Electrochromic material, preparation method of electrochromic device and electrochromic device

Abstract

The invention provides an electrochromic material, a preparation method of an electrochromic device and the electrochromic device.The electrochromic material comprises a solvent, a black dye, an ionic conductive agent, electrogenerated alkali-producing molecules, a plasticizer, a high-molecular polymer and electrogenerated acid-producing molecules; the situation that the black fluorane dye moves to other film layers in the color changing process of the electrochromic device, and consequently the subsequent color changing reaction cannot be conducted can be prevented, and therefore the cycling stability of the electrochromic device can be improved.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an electrochromic material, a method for preparing an electrochromic device, and an electrochromic device. Background Technology

[0002] Electrochromic materials, due to their ability to stably and reversibly change their optical properties (such as reflectivity, transmittance, and absorptivity) and color under an applied electric field, have broad application prospects in fields such as smart windows, displays, and camouflage. There are various materials with electrochromic properties, such as transition metal oxides represented by tungsten oxide and nickel oxide, and complexes represented by Prussian blue; these materials belong to inorganic electrochromic materials. In addition, electrochromic materials also include organic polymer materials represented by polyaniline and organic small-molecule electrochromic materials represented by violetin. Compared to inorganic electrochromic materials with limited color changes (one or a few) and slower response, organic electrochromic materials typically exhibit richer color changes and faster response speeds. Thanks to these characteristics, organic electrochromic materials have attracted considerable attention and research from scholars both domestically and internationally in recent years. In these studies, newly emerging electrochromic organic small molecule materials based on the proton-coupled electron transfer (PCET) reaction principle have shown rich color changes and demonstrated great application potential in areas such as smart windows and displays.

[0003] Fluorescein dyes are electrochromic materials that can achieve a variety of color changes based on the principle of proton-coupled electron transfer reaction. Their advantages, such as low driving voltage and rich color variations, make them a promising candidate for applications in smart windows and displays. However, current electrochromic devices based on these materials exhibit poor cycling stability in practical applications because the dye easily diffuses from the electrochromic layer to the electrolyte and counter-electrode layers, failing to meet real-world application requirements.

[0004] Therefore, it is necessary to provide an electrochromic material, a method for preparing an electrochromic device, and an electrochromic device to improve this defect. Summary of the Invention

[0005] The embodiments of this application provide an electrochromic material, a method for preparing an electrochromic device, and an electrochromic device, which can improve the cycle stability of the electrochromic device.

[0006] An embodiment of this application provides an electrochromic material, comprising a solvent, a black dye, an ionic conductive agent, an electro-alkali-generating molecule, a plasticizer, a polymer, and an electro-acid-generating molecule;

[0007] The black dye comprises a polymer backbone and a black fluorane dye located within the polymer backbone.

[0008] According to one embodiment of this application, the polymer backbone comprises polystyrene.

[0009] According to one embodiment of this application, the contents of each component in the electrochromic material, by mass percentage, are as follows: solvent 40-96 wt%, black dye 0.02-6 wt%, ionic conductive agent 0.8-23 wt%, electro-alkali-generating molecules 0.04-3.0 wt%, plasticizer 0.7-22 wt%, polymer 1.5-37 wt%, and electro-acid-generating molecules 0.07-5.5 wt%.

[0010] According to one embodiment of this application, the black fluorane dye is selected from at least one of 3-diethylamino-6-methyl-7-phenylaminofluorane, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and 2-(2-4-dimethylamino)-3-methyl-6-diethylaminofluorane.

[0011] According to one embodiment of this application, the ionic conductive agent is selected from at least one of tetrabutylammonium hexafluorophosphate and tetrabutylammonium perchlorate.

[0012] According to one embodiment of this application, the electro-alkali-producing molecule is selected from at least one of benzoquinone and p-benzoquinone.

[0013] According to one embodiment of this application, the plasticizer is selected from at least one of propylene esters, phosphate esters and epoxy esters, the polymer is selected from at least one of polymethyl methacrylate and polyvinylidene fluoride, and the electrogenic acid molecule is selected from at least one of hydroquinone and aminourea.

[0014] Embodiments of this application also provide a method for fabricating an electrochromic device, comprising:

[0015] A counter-current layer is formed on the first electrode layer;

[0016] An electrolyte layer is formed on the electrode layer;

[0017] The electrochromic materials described above are mixed and stirred to obtain an electrochromic solution;

[0018] The electrochromic solution is coated onto the electrolyte layer and cured to form an electrochromic layer.

[0019] A second electrode layer is formed on the electrochromic layer.

[0020] According to one embodiment of this application, the steps for preparing the black dye include:

[0021] Styrene and divinylbenzene are mixed to form an oil phase, wherein the styrene accounts for 50-80 wt% of the oil phase by mass, the divinylbenzene accounts for 2-10 wt% of the oil phase by mass, and the black fluorane dye accounts for 10-50 wt% of the oil phase by mass.

[0022] The oil phase is added to a deionized aqueous solution containing a surfactant, and an emulsion is obtained after emulsification.

[0023] An initiator is added to the emulsion, and the mixture is stirred to obtain the black dye. The initiator accounts for 0.1-3 wt% of the mass of the emulsion.

[0024] An embodiment of this application also provides an electrochromic device, which is prepared by the above-described method for preparing an electrochromic device.

[0025] The beneficial effects of the embodiments of this application are as follows: The embodiments of this application provide an electrochromic material, a method for preparing an electrochromic device, and an electrochromic device. The electrochromic material includes a solvent, a black dye, an ionic conductive agent, an electro-alkali-producing molecule, a plasticizer, a polymer, and an electro-acid-producing molecule. By encapsulating the black fluorane dye in the polymer backbone, the black fluorane dye can be prevented from migrating to other film layers during the color-changing process of the electrochromic device, thus preventing subsequent color-changing reactions from occurring. This can improve the cycle stability of the electrochromic device. Attached Figure Description

[0026] Figure 1 A schematic diagram of the structure of an electrochromic device provided for an embodiment of this application;

[0027] Figure 2 A schematic flowchart of the preparation method provided for the embodiments of this application;

[0028] Figure 3 The cycling performance of the conventional electrochromic device prepared for Comparative Example 1 at a characteristic wavelength of 590 nm is shown in the figure.

[0029] Figure 4 The cycling performance of the electrochromic device prepared in Comparative Example 2 at a characteristic wavelength of 590 nm is shown.

[0030] Figure 5 The fading transmission spectrum of the electrochromic device prepared in Example 1;

[0031] Figure 6 The image shows the cycling performance of the electrochromic device prepared in Example 2 at a characteristic wavelength of 590 nm. Detailed Implementation

[0032] The following descriptions of the embodiments are based on the accompanying illustrations and are used to illustrate specific embodiments in which this application can be implemented. Directional terms used in this application, such as [up], [down], [front], [back], [left], [right], [inner], [outer], [side], etc., are only for reference to the accompanying drawings. Therefore, the directional terms used are for illustrative and understanding purposes and not for limiting the application. In the figures, structurally similar units are represented by the same reference numerals.

[0033] The present application will be further described below with reference to the accompanying drawings and specific embodiments.

[0034] The embodiments of this application provide an electrochromic material, a method for preparing an electrochromic layer, and an electrochromic device, which can improve the cycle stability of the electrochromic device.

[0035] Electrochromic materials include solvents, black dyes, ionic conductive agents, electro-alkali-generating molecules, plasticizers, polymers, and electro-acid-generating molecules. The black dye includes a polymer backbone and a black fluorane dye located within the polymer backbone. By encapsulating the black fluorane dye within the polymer backbone, it is possible to prevent the black fluorane dye from migrating to other film layers during the color-changing process of the electrochromic device, thus preventing it from undergoing subsequent color-changing reactions. This improves the cycling performance of the electrochromic device and avoids fading caused by decreased transmittance after a certain number of cycles.

[0036] For example, the polymer framework includes polystyrene. Carbon-based framework materials such as hollow carbon spheres and carbon nanotubes have low transmittance, which leads to a decrease in the transmittance of electrochromic devices. Compared with framework materials such as hollow carbon spheres and carbon nanotubes, polystyrene has higher transmittance. Therefore, using polystyrene as a polymer framework to coat black fluorescein dye can not only increase the transmittance of electrochromic devices, but also improve the cycling stability of electrochromic devices.

[0037] For example, the solvent is selected from at least one of acetonitrile, ethanol and propylene glycol methyl ether acetate.

[0038] For example, the solvent content, by mass percentage, accounts for 40 wt% to 96 wt% of the total content of the electrochromic material. For instance, the solvent content accounts for 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, or 96 wt% of the total content of the electrochromic material.

[0039] For example, the black fluorane dye is selected from at least one of 3-diethylamino-6-methyl-7-phenylaminofluorane, 2-phenylamino-3-methyl-6-dibutylaminofluorane, and 2-(2-4-dimethylamino)-3-methyl-6-diethylaminofluorane.

[0040] For example, the content of black dye accounts for 0.02 wt% to 6 wt% of the total content of the electrochromic material. For example, the content of black dye accounts for 0.02 wt%, 0.05 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 3 wt%, 5 wt%, or 6 wt% of the total content of the electrochromic material.

[0041] For example, the ionic conductive agent is selected from at least one of tetrabutylammonium hexafluorophosphate and tetrabutylammonium perchlorate.

[0042] For example, the content of the ionic conductive agent is between 0.8 wt% and 23 wt% of the total content of the electrochromic material. For instance, the content of the ionic conductive agent is 0.8 wt%, 1 wt%, 3 wt%, 5 wt%, 10 wt%, 13 wt%, 15 wt%, 18 wt%, 20 wt%, or 23 wt% of the total content of the electrochromic material.

[0043] For example, the electro-alkali-producing molecule is selected from at least one of benzoquinone and p-benzoquinone.

[0044] For example, the content of electro-alkali-producing molecules accounts for 0.04 wt% to 3.0 wt% of the total content of the electrochromic material. For instance, the content of electro-alkali-producing molecules accounts for 0.04 wt%, 0.08 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, or 3.0 wt% of the total content of the electrochromic material.

[0045] For example, the plasticizer is selected from at least one of propylene esters, phosphate esters and epoxy esters.

[0046] For example, the content of plasticizer is from 0.7 wt% to 22 wt% of the total content of electrochromic material. For example, the content of plasticizer is 0.7 wt%, 1 wt%, 5 wt%, 10 wt%, 13 wt%, 17 wt%, 20 wt%, or 22 wt% of the total content of electrochromic material.

[0047] For example, the polymer is selected from at least one of polymethyl methacrylate and polyvinylidene fluoride.

[0048] For example, the content of the polymer is between 1.5 wt% and 37 wt% of the total content of the electrochromic material. For instance, the content of the polymer is 1.5 wt%, 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, 33 wt%, or 37 wt% of the total content of the electrochromic material.

[0049] For example, the electrogenic acid-producing molecule is selected from at least one of hydroquinone and aminourea.

[0050] For example, the content of electroacid-producing molecules is between 0.07 wt% and 5.5 wt% of the total content of the electrochromic material. For instance, the content of electroacid-producing molecules is 0.07 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, or 5.5 wt% of the total content of the electrochromic material.

[0051] Based on the electrochromic material provided in the above embodiments of this application, embodiments of this application also provide a method for preparing an electrochromic device, combined with... Figure 1 and Figure 2 As shown, Figure 1 A schematic diagram of the structure of an electrochromic device provided for an embodiment of this application. Figure 2 The flowchart of the preparation method provided in the embodiments of this application is shown. The preparation method of the electrochromic device includes the following steps: forming a counter-current layer 2 on a first electrode layer 1; forming an electrolyte layer 3 on the counter-current layer 2; mixing and stirring a solvent, a black dye, an ionic conductive agent, an electro-alkali-generating molecule, a plasticizer, a polymer, and an electro-acid-generating molecule to obtain an electrochromic solution; coating the electrochromic solution on the electrolyte layer 3, and curing it to form an electrochromic layer 4; and forming a second electrode layer 5 on the electrochromic layer 4.

[0052] In the preparation method of the electrochromic device of this application, the electrochromic material composed of solvent, black dye, ionic conductive agent, electro-alkali-generating molecule, plasticizer, polymer and electro-acid-generating molecule can be replaced with the electrochromic material provided in any of the above embodiments to achieve the same technical effect.

[0053] For example, the electrochromic solution can be applied to the electrolyte layer 3 by scraping or spin coating.

[0054] In this embodiment, the black dye includes a polymer backbone and a black fluorane dye located within the polymer backbone. By encapsulating the black fluorane dye in the polymer backbone, the black fluorane dye can be prevented from migrating to other film layers during the color-changing process of the electrochromic device, thus preventing subsequent color-changing reactions from occurring. This can improve the cycle performance of the electrochromic device and avoid the situation where the transmittance of the electrochromic device decreases after a certain number of cycles, leading to fading.

[0055] For example, the formulation of the electrostatic layer includes: a solvent, an ionic conductive agent, a polymer, a plasticizer, an electroacid-producing molecule, and an electroalkali-producing molecule.

[0056] For example, the contents of each component in the formulation of the electroplating layer, by mass percentage, are as follows: solvent 35wt% to 95wt%, ionic conductive agent 1wt% to 25wt%, polymer 2wt% to 40wt%, plasticizer 0.5wt% to 24wt%, electroacid-producing molecules 0.75wt% to 2wt%, and electroalkali-producing molecules 0.75wt% to 2wt%.

[0057] For example, the solvent in the electrostatic layer formulation is selected from at least one of acetonitrile, ethanol and propylene glycol methyl ether acetate; the ionic conductive agent is selected from at least one of tetrabutylammonium hexafluorophosphate and tetrabutylammonium perchlorate; the polymer is selected from at least one of polymethyl methacrylate and polyvinylidene fluoride; the plasticizer is selected from at least one of propylene ester, phosphate ester and epoxy ester; the electro-acid-producing molecule is selected from at least one of hydroquinone and aminourea; and the electro-alkali-producing molecule is selected from at least one of benzoquinone and p-benzoquinone.

[0058] For example, the step of forming a counter-electrode layer on the first electrode layer includes: mixing and stirring a solvent, an ionic conductive agent, a polymer, a plasticizer, an electro-acid-producing molecule and an electro-alkali-producing molecule for 4 to 8 hours to obtain a counter-electrode layer solution; coating the counter-electrode layer solution on the first electrode layer 1, and curing it to obtain a counter-electrode layer 2.

[0059] It should be noted that the counter electrode layer 2 and the electrochromic layer 4 are counter electrodes to each other. The hydroquinone and benzoquinone contained in the counter electrode layer 2 will participate in the redox reaction during the color change process of the electrochromic device, and play a role in balancing the reaction charge of the electrochromic layer 4.

[0060] For example, the formulation of electrolyte layer 3 includes: solvent, ionic conductive agent, polymer, and plasticizer.

[0061] For example, the contents of each component in the formulation of electrolyte layer 3 by mass percentage are as follows: solvent 24wt% to 95wt%, ionic conductive agent 0.6wt% to 33wt%, polymer 2.5wt% to 53wt%, and plasticizer 0.6wt% to 50wt%.

[0062] For example, the solvent in the electrolyte layer formulation is selected from at least one of acetonitrile, ethanol and propylene glycol methyl ether acetate, the ionic conductive agent is selected from at least one of tetrabutylammonium hexafluorophosphate and tetrabutylammonium perchlorate, the polymer is selected from at least one of polymethyl methacrylate and polyvinylidene fluoride, and the plasticizer is selected from at least one of propylene ester, phosphate ester and epoxy ester.

[0063] For example, the step of forming an electrolyte layer 3 on the counter electrode layer 2 includes: mixing and stirring a solvent, an ionic conductive agent, a polymer, and a plasticizer for 4 to 8 hours to obtain an electrolyte solution; coating the electrolyte solution onto the counter electrode layer 2 and curing it to obtain the electrolyte layer 3.

[0064] For example, the contents of each component in the formulation of the electrochromic layer 4 by mass percentage are as follows: solvent 40-96 wt%, black dye 0.02-6 wt%, ionic conductive agent 0.8-23 wt%, electro-alkali-generating molecules 0.04-3.0 wt%, plasticizer 0.7-22 wt%, polymer 1.5-37 wt%, and electro-acid-generating molecules 0.07-5.5 wt%.

[0065] For example, the polymer backbone includes polystyrene, and the steps for preparing the black dye include: mixing styrene with divinylbenzene and black fluorane dye to form an oil phase, wherein styrene accounts for 50-80 wt% of the oil phase by mass, divinylbenzene accounts for 2-10 wt% of the oil phase by mass, and black fluorane dye accounts for 10-50 wt% of the oil phase by mass; adding the oil phase to a deionized aqueous solution containing a surfactant, and emulsifying it to obtain an emulsion; adding an initiator to the emulsion, and stirring and reacting it in a constant temperature water bath at 60-90°C under a nitrogen atmosphere for 8-24 hours to obtain a polymer-coated black fluorane dye material, wherein the initiator accounts for 0.1-3 wt% of the emulsion by mass.

[0066] For example, the materials of the first electrode layer 1 and the second electrode layer 5 are both transparent conductive materials, specifically indium tin oxide (ITO).

[0067] Based on the preparation method of the electrochromic device provided in the above embodiments of this application, the embodiments of this application also provide an electrochromic device, which is prepared by the preparation method of the electrochromic device provided in any of the above embodiments.

[0068] The electrochromic devices designed in the following comparative examples and embodiments were fabricated using the following methods:

[0069] Comparative Example 1

[0070] This comparative example provides an electrochromic device: the first electrode layer is ultrasonically cleaned sequentially with acetone, ethanol and ultrapure water, and then dried; a 35 wt% acetonitrile solution, 25 wt% tetrabutylammonium hexafluorophosphate, 14.5 wt% polymethyl methacrylate, 24 wt% propylene carbonate, 0.75 wt% hydroquinone and 0.75 wt% benzoquinone are mixed and stirred for 4 to 8 hours to obtain a counter-electrode layer solution, which is then coated onto the first electrode layer and cured to obtain the counter-electrode layer.

[0071] A 24 wt% acetonitrile solution, 33 wt% tetrabutylammonium hexafluorophosphate, 37 wt% polymethyl methacrylate and 6 wt% propylene carbonate were mixed and stirred for 4 to 8 hours to obtain an electrolyte solution. The electrolyte solution was then coated onto the counter-current layer and cured to obtain the electrolyte layer.

[0072] A mixture of 40 wt% acetonitrile solution, 6 wt% black fluorane dye, 23 wt% tetrabutylammonium hexafluorophosphate, 3 wt% p-benzoquinone, 22 wt% propylene carbonate, 1.5 wt% polymethyl methacrylate, and 4.5 wt% aminourea was stirred for 8 hours to obtain an electrochromic solution. The electrochromic solution was coated onto an electrolyte layer and cured to obtain an electrochromic layer. A second electrode layer was formed on the electrochromic layer to obtain an electrochromic device. The electrochromic layer of this electrochromic device does not contain polystyrene.

[0073] Comparative Example 2

[0074] This comparative example provides an electrochromic device: the first electrode layer is ultrasonically cleaned sequentially with acetone, ethanol and ultrapure water, and then dried;

[0075] A 35 wt% acetonitrile solution, 25 wt% tetrabutylammonium hexafluorophosphate, 14.5 wt% polymethyl methacrylate, 24 wt% propylene carbonate, 0.75 wt% hydroquinone, and 0.75 wt% p-benzoquinone were mixed and stirred for 4 hours to obtain a counter-electrode layer solution. The counter-electrode layer solution was then coated onto the first electrode layer and cured to obtain the counter-electrode layer.

[0076] A 24 wt% acetonitrile solution, 33 wt% tetrabutylammonium hexafluorophosphate, 37 wt% polymethyl methacrylate and 6 wt% propylene carbonate were mixed and stirred for 4 to 8 hours to obtain an electrolyte solution. The electrolyte solution was then coated onto the counter-current layer and cured to obtain the electrolyte layer.

[0077] A polystyrene-coated black fluorane dye was synthesized in situ using an emulsion method. 50 wt% styrene, 2 wt% divinylbenzene, and 48 wt% 3-diethylamino-6-methyl-7-phenylaminofluorane were mixed to form an oil phase, which was then added dropwise to a deionized aqueous solution containing sodium dodecylbenzenesulfonate and sonicated to form a homogeneous fine emulsion. The emulsion was then placed in a three-hole flask, and 0.1 wt% potassium persulfate initiator was added. The mixture was then reacted under a nitrogen atmosphere in a constant temperature water bath at 60°C with magnetic stirring for 8 hours to obtain the black dye.

[0078] A mixture of 40 wt% acetonitrile solution, 6 wt% black dye, 23 wt% tetrabutylammonium hexafluorophosphate, 3 wt% p-benzoquinone, 22 wt% propylene carbonate, 1.5 wt% polymethyl methacrylate, and 4.5 wt% aminourea was stirred for 4 to 8 hours to obtain an electrochromic solution. The electrochromic solution was then coated onto an electrolyte layer and cured to obtain an electrochromic layer. A second electrode layer was formed on the electrochromic layer to finally obtain an electrochromic device.

[0079] Example 1

[0080] This embodiment provides an electrochromic device: the first electrode layer is ultrasonically cleaned sequentially with acetone, ethanol and ultrapure water, and then dried;

[0081] A 95 wt% acetonitrile solution, 1 wt% tetrabutylammonium hexafluorophosphate, 2 wt% polymethyl methacrylate, 0.5 wt% propylene carbonate, 0.75 wt% aminourea, and 0.75 wt% p-benzoquinone were mixed and stirred for 8 hours to obtain a counter-electrode layer solution. The counter-electrode layer solution was then coated onto the first electrode layer and cured to obtain the counter-electrode layer.

[0082] A 95 wt% acetonitrile solution, 1.9 wt% tetrabutylammonium hexafluorophosphate, 2.5 wt% polymethyl methacrylate and 0.6 wt% propylene carbonate were mixed and stirred for 4 to 8 hours to obtain an electrolyte solution. The electrolyte solution was then coated onto the counter-current layer and cured to obtain the electrolyte layer.

[0083] A polystyrene-coated black fluorane dye was synthesized in situ using an emulsion method. 80 wt% styrene, 10 wt% divinylbenzene, and 10 wt% 2-phenylamino-3-methyl-6-dibutylaminofluorane were mixed to form an oil phase, which was then added dropwise to a deionized aqueous solution containing sodium dodecylbenzenesulfonate and sonicated to form a homogeneous fine emulsion. The emulsion was then placed in a three-hole flask, and 3 wt% azobisisoheptane, the initiator, was added. The mixture was then reacted in a constant temperature water bath at 90°C under a nitrogen atmosphere with magnetic stirring for 24 hours to obtain the black dye.

[0084] A mixture of 94 wt% acetonitrile solution, 2 wt% black dye, 0.8 wt% tetrabutylammonium perchlorate, 0.04 wt% benzoquinone, 0.7 wt% propylene carbonate, 2.37 wt% polymethyl methacrylate, and 0.09 wt% hydroquinone was stirred for 4 hours to obtain an electrochromic solution. The electrochromic solution was then coated onto an electrolyte layer and cured to obtain an electrochromic layer. A second electrode layer was formed on the electrochromic layer to finally obtain an electrochromic device.

[0085] Example 2

[0086] This embodiment provides an electrochromic device: the first electrode layer is ultrasonically cleaned sequentially with acetone, ethanol and ultrapure water, and then dried;

[0087] A 35 wt% acetonitrile solution, 17 wt% tetrabutylammonium hexafluorophosphate, 40 wt% polymethyl methacrylate, 4 wt% propylene carbonate, 2 wt% hydroquinone, and 2 wt% p-benzoquinone were mixed and stirred for 8 hours to obtain a counter-electrode layer solution. The counter-electrode layer solution was then coated onto the first electrode layer and cured to obtain the counter-electrode layer.

[0088] A 40 wt% acetonitrile solution, 0.6 wt% tetrabutylammonium hexafluorophosphate, 53 wt% polymethyl methacrylate and 6.4 wt% propylene carbonate were mixed and stirred for 7 hours to obtain an electrolyte solution. The electrolyte solution was then coated onto the counter-current layer and cured to obtain the electrolyte layer.

[0089] A polystyrene-coated black fluorane dye was synthesized in situ using an emulsion method. 40 wt% styrene, 10 wt% divinylbenzene, and 50 wt% 2-(2-4-dimethylamino)-3-methyl-6-diethylaminofluorane were mixed to form an oil phase, which was then added dropwise to a deionized aqueous solution containing sodium dodecylbenzenesulfonate and sonicated to form a homogeneous fine emulsion. The emulsion was then placed in a three-hole flask, and 1 wt% potassium persulfate initiator was added. The mixture was then reacted in a constant temperature water bath at 70°C under a nitrogen atmosphere with magnetic stirring for 16 hours to obtain the black dye.

[0090] A mixture of 19.5 wt% acetonitrile solution, 4 wt% black dye, 15 wt% tetrabutylammonium hexafluorophosphate, 1 wt% p-benzoquinone, 18 wt% propylene carbonate, 37 wt% polymethyl methacrylate, and 5.5 wt% aminourea was stirred for 5 hours to obtain an electrochromic solution. The electrochromic solution was then coated onto an electrolyte layer and cured to obtain an electrochromic layer. A second electrode layer was formed on the electrochromic layer to finally obtain an electrochromic device.

[0091] Combination Figure 3 As shown, Figure 3 The image shows the cycling performance of the conventional electrochromic device prepared in Comparative Example 1 at a characteristic wavelength of 590 nm. The electrochromic layer of the conventional electrochromic device prepared in Comparative Example 1 does not contain polystyrene. The color transmittance of the electrochromic device is low, only about 20%, and the fading transmittance is about 80%. As the number of cycles increases, both the color transmittance and the fading transmittance of the electrochromic device gradually decrease.

[0092] Combination Figure 4 As shown, Figure 4The image shows the cycling performance of the electrochromic device prepared in Comparative Example 2 at a characteristic wavelength of 590 nm. Compared with Comparative Example 1, Comparative Example 2 uses polystyrene to coat black fluorane dye in the electrochromic layer. The color transmittance and fading transmittance of the electrochromic device prepared in Comparative Example 2 did not change with the normal number of cycles, and it has good cycling stability.

[0093] Combination Figure 5 As shown, Figure 5 The image shows the color transmittance spectrum of the electrochromic device prepared in Example 1. The color transmittance and color transmittance of the electrochromic device prepared in Example 1 are both above 40% for light with wavelengths in the range of 300 to 1000 nm.

[0094] Combination Figure 6 As shown, Figure 6 The image shows the cycling performance of the electrochromic device prepared in Example 2 at a characteristic wavelength of 590 nm. The color transmittance of the electrochromic device prepared in Example 2 is greater than 40%, which is a significant increase compared with Comparative Example 1 and Comparative Example 2. Furthermore, the color transmittance and fading transmittance of the electrochromic device do not change with the normal number of cycles, indicating good cycling stability.

[0095] The results above show that electrochromic devices using a polymer backbone to coat black fluorane dye can avoid the degradation of cycling performance caused by dye diffusion because the dye is confined in the polymer backbone, resulting in better fading transmittance and cycling stability.

[0096] The beneficial effects of the embodiments of this application are as follows: The embodiments of this application provide an electrochromic material, a method for preparing an electrochromic device, and an electrochromic device. The electrochromic material includes a solvent, a black dye, an ionic conductive agent, an electro-alkali-producing molecule, a plasticizer, a polymer, and an electro-acid-producing molecule. By encapsulating the black fluorane dye in the polymer backbone, the black fluorane dye can be prevented from migrating to other film layers during the color-changing process of the electrochromic device, thus preventing subsequent color-changing reactions from occurring. This can improve the cycle stability of the electrochromic device.

[0097] In summary, although the present application discloses the preferred embodiments as described above, the above preferred embodiments are not intended to limit the present application. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present application. Therefore, the scope of protection of the present application is based on the scope defined by the claims.

Claims

1. An electrochromic material, characterized in that, The black dye, the ion conductive agent, the electrochromic material, the electrochromic device, the preparation method of the electrochromic device, and the preparation method of the black dye. The black dye includes a polymer skeleton and a black fluoran dye located in the polymer skeleton.

2. The electrochromic material of claim 1, wherein, The polymer skeleton includes polystyrene.

3. The electrochromic material of claim 1, wherein, The content of each component in the electrochromic material is as follows in terms of mass percentage: solvent 40-96 wt%, black dye 0.02-6 wt%, ion conductive agent 0.8-23 wt%, electrochromic material 0.04-3.0 wt%, plasticizer 0.7-22 wt%, high molecular polymer 1.5-37 wt%, and electrochromic material 0.07-5.5 wt%.

4. The electrochromic material of claim 1, wherein, The black fluoran dye is selected from at least one of 3-diethylamino-6-methyl-7-anilino fluoran, 2-anilino-3-methyl-6-dibutylamino fluoran, and 2-(2-4-dimethylanilino)-3-methyl-6-diethylamino fluoran.

5. The electrochromic material of claim 1, wherein, The ion conductive agent is selected from at least one of tetrabutylammonium hexafluorophosphate and tetrabutylammonium perchlorate.

6. The electrochromic material of claim 1, wherein, The electrochromic material is selected from at least one of benzoquinone and p-benzoquinone.

7. The electrochromic material of claim 1, wherein, The plasticizer is selected from at least one of acrylate, phosphate ester, and epoxy ester, the high molecular polymer is selected from at least one of polymethyl methacrylate and polyvinylidene fluoride, and the electrochromic material is selected from at least one of hydroquinone and amino urea.

8. A method for producing an electrochromic device, characterized by, The black dye includes a polymer skeleton and a black fluoran dye located in the polymer skeleton. forming a counter electrode layer on the first electrode layer; forming an electrolyte layer on the counter electrode layer; mixing and stirring the electrochromic material as claimed in any one of claims 1 to 7 to obtain an electrochromic solution; coating the electrochromic solution on the electrolyte layer to form an electrochromic layer after solidification; forming a second electrode layer on the electrochromic layer.

9. The method of claim 8, wherein the electrochromic device is prepared by the steps of: The preparation of the black dye includes: mixing styrene, divinylbenzene, and a black fluoran dye into an oil phase, the content of the styrene is 50-80 wt% of the oil phase, the content of the divinylbenzene is 2-10 wt% of the oil phase, and the content of the black fluoran dye is 10-50 wt% of the oil phase; adding the oil phase into a deionized water solution containing a surfactant to obtain an emulsion after emulsification treatment; adding an initiator into the emulsion, stirring and reacting to obtain the black dye, and the content of the initiator is 0.1-3 wt% of the emulsion.

10. An electrochromic device, characterized in that, The electrochromic device is prepared by the preparation method of the electrochromic device as claimed in any one of claims 8 to 9.

Images