A dimming material composition and a dimming device

Abstract

The present invention relates to a dimming material composition and a dimming device. The composition is a suspension containing MOFs nanoparticles, a viscosity regulator and a dispersant. The dimming material composition is applied to the dimming device to effectively solve the technical problems of the existing dimming device, such as narrow optical dynamic range, slow response speed and slow color change.

Description

Technical Field

[0001] The present invention relates to the technical field of dimming material compositions, and in particular to a dimming material composition and a dimming device. Background Art

[0002] Light valves are devices that can control light transmittance. Common light valves are mainly divided into thermochromic systems, photochromic systems and electrochromic systems. Among them, electrochromic systems can be further classified into polymer dispersed liquid crystal systems (PDLC, such as US Patent US3585381), electrochemical color systems (EC, such as US Patent US9581877) and suspended particle systems (SPD, such as US Patent US6606185). Although the above technologies have become mature, such as PDLC has been commercialized, current products still have varying degrees of shortcomings in terms of transmittance, economic efficiency (energy saving), convenient operation, adjustability, cost, etc. EC (electrochromic) achieves color change dimming through redox reaction, but the response speed is slow (~5min / m 2 ), and the larger the glass size, the slower the color change, which is prone to uneven color change. Therefore, the development of core materials is still very important for the development of the light valve field.

[0003] Because SPD dimming technology combines the advantages of both EC and PDLC dimming glass, it also boasts simple assembly, stepless dimming, instantaneous color change, low energy consumption, low manufacturing cost, product safety and reliability, and a wide range of compatible substrates. Therefore, it is theoretically the most ideal intelligent dimming technology with a promising market. In SPDs, the core material must possess anisometric particles. Furthermore, such materials must be able to form a colloidal dispersion under certain conditions and possess a high aspect ratio. Therefore, nanowires, nanorods, nanoribbons, nanocones, and nanosheets with one- or two-dimensional structures are the preferred morphologies for SPD core materials. Currently, materials such as carbon nanotubes, graphene, TiO2 nanowires, and V2O5 nanorods have been found to be suitable SPD materials (Nanotechnology, 2014, 25, 415-703; Optical Materials, 2015, 46, 418-422; RSC Advance, 2013, 3, 10414-10419). However, due to the defects of these inorganic materials such as single component, narrow optical dynamic range, and low stability, their actual application range is very limited.

[0004] Metal-organic frameworks (MOFs) are a class of porous organic-inorganic hybrid materials characterized by well-defined coordination structures, large surface areas, high porosity, and ease of modification. Due to the wide range of metal ions and organic ligands in their structures, the ease of morphology control and structural modification, and the fact that the metal coordination nodes can be roughly considered inorganic building blocks, these materials hold enormous potential for applications in sensing, optics, catalysis, gas storage, and separation. Summary of the Invention

[0005] The object of the present invention is to provide a dimming material composition, which is applied to an SPD dimming device to solve the technical problems of narrow optical dynamic range, slow response speed and slow color change of the dimming device in the prior art.

[0006] To achieve the above-mentioned objectives, the present application provides a dimming material composition, which is a suspension comprising MOFs nanoparticles, a viscosity regulator and a dispersant. Since the MOFs nanoparticles as suspended particles have high stability, large specific surface area, high porosity, easy surface modification, controllable structural morphology and other characteristics, they can form a colloidal dispersion system under certain conditions. Therefore, applying them to dimming devices can effectively solve the technical problems of narrow light transmittance variation range and slow response speed in dimming devices.

[0007] As a further improvement of the present application, in the suspension:

[0008] The mass fraction of MOFs nanoparticles ranges from 0.1% to 50%.

[0009] The mass fraction of viscosity regulator ranges from 0.1% to 20%.

[0010] The mass fraction of the dispersant ranges from 30% to 99.8%.

[0011] As a further improvement of the present application, the microscopic morphology of the MOFs nanoparticles is selected from one or more of flake, rod, and wire.

[0012] As a further improvement of the present application, the MOFs nanoparticles have a rod-shaped micromorphology with an axis-to-diameter ratio in the range of 4-100.

[0013] As a further improvement of the present application, the metal ions in the MOFs nanoparticles are selected from Mg 2+ , Ca 2+ 、Co 2+ 、Fe 2 + 、Zn 2+ 、Mn 2+ 、Ni 2+ 、Cd 2+ 、Cu 2+、Co 3+ 、Al 3+ 、Fe 3+ 、Mn 3+ Cr 3+ 、Zr 4+ 、Ti 4+ One or more of, but not limited to, the above metal ions.

[0014] As a further improvement of the present application, the organic ligands in the MOFs nanoparticles are selected from one or more of porphyrin derivatives, conjugated benzene derivatives and pyrazine derivatives, but are not limited to the above organic ligands.

[0015] As a further improvement of the present application, the porphyrin derivative is selected from one or more of tetrakis(4-carboxyphenyl)porphyrin (TCPP), tetrakis(4-hydroxyphenyl)porphyrin, tetraaminophthalocyanine, and tetracarboxylic acid phthalocyanine.

[0016] As a further improvement of the present application, the conjugated benzene derivative is selected from one or more of terephthalic acid, trimesic acid, and 4,4'-biphenyldicarboxylic acid.

[0017] As a further improvement of the present application, the pyrazine derivative is selected from one or more of 2,5-pyrazinedicarboxylic acid, 2,3-pyrazinedicarboxylic acid, and 2,6-pyrazinedicarboxylic acid.

[0018] As a further improvement of the present application, the viscosity regulator is selected from one or more of cellulose ester and polyacrylate.

[0019] As a further improvement of the present application, the cellulose ester is selected from one or more of nitrocellulose, cellulose acetate, cellulose propionate, and cellulose butyl acetate.

[0020] As a further improvement of the present application, the polyacrylate is selected from one or more of polymethyl methacrylate, polyisobutyl methacrylate (PMMA), and polyethyl methacrylate.

[0021] As a further improvement of the present application, the dispersion is selected from one or more of PDMS (polydimethylsiloxane), DOA (dioctyl adipate), DOS (dioctyl sebacate), DINP (diisononyl phthalate), DOP (dioctyl phthalate), BBP (butyl benzyl phthalate), DOTP (dioctyl terephthalate), TOTM (triisooctyl trimellitate), and D13P (ditridecyl phthalate), but is not limited to the above dispersions.

[0022] To achieve the above objectives, the present application also provides a dimming device, which includes a first transparent conductive layer, a second transparent conductive layer, and a dimming material layer located between the first transparent conductive layer and the second transparent conductive layer, and the dimming material layer contains the above-mentioned dimming material composition.

[0023] As a further improvement of the present application, the gap between the first transparent conductive layer and the second transparent conductive layer ranges from 1 μm to 100 μm.

[0024] As a further improvement of the present application, the first transparent conductive layer and the second transparent conductive layer are transparent conductive layers.

[0025] As a further improvement of the present application, a first transparent substrate is provided on a side of the first transparent conductive layer away from the dimming material layer, and a second transparent substrate is provided on a side of the second transparent conductive layer away from the dimming material layer.

[0026] This application provides a dimming material composition, which is a suspension comprising MOF nanoparticles, a viscosity modifier, and a dispersant. This application also provides a dimming device comprising this dimming material composition. When applied to a dimming device, the suspension provided by the present invention exhibits a wider optical dynamic range in the on state than in the off state, and exhibits a faster response speed. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A dimming device according to an embodiment;

[0028] Figure 2 A dimming device according to an embodiment;

[0029] Figure 3 In one embodiment, before power is applied, the MOFs are disordered and the device is colored.

[0030] Figure 4 In one embodiment, after power is applied, the MOFs are arranged in an orderly manner and the device becomes transparent.

[0031] Figure 5 Scanning electron microscope image of MOFs material for preparation example 2;

[0032] Figure 6 XRD pattern of MOFs material for preparation example 2;

[0033] Figure 7 Scanning electron microscope image of MOFs material for preparation example 6;

[0034] Figure 8 XRD pattern of MOFs material for preparation example 6;

[0035] In the figure: 1. dimming material layer; 2. first transparent conductive layer; 3. second transparent conductive layer; 4. first transparent substrate; 5. second transparent substrate; 6. MOFs nanoparticles. DETAILED DESCRIPTION

[0036] To make the purpose, technical solutions and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with the specific embodiments and drawings of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of them, and are not intended to limit the scope of the invention. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0037] In order to prepare a dimming device with a wide optical dynamic range and fast response speed, the present application provides a dimming material composition, which is a suspension containing MOFs nanoparticles, a viscosity control agent and a dispersant. As a preferred embodiment of the present application, the mass fraction of MOFs nanoparticles in the suspension ranges from 0.1% to 50%. When the mass fraction of MOFs nanoparticles is lower than 0.1%, the transmittance of the dark state increases, but the transmittance of the transparent state increases by an unequal value. When the mass fraction of MOFs nanoparticles is greater than 50%, the transmittance of the dark state decreases, and the transmittance of the transparent state also decreases. The mass fraction of the viscosity control agent ranges from 0.1% to 20%. The main function of the viscosity control is to increase the dispersibility of the material and reduce the agglomeration of the material. Different viscosity control agents need to be added in different amounts. If the viscosity is too low, the response speed is fast, but the material is easy to settle. Therefore, it is necessary to choose to add an amount above a certain limit to obtain the corresponding suspension; if the viscosity is too high, the response is very slow. The mass fraction of the dispersant is in the range of 30%-99.8%. The main function of the dispersant is to disperse the MOFs particles and dissolve the viscosity regulator. As a preferred embodiment of the present application, the axis-to-diameter ratio of the MOFs nanoparticles is in the range of 4-100. As a preferred embodiment of the present application, the metal ions in the MOFs nanoparticles are selected from Zn 2+ 、Cu 2+ 、Ni 2+ ,Co 3+ 、Zr 4+ As a preferred embodiment of the present application, the organic ligands in the MOFs nanoparticles are selected from tetrakis (4-carboxyphenyl) porphyrin (TCPP), terephthalic acid and 2,5-pyrazine dicarboxylic acid, but are not limited to the above organic ligands.

[0038] To prepare a dimming device with a wide optical dynamic range and fast response speed, the present application provides a dimming material layer comprising the dimming material composition described above, and a dimming device comprising the dimming material layer. As a preferred embodiment of the present application, the dimming device includes a first transparent conductive layer, a second transparent conductive layer, and the dimming material layer described above positioned between the first and second transparent conductive layers. A first transparent substrate is disposed on the side of the first transparent conductive layer away from the dimming material layer, and a second transparent substrate is disposed on the side of the second transparent conductive layer away from the dimming material layer. The gap between the first and second transparent conductive layers ranges from 1 μm to 100 μm. A gap of less than 1 μm in the box with a reserved space is too small, affecting the free rotation of suspended particles and the unit concentration of particles, resulting in higher dark state transmittance and a narrower dynamic range. A gap that is too large not only increases the driving voltage but also affects the device's manufacturing process, the dynamic range from the dark state to the transparent state, and haze.

[0039] This application also provides a series of preferred methods for preparing MOFs nanoparticles, as follows:

[0040] Preparatory Example 1:

[0041] 2.4 mg of copper nitrate, 40 μL of trifluoroacetic acid, and 10 mg of PVP were dissolved in 9 mL of DMF. 3 mL of ethanol was added and stirred thoroughly. Then, 3 mL of a DMF solution of tetrakis(4-carboxyphenyl)porphyrin was added dropwise. The mixture was then placed in an autoclave and reacted at 80°C for 4 hours. The reaction product was washed with ethanol and centrifuged to obtain MOF material I, which consisted of Cu-TCPP nanosheets.

[0042] Preparatory Example 2:

[0043] 0.35 g ZrCl4 and 0.5 g 2,5-pyrazine dicarboxylic acid were dissolved in 30 mL DMF until fully dissolved. The solution was then placed in a 50 mL hydrothermal reactor and reacted at 120°C for 12 h. The reaction product was washed with DMF and finally centrifuged to obtain MOFs material II, which was Zr-H2PzDC nanosheets. The micromorphology is shown in Figure 2. Figure 5 The scanning electron micrograph shown, Figure 6 The corresponding XRD pattern is shown.

[0044] Preparatory Example 3:

[0045] 0.75 mmol of terephthalic acid was dissolved in 32 mL of DMF, followed by 2 mL of ethanol and 2 mL of ultrapure water. Subsequently, 0.75 mmol of nickel chloride was added. Once completely dissolved, 0.8 mL of triethylamine was added and stirred to obtain a homogeneous colloidal suspension. The suspension was then sonicated at 40 kHz for 8 hours. The resulting solid was washed five times with water and five times with ethanol, respectively, and centrifuged to yield green MOFs material III consisting of Ni-BDC nanosheets.

[0046] Preparatory Example 4:

[0047] 0.75 mmol of terephthalic acid was dissolved in 32 mL of DMF, followed by the addition of 2 mL of ethanol and 2 mL of ultrapure water. Subsequently, 0.5 mmol of nickel chloride and 0.25 mmmol of cobalt nitrate were added. Once completely dissolved, 0.8 mL of triethylamine was added and stirred to obtain a homogeneous colloidal suspension. The suspension was then sonicated at 40 kHz for 8 hours. The resulting solid was washed five times with water and five times with ethanol, respectively, and centrifuged to yield dark green MOF material IV, consisting of Ni / Co-BDC nanosheets.

[0048] Preparatory Example 5:

[0049] 0.35 g ZnI2, 0.75 g I2, and 0.5 g 2,5-pyrazinedicarboxylic acid were dissolved in 30 mL DMF until fully dissolved. The solution was then placed in a 50 mL hydrothermal reactor and reacted at 180°C for 12 h. The reaction product was washed with DMF and centrifuged to obtain MOFs material V, which was Zn-H2PzDC nanosheets.

[0050] Preparatory Example 6:

[0051] 0.35 g ZrCl4, 0.75 g I2, 0.49 g KI, and 0.3 g PVP were dissolved in 30 mL DMF until fully dissolved. The solution was then placed in a 100 mL three-necked flask and refluxed at 150°C for 12 h. The reaction product was washed with DMF and centrifuged to obtain MOFs material VI, which was Zr / I2-H2PzDC nanorods. The aspect ratio of the nanorods was 100 at most, 4 at least, and 38 at most. The micromorphology is shown in Figure 2. Figure 7 The scanning electron micrograph shown, Figure 8 The corresponding XRD pattern is shown.

[0052] Examples 1-8:

[0053] The MOFs nanoparticles in Preparative Examples 1-6 were dispersed in a dispersion containing a viscosity modifier, and the dispersion was then encapsulated between a first transparent conductive layer and a second transparent conductive layer to form a dimming material layer. A first transparent substrate was further provided on a side of the first transparent conductive layer away from the dimming material layer, and a second transparent substrate was further provided on a side of the second transparent conductive layer away from the dimming material layer to form a dimming device. The specific mass fractions of the components of the dimming material composition and the test results of the dimming device containing the above-mentioned dimming material composition are shown in Table 1.

[0054] Comparative Example 1:

[0055] Titanium dioxide nanowires (TiO2, commercial product) were dispersed in a dispersion containing a viscosity modifier. The dispersion was then encapsulated between a first transparent conductive layer and a second transparent conductive layer to form a dimming material layer. A first transparent substrate was also placed on the side of the first transparent conductive layer facing away from the dimming material layer, and a second transparent substrate was also placed on the side of the second transparent conductive layer facing away from the dimming material layer to form a dimming device. Component contents and test results are shown in Table 1.

[0056] Comparative Examples 2-4

[0057] The material of Preparatory Example 6 was dispersed in a dispersion containing a viscosity modifier. The dispersion was then encapsulated between a first transparent conductive layer and a second transparent conductive layer to form a dimming material layer. A first transparent substrate was also provided on the side of the first transparent conductive layer away from the dimming material layer, and a second transparent substrate was also provided on the side of the second transparent conductive layer away from the dimming material layer to form a dimming device. The test results are shown in Table 1.

[0058]

[0059]

[0060] Table 1

[0061] It can be seen from the above embodiments and comparative examples that materials other than MOFs have poor effects and narrow optical dynamic ranges. When the mass fraction of MOFs nanoparticles is lower than 0.1%, the transmittance of the dark state is greater, but the transmittance of the transparent state does not increase by equal values. When the mass fraction of MOFs nanoparticles is greater than 50%, the transmittance of the dark state is smaller, and the transmittance of the transparent state will also become smaller. The viscosity control agent mass fraction range is 0.1%-20%. The main function of the viscosity control is to increase the dispersibility of the material and reduce the agglomeration of the material. Different viscosity control agents need to be added in different amounts. If the viscosity is too small, the response speed is fast, but the material is easy to settle. If the viscosity is too large, the response time is slow. The suspension provided by the present invention has a wider optical dynamic range and a faster response speed when applied to the dimming device in the on state than in the off state.

[0062] Although this specification is described according to implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each implementation method can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0063] The series of detailed descriptions listed above are only specific descriptions of feasible implementation methods of the present invention. They are not intended to limit the scope of protection of the present invention. Any equivalent implementation methods or changes that do not deviate from the technical spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. A dimming material composition, characterized in that: The composition is a suspension comprising MOFs nanoparticles, a viscosity modifier, and a dispersant; the microscopic morphology of the MOFs nanoparticles is selected from rods; in the suspension: The mass fraction of MOFs nanoparticles ranges from 0.1% to 0.5%. The mass fraction of viscosity regulator ranges from 0.1% to 5%. The mass fraction of dispersant ranges from 94.5% to 99.8%; The MOFs nanoparticles have a rod-like micromorphology and an axis-to-diameter ratio ranging from 4 to 100; The metal ions in the MOFs nanoparticles are selected from Zr 4+ ; The organic ligands in the MOFs nanoparticles are selected from pyrazine derivatives; The pyrazine derivative is selected from one or more of 2,5-pyrazinedicarboxylic acid, 2,3-pyrazinedicarboxylic acid, and 2,6-pyrazinedicarboxylic acid.

2. The dimming material composition according to claim 1, characterized in that: The viscosity control agent is selected from one or more of cellulose ester and polyacrylate.

3. The dimming material composition according to claim 2, characterized in that: The cellulose ester is selected from one or more of nitrocellulose, cellulose acetate, cellulose propionate, and butyl cellulose acetate.

4. The dimming material composition according to claim 2, characterized in that: The polyacrylate is selected from one or more of polymethyl methacrylate, polyisobutyl methacrylate, and polyethyl methacrylate.

5. The dimming material composition according to claim 1, characterized in that: The dispersion is selected from one or more of PDMS, DOA, DOS, DINP, DOP, BBP, DOTP, TOTM, and D13P.

6. A dimming device, comprising a first transparent conductive layer, a second transparent conductive layer, and a dimming material layer located between the first transparent conductive layer and the second transparent conductive layer, characterized in that: The dimming material layer comprises the dimming material composition according to any one of claims 1 to 5.

7. The dimming device according to claim 6, characterized in that: The gap between the first transparent conductive layer and the second transparent conductive layer ranges from 1 μm to 100 μm.

8. The dimming device according to claim 6, characterized in that: The first transparent conductive layer and the second transparent conductive layer are transparent conductive layers.

9. The dimming device according to claim 6, characterized in that: A first transparent substrate is disposed on a side of the first transparent conductive layer away from the dimming material layer, and a second transparent substrate is disposed on a side of the second transparent conductive layer away from the dimming material layer.

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