Refractive index regulation and control method for optical material based on silicon oxide hollow nanospheres

Abstract

The invention belongs to the field of optical materials, and particularly relates to an optical material refractive index regulation and control method based on silicon oxide hollow nanospheres, which comprises the following steps: by taking tetraethoxysilane as a silicon source and polystyrene or polymethylacrylic acid as a template, adding a proper amount of ammonia water as a catalyst into a mixed solution of ethanol and water; reacting at the temperature of 15-50 DEG C to generate silicon oxide nano hollow spheres; the obtained silicon oxide hollow nanospheres are deposited on a substrate material through a spin-coating method, the stacking density of the hollow spheres is controlled, the refractive index of the optical material is regulated and controlled in a stacking mode, the size range of the diameter of the silicon oxide hollow nanospheres is 50-500 nm, and the size range of the wall thickness is 5-50 nm. The method can realize continuous regulation and control of the refractive index of the optical material or the optical film, and is easy for large-scale production.

Description

Technical Field

[0001] The invention belongs to the field of optical materials, and in particular relates to a method for regulating the refractive index of optical materials based on hollow silicon oxide nanospheres. Background Art

[0002] Optical materials play an important role in modern optical design. Refractive index is an important parameter of optical materials, which has a direct impact on the design of optical films and optical systems. At present, the refractive index of optical materials usually depends on the inherent material properties and is difficult to adjust through post-processing. This limitation of refractive index adjustment brings challenges to the design of multilayer optical films and optical systems, especially when it is necessary to meet specific optical requirements, there is a lack of a material that can freely adjust the refractive index according to design requirements.

[0003] Silicon oxide (SiO2) is a widely used optical material. It is often used in the design and manufacture of optical films and various lenses due to its good transparency and low refractive index. However, in some application scenarios, the refractive index of silicon oxide is still not low enough, and its refractive index is a fixed value and cannot be adjusted, which makes it difficult to meet the diverse refractive index requirements of complex optical systems and multilayer films. Therefore, how to develop an optical material with an adjustable refractive index to achieve more flexible optical design has become an important research direction in the field of optical device design. Summary of the invention

[0004] The present invention aims to overcome the shortcomings of the prior art and provide a method for controlling the refractive index of optical materials or optical films, which can achieve continuous control of the refractive index of the material from low to high and is easy to mass produce.

[0005] To solve the above technical problems, the present invention is achieved as follows:

[0006] The method for regulating the refractive index of optical materials based on hollow silicon oxide nanospheres comprises the following steps:

[0007] (1) tetraethoxysilane is used as a silicon source, polystyrene or polymethacrylic acid is used as a template, and an appropriate amount of ammonia water is added as a catalyst in a mixed solution of ethanol and water to react and generate hollow silicon oxide nanospheres;

[0008] (2) The hollow silicon oxide nanospheres obtained in step (1) are deposited on a substrate material by spin coating or gravity, and the stacking density of the hollow spheres is controlled to adjust the refractive index of the optical material by stacking.

[0009] Furthermore, in step (1), the reaction temperature is 15 to 50°C.

[0010] Furthermore, the diameter of the silicon oxide hollow nanospheres ranges from 50 to 500 nm, and the wall thickness ranges from 5 to 50 nm.

[0011] Furthermore, the refractive index of the optical material can be adjusted within a range of 1.1 to 1.6.

[0012] The present invention can realize continuous regulation of the refractive index of optical materials or optical films, and is easy to mass produce. The beneficial effects are as follows:

[0013] (1) By synthesizing hollow silicon oxide nanospheres of different sizes and utilizing their stacking structure, the refractive index of optical materials can be flexibly controlled, providing a convenient method for refractive index control;

[0014] (2) The method of the present invention can achieve continuous adjustment of the material refractive index from low to high by changing the size and stacking method of the hollow spheres according to different optical design requirements, thus providing a wide range of options for the design of multilayer optical films and complex optical devices;

[0015] (3) The preparation process is simple and easy to scale up, and has good application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the preparation process of hollow silicon oxide nanospheres in an embodiment of the present invention;

[0017] Figure 2 Electron microscope images of hollow silicon oxide nanospheres of different sizes of the present invention;

[0018] Figure 3 This is a schematic diagram of the stacking structure of hollow silicon oxide nanospheres of the present invention;

[0019] Figure 4 The graph is a graph showing the change in the refractive index of the optical film with the size of the hollow spheres under different stacking modes of the present invention. DETAILED DESCRIPTION

[0020] In order to make those skilled in the art better understand the technical solution of the present invention, the present invention is further described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. These embodiments should be understood to be only used to illustrate the present invention and not to limit the protection scope of the present invention. After reading the contents recorded in the present invention, all other embodiments obtained after various changes or modifications made to the present invention based on the technical solution and embodiments of the present invention also fall within the scope of protection of the claims of the present invention.

[0021] The present invention provides an optical material with adjustable refractive index based on hollow silicon oxide nanospheres and a preparation method thereof. Hollow silicon oxide nanospheres are synthesized by a solution chemical method, and the size of the hollow spheres is regulated by controlling the reaction conditions. By stacking hollow spheres of different sizes, the refractive index of optical materials or optical films can be continuously regulated, which solves the problem of the difficulty in continuously editing the refractive index of optical materials in the prior art, thereby providing a richer solution for optical design. Specifically, hollow silicon oxide nanospheres of different sizes are synthesized by a solution chemical method; the size of the hollow spheres is precisely controlled by adjusting the experimental parameters (including reactant concentration, temperature, and time, etc.); the stacking of hollow spheres of different sizes is utilized, and the filling density and stacking structure of the hollow spheres are controlled to achieve continuous regulation of the refractive index of the optical material or film. See. Figures 1 to 4 As shown, the method for regulating the refractive index of optical materials based on hollow silicon oxide nanospheres comprises the following steps:

[0022] (1) tetraethoxysilane is used as a silicon source, polystyrene or polymethacrylic acid is used as a template, and an appropriate amount of ammonia water is added as a catalyst in a mixed solution of ethanol and water to react to generate hollow silicon oxide nanospheres; the reaction temperature is 15 to 50° C.; the diameter of the hollow silicon oxide nanospheres ranges from 50 to 500 nm, and the wall thickness ranges from 5 to 50 nm;

[0023] (2) depositing the hollow silicon oxide nanospheres obtained in step (1) on a substrate material by spin coating, controlling the stacking density of the hollow spheres, and regulating the refractive index of the optical material by stacking; the refractive index of the optical material is regulated in the range of 1.1 to 1.6.

[0024] Example 1 Preparation of hollow silicon oxide nanospheres with an outer diameter of 100 nm and a wall thickness of 15 nm

[0025] 1. Use tetraethoxysilane (TEOS) as a silicon source, polystyrene (PS) or polyacrylic acid (PAA) as a template, add an appropriate amount of ammonia water as a catalyst to a mixed solution of ethanol and water, and control the reaction temperature to 15-50°C, and stir the reaction for 4 hours. After the reaction, the generated hollow silicon oxide nanospheres are collected by centrifugation and washed 3 times with deionized water to finally obtain hollow silicon oxide nanospheres with an outer diameter of about 100 nm. The amount of each reactant is shown in Table 1. If polyacrylic acid is replaced with monodisperse polystyrene spheres with a diameter of 70 nm, the same size of silicon oxide spheres can be obtained.

[0026] Table 1 Concentration and dosage of each reactant in Example 1

[0027]

[0028] 2. The obtained hollow silicon oxide nanospheres are dispersed in anhydrous ethanol to prepare a 7% mass fraction solution, and deposited on the substrate material by spin coating or gravity, and the drying temperature is controlled at 20-50°C. The packing density of the hollow spheres is controlled by adjusting the solvent evaporation rate, and the refractive index of the material is controlled by the packing density. Slow evaporation at room temperature can obtain a large packing density, and adding a small amount of ammonia water to the solution can obtain a structure with a lower packing density.

[0029] Example 2 Preparation of hollow silicon oxide nanospheres with an outer diameter of 200 nm and a wall thickness of 15 nm

[0030] 1. On the basis of Example 1, the dosage of tetraethoxysilane and polyacrylic acid is appropriately increased to obtain hollow silicon oxide nanospheres with an outer diameter of about 200nm. Adjusting the usage ratio of tetraethoxysilane and polyacrylic acid can obtain hollow spheres with different wall thicknesses. The dosage of each reactant is shown in Table 2. Replacing polyacrylic acid with monodisperse polystyrene spheres with a diameter of 170nm can also obtain silicon oxide spheres of the same size. Table 2 shows the dosage of reactants for hollow silicon oxide spheres with an outer diameter of 200nm and a wall thickness of 15nm in Example 2.

[0031] Table 2

[0032]

[0033] 2. Under the condition of close packing, by keeping the inner diameter of the hollow sphere at 170 nm, adjusting the amount of tetraethoxysilane can control the wall thickness of the hollow silica sphere, and the refractive index of the material can be continuously regulated from 0.5 to 1.1. The amounts of reactants for hollow silica spheres of several typical sizes are shown in Table 3. Table 3 shows the amounts of reactants for hollow silica spheres with an inner diameter of 170 nm and different wall thicknesses.

[0034] Table 3

[0035]

[0036] Example 3 Preparation of hollow silicon oxide nanospheres of other sizes

[0037] 1. Combining Example 1 and Example 2, the diameter of the polystyrene template and the amount of tetraethoxysilane were adjusted to obtain hollow silicon oxide nanospheres with an inner diameter of about 10-200 nm and a wall thickness of 5-200 nm. The specific experimental data are shown in Table 4. Table 4 shows the amounts of reactants for hollow spheres of certain sizes.

[0038] Table 4

[0039]

[0040] 2. Mix silica spheres (hollow or solid) of different sizes, and adjust the overall refractive index of the optical material by stacking hollow spheres of different sizes to achieve refractive index regulation from 1.1 to 1.5.

[0041] The above-described embodiments are only preferred embodiments of the present invention and are not intended to limit the present invention. It should be noted that for those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for controlling the refractive index of optical materials based on hollow silicon oxide nanospheres, characterized in that: The steps include: (1) Tetraethoxysilane is used as a silicon source, polystyrene or polymethacrylic acid is used as a template, and an appropriate amount of ammonia water is added as a catalyst to a mixed solution of ethanol and water to react and generate hollow silicon oxide nanospheres; (2) The hollow silicon oxide nanospheres obtained in step (1) are deposited on a substrate material by spin coating or gravity, and the stacking density of the hollow spheres is controlled to adjust the refractive index of the optical material by the stacking method.

2. The method for controlling the refractive index of optical materials based on hollow silicon oxide nanospheres according to claim 1, characterized in that: In step (1), the reaction temperature is 15 to 50°C.

3. The method for controlling the refractive index of optical materials based on hollow silicon oxide nanospheres according to claim 2, characterized in that: The diameter of the silicon oxide nano hollow spheres ranges from 50 to 500 nm, and the wall thickness ranges from 5 to 50 nm.

4. The method for controlling the refractive index of optical materials based on hollow silicon oxide nanospheres according to claim 3, characterized in that: The refractive index of optical materials can be adjusted in the range of 1.1 to 1.6.

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