CN102540610A - Flexible electrochromic film and device and methods for producing same - Google Patents

Abstract

The invention provides a flexible electrochromic film and device and methods for producing the flexible electrochromic film and device, belonging to the technical field of functional materials and devices. The flexible electrochromic film comprises an electrochromic film and a porous flexible substrate. The electrochromic film is made from an electrochromic material and deposited on the surface of the porous flexible substrate by adopting the chemical in situ polymerization process. The flexible electrochromic film is uniform, can exist independently without depending on an electrode, has good adhesive force, has no special requirement for the electrochromic material and can be made from the electrochromic material by adopting the chemical in situ polymerization process. The method for producing the flexible electrochromic film is simple. The complexity of the process for producing the flexible electrochromic film is simplified effectively, and the cost is lowered effectively. The flexible electrochromic film provided by the invention can be packaged into a flexible electrochromic device, thus the complexity of the process for producing the flexible electrochromic device is simplified, the cost is lowered, and the large-area flexible electrochromic device is expected to be popularized and applied.

Description

A kind of flexible electrochromic film and device and preparation method thereof

technical field

The invention belongs to the technical field of functional materials and devices, and relates to a flexible electrochromic film, a flexible electrochromic device and a preparation method thereof.

Background technique

Electrochromism (EC) refers to the phenomenon that under the action of an external electric field, the oxidation or reduction reaction of a material causes a reversible change in its transmission or reflection of light, which is manifested as a reversible change in color and transparency in appearance. In 1969, SKDeb first used amorphous WO ₃ film to make electrochromic devices, and proposed the "oxygen vacancy color center mechanism". Since then, people have gradually realized the unique advantages and potential applications of electrochromism. Electrochromic devices have been widely used in daily life: electrochromic energy-saving smart windows, automobile rearview anti-glare mirrors and display devices, etc.

Most of the existing electrochromic films are deposited on the transparent electrodes and packaged as a device as shown in Figure 1. 1 represents the color-changing film deposited on the transparent upper electrode, and 2 represents the liquid electrolyte layer and gel electrolyte layer. Or solid electrolyte layer, 3 represents the transparent lower electrode. The electrochromic film in this type of device is deposited on the transparent electrode by methods such as electrochemical deposition, pulling method, spin coating method, screen printing and magnetron sputtering. However, these methods need to consider Due to the unevenness of the film caused by the large square resistance of the electrode, the adhesion between the material and the transparent electrode, and the solubility of the electrochromic material, the preparation of the electrochromic film has a certain impact on the electrode and the electrode material. selectivity. If the electrochromic film can be deposited on other flexible substrates to obtain a layer of electrochromic film that is not attached to the electrode alone, it can overcome the difficulties in the preparation of electrochromic films, simplify the preparation process, and is expected to prepare flexible large-area Electrochromic devices.

The inventors of this patent application have devoted themselves to the research of electrochromic thin films and devices for a long time, and found that if an electrochromic film that does not adhere to the substrate can be obtained, the performance of the thin films and devices will be greatly improved. A method for preparing an electrochromic film that is not attached to any substrate was reported before, which opened up a new path for the structural assembly of new electrochromic devices (see Chinese patent application CN102109725A for details); but in subsequent In the work, it was found that the preparation of this type of film requires good solubility of the polymer in volatile organic solvents, and it also requires the polymer to form a flexible film by itself, which makes the method a little selective for the type of polymer , limiting the application of this type of device.

Contents of the invention

The invention provides a novel flexible electrochromic film and device and a preparation method thereof. The provided electrochromic film is deposited on a porous flexible substrate by a chemical in-situ polymerization method. The flexible electrochromic film can be applied to any electrochromic material that can be chemically in-situ polymerized; the electrochromic film prepared by this method is uniform, has good adhesion, and does not depend on the electrode to exist alone, which effectively improves the performance of the electrochromic film on the transparent electrode. Various limitations of preparing electrochromic film; the electrochromic film prepared by this method can also be packaged as a flexible device, reducing the complexity and cost of the electrochromic device manufacturing process, which is expected to make large-area flexible electrochromic devices popularized application.

Technical scheme of the present invention is as follows:

A flexible electrochromic film, as shown in Figure 2, includes an electrochromic film 2 and a porous flexible substrate 3, and the electrochromic film 2 is deposited on the porous film by chemical in-situ polymerization from an electrochromic material. Flexible substrate 3 surface.

A flexible electrochromic device, as shown in Figure 3, includes a four-layer structure packaged together, from top to bottom are a transparent upper electrode 1, a flexible electrochromic film, a porous film material 4 that has absorbed an electrolyte, and Transparent lower electrode 5; wherein said flexible electrochromic film as shown in Figure 2, comprises electrochromic film 2 and porous flexible substrate 3, and said electrochromic film 2 adopts chemical in-situ polymerization method by electrochromic material deposited on the surface of the porous flexible substrate 3 .

A method for preparing a flexible electrochromic film. Firstly, an organic monomer that can be polymerized into a conductive polymer is dissolved in water under the aid of a protonic acid, and ultrasonically stirred to prepare a uniform solution; then the porous flexible substrate is soaked in In the solution, slowly add ammonium persulfate oxidant under stirring; after the reaction is over, take out the porous flexible film deposited with conductive polymer, wash it with deionized water, and ultrasonically remove the oligomers on the surface, and finally deposit the conductive polymer The flexible electrochromic film was obtained after the porous flexible film was dried.

In the above method for preparing the flexible electrochromic film, the organic monomer is aniline, thiophene, pyrrole or their derivatives. On the one hand, the protic acid acts as a co-solvent (conventional organic monomers are difficult to dissolve in water); on the other hand, it provides hydrogen ions for the polymerization process of the conductive polymer, so that the deposited conductive polymer is a conductive polymer doped with hydrogen ions. have reversible oxidation-reduction properties.

A method for preparing a flexible electrochromic device, comprising the following steps:

Step 1: Preparation of flexible electrochromic film.

Firstly, the organic monomer that can be polymerized into a conductive polymer is dissolved in water under the aid of protonic acid, and ultrasonically stirred to prepare a uniform solution; then the porous flexible substrate is soaked in the solution, and the ammonium persulfate oxidant is slowly added under stirring After the reaction is finished, take out the porous flexible film deposited with conductive polymer, rinse with deionized water, and ultrasonically remove the oligomers on the surface, and finally obtain the flexible electro-conductive film after drying the porous flexible film deposited with conductive polymer. Color-changing film.

Step 2: Assembly of the electrochromic device.

Stack the transparent upper electrode, the flexible electrochromic film prepared in step 1, the porous film material and the transparent lower electrode in order from top to bottom, and then preliminarily encapsulate and expose part of the porous film material; then use the exposed part of the porous film The material absorbs the configured electrolyte; finally, the device is sealed.

The core technical solution of the present invention is to provide a flexible electrochromic film and its preparation method. The flexible electrochromic film is deposited on a porous flexible substrate by chemical in-situ polymerization, and the film layer is uniform and has good adhesion. A flexible electrochromic film that is not attached to electrodes and exists alone, and has no special requirements for electrochromic materials. Any electrochromic material capable of chemical in-situ polymerization can be prepared to obtain this type of flexible film; its preparation method is simple and effectively reduces The complexity and manufacturing cost of the electrochromic film preparation process are reduced; the electrochromic film provided by the present invention can also be packaged as a flexible device, which reduces the complexity and cost of the electrochromic device preparation process, thereby making it possible to make large-area flexible electrochromic devices Color-changing devices have been popularized and applied.

Description of drawings

Figure 1 Schematic diagram of the structure of a traditional electrochromic device. 1 indicates the color-changing film deposited on the transparent upper electrode, 2 indicates the liquid electrolyte layer, gel electrolyte layer or solid electrolyte layer, and 3 indicates the transparent lower electrode.

Fig. 2 is a schematic structural view of the flexible electrochromic film provided by the present invention. Among them, 2 represents the electrochromic film, and 3 represents the porous flexible substrate.

Fig. 3 is a schematic structural diagram of the flexible electrochromic device provided by the present invention. Among them, 1 represents a transparent upper electrode, 2 represents an electrochromic film, 3 represents a porous flexible substrate, 4 represents a porous film material adsorbed with an electrolyte, and 5 represents a transparent lower electrode.

Fig. 4 is a cyclic voltammetry scanning curve of a flexible electrochromic film provided by the present invention.

Detailed ways

Specific embodiments of the present invention will be described in detail below.

A flexible electrochromic film, as shown in Figure 2, includes an electrochromic film 2 and a porous flexible substrate 3, and the electrochromic film 2 is deposited on the porous film by chemical in-situ polymerization from an electrochromic material. Flexible substrate 3 surface.

In the above-mentioned flexible electrochromic film, the electrochromic material is a conductive polymer (including: conductive polymers such as polyaniline, polythiophene or polypyrrole) or its derivatives; the porous flexible substrate is an organic filter membrane, PVDF (polyvinylidene fluoride) membrane or porous filter cloth.

Fig. 4 is a cyclic voltammetry scanning curve of a specific flexible electrochromic film sample prepared in the present invention. The electrochromic material of this sample is polyaniline, and the porous flexible substrate is an organic filter membrane. Paste the sample on ITO glass as the working electrode, Pt wire as the counter electrode, Ag/AgCl as the reference electrode, and perform cyclic voltammetry scanning in 0.4mol/L H ₂ SO ₄ electrolyte. The scanning parameters are: voltage range: -0.3V-1.2V; scanning speed: 50mV/s. The cyclic voltammetry scanning curve shown in Figure 4 is obtained, from which the three pairs of redox peaks of polyaniline can be seen, indicating that the electrochromic film prepared by this method can realize the reversible change of ion implantation and extraction, and can be applied in electrochromic devices.

A flexible electrochromic device, as shown in Figure 3, includes a four-layer structure, from top to bottom is a transparent upper electrode 1, a flexible electrochromic film, a porous film material 4 that absorbs an electrolyte, and a transparent lower electrode 5 ; Wherein the flexible electrochromic film as shown in Figure 2, includes an electrochromic film 2 and a porous flexible substrate 3, the electrochromic film 2 is deposited on the described electrochromic film 2 by chemical in situ polymerization Porous flexible substrate 3 surface.

In the above-mentioned flexible electrochromic device, the electrochromic material is a conductive polymer (including: conductive polymers such as polyaniline, polythiophene or polypyrrole) or its derivatives; the porous flexible substrate 3 is an organic filter membrane , PVDF membrane or porous filter cloth.

In the above-mentioned flexible electrochromic device, the porous film material 4 is filter paper, sponge or other materials capable of absorbing electrolyte; the electrolyte is LiClO ₄ and HClO ₄ acetonitrile solution or LiClO ₄ polycarbonate solution; The transparent upper electrode 1 or the transparent lower electrode 5 is an ITO conductive film or other flexible transparent conductive films.

A method for preparing a flexible electrochromic film. Firstly, an organic monomer that can be polymerized into a conductive polymer is dissolved in water under the aid of a protonic acid, and ultrasonically stirred to prepare a uniform solution; then the porous flexible substrate is soaked in In the solution, slowly add ammonium persulfate oxidant under stirring; after the reaction is over, take out the porous flexible film deposited with conductive polymer, wash it with deionized water, and ultrasonically remove the oligomers on the surface, and finally deposit the conductive polymer The flexible electrochromic film was obtained after the porous flexible film was dried.

In the above method for preparing the flexible electrochromic film, the organic monomer is aniline, thiophene, pyrrole or their derivatives. On the one hand, the protic acid acts as a co-solvent (conventional organic monomers are difficult to dissolve in water); on the other hand, it provides hydrogen ions for the polymerization process of the conductive polymer, so that the deposited conductive polymer is a conductive polymer doped with hydrogen ions. have reversible oxidation-reduction properties.

A method for preparing a flexible electrochromic device, comprising the following steps:

Step 1: Preparation of flexible electrochromic film.

Firstly, the organic monomer that can be polymerized into a conductive polymer is dissolved in water under the aid of protonic acid, and ultrasonically stirred to prepare a uniform solution; then the porous flexible substrate is soaked in the solution, and the ammonium persulfate oxidant is slowly added under stirring After the reaction is finished, take out the porous flexible film deposited with conductive polymer, rinse with deionized water, and ultrasonically remove the oligomers on the surface, and finally obtain the flexible electro-conductive film after drying the porous flexible film deposited with conductive polymer. Color-changing film.

Step 2: Assembly of the electrochromic device.

Stack the transparent upper electrode, the flexible electrochromic film prepared in step 1, the porous film material and the transparent lower electrode in order from top to bottom, and then preliminarily encapsulate and expose part of the porous film material; then use the exposed part of the porous film The material absorbs the configured electrolyte; finally, the device is sealed.

In the preparation method of the above-mentioned flexible electrochromic device, the organic monomer of the conductive polymer described in step 1 is aniline, thiophene, pyrrole or their derivatives; the transparent upper electrode and transparent lower electrode described in step 2 are ITO conductive Membrane or other flexible transparent conductive film; Described porous film material is filter paper, sponge or other materials that can absorb electrolyte; Described electrolyte is LiClO ₄ and HClO ₄ acetonitrile solution or LiClO ₄ polycarbonate solution; Step 2 During the preliminary packaging of the device, it is packaged in plastic packaging, and in the final sealing, it is sealed with epoxy resin.

Claims (16)

1. a flexible electrochromic film comprises electrochromic film (2) and porous flexible substrate (3); It is characterized in that said electrochromic film (2) adopts chemical situ aggregation method to be deposited on said porous flexible substrate (3) surface by electrochromic material.

2. flexible electrochromic film according to claim 1 is characterized in that, said electrochromic material is the conducting polymer or derivatives thereof.

3. flexible electrochromic film according to claim 1 is characterized in that, said conducting polymer is polyaniline, polythiophene or polypyrrole.

4. flexible electrochromic film according to claim 1 is characterized in that, said porous flexible substrate is organic filter membrane, pvdf membrane or porous filter cloth.

5. a flexible electrochromic device comprises the four-layer structure that is packaged together, and is transparent upper electrode (1), flexible electrochromic film from top to bottom successively, has adsorbed the porous film material (4) and the transparent bottom electrode (5) of electrolytic solution; Wherein said flexible electrochromic film comprises electrochromic film (2) and porous flexible substrate (3), and said electrochromic film (2) adopts chemical situ aggregation method to be deposited on said porous flexible substrate (3) surface by electrochromic material.

6. flexible electrochromic device according to claim 5 is characterized in that, said electrochromic material is the conducting polymer or derivatives thereof.

7. flexible electrochromic device according to claim 6 is characterized in that, said conducting polymer is polyaniline, polythiophene or polypyrrole.

8. flexible electrochromic device according to claim 5 is characterized in that, said porous flexible substrate is organic filter membrane, pvdf membrane or porous filter cloth.

9. flexible electrochromic device according to claim 5 is characterized in that, said porous film material is that filter paper, sponge or other can adsorb the material of electrolytic solution.

10. flexible electrochromic device according to claim 5 is characterized in that, said electrolytic solution is LiClO ₄And HClO ₄Acetonitrile solution or LiClO ₄Polycarbonate solution.

11. flexible electrochromic device according to claim 5 is characterized in that, said transparent upper electrode (1) or transparent bottom electrode (5) are ITO conducting film or other flexible transparent conducting film.

12. the preparation method of a flexible electrochromic film, the organic monomer that at first can aggregate into conducting polymer is soluble in water under the hydrotropy of Bronsted acid, and ultrasonic agitation is mixed with uniform solution; Then the porous flexible substrate is soaked in the solution, stirs down slowly adding ammonium persulfate oxygenant; Question response finishes the back and takes out the porous flexible film that deposits conducting polymer, with deionized water rinsing, ultrasonic, to remove surperficial oligomer, obtains flexible electrochromic film after the porous flexible film that will deposit conducting polymer at last dries.

13. the preparation method of flexible electrochromic film according to claim 12 is characterized in that, said organic monomer is aniline, thiophene, pyrroles or their derivant.

14. a flexible electrochromism preparation of devices method may further comprise the steps:

Step 1: prepare flexible electrochromic film;

The organic monomer that at first can aggregate into conducting polymer is soluble in water under the hydrotropy of Bronsted acid, and ultrasonic agitation is mixed with uniform solution; Then the porous flexible substrate is soaked in the solution, stirs down slowly adding ammonium persulfate oxygenant; Question response finishes the back and takes out the porous flexible film that deposits conducting polymer, with deionized water rinsing, ultrasonic, to remove surperficial oligomer, obtains flexible electrochromic film after the porous flexible film that will deposit conducting polymer at last dries;

Step 2: the assembling of electrochromic device;

Order according to from top to bottom stacks flexible electrochromic film, porous film material and the transparent bottom electrode that transparent upper electrode, step 1 prepare, preliminary then encapsulation and exposed portions serve porous film material; Utilize the partially porous membraneous material that exposes to adsorb the electrolytic solution that configures then; The finally sealed device.

15. flexible electrochromism preparation of devices method according to claim 14 is characterized in that the organic monomer of conducting polymer described in the step 1 is aniline, thiophene, pyrroles or their derivant.

16. flexible electrochromism preparation of devices method according to claim 14 is characterized in that transparent upper electrode described in the step 2 and transparent bottom electrode are ITO conducting film or other flexible transparent conducting film; Said porous film material is that filter paper, sponge or other can adsorb the material of electrolytic solution; Said electrolytic solution is LiClO ₄And HClO ₄Acetonitrile solution or LiClO ₄Polycarbonate solution; Adopt the plastic packaging mode to encapsulate when device tentatively encapsulates in the step 2, adopt epoxy resin to seal during finally sealed.

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