CN110488551A - A kind of flexibility electrochromism sull, device and preparation method thereof - Google Patents

Abstract

The invention discloses a flexible electrochromic oxide film, a device and a preparation method thereof. The preparation method of the flexible electrochromic oxide film is: (1) isolating a plurality of independent regions on a flexible substrate; (2) Dissolving the halide powder in a solvent to prepare an electrochromic oxide precursor solution, preparing different concentrations and different types of electrochromic oxide precursor solutions; (3) using one or more electrochromic oxide precursors obtained in step (2) The mutagenic oxide precursor liquid is drop-coated to one or more independent regions isolated in step (1), and then photochemically deposited in a UV light box, and repeated several times; (4) the oxide obtained in step (3) The thin film electrode is heat-treated to obtain the flexible electrochromic oxide thin film. The electrochromic thin film and the preparation method of the device provided by the invention have a certain prospect in the popularization and application of large-area flexible electrochromic devices.

Description

A flexible electrochromic oxide film, device and preparation method thereof

technical field

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

Background technique

The so-called electrochromism refers to the phenomenon that the optical properties such as absorption coefficient, reflectivity, and transmittance of material materials undergo reversible color changes under the action of an external electric field. The basic principle is that under the action of an external electric field, redox reactions occur through the injection or extraction of charges (ions or electrons), which changes the apparent color and transparency of the material. Materials with such characteristics are collectively referred to as electrochromic materials, which are usually divided into two categories, namely organic electrochromic materials and inorganic electrochromic materials. Devices made of electrochromic materials are called electrochromic devices. . Electrochromic devices are widely used in important fields such as building energy saving, military anti-counterfeiting, and information display. Common electrochromic devices include smart windows, glare-free mirrors, electrochromic displays, and memory devices.

Transition metal oxide electrochromic materials mainly include Ti, V, Cr, Mn, Fe, Co, Ni, Nb, Mo, Tc, Ru, Rh, Ta, W, Ir and other elements. According to different coloring voltages, it can be divided into cathode coloring materials (WO ₃ , TiO ₂ , Ta ₂ O ₅ , etc.) and anode coloring materials (NiO, IrO ₂ , V ₂ O ₅ , etc.). Due to the advantages of high electrochromic color contrast, good cycle stability and good thermal stability, transition metal oxides have attracted extensive attention from enterprises and researchers in recent years. The common industrial preparation of electrochromic metal oxide films is mainly through magnetron sputtering, but this preparation method has problems such as complicated preparation equipment, uncontrollable sputtering area, expensive metal targets, and harsh vacuum conditions. In addition, at present, the substrates of electrochromic thin films, both in laboratory research and in actual use, are mainly rigid ITO (tin-doped indium oxide) or FTO (fluorine-doped tin oxide) glass, and the electrodes are very difficult to bend during bending. It is vulnerable to damage and cannot meet the requirements of flexible devices. Compared with electrochromic devices made of traditional rigid glass substrates, flexible electrochromic devices can not only be arbitrarily mounted on the surface of non-planar objects, but also lighter in weight and more in line with commercial needs. Therefore, the present invention aims to design a simple and general thin film preparation method, and develop a method for manufacturing multicolor flexible electrochromic devices, so as to realize the controllable preparation of one or more types of electrochromic devices with different areas and types on a flexible transparent substrate. Chromogenic oxide films.

Chinese patent CN 106676488A discloses a NiO electrochromic film production process and glass based on magnetron sputtering. The process is realized based on vertical continuous vacuum magnetron sputtering equipment. The ITO nano film layer is deposited by magnetron sputtering, and then the NiO anode electrochromic film layer is deposited on the ITO nano film layer by DC magnetron sputtering. However, the cost of this method is very high, it is not conducive to large-scale continuous production, and it is only suitable for the preparation of NiO thin films. Chinese patent CN 103969904 B discloses a method for preparing a flexible electrochromic layer and a device. The flexible electrochromic layer is coated with an electrochromic slurry on a metal foam, and then pressed into a sheet to obtain a dense electrochromic layer. . The preparation process of this method is simple, the cost is low, overcomes the difficult problem that the electrochromic powder particles are not easy to form a film, and is applicable to all electrochromic powder particles, but the electrochromic film prepared by this method is relatively thick and has relatively low electrochromic performance. Difference.

Contents of the invention

The purpose of the present invention is to solve the problems existing in the above-mentioned flexible electrochromic oxide film and its device preparation method, to propose a method for preparing a flexible electrochromic oxide film and a method for preparing a flexible electrochromic device based on the film .

In order to achieve the above object, the technical scheme adopted in the present invention is:

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

(1) Multiple independent regions are isolated on the flexible substrate;

(2) Dissolving the halide powder in a solvent to prepare an electrochromic oxide precursor solution, preparing different concentrations and different types of electrochromic oxide precursor solutions;

(3) drop-coating one or more of the electrovariable oxide precursor liquid obtained in step (2) to one or more isolated independent areas of step (1), and then performing photochemical deposition in a UV light box, and Repeat several times;

(4) heat-treating the oxide thin film electrode obtained in step (3) to obtain the flexible electrochromic oxide thin film.

Preferably, in the step (1), the flexible substrate is one of PET conductive film, polyimide (PI) conductive film, silver-based transparent conductive film, and graphene-based transparent conductive film.

Preferably, in the step (1), the manner of isolating a plurality of independent regions on the flexible substrate is: adhering the material used for isolating the independent regions to the flexible substrate through an epoxy resin adhesive.

As a preference, the material used to isolate the independent area is polyethylene, PET, polyethylene (PEI), polyimide (PI), polypropylene (PP), polycarbonate (PC), polyurethane (PU) or A type of dimethylsiloxane (PDMS).

Preferably, in the step (2), the halide is one or more of WCl ₆ , VCl ₃ , NbCl ₅ , MoCl ₅ .

Preferably, the halide concentration in the electrochromic oxide precursor solution is 0.1-2 g/mL.

Preferably, in the step (2), the solvent is a mixture of one or more of water, ethanol, methanol, n-propanol, isopropanol, n-butanol, tetrahydrofuran, dimethyl ether or acetone.

Preferably, in the step (3), during the photochemical deposition process, the wavelength of the ultraviolet light source is 185-254 nm, and the photo-deposition time is 2-15 min.

Preferably, in the step (4), the heat treatment atmosphere is an air atmosphere, the temperature is 80-160° C., and the time is 0.5-3 hours.

A flexible electrochromic oxide film prepared by the above method.

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

(1) Multiple independent regions are isolated on the flexible substrate;

(2) Dissolving the halide powder in a solvent to prepare an electrochromic oxide precursor solution, preparing different concentrations and different types of electrochromic oxide precursor solutions;

(3) drop-coating one or more of the electrovariable oxide precursor liquid obtained in step (2) to one or more isolated independent areas of step (1), and then performing photochemical deposition in a UV light box, and Repeat several times;

(4) heat-treating the oxide film electrode obtained in step (3) to obtain the flexible electrochromic oxide film;

(5) Epoxy resin is evenly coated on the isolation barrier between the independent regions on the flexible substrate obtained in step (1), and then it is adhered to another clean flexible electrode, and finally the two electrodes Electrolyte solution is injected into the gap between them to obtain a flexible electrochromic device.

Preferably, in the step (5), the electrolyte is a polycarbonate (PC) solution of lithium perchlorate, lithium carbonate or lithium tetrafluoroborate, with a concentration of 0.1-0.5M.

A flexible electrochromic device prepared by the above method.

The flexible electrochromic oxide film prepared by the present invention has a loose and porous morphology and a relatively high porosity. This loose and porous morphology is not only beneficial to the contact and penetration of the electrolyte, but also shortens the charge during the electrochromic process. transfer path. Taking the WO ₃ flexible electrochromic film as an example, the thickness of the film is about 700nm, and it has a relatively fast electrochromic speed (fade time 5s, coloring time 15s), and the transmittance in the faded state is greater than 90%, almost transparent, and the coloring In the state, the light transmittance is less than 40%, and the optical modulation range ΔT is about 60%, which has a large optical modulation range. In addition, the electrochromic film is flexible and bendable, which can be applied to the preparation of flexible electrochromic devices, and has a prospect in the field of flexible wearable electronic devices.

Beneficial effect:

(1) The present invention adopts the method of light deposition, one or more kinds of transition metal chloride precursor liquid droplets are coated on the flexible substrate surface, utilize the method of ultraviolet light deposition to reduce it to the transition metal oxide with electrochromic characteristic thin film, and finally heat-treated to obtain an electrochromic thin film. The electrochromic thin film is an amorphous oxide thin film with loose and porous surface morphology, which is beneficial to electrolyte penetration and ion diffusion, and has good electrochromic performance. At the same time, the thickness of the film can be adjusted, and it has strong adhesion to the substrate and is not easy to fall off.

(2) The assembly method of the flexible electrochromic device developed by the present invention has simple process, low requirements on experimental conditions, no high temperature and no vacuum. It overcomes the long reaction time of traditional magnetron sputtering, sol-gel, hydrothermal, electrodeposition and other methods, requires complex and precise instruments and equipment, requires high annealing temperature (>300°C), and is suitable for vacuum environments. Disadvantages such as strict requirements and high cost.

(3) The preparation method of the flexible electrochromic oxide thin film and its device disclosed in the present invention is not only universally applicable to a variety of electrochromic oxides, but also can freely adjust the types and types of oxides in each independent electrochromic area according to requirements. The shape and size of the electrochromic region can truly realize the controllable preparation of multi-species, multi-shape, and multi-size flexible electrochromic devices.

Description of drawings

Figure 1 is a schematic diagram of the preparation process of a flexible electrochromic oxide film disclosed in the present invention;

Fig. 2 is a schematic structural diagram of a flexible electrochromic device disclosed in the present invention;

Fig. ₃ is the WO3 flexible electrochromic thin film X-ray diffraction (XRD) spectrum prepared by embodiment 1;

Fig. 4 is the transmission spectrum of the faded state and the colored state corresponding to the WO3 flexible electrochromic device prepared in embodiment ₂ ;

Fig. 5 is the response time curve of the WO ₃ flexible electrochromic device prepared in Example 3 during the discoloration process at a wavelength of 650nm.

Detailed ways

A preparation method of a flexible electrochromic oxide thin film and a device of the present invention, firstly isolate a plurality of regions on a flexible substrate, and then use ultraviolet light and ozone generated by ultraviolet light to convert transition metal precursors into non-crystalline Based on the principle of transition metal oxides, one or more transition metal oxide films are prepared in different isolation regions, and finally packaged with a flexible counter electrode to form an electrochromic device. Specifically include the following steps:

(1) Multiple independent regions are isolated on the flexible substrate;

Among them, the flexible substrate is preferably PET conductive film, PI conductive film, silver-based transparent conductive film, graphene-based transparent conductive film, but not limited thereto;

Among them, the way of isolating multiple independent regions on the flexible substrate is: the material used for isolating the independent regions is adhered to the flexible substrate through an adhesive; the material used for isolating the independent regions is preferably polyethylene, poly Ethylene Phthalate (PET), Polyethylene (PEI), Polyimide (PI), Polypropylene (PP), Polycarbonate (PC), Polyurethane (PU) or Dimethicone alkanes (PDMS), etc., but not limited thereto; the adhesive is preferably epoxy resin adhesive, but not limited to this adhesive.

(2) Dissolving the halide powder in a solvent to prepare an electrochromic oxide precursor solution, preparing different concentrations and different types of electrochromic oxide precursor solutions;

Among them, the halides are WCl ₆ , VCl ₃ , NbCl ₅ , MoCl ₅ and other halides, but not limited thereto; the concentration of halides in the precursor solution is 0.1-2 g/mL;

Wherein, the solvent is one or more mixtures of water, ethanol, methanol, n-propanol, isopropanol, n-butanol, tetrahydrofuran, dimethyl ether or acetone;

(3) Drop-coating one or more oxide precursor liquids obtained in step (2) to one or more isolated independent areas of step (1), then performing photochemical deposition in a UV light box, and repeating several times;

Wherein, during the photochemical deposition process, the wavelength of the ultraviolet light source is 185-254 nm, and the light deposition time is 2-15 minutes.

(4) heat-treating the oxide film electrode obtained in step (3) to obtain a flexible electrochromic oxide film;

Wherein, the heat treatment atmosphere is an air atmosphere, the temperature is 80-160° C., and the time is 0.5-3 hours;

So far, the preparation of the flexible electrochromic oxide thin film of the present invention is completed.

(5) Epoxy resin is evenly coated on the isolation barrier between the independent regions on the flexible substrate obtained in step (1), and then it is adhered to another clean flexible electrode, and finally the two electrodes Electrolyte solution is injected into the gap between them to obtain a flexible electrochromic device;

Wherein, the electrolytic solution is a polycarbonate (PC) solution of lithium perchlorate, lithium carbonate or lithium tetrafluoroborate, and the concentration is 0.1-0.5M.

So far, the preparation of the flexible electrochromic device of the present invention is completed.

The present invention will be described in detail below in conjunction with specific embodiments.

The scope of protection of the present invention is not limited to the embodiments, but only elaborates on the protection. For example, polyethylene terephthalate (PET) is selected as the material used to isolate the independent regions in the embodiment, and polyethylene, polyethylene (PEI), polyimide (PI), polypropylene ( PP), polycarbonate (PC), polyurethane (PU) or dimethylsiloxane (PDMS); the electrochromic oxide film precursor is WCl ₆ , or VCl ₃ , NbCl ₅ , MoCl ₅ halogenated The solvent is ethanol, and water, methanol, n-propanol, isopropanol, n-butanol, tetrahydrofuran, dimethyl ether or acetone can also be used instead.

Example 1

First, the PET flexible substrate with a size of 2×4 cm was ultrasonically cleaned with acetone, absolute ethanol, and deionized water for 10 minutes to remove dust, organic matter and other stains on the surface. Then, the flexible substrate is isolated into two independent regions by using PET, and the material used for isolating the independent regions is adhered to the flexible substrate through an epoxy resin adhesive.

Prepare a tungsten hexachloride precursor solution with a concentration of 0.25M, weigh 0.4g of tungsten hexachloride powder and dissolve it in 40mL of absolute ethanol, and magnetically stir for 2 hours at room temperature to obtain a uniform dark blue precursor solution.

The tungsten hexachloride precursor solution was drop-coated in two areas separated by PET, and then transferred to a UV light box with a wavelength of 185-254nm, and irradiated by ultraviolet light deposition for 5 minutes. Alternately repeat the steps of drop coating and UV light 7 times.

The obtained tungsten oxide thin film is heat-treated at 100° C. for 1 hour in an air atmosphere, and the heating rate is set at 10° C./min to obtain a flexible electrochromic oxide thin film.

On the isolation barrier prepared by homogeneous PET with epoxy resin, it is then adhered to another clean flexible electrode, and finally lithium perchlorate/propylene carbonate (LiClO ₄ ) is injected into the gap between the two electrodes. /PC) solution to obtain a flexible electrochromic device.

Example 2

First, the PET flexible substrate with a size of 2×4 cm was ultrasonically cleaned with acetone, absolute ethanol, and deionized water for 10 minutes to remove dust, organic matter and other stains on the surface. Then, the flexible substrate is isolated into four independent regions by using PET, and the material used for isolating the independent regions is adhered to the flexible substrate through an epoxy resin adhesive.

Prepare a tungsten hexachloride precursor solution with a concentration of 0.25M, weigh 0.4g of tungsten hexachloride powder and dissolve it in 40mL of absolute ethanol, and magnetically stir for 2 hours at room temperature to obtain a uniform dark blue precursor solution.

The tungsten hexachloride precursor was drop-coated in four areas separated by PET, and then transferred to a UV light box with a wavelength of 185-254nm, and irradiated by UV light deposition for 10 minutes. Alternately repeat the steps of drip coating and UV light 6 times.

The obtained tungsten oxide thin film is heat-treated at 90° C. for 2 hours in an air atmosphere, and the heating rate is set at 10° C./min to obtain a flexible electrochromic oxide thin film.

On the isolation barrier prepared by homogeneous PET with epoxy resin, it is then adhered to another clean flexible electrode, and finally lithium perchlorate/propylene carbonate (LiClO ₄ ) is injected into the gap between the two electrodes. /PC) solution to obtain a flexible electrochromic device.

Example 3

First, the PET flexible substrate with a size of 2×4 cm was ultrasonically cleaned with acetone, absolute ethanol, and deionized water for 10 minutes to remove dust, organic matter and other stains on the surface. Then, PET is used to isolate 8 independent regions from the flexible substrate, and the material used for isolating the independent regions is adhered to the flexible substrate through an epoxy resin adhesive.

Prepare a tungsten hexachloride precursor solution with a concentration of 0.25M, weigh 0.4g of tungsten hexachloride powder and dissolve it in 40mL of absolute ethanol, and magnetically stir for 2 hours at room temperature to obtain a uniform dark blue precursor solution.

The tungsten hexachloride precursor solution was drop-coated in 8 areas separated by PET, and then transferred to a UV light box with a wavelength of 185-254nm, and irradiated by UV light deposition for 15 minutes. Alternately repeat the steps of drop coating and UV light 5 times.

The obtained tungsten oxide thin film is heat-treated at 80° C. for 3 hours in an air atmosphere, and the heating rate is set at 10° C./min to obtain a flexible electrochromic oxide thin film.

On the isolation barrier prepared by homogeneous PET with epoxy resin, it is then adhered to another clean flexible electrode, and finally lithium perchlorate/propylene carbonate (LiClO ₄ ) is injected into the gap between the two electrodes. /PC) solution to obtain a flexible electrochromic device.

The above is only a preferred embodiment of the present invention, it should be pointed out that, for those of ordinary skill in the art, without departing from the principle of the present invention, some improvements and modifications can also be made, and these improvements and modifications can also be made. It should be regarded as the protection scope of the present invention.

Claims (10)

1. a kind of preparation method of flexibility electrochromism sull, it is characterised in that: the following steps are included:

(1) multiple independent regions are isolated on a flexible substrate；

(2) halide powder is dissolved in solvent, is formulated as electrochromism oxide precursor liquid, prepare various concentration, difference The electrochromism oxide precursor liquid of type；

(3) the resulting electroluminescent change oxide forerunner drop-coated of one or more steps (2) to one or more steps (1) is isolated In isolated area out, photochemical precipitation is then carried out in ultraviolet lamp box, and be repeated several times；

(4) step (3) resulting oxide film electrode is heat-treated, it is thin obtains the flexible electrochromism oxide Film.

2. the preparation method of flexibility electrochromism sull according to claim 1, it is characterised in that: the step (1) in, flexible substrates are PET conductive film, polyimides conductive film, silver-based transparent conductive film, graphene-based transparent conductive film It is a kind of；The mode for isolating multiple independent regions on a flexible substrate is: material used in independent region will be isolated and pass through Epoxy resin binder adheres on a flexible substrate；It is polyethylene, PET, polyethylene that material used in independent region, which is isolated, Asia, polyimides, polypropylene, one kind of polycarbonate, polyurethane or dimethyl siloxane.

3. the preparation method of flexibility electrochromism sull according to claim 1, it is characterised in that: the step (2) in, the halide is WCl₆, VCl₃, NbCl₅, MoCl₅It is one or more；Halogenation in electrochromism oxide precursor liquid Object concentration is 0.1~2g/mL.

4. the preparation method of flexibility electrochromism sull according to claim 1, it is characterised in that: the step (2) in, solvent is one kind or more of water, ethyl alcohol, methanol, normal propyl alcohol, isopropanol, n-butanol, tetrahydrofuran, dimethyl ether or acetone The mixture of kind.

5. the preparation method of flexibility electrochromism sull according to claim 1, it is characterised in that: the step (3) in, during photochemical precipitation, ultraviolet source wavelength is 185~254nm, and the light deposition time is 2~15min.

6. the preparation method of flexibility electrochromism sull according to claim 1, it is characterised in that: the step (4) in, heat-treating atmosphere is air atmosphere, and temperature is 80~160 DEG C, and the time is 0.5~3 hour.

7. a kind of flexible electrochromism sull being prepared by any method of claim 1-6.

8. a kind of preparation method of flexible electro-chromic device, it is characterised in that: the following steps are included:

(1) multiple independent regions are isolated on a flexible substrate；

(2) halide powder is dissolved in solvent, is formulated as electrochromism oxide precursor liquid, prepare various concentration, difference The electrochromism oxide precursor liquid of type；

(3) the resulting electroluminescent change oxide forerunner drop-coated of one or more steps (2) to one or more steps (1) is isolated In isolated area out, photochemical precipitation is then carried out in ultraviolet lamp box, and be repeated several times；

(4) step (3) resulting oxide film electrode is heat-treated, it is thin obtains the flexible electrochromism oxide Film；

(5) by epoxy resin be evenly applied to the isolation barrier in flexible substrates obtained by step (1) between independent region it On, it is got up with another clean flexible electrode adherency then, electrolyte is finally injected in gap between two electrodes Solution obtains a kind of flexible electro-chromic device.

9. the preparation method of flexible electro-chromic device according to claim 8, it is characterised in that: in the step (5), Electrolyte is the polycarbonate solution of lithium perchlorate, lithium carbonate or LiBF4, and concentration is 0.1~0.5M.

10. a kind of flexible electro-chromic device of the preparation of the method as described in claim 8 or 9.