CN113156729B - Flexible electrochromic device and manufacturing method thereof - Google Patents

Abstract

The invention provides a flexible electrochromic device and a manufacturing method thereof. According to the flexible electrochromic device and the manufacturing method thereof, on one hand, the grid structure without the substrate is used as the conducting layer, so that the thickness of the flexible electrochromic device is lower than that of the conventional electrochromic device, the conductivity and the integral transmittance of the electrochromic device are improved, and the manufacturing cost is reduced; on the other hand, the grid structure without the substrate is used as the conducting layer, and the bending degree which is far higher than that of the conventional electrochromic device can be realized by matching the conducting gel layer. In addition, the conductive gel layer has viscosity, can be adhered to the surfaces of most objects, and realizes the pasting function of the electrochromic device.

Description

A flexible electrochromic device and method of making the same

technical field

The invention relates to the technical field of flexible electrochromic devices, in particular to a flexible electrochromic device and a manufacturing method thereof.

Background technique

Electrochromism is a phenomenon in which the optical properties (reflectivity, transmittance, absorptivity, etc.) of a material undergo a stable and reversible color change under the action of an external electric field, which is manifested as a reversible change in color and transparency in appearance. Materials with electrochromic properties are called electrochromic materials, and devices made of electrochromic materials are called electrochromic devices.

Electrochromic device refers to a device whose color can also change reversibly by coloring and fading under the action of alternating positive and negative voltages. Its application areas mainly include smart windows, display technology, military camouflage, flexible wearable devices and anti-glare rearview mirrors. For example, electrochromic smart windows can control the color of the window by adjusting the voltage and then adjust the amount of sunlight radiation, so as to maximize the utilization of sunlight. This is a technology with great potential, which will greatly change the way of life of human beings in the future. At present, the conductive layers of the existing electrochromic devices are mostly coated with a layer of metal oxide on the surface of glass and PET (polyethylene terephthalate) as the substrate, or a layer of metal oxide is cured on the PET substrate. Layers of conductive metals (silver, nickel, iron, copper, etc.). Glass-based ITO (tin-doped indium oxide) and FTO (fluorine-doped tin oxide) are fragile and cannot be bent, and have poor electrical conductivity, which greatly reduces the performance of electrochromic devices and limits electrochromic range of device applications.

In addition, the thickness of the glass is more than 1 mm, which will increase the thickness of the electrochromic device and look bulky as a whole, which deviates from the purpose of the continuous development of electronic products in the direction of lightweight and intelligence. Although the thickness of PET is much smaller than that of glass, it also has a certain degree of bendability, but its thickness is also ranging from 20-200μm, and the bendability is also limited to a certain extent. It is impossible to achieve a small enough bending radius. The loss is relatively large, and it cannot be used in some electronic products with high transparency requirements.

Therefore, the existing electrochromic devices are often thick in thickness, low in bendability or poor in electrical conductivity, and cannot be applied to fields such as flexible wearables that require high flexibility.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a flexible electrochromic device and a manufacturing method thereof, so as to solve the problems that the existing electrochromic device has a relatively large thickness, low bendability and poor electrical conductivity.

The present invention solves its technical problems by adopting the following technical solutions.

The present invention provides a flexible electrochromic device, comprising a conductive layer, a color-changing layer and a conductive gel layer, wherein the conductive layer has no substrate and can be freely bent, the color-changing layer is arranged above the conductive layer, and the The conductive gel layer is arranged above the color-changing layer; the color-changing layer includes a first sub-color-changing layer and a second sub-color-changing layer, the first sub-color-changing layer is filled in the gap of the conductive layer, and the first sub-color-changing layer is filled in the gap of the conductive layer. Two sub-color-changing layers are disposed on the upper surface of the conductive layer, and there is a distance between the first sub-color-changing layer and the second sub-color-changing layer.

In an embodiment of the present invention, the main body of the conductive layer is in a grid structure, and the grid structure of the conductive layer is a connected patterned structure or a periodic structure.

In an embodiment of the present invention, when the grid structure is a connected periodic structure, the periodic structure may be any one or a combination of a circle, an ellipse, or a polygon.

In an embodiment of the present invention, the conductive layer is a transparent structure, and the material of the conductive layer is any metal material among iron, copper, nickel, aluminum, gold and silver, or graphene, carbon nanomaterials Any kind of non-metallic conductive material in tube and carbon powder.

The present invention also provides a method for manufacturing a flexible electrochromic device, which is used for preparing the flexible electrochromic device as described above, comprising the steps of:

providing a substrate;

fabricating a conductive layer having a mesh structure on the substrate, the conductive layer remaining on the substrate;

Making a color-changing layer, and distributing the color-changing layer on the substrate with the conductive layer;

Making a conductive gel layer, and fixing the conductive gel layer on the substrate after the discoloration layer is distributed;

The conductive gel layer, the color-changing layer and the conductive layer with grid structure are peeled off from the substrate to obtain a flexible electrochromic device.

In one embodiment of the present invention, fabricating a conductive layer with a grid structure on the substrate includes: selecting indium tin oxide conductive glass or fluorine-doped SnO ₂ conductive glass as the substrate, and on the indium tin oxide conductive glass Or a layer of photoresist is coated on the surface of the fluorine-doped SnO ₂ conductive glass, and the conductive layer of the grid structure is obtained through heating, ultraviolet exposure, development, electroforming, and degumming.

In an embodiment of the present invention, fixing the conductive gel layer on the substrate after the discoloration layer is distributed further includes: forming a conductive gel layer after curing the prepared inorganic gel or organic gel, The adhesive layer is pressed and fixed to the conductive layer coated with the color-changing layer.

In an embodiment of the present invention, fixing the conductive gel layer on the substrate after distributing the color-changing layer further includes: first spin-coating or blade-coating the prepared inorganic or organic gel liquid on the material coated with the color-changing layer on the conductive layer, and then cured on a hot plate to form a conductive gel layer, so that the conductive gel layer is fixed on the conductive layer coated with the color-changing layer.

In an embodiment of the present invention, making the color-changing layer further includes: uniformly distributing the tungsten trioxide color-changing material on the substrate having the conductive layer with a grid structure by means of spin coating, blade coating or electrodeposition.

In an embodiment of the present invention, making the conductive gel layer further includes: mixing acrylamide, sodium chloride, lithium chloride, sodium hypochlorite, lithium hypochlorite, tetramethylethylenediamine, ammonium persulfate, methylenebis After the acrylamide and deionized water are uniformly stirred, the conductive gel layer is formed by curing.

In the flexible electrochromic device and the manufacturing method thereof provided by the present invention, on the one hand, by using a grid structure without a substrate as the conductive layer, the structure of the flexible electrochromic device is simplified, and the thickness is much lower than that of the existing electrochromic device. The device improves the conductivity and overall transmittance of the electrochromic device, and reduces the manufacturing cost; The degree of bending of existing electrochromic devices. In addition, the conductive gel layer itself has stickiness and can be adhered to the surface of most objects, thus realizing the applicability of the electrochromic device.

Description of drawings

FIG. 1 is a bottom view of the flexible electrochromic device in the first embodiment of the present invention.

FIG. 2 is a schematic diagram of an exploded structure of the flexible electrochromic device after bending according to the first embodiment of the present invention.

FIG. 3a is a cross-sectional view of the flexible electrochromic device before being peeled off from the substrate in the first embodiment of the present invention.

FIG. 3b is a cross-sectional view of the flexible electrochromic device in FIG. 1 after being peeled off from the substrate.

4a to 4g are the manufacturing method of the flexible electrochromic device in the second embodiment of the present invention.

5 is a bottom view of a flexible electrochromic device in a third embodiment of the present invention.

Detailed ways

In order to further illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the specific embodiments, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and examples.

[First Embodiment]

1 is a bottom view of the flexible electrochromic device in the first embodiment of the present invention, FIG. 2 is a schematic diagram of the exploded structure of the flexible electrochromic device in the first embodiment of the present invention after bending, and FIG. 3a is the first embodiment of the present invention Figure 3b is a cross-sectional view of the flexible electrochromic device in Figure 1 after it is peeled off from the substrate. Please refer to FIG. 1 , FIG. 2 , and FIGS. 3 a to 3 b , the flexible electrochromic device provided by the first embodiment of the present invention includes a conductive layer 10 , a color-changing layer 20 and a conductive gel layer 30 , and the conductive layer 10 has no substrate 40 and It can be freely bent, wherein the color changing layer 20 is arranged above the conductive layer 10 , and the conductive gel layer 30 is arranged above the color changing layer 20 . The color-changing layer 20 includes a first sub-color-changing layer 21 and a second sub-color-changing layer 22. The first sub-color-changing layer 21 is filled in the gap of the conductive layer 10, and the second sub-color-changing layer 22 is arranged on the upper surface of the conductive layer 10. There is a distance between the sub-color-changing layer 21 and the second sub-color-changing layer 22 .

Please refer to FIG. 1 and FIG. 2 , the main body of the conductive layer 10 is a grid structure 11 , and the grid structure 11 of the conductive layer 10 is a connected patterned structure or a periodic structure. When the grid structure 11 is a connected graphical structure, the graphics can be any one or a combination of cartoon characters, objects, buildings and landscapes; when the grid structure 11 is a connected periodic structure, the periodic The structure may be any one or a combination of circles, ellipses or polygons. In this embodiment, the conductive layer 10 has a periodic structure, and the material of the conductive layer 10 is any metal material among iron, copper, nickel, aluminum, and gold, or any metal material among graphene, carbon nanotube, and carbon powder. A non-metallic conductive material, the periodic structure can be hexagonal, for example.

The color-changing layer 20 includes electrochromic materials, selected from any one or more of organic electrochromic materials, inorganic electrochromic materials or composite electrochromic materials. Inorganic electrochromic materials include metal oxides, preferably tungsten trioxide or nickel oxide. The organic electrochromic material is preferably any one or more of viologens, isophthalates, metal phthalocyanines, pyridine metal complexes, polyanilines, polypyrroles, and polythiophenes .

The conductive gel layer 30 is an inorganic gel layer or an organic gel layer, and the inorganic gel layer includes acrylamide, electrolytes such as sodium chloride, lithium chloride, sodium perchlorate, lithium perchlorate, etc., and tetramethylethylene glycol Amine, Ammonium Persulfate, Methylenebisacrylamide. The organic gel layer includes organic polymers such as acrylonitrile-styrene, curing agents such as 1-methylimidazole and 4-methylimidazole, and electrolytes such as sodium chloride, lithium chloride, sodium perchlorate, and lithium perchlorate. And acetonitrile, tetrahydrofuran, toluene and other organic solvents.

After the conductive layer 10, the discoloration layer 20 and the conductive gel layer 30 are fabricated, the conductive layer 10 is connected to the negative electrode, and the conductive gel layer 30 is connected to the positive electrode, a process of changing from transparent to colored can be realized; the conductive layer 10 is connected to the positive electrode. The positive electrode, the conductive gel layer 30 is connected to the negative electrode, and a change process from colored to transparent can be realized.

[Second Embodiment]

4a to 4g are the manufacturing process of the flexible electrochromic device in the second embodiment of the present invention. Please refer to FIG. 4a to FIG. 4g , this embodiment provides a method for manufacturing a flexible electrochromic device, which specifically includes the following steps:

providing a substrate 40;

The conductive layer 10 having the mesh structure 11 is fabricated on the substrate 40, and the conductive layer 10 remains on the substrate 40;

Making the color-changing layer 20, and distributing the color-changing layer 20 on the substrate 40 with the conductive layer 10;

making the conductive gel layer 30, and fixing the conductive gel layer 30 on the substrate 40 after the discoloration layer 20 is distributed;

The conductive gel layer 30, the color-changing layer 20 and the conductive layer 10 having the mesh structure 11 are peeled off from the substrate 40 to obtain a flexible electrochromic device.

Further, fixing the conductive gel layer 30 on the substrate 40 on which the discoloration layer 20 is distributed may further include: forming the conductive gel layer 30 after curing the prepared inorganic gel or organic gel; 30 is pressed and fixed to the conductive layer 10 coated with the color-changing layer 20 . In other embodiments, fixing the conductive gel layer 30 on the substrate 40 after the discoloration layer 20 is distributed may further include: spin-coating or scraping the prepared inorganic or organic gel liquid on the discoloration layer 20 coated with The conductive layer 10 of the material is then cured on a hot plate to form a conductive gel layer 30 , so that the conductive gel layer 30 is fixed to the conductive layer 10 coated with the color-changing layer 20 .

Referring to FIGS. 4a to 4d , the manufacturing method of the flexible electrochromic device provided in this embodiment includes the manufacture of the conductive layer 10 , and the manufacture of the conductive layer 10 specifically includes:

Select ITO conductive glass (or FTO conductive glass) as the substrate 40, clean the surface of the ITO conductive glass with a dust remover, apply a layer of photoresist 41 on the surface of the ITO conductive glass by spin coating or blade coating, and place it on the surface of the ITO conductive glass. It is heated in an oven at 90° for one hour, and then undergoes ultraviolet exposure, development, electroforming, and degumming to obtain a periodically arranged conductive layer 10 with a regular hexagonal structure. At this time, the conductive layer 10 remains on the ITO conductive glass. In this embodiment, the type of the photoresist 41 is, for example, AZ4620 or AZ4562, and the material of the conductive layer 10 is, for example, metallic nickel.

In an embodiment of the present invention, the substrate 40 may also be made of materials such as PET.

In an embodiment of the invention, the material of the conductive layer 10 may also be any metal material selected from iron, copper, aluminum, gold and silver, or any non-metal material selected from graphene, carbon nanotubes and carbon powder. Metal conductive material.

In an embodiment of the present invention, the periodic structure of the conductive layer 10 may be a polygon such as a regular quadrilateral, a regular octagon, or any one of a circle and an ellipse.

Referring to FIG. 4e, the manufacturing process of the flexible electrochromic device provided in this embodiment includes the manufacture of the color-changing layer 20, and the manufacture of the color-changing layer 20 specifically includes:

Put 2.5g of tungsten powder into 10ml of hydrogen peroxide (30% concentration) solution, stir until the tungsten powder is completely dissolved, then remove excess hydrogen peroxide, add 10g of ethanol, condense and reflux at 80°C for 6 hours to obtain tungsten trioxide discoloration material . The tungsten trioxide color-changing material is uniformly distributed on the ITO conductive glass having the conductive layer 10 periodically arranged in a regular quadrilateral structure by means of spin coating, blade coating or electrodeposition.

Please refer to FIG. 4f to FIG. 4g. The manufacturing process of the flexible electrochromic device provided in this embodiment includes the manufacture of the conductive gel layer 30. In this embodiment, the conductive gel layer 30 is an inorganic gel layer. The process includes:

Provide 0.782g acrylamide, and 1.12g sodium chloride, lithium chloride, sodium hypochlorite, lithium hypochlorite and other electrolytes, prepare 0.47㎎ tetramethylethylenediamine, 1.33㎎ ammonium persulfate, 2.5㎎ methylenebisacrylamide and 5 g of deionized water, then stir the above mixed solution evenly, use a hot plate to heat at 60° for 1 hour, and then solidify the above mixed solution to obtain a conductive gel layer 30, and then apply the cured conductive gel layer 30 to a distributed surface. on the ITO conductive glass of the color changing layer 20 . In other embodiments, the addition amount of each substance can be appropriately changed. The ultra-thin flexible electrochromic device has a conductive layer 10 on one side and an adhesive conductive gel layer 30 on the other side, so it can be applied to the surface of most objects at will.

[Third Embodiment]

5 is a bottom view of a flexible electrochromic device in a third embodiment of the present invention. The difference between this embodiment and the first embodiment is that the periodic structure of the conductive layer 10 is a regular quadrilateral.

Please refer to FIG. 5 , the main body of the conductive layer 10 is a grid structure 11 , and the grid structure 11 of the conductive layer 10 is a connected graphic structure or periodic structure. When the grid structure 11 is a connected graphic structure, the graphics can be It is a combination of any one or more of cartoon characters, objects, buildings and landscapes; when the grid structure 11 is a connected periodic structure, the periodic structure can be any one of circles, ellipses or polygons or various combinations. In this embodiment, the conductive layer 10 is a transparent structure, and the material of the conductive layer 10 is any metal material among iron, copper, nickel, aluminum, and gold, or any one among graphene, carbon nanotubes, and carbon powder. A non-metallic conductive material.

[Fourth Embodiment]

This embodiment provides a method for manufacturing a flexible electrochromic device. The difference between this embodiment and the second embodiment is that the conductive gel layer 30 is an organic gel layer, and the specific manufacturing process includes:

After mixing the organic solvent acetonitrile and tetrahydrofuran in a volume ratio of 4:1, pour it into a weighing bottle, and then place the weighing bottle on a magnetic constant temperature stirrer and stir for 1 minute. Weigh 10% of sodium chloride and 20% of acrylonitrile-styrene organic polymer, slowly add them to the organic solvent, seal and stir at a constant temperature of 75-85 degrees Celsius for 10-15 minutes to acrylonitrile-styrene, etc. The organic polymer was completely dissolved, and finally 1% 1-methylimidazole was added and stirred for 1 minute. In other embodiments, the volume ratio of the organic solvent acetonitrile and tetrahydrofuran can be adjusted appropriately.

When the cured conductive gel layer 30 is attached to the ITO conductive glass on which the color-changing layer 20 is distributed, the conductive gel layer 30 is integrated with the color-changing layer 20 and the conductive layer 10 to form a flexible electrochromic device. Then, the conductive gel layer 30 is pressed hard, and the flexible electrochromic device is peeled off from the ITO conductive glass, thereby obtaining an ultra-thin flexible electrochromic device. The ultra-thin flexible electrochromic device has a conductive layer 10 on one side and an adhesive conductive gel layer 30 on the other side, so it can be applied to the surface of most objects at will.

In the flexible electrochromic device and the manufacturing method thereof provided by the present invention, on the one hand, by using the grid structure 11 without the substrate 40 as the conductive layer 10, the structure of the flexible electrochromic device is simplified, and the thickness is much lower than that of the existing flexible electrochromic device. The electrochromic device improves the conductivity and overall transmittance of the electrochromic device, and reduces the manufacturing cost; on the other hand, the present invention adopts the grid structure 11 without the substrate 40 as the conductive layer 10, and cooperates with the conductive gel The layer 30 can achieve a bending degree much higher than that of the existing electrochromic device. In addition, the conductive gel layer 30 itself has stickiness, and can be adhered to the surfaces of most objects, thereby realizing the attachable function of the electrochromic device.

As used herein, the terms "comprising", "comprising" or any other variation thereof are intended to encompass non-exclusive inclusion, in addition to those elements listed, but also other elements not expressly listed.

In this document, the related terms such as front, rear, upper and lower are defined by the positions of the components in the drawings and the positions between the components, which are only for the clarity and convenience of expressing the technical solution. It should be understood that the use of the locative words should not limit the scope of protection claimed in this application.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection of the present invention. within the range.

The above-described embodiments and features of the embodiments herein may be combined with each other without conflict.

Claims (9)

1. a flexible electrochromic device, is characterized in that, comprises conductive layer, discoloration layer and conductive gel layer, described conductive layer has no substrate and can be bent freely, and the main body of described conductive layer is in grid structure, The grid structure of the conductive layer is a continuous patterned structure or a periodic structure; the color-changing layer is arranged above the conductive layer, and the conductive gel layer is arranged above the color-changing layer; the color-changing layer It includes a first sub-color-changing layer and a second sub-color-changing layer, the first sub-color-changing layer is filled in the gap of the conductive layer, the second sub-color-changing layer is arranged on the upper surface of the conductive layer, and the first sub-color-changing layer is There is a distance between a sub-color-changing layer and the second sub-color-changing layer. 2 . The flexible electrochromic device according to claim 1 , wherein when the grid structure is a connected periodic structure, the periodic structure can be any one of a circle, an ellipse or a polygon. 3 . or a combination of various. 3 . The flexible electrochromic device according to claim 1 , wherein the conductive layer is a transparent structure, and the material of the conductive layer is any one of iron, copper, nickel, aluminum, gold and silver. 4 . The metal material is either an alloy material containing at least two metals among iron, copper, nickel, aluminum, gold and silver, or any non-metal conductive material among graphene, carbon nanotubes and carbon powder. 4. A manufacturing method of a flexible electrochromic device, for preparing the flexible electrochromic device according to any one of claims 1 to 3, characterized in that, comprising the steps of: providing a substrate; fabricating a conductive layer having a mesh structure on the substrate, the conductive layer remaining on the substrate; Making a color-changing layer, and distributing the color-changing layer on the substrate with the conductive layer; Making a conductive gel layer, and fixing the conductive gel layer on the substrate after the discoloration layer is distributed; The conductive gel layer, the color-changing layer and the conductive layer with grid structure are peeled off from the substrate to obtain a flexible electrochromic device. 5 . The method for manufacturing a flexible electrochromic device according to claim 4 , wherein manufacturing a conductive layer with a grid structure on the substrate comprises: selecting indium tin oxide conductive glass or fluorine-doped SnO 2 . Conductive glass is used as a substrate, and a layer of photoresist is coated on the surface of indium tin oxide conductive glass or fluorine-doped SnO2 conductive glass, and a conductive layer of grid structure is obtained after heating, ultraviolet exposure, development, electroforming, and degumming. 6 . The method for manufacturing a flexible electrochromic device according to claim 4 , wherein fixing the conductive gel layer on the substrate after the discoloration layer is distributed further comprises: applying the prepared inorganic gel or organic After the gel is cured, a conductive gel layer is formed, and the conductive gel layer is pressed and fixed on the conductive layer coated with the discoloration layer. 7. The method for manufacturing a flexible electrochromic device according to claim 4, wherein fixing the conductive gel layer on the substrate after the discoloration layer is distributed further comprises: preparing the prepared inorganic or organic gel The liquid is spin-coated or blade-coated on the conductive layer coated with the color-changing layer material, and then cured on a hot plate to form a conductive gel layer, so that the conductive gel layer is fixed on the conductive layer coated with the color-changing layer. 8. The method for manufacturing a flexible electrochromic device according to claim 4, wherein the manufacturing of the color-changing layer further comprises: using spin coating, blade coating or electrodeposition to evenly distribute the tungsten trioxide color-changing material on a surface with on the substrate of the conductive layer of the mesh structure. 9 . The method for manufacturing a flexible electrochromic device according to claim 4 , wherein the manufacturing of the conductive gel layer further comprises: mixing acrylamide, sodium chloride, lithium chloride, sodium hypochlorite, lithium hypochlorite, Ethylenediamine, ammonium persulfate, methylenebisacrylamide and deionized water are mixed uniformly, and then cured to form a conductive gel layer.

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