 hours of storage at high temperature and humidity, △y is the value of the color coordinate y minus the initial color coordinate y after 1000 hours of storage at high temperature and humidity, and △L is the difference in brightness before and after storage at high temperature and humidity divided by the initial brightness value. The stability of the quantum dot optical film made of the multi-layer silica-coated quantum dots of the present invention under the conditions of 60°C and 90% RH is significantly improved.

[0022] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing multi-layer silica-coated quantum dots, characterized in that: The following steps are involved: The pore size and concentration of SiO2 porous microspheres are controlled, and the mixing rate and time of the SiO2 porous microsphere solution and the quantum dot solution are adjusted to obtain the silicon dioxide-coated quantum dots.

2. The method for preparing multi-layer silica-coated quantum dots according to claim 1, characterized in that: The pore size of the SiO2 porous microspheres is 50-150 nm.

3. The method for preparing multi-layer silica-coated quantum dots according to claim 1, characterized in that: The solvent of the SiO2 porous microsphere solution is one or a mixture of n-hexane, n-heptane, toluene, xylene, dichloromethane, chloroform, and ethanol, and the concentration of the SiO2 porous microsphere is 1% to 10%.

4. The method for preparing silicon dioxide-coated quantum dots according to claim 1, characterized in that: The quantum dot solution is a CdSe quantum dot solution or an InP quantum dot solution.

5. The method for preparing multi-layer silica-coated quantum dots according to claim 1, characterized in that: The injection rate of the SiO2 porous microsphere solution is 10 to 50 mL / h, the injection rate of the quantum dot solution is 2 to 30 mL / h, and the injection rate ratio of the SiO2 porous microsphere solution to the quantum dot solution is 1:1 to 5:1; the mixing time of the SiO2 porous microsphere solution and the quantum dot solution is 30 to 60 min.

6. Use of multi-layer silica-coated quantum dots prepared by the preparation method according to any one of claims 1 to 5 in the preparation of optical films, characterized in that: The silane coupling agent and acrylic resin are mixed and stirred, and after stirring evenly, multi-layer silica-coated quantum dots are added for secondary coating. After sufficient stirring, a quantum dot optical film is prepared through a high-precision roll-to-roll coating process.

7. The method for preparing multi-layer silica-coated quantum dots and optical films according to claim 6, characterized in that: The silane coupling agent is one or more of tetramethoxysilane, tetraethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

8. The method for preparing multi-layer silica-coated quantum dots and optical films according to claim 6, characterized in that: The silane coupling agent and the acrylic resin are mixed in a mass ratio of 1:50 to 1:10, with a stirring speed of 500 to 2000 rpm / min and a stirring time of 30 to 90 min.

9. The method for preparing multi-layer silica-coated quantum dots and optical films according to claim 6, characterized in that: The mass ratio of the multilayer silica-coated quantum dots to the acrylic resin is 1:20-1:5, the stirring speed is 500-2000 rpm / min, and the stirring time is 30-90 min.

10. The method for preparing multi-layer silica-coated quantum dots and optical films according to claim 6, characterized in that: The quantum dot optical film has a thickness of 300-350 μm.