A CWO@KSiO2 core-shell structured nanoparticle, a dye liquid crystal dimming film, its preparation method and application

Abstract

The present application relates to liquid crystal dimming film technical field, disclose a kind of CWO@KSiO2 core-shell structure nanoparticle, dye liquid crystal dimming film and its preparation method and application.The liquid crystal dimming film, by weight fraction includes: small molecule liquid crystal 70~50 parts, polymerizable monomer 30~50 parts, CWO@KSiO2 core-shell structure nanoparticle 1~5 parts, dichroic anthraquinone dye 0.1~5 parts, photoinitiator 0.1~1 part and spacer particle 0.1~1 part.The dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structure nanoparticle provided by the present application introduces CWO@KSiO2 core-shell structure nanoparticle, utilizes its core-shell synergistic effect, enhances the optical control performance of dimming film in visible light and near infrared wave band and the emissivity in mid-infrared wave band, simultaneously provides heat insulation and cooling function.The addition of dichroic anthraquinone dye gives the color tunability of dimming film, expands its potential in privacy and display field.

Description

Technical Field

[0001] This invention relates to the field of liquid crystal dimming film technology, specifically to a CWO@KSiO2 core-shell structured nanoparticle, a dye liquid crystal dimming film, its preparation method, and its application. Background Technology

[0002] With the rapid development of intelligent dimming technology, the demand for dimming film materials that combine visual comfort and efficient thermal management is becoming increasingly urgent. An ideal intelligent dimming material must not only have the ability to dynamically adjust visible light transmission, but also effectively regulate solar thermal radiation, significantly reducing cooling energy consumption while ensuring indoor lighting and visual comfort.

[0003] However, current dimming technologies mostly focus on single-band control of visible light, making it difficult to simultaneously shield near-infrared thermal radiation and efficiently dissipate heat in the mid-infrared band, leading to a continuous increase in indoor heat load. Radiative cooling technology, as a zero-energy passive cooling method, can effectively alleviate overheating, but traditional radiative cooling materials typically maintain a white or silver appearance, lacking color adjustability and dynamic optical response capabilities, making it difficult to adapt to diverse architectural aesthetics and scenario-based application needs. Dye-liquid crystal light modulation devices are fabricated using dichroic dyes. Due to the significant direction dependence of their light absorption characteristics, under an applied voltage, the orientation of liquid crystal molecules can be controlled, synergistically driving the dye molecules to align in an orderly manner, thereby achieving dynamic and reversible switching of color depth and transmittance. Simultaneously, introducing near-infrared shielding materials (such as cesium tungsten bronze) can further endow the materials with excellent thermal regulation capabilities, effectively blocking solar thermal radiation. These materials have broader application prospects in areas such as automotive sunroofs and smart windows in energy-efficient buildings.

[0004] Therefore, developing a dye-based liquid crystal dimming film that integrates multiple functions such as dynamic light control, color diversification, and radiative cooling is of great significance, providing innovative technical solutions for next-generation smart windows in buildings and automobiles. Summary of the Invention

[0005] To address the aforementioned technical problems, the main objective of this invention is to provide CWO@KSiO2 core-shell structured nanoparticles, dye liquid crystal dimming films, their preparation methods, and applications.

[0006] To achieve the above objectives, the present invention provides a method for preparing CWO@KSiO2 core-shell structured nanoparticles, characterized by comprising the following steps: S1, in the presence of Cs 0.33 Adding polyvinylpyrrolidone (PVP) to a dispersion of WO3 nanoparticles to Cs 0.33WO3 nanoparticles were surface-modified and centrifuged to obtain CWO nanoparticles. S2. CWO nanoparticles were added to a mixed solution of ethanol and water and dispersed evenly. Tetraethyl orthosilicate and ammonia were added to react and centrifuged to prepare CWO@SiO2 core-shell structured nanoparticles. S3. CWO@SiO2 core-shell nanoparticles were added to toluene and dispersed evenly. Then, γ-(methacryloyloxy)propyltrimethoxysilane (KH570) was added and the mixture was heated under reflux to prepare CWO@KSiO2 core-shell nanoparticles.

[0007] As a further preferred technical solution of the present invention, the proportions of each component in step S2 are as follows: 0.1~1 g of CWO nanoparticles, 10~30 mL of ethanol, 2~6 mL of water, 0.1~1 mL of tetraethyl orthosilicate, and 1~5 mL of ammonia.

[0008] As a further preferred technical solution of the present invention, the proportions of each component in step S3 are as follows: 0.1~1 g of CWO@SiO2 core-shell structured nanoparticles, 10~50 mL of toluene, and 1~10 mL of γ-(methacryloyloxy)propyltrimethoxysilane.

[0009] According to a second aspect of the present invention, the present invention also provides a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles, wherein the raw materials for preparation, by weight, include: 70-50 parts of small molecule liquid crystal, 30-50 parts of polymerizable monomer, 1-5 parts of CWO@KSiO2 core-shell structured nanoparticles prepared by the preparation method according to any one of claims 1-3, 0.1-5 parts of dichroic anthraquinone dye, 0.1-1 parts of photoinitiator, and 0.1-1 parts of spacer particles; The small molecule liquid crystal is one or a combination of several of the following: cyano-containing liquid crystals (such as E7 and E8) and fluorine-containing liquid crystals (such as GXP-6033).

[0010] The composition of the E7 liquid crystal mixture is: 5CB (51 wt%), 7CB (25 wt%), 8OCB (16 wt%), and 5CT (8 wt%).

[0011] The composition of the E8 liquid crystal mixture is: 5CB (45 wt%), 3OCB (16 wt%), 5OCB (12 wt%), 8OCB (16 wt%), and 5CT (11 wt%); the structural formulas of each component are as follows: ; The composition (by mass percentage) of the GXP-6033 liquid crystal mixture is as follows: In each structural formula, n is independently chosen as an integer of 1 ≤ n ≤ 10.

[0012] As a further preferred embodiment of the present invention, the polymerizable monomer is any one or a combination of several of the following: lauryl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, 3,5,5-trimethylhexyl acrylate, cyclohexyl methacrylate, tricyclodecanedimethyl diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, 1H,1H-perfluoropropyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, tetrafluoropropyl acrylate, etc. And / or, the dichroic anthraquinone dye is composed of a mixture of components containing at least four anthraquinone dyes: yellow, orange, purple, and blue; And / or, the photoinitiator is an ultraviolet photoinitiator; more preferably, the photoinitiator includes, but is not limited to, benzoin diethyl ether (Irgacure 651) and 1-hydroxycyclohexylphenyl ketone (Irgacure 184). And / or, the spacer particles are silica microspheres or polymer microspheres with a particle size of 10~100 μm.

[0013] More preferably, the dichroic anthraquinone dye is composed of the following components in weight percentages: 15-45 wt% anthraquinone yellow dye; 15-45 wt% anthraquinone orange dye; 15-45 wt% anthraquinone purple dye; and 15-45 wt% anthraquinone blue dye. The anthraquinone yellow dye has the structural formula shown in formula (1) or formula (2) below: (1) (2) Anthraquinone-type orange dyes have the following structural formulas (3) or (4): (3) (4) Anthraquinone-type purple dyes have the following structural formulas (5) or (6): (5) (6) Anthraquinone-type blue dyes have the following structural formulas (7) or (8): (7) (8) In the above equations (1)-(8), n is an integer, and 0≦n≦12.

[0014] Specifically, when a single dye is added, its absorption spectrum corresponds to the incident light at a specific wavelength. In order to achieve an absorption-complementary dye that covers the entire visible light spectrum and expand its applications, an optimized black dye was obtained after repeated additions of different dyes for tuning and screening.

[0015] As a further preferred embodiment of the present invention, the particle size range of the CWO@KSiO2 core-shell structured nanoparticles is 30~60 nm, and the thickness of its shell silica layer is 3~30 nm.

[0016] According to a third aspect of the present invention, the present invention also provides a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles, comprising the following steps: (1) Mix small molecule liquid crystal, polymerizable monomer, CWO@KSiO2 core-shell structured nanoparticles, dichroic anthraquinone dye, photoinitiator and spacer particles in a preset ratio, and shake or stir at room temperature to form a uniform isotropic liquid. (2) The above-mentioned isotropic liquid is poured into a liquid crystal cell made of two transparent films with conductive layers on their surfaces; (3) The liquid crystal cell is placed in an ultraviolet curing device and cured under ultraviolet light to obtain a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structure nanoparticles.

[0017] As a further preferred embodiment of the present invention, the intensity of the ultraviolet light is 10~30 mW / cm². 2 The curing time is 5-10 minutes.

[0018] As a further preferred embodiment of the present invention, the conductive layer is selected from one or more of indium tin oxide (ITO), zinc tin oxide (Sn-ZnO), metal mesh, or polymer conductive layer.

[0019] According to a fourth aspect of the present invention, the present invention also provides an application of a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles in dimming devices, such as for smart windows in buildings, automotive sunroofs, and flexible display devices.

[0020] Compared with the prior art, the present invention can achieve the following beneficial effects: This invention provides a dye-based liquid crystal dimming film doped with CWO@KSiO2 core-shell nanoparticles. By introducing CWO@KSiO2 core-shell nanoparticles, the film's optical modulation performance in the visible and near-infrared bands and its emissivity in the mid-infrared band are enhanced through the core-shell synergistic effect, while also providing heat insulation and cooling functions. The addition of dichroic anthraquinone dyes endows the dimming film with color tunability, expanding its potential applications in privacy and display fields. In the absence of an electric field, the dye and liquid crystal molecules are randomly arranged, scattering light, and the film is opaque. When an electric field is applied, the liquid crystal molecules align along the field direction, causing the dye molecules to simultaneously align in an ordered manner, achieving reversible switching of color depth in the visible light region. Furthermore, in the scattering state, the film exhibits excellent light-shielding performance and privacy protection, showing broad application prospects in fields such as automotive sunroofs, smart building windows, and flexible display devices. Attached Figure Description

[0021] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0022] Figure 1 Transmission electron microscope image of the CWO@SiO2 core-shell structured nanoparticles successfully prepared according to Example 1 of the present invention.

[0023] Figure 2 The EDS spectrum of the CWO@SiO2 core-shell structured nanoparticles successfully prepared in Example 1 of this invention.

[0024] Figure 3 Transmission electron microscope image of CWO@SiO2 core-shell structured nanoparticles successfully modified according to Example 1 of the present invention.

[0025] Figure 4 The infrared spectrum of the CWO@KSiO2 core-shell structured nanoparticles provided in Example 1 of this invention.

[0026] Figure 5 The stability spectrum of CWO nanoparticles provided in Example 1 of this invention under neutral conditions.

[0027] Figure 6 The stability spectrum of CWO nanoparticles provided in Example 1 of this invention under acidic conditions.

[0028] Figure 7 The stability spectrum of CWO@SiO2 core-shell structured nanoparticles provided in Example 1 of this invention under neutral conditions.

[0029] Figure 8 The stability spectrum of CWO@SiO2 core-shell structured nanoparticles provided in Example 1 of this invention under acidic conditions.

[0030] Figure 9 The image shows the cyclic stability changes of the dye liquid crystal dimming film doped with CWO@KSiO2 core-shell nanoparticles before and after being charged, as provided in Example 2 of this invention.

[0031] Figure 10 The graph shows the cyclic stability of the dye liquid crystal dimming film doped with CWO@KSiO2 core-shell nanoparticles provided in Example 2 of this invention under light-on-off conditions.

[0032] Figure 11 The image shows the transmittance of the dye liquid crystal dimming film doped with CWO@KSiO2 core-shell nanoparticles as a function of CWO@KSiO2 content, as provided in Example 2 of this invention. The six sets of curves correspond to the doping amount of CWO@KSiO2 core-shell nanoparticles from 0 to 5.

[0033] Figure 12 The transmittance spectrum of the dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles provided in Example 2 of the present invention varies with the applied voltage.

[0034] Figure 13 This is a comparison image of the dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles provided in Embodiment 2 of the present invention when a voltage is applied, with a background containing an array of USTB letters.

[0035] Figure 14 The mid-infrared emission spectrum of the dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles provided in Example 2 of this invention.

[0036] Figure 15 The image shows the transmittance of the dye liquid crystal dimming film doped with CWO@SiO2 core-shell nanoparticles as a function of CWO@SiO2 content, as provided in Comparative Example 1 of this invention. The six sets of curves correspond to the doping amount of CWO@SiO2 core-shell nanoparticles from 0 to 5.

[0037] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0038] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0039] Unless otherwise defined, the technical terms used in the following embodiments have the same meanings as commonly understood by those skilled in the art to which this invention pertains. Unless otherwise specified, the experimental reagents used in the following embodiments are conventional biochemical reagents; and the experimental methods described are conventional methods. Example 1

[0040] This embodiment provides a method for preparing CWO@KSiO2 core-shell structured nanoparticles, as detailed below: Step S1: Add 1.5 g of Cs 0.33 WO3 nanoparticles were added to 50 mL of deionized water, and Cs was obtained by sonication. 0.33 Aqueous dispersion of WO3 nanoparticles: 1.2 g of polyvinylpyrrolidone (PVP) was added to 50 mL of deionized water and ultrasonically dispersed to obtain an aqueous solution of PVP. Subsequently, the above-mentioned Cs... 0.33 Aqueous dispersions of WO3 nanoparticles and aqueous solutions of PVP were mixed and stirred at room temperature for 24 h. Cs surface-modified PVP was obtained by centrifugation. 0.33 WO3 nanoparticles, also known as CWO nanoparticles.

[0041] Step S2: Add 0.2 g of CWO nanoparticles to a mixture of 14 mL of ethanol and 2 mL of water, sonicate to disperse them evenly, then add 0.1 mL of tetraethyl orthosilicate and 1.5 mL of ammonia, stir at room temperature for 24 h, and centrifuge to obtain CWO@SiO2 core-shell structured nanoparticles.

[0042] Step S3: 0.1 g of CWO@SiO2 core-shell structure was added to 15 mL of toluene and ultrasonically dispersed to ensure uniformity. Then, 1 mL of γ-(methacryloyloxy)propyltrimethoxysilane (KH570) was added and the mixture was heated under reflux for 24 h to successfully prepare CWO@KSiO2 core-shell structured nanoparticles.

[0043] TEM analysis was performed on the CWO@SiO2 core-shell structured nanoparticles prepared above, and the results were as follows: Figure 1 The results are shown. (By...) Figure 1 As can be seen, a thin shell clearly coats the surface of the CWO nanoparticles, and the interface between the shell and the core is distinct, indicating that SiO2 has been successfully coated on the CWO surface, forming core-shell structured nanoparticles. Furthermore, EDS energy dispersive spectroscopy analysis was performed, yielding the following results: Figure 2 The results are shown. (By...) Figure 2 As can be seen, EDS can clearly observe the characteristic peaks corresponding to Cs, W, Si and O elements, and the spots of various colors on the dark background represent the uniform distribution of the corresponding elements, further confirming the successful preparation of CWO@SiO2 core-shell structured nanoparticles.

[0044] Transmission electron microscopy analysis of the above-mentioned CWO@KSiO2 core-shell structure yielded the following results: Figure 3 The results are shown. (By...) Figure 3 It can be seen that, compared with the unmodified sample, the core-shell structure modified with KH570 silane coupling agent maintained a complete coating state in terms of morphology and had better dispersibility. Figure 4 It can be seen that, compared with CWO@SiO2 nanoparticles, a new characteristic absorption peak appears, located at approximately 1716 cm⁻¹. -1 At this location, corresponding to the vibration of the carbonyl group (C=O), this phenomenon indicates that KH570 was successfully grafted onto the surface of CWO@SiO2 nanoparticles.

[0045] Furthermore, the stability of CWO nanoparticles and CWO@SiO2 core-shell structured nanoparticles was analyzed, and the results were as follows: Figure 5-8 The results shown are from Figure 5-8 It was found that both types of nanoparticles maintained good stability under neutral conditions. However, in acidic environments, the core-shell structure of CWO@SiO2 exhibited superior stability. This result demonstrates that constructing a core-shell structure can enhance the tolerance of CWO nanoparticles to complex environments, thereby further improving their reliability in practical applications. Example 2

[0046] Using the CWO@KSiO2 core-shell structured nanoparticles prepared in Example 1, this example provides a method for preparing a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles, as detailed below: The raw materials include: 30 parts by weight of polymerizable monomers obtained by mixing 18 parts isobornyl acrylate, 6 parts tricyclodecanedimethylethanol diacrylate, and 6 parts tetrafluoropropyl acrylate; 70 parts liquid crystal mixture E8; 4 parts CWO@KSiO2 core-shell structured nanoparticles; 0.5 parts dichroic anthraquinone dye; 1 part photoinitiator (Irgacure 651); and 0.5 parts 20 µm spacer particles. The dichroic anthraquinone dye is composed of the following components in weight percentage: 25 wt% anthraquinone yellow dye, 25 wt% anthraquinone orange dye, 25 wt% anthraquinone purple dye, and 25 wt% anthraquinone blue dye. The structure of the anthraquinone yellow dye is as follows:

[0047] The structure of the anthraquinone-type orange dye is as follows:

[0048] The structure of the anthraquinone purple dye is as follows: The structure of the anthraquinone-type blue dye is as follows: .

[0049] The raw materials for preparing the dye-based liquid crystal dimming film were added to a sample vial and shaken or stirred at room temperature to form a homogeneous isotropic liquid. This isotropic liquid was then poured into a liquid crystal cell made of two PET transparent films with indium tin oxide conductive layers on their surfaces. The thickness of the liquid crystal cell was controlled by spacer particles. The cell was then placed in an ultraviolet curing device at an ultraviolet light intensity of 10 mW / cm². 2 Irradiation under the specified conditions for 10 min yielded a dye liquid crystal dimming film based on CWO@KSiO2 core-shell structured nanoparticles.

[0050] The stability of the dye-liquid crystal dimming film in Example 2 before and after power application was tested to evaluate its long-term reliability. The results were as follows: Figure 9 The results are shown. (By...) Figure 9 It can be seen that after multiple power-on-off cycles, the transmittance curve of the film remains almost unchanged compared with the initial state, without significant attenuation. This indicates that the dimming film has excellent cycle stability under repeated external electric field regulation and can meet the reliability requirements for long-term use.

[0051] The temperature change of the dye-liquid crystal dimming film of Example 2 under cyclic illumination switching conditions was tested, and the results were as follows: Figure 10 The results are shown. (By...) Figure 10 It can be seen that the film temperature did not fluctuate significantly during continuous light switching tests, indicating that the dimming film has excellent photothermal stability during dynamic optical control.

[0052] To further demonstrate the beneficial technical effects of the present invention, the following comparative experiment was conducted based on Example 2. Specifically, based on the preparation method of Example 2, only the content of CWO@KSiO2 core-shell structured nanoparticles was changed to 0 parts, 1 part, 2 parts, 3 parts, 4 parts, and 5 parts, respectively, ultimately obtaining a series of dye liquid crystal dimming films doped with different contents of CWO@KSiO2 core-shell structured nanoparticles. The transmittance of the obtained dye liquid crystal dimming films as a function of CWO@KSiO2 content was tested, and the results were as follows: Figure 11 The results are shown. (By...) Figure 11It can be seen that as the CWO@KSiO2 content increases, the transmittance of the dimming film in the visible to near-infrared bands generally decreases. Especially in the near-infrared region, the material exhibits significant shielding properties, effectively blocking solar radiation heat and improving the thermal regulation performance of the dimming film. Doping with inorganic nanoparticles usually leads to a decrease in the overall transmittance of the material. However, when CWO@KSiO2 nanoparticles are introduced in this invention, their effect in the visible and near-infrared bands shows significant differences: the transmittance in the visible region only decreases to a certain extent, while it exhibits significant shielding properties in the near-infrared band.

[0053] The transmittance of the dye-liquid crystal dimming film of Example 2 as a function of voltage was tested, and the results were as follows: Figure 12 The results are shown. (By...) Figure 12 It is evident that by applying voltage, the transmittance of the dimming film in the visible light region is significantly improved, while maintaining efficient shielding capability in the near-infrared band. This enables on-demand temperature control of the indoor environment, reducing energy consumption for air conditioning and lighting. Based on these optical characteristics, this dimming film demonstrates excellent application potential in building smart windows and automotive sunroof energy-saving applications. While meeting the needs for natural lighting and color adjustment, it can effectively block solar radiation heat, significantly improving indoor thermal comfort.

[0054] To more intuitively demonstrate the optical modulation performance of the dye-liquid crystal dimming film of Example 2, comparative images of the film under different voltage conditions were captured under natural light, as shown below. Figure 13 The results are shown. (By...) Figure 13 It is known that without an applied electric field, the film is in a scattering state, and the background letters are not observable. When an electric field is applied, the film switches from a scattering state to a transparent state, its transmittance increases significantly, the background letters gradually become clearer, and the overall color of the film gradually lightens. This is mainly due to the orientation modulation mechanism of the dye liquid crystal system under an external electric field. In the initial state, the host-guest mixture of the doped dyes is aligned parallel to the liquid crystal cell, and the incident light direction is orthogonal to the long axis of the dye, resulting in strong absorption and low transmittance. After applying an electric field, the orientation of the LC molecules changes to a vertical alignment, inducing the dyes to undergo synchronous orientation. This reorientation leads to a reduction in the absorption of incident light, thereby achieving high transmittance. Therefore, by adjusting the voltage, efficient dynamic light modulation can be achieved.

[0055] Furthermore, the mid-infrared emissivity of the dye-liquid crystal dimming film of Example 2 was tested, and the results were as follows: Figure 14 The results shown are from Figure 14 It can be seen that, compared with the dimming film without SiO2, the dye liquid crystal dimming film with CWO@KSiO2 core-shell structure exhibits a mid-infrared emissivity of over 94% in the atmospheric window band, indicating its excellent cooling capability.

[0056] The results above indicate that this film helps to minimize radiative heat exchange between indoor and outdoor environments, thereby saving energy for cooling and heating throughout the year while meeting the desired aesthetic effects. Due to its color characteristics, near-infrared shielding, and efficient cooling performance, the film is suitable for applications such as smart buildings and automotive windows.

[0057] Comparative Example 1

[0058] As a control experiment for Example 2, the only difference between it and Example 2 is that the CWO@KSiO2 core-shell structured nanoparticles are replaced with the CWO@SiO2 core-shell structured nanoparticles in Example 1.

[0059] The comparative tests are as follows: By changing the content of CWO@SiO2 core-shell structured nanoparticles to 0 parts, 1 part, 2 parts, 3 parts, 4 parts, and 5 parts, a series of dye-based liquid crystal dimming films with different contents of CWO@SiO2 core-shell structured nanoparticles were finally prepared. The transmittance of the obtained dye-based liquid crystal dimming films as a function of CWO@SiO2 content was tested, and the results are as follows: Figure 15 The results are shown. (By...) Figure 15 It can be seen that as the CWO@SiO2 content increases, the transmittance of the dimming film in the visible to near-infrared bands generally decreases, while it also exhibits significant shielding properties in the near-infrared region. Compared with Example 2 and related examples, the CWO@KSiO2 nanoparticles with further surface modification result in higher transmittance in the visible light band and superior shielding performance in the near-infrared band under the same test conditions. Example 3

[0060] The only difference from Example 2 is that the liquid crystal mixture E8 was replaced in equal amounts with GXP-6033 liquid crystal mixture purchased from Yantai Xianhua Technology Group Co., Ltd. (n is 2 in all component structural formulas). The dimming film obtained in Example 3 has the same dynamic light modulation effect as that in Example 2, with only a certain degree of decrease in transmittance in the visible light region, while exhibiting significant shielding characteristics in the near-infrared band.

[0061] While specific embodiments of the present invention have been described above, those skilled in the art should understand that these are merely illustrative examples, and various changes or modifications can be made to these embodiments without departing from the principles and essence of the present invention. The scope of protection of the present invention is defined only by the appended claims.

Claims

1. A method for preparing CWO@KSiO2 core-shell structured nanoparticles, characterized in that, Includes the following steps: S1, in the presence of Cs 0.33 Adding polyvinylpyrrolidone to a dispersion of WO3 nanoparticles to Cs 0.33 WO3 nanoparticles were surface-modified and centrifuged to obtain CWO nanoparticles. S2. CWO nanoparticles were added to a mixed solution of ethanol and water and dispersed evenly. Tetraethyl orthosilicate and ammonia were added to react and centrifuged to prepare CWO@SiO2 core-shell structured nanoparticles. S3. CWO@SiO2 core-shell nanoparticles were added to toluene and dispersed evenly. Then, γ-(methacryloyloxy)propyltrimethoxysilane was added and the mixture was heated under reflux to prepare CWO@KSiO2 core-shell nanoparticles.

2. The method for preparing CWO@KSiO2 core-shell structured nanoparticles according to claim 1, characterized in that, The proportions of each component in step S2 are as follows: 0.1-1 g of CWO nanoparticles, 10-30 mL of ethanol, 2-6 mL of water, 0.1-1 mL of tetraethyl orthosilicate, and 1-5 mL of ammonia.

3. The method for preparing CWO@KSiO2 core-shell structured nanoparticles according to claim 1, characterized in that, The proportions of each component in step S3 are as follows: 0.1~1 g of CWO@SiO2 core-shell nanoparticles, 10~50 mL of toluene, and 1~10 mL of γ-(methacryloyloxy)propyltrimethoxysilane.

4. A dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles, characterized in that, The raw materials for its preparation, by weight, include: 70-50 parts of small molecule liquid crystal, 30-50 parts of polymerizable monomer, 1-5 parts of CWO@KSiO2 core-shell structured nanoparticles prepared by the preparation method according to any one of claims 1-3, 0.1-5 parts of dichroic anthraquinone dye, 0.1-1 parts of photoinitiator and 0.1-1 parts of spacer particles; The small molecule liquid crystal is one or a combination of several of the following: cyano-containing liquid crystal and fluorine-containing liquid crystal.

5. The dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles according to claim 4, characterized in that, The polymerizable monomer is any one or a combination of several of the following: lauryl acrylate, 2-ethylhexyl acrylate, isobornyl acrylate, 3,5,5-trimethylhexyl acrylate, cyclohexyl methacrylate, tricyclodecanedimethyl diacrylate, triethylene glycol diacrylate, polyethylene glycol diacrylate, 1H,1H-perfluoropropyl methacrylate, 2-(perfluorobutyl)ethyl methacrylate, and tetrafluoropropyl acrylate. And / or, the dichroic anthraquinone dye is composed of a mixture of components containing at least four anthraquinone dyes: yellow, orange, purple, and blue; And / or, the photoinitiator is an ultraviolet photoinitiator; And / or, the spacer particles are silica microspheres or polymer microspheres with a particle size of 10~100 μm.

6. The dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles according to claim 4, characterized in that, The CWO@KSiO2 core-shell structured nanoparticles have a particle size range of 30~60 nm, and the thickness of their shell silica layer is 3~30 nm.

7. The method for preparing a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles according to any one of claims 4-6, characterized in that, Includes the following steps: (1) Mix small molecule liquid crystal, polymerizable monomer, CWO@KSiO2 core-shell structured nanoparticles, dichroic anthraquinone dye, photoinitiator and spacer particles in a preset ratio, and shake or stir at room temperature to form a uniform isotropic liquid. (2) The above-mentioned isotropic liquid is poured into a liquid crystal cell made of two transparent films with conductive layers on their surfaces; (3) The liquid crystal cell is placed in an ultraviolet curing device and cured under ultraviolet light to obtain a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structure nanoparticles.

8. The method for preparing a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles according to claim 7, characterized in that, The intensity of the ultraviolet light is 10~30 mW / cm. 2 The curing time is 5-10 minutes.

9. The method for preparing a dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles according to claim 7, characterized in that, The conductive layer is selected from one or more of indium tin oxide, zinc tin oxide, metal mesh, or polymer conductive layer.

10. The application of the dye liquid crystal dimming film doped with CWO@KSiO2 core-shell structured nanoparticles as described in claim 4 in dimming devices.

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