CN100410791C - Sol-gel method for preparing all-solid-state electrochromic devices - Google Patents

Abstract

The invention belongs to the technical field of functional devices and electrochemical materials, and in particular relates to a preparation method of an all-solid-state electrochromic device. Specifically, a sol-gel (sol-gel) method is used to prepare the transparent conductive layer, electrochromic layer, ion conductive layer, and ion storage layer of the all-solid-state electrochromic device, and then assemble the device. Compared with other traditional preparation methods, the method of the present invention has the advantages of low cost, low process temperature, easy quantitative control, etc., and is easy to develop towards industrialization and large-scale production.

Description

Sol-gel method for preparing all-solid-state electrochromic devices

technical field

The invention belongs to the technical field of functional devices and electrochemical materials, and in particular relates to a method for preparing an all-solid-state electrochromic device.

Background technique

The so-called electrochromic (EC for short) refers to the phenomenon that the material undergoes a stable and reversible color change under the action of an external electric field. In terms of appearance performance, it is manifested as a reversible change in color and transparency. With the deepening of energy saving, environmental protection, and aesthetic concepts, Lampert et al. (Lampert CM, Solar Energy Mater. & Solar Cells, 1994, 32: 307-321) proposed to apply electrochromic devices (ECD) to buildings, vehicles, etc. Energy-saving daylighting system, development of electrochromic windows (Smart Window). Using this kind of smart window can effectively control the solar radiation energy entering the building while obtaining the best lighting conditions, thereby reducing the energy consumed by indoor temperature control. It has high efficiency, low consumption, green, pollution-free and intelligent. features. At the same time, electrochromic devices (ECDs) have broad application prospects in automotive anti-glare rearview mirrors, controllable smart windows, photoelectrochemical energy conversion and storage, and low-energy display screens. Traditional electrochromic devices consist of a five-layer structure of transparent conductive layer/electrochromic (EC) layer/ion conductive layer/ion storage (IS) layer/transparent conductive layer (as shown in Figure 1). The transparent conductive layer acts as an electrode to conduct electrons. At present, the DC magnetron sputtering method is mainly used to prepare transparent conductive films, but the high price of large-scale magnetron sputtering equipment leads to high cost of preparing the film. The electrochromic layer plays a decisive role in the performance of the entire electrochromic smart window. With the injection or extraction of small ions such as H ⁺ and L ₁ ⁺ , the light absorption characteristics of the film will change reversibly. Currently, the most comprehensive and in-depth research is For WO ₃ , sputtering technology is also mainly used to prepare the WO ₃ layer, the process control of which is complicated and the manufacturing cost is high. The function of the ion storage layer is to prevent the deposition of ions on the electrode. When the EC layer is injected with ions, the IS layer supplies ions to the electrolyte layer, and when the EC layer is extracted from the ions, the IS layer collects the ions to maintain the electrolyte layer. Electrically neutral. Nickel oxide has been proved to be an excellent ion storage layer material. The preparation methods of nickel oxide thin films mainly include physical methods such as electron beam evaporation and sputtering, which also have the problem of high cost. The ion-conducting layer provides a transport channel for the ions required for the electrochromic effect. The traditional electrolytes in ECD are generally liquid electrolytes. Such electrolytes have problems such as device packaging, liquid freezing, and accumulation of side reaction products. Therefore, solid materials with high ionic conductivity have been studied to replace liquid electrolytes. The process control of each layer of the traditional preparation of electrochromic devices is complicated, and the manufacturing cost is high, which limits the development of electrochromic devices in the direction of large-scale and industrialization.

Contents of the invention

The purpose of the present invention is to provide a method for preparing an all-solid-state electrochromic device with convenient process control, low manufacturing cost and easy industrialization.

The structure of the all-solid-state electrochromic device involved in the present invention is shown in Figure 1, and consists of a five-layer structure of transparent conductive layer/electrochromic layer/ion conductive layer/ion storage layer/transparent conductive layer, wherein the transparent conductive layer, Each layer such as the electrochromic layer, the ion storage layer, and the ion conductive layer is prepared by a sol-gel method.

The composition of described transparent conductive layer is as follows by weight share:

Nanoscale metal oxide powder uniformly dispersed slurry 100 parts,

Film-forming agent 0.1-80 parts,

pH adjuster 0-50 parts,

Co-solvent 0-50 parts,

Here, the nanoscale metal oxide powder uniformly dispersed slurry is one of indium tin oxide, tin antimony oxide, aluminum-doped zinc oxide or titanium dioxide, and the slurry is formed by uniformly dispersing the above metal oxide powder in ethanol. Its weight concentration is 20-30%.

The film-forming agent refers to a substance that can bond nano-scale powders together and adhere to the surface of the matrix material, and its composition ratio is as follows:

Silane coupling agent (such as KH560) 25 parts by weight,

Silica sol (such as FSI) 50-70 parts by weight,

Ethanol (analytical pure AR) 20-60 parts (weight),

Tetraethyl silicate 20-80 parts (weight),

Epoxy resin (such as E-51) 0.5-1 parts by weight,

Maleic acid (analytical pure AR) 2-4 parts (by weight).

The pH regulator refers to acidic or basic components added to the system to adjust the pH value of the system, such as hydrochloric acid, acetic acid, ammonia water, etc., but not limited thereto.

The co-solvent refers to the solvent added to control the volatilization rate of the solvent, such as n-butanol.

The ^{electrochromic} layer refers to a metal oxide or a coating of a polymer with a conjugated structure, such as tungsten oxide, molybdenum oxide, etc. , iridium oxide, polyaniline, polypyrrole, polypyridine or polythiophene, etc., but not limited thereto.

The ion storage layer refers to an inorganic or organic material that supplies ions to the electrolyte layer when the electrochromic layer of the working electrode is implanted with ions, and collects the ions to keep the electrolyte layer electrically neutral when the ions are extracted from the working electrode. Organic coatings, such as nickel oxide (N ₁ O _x ), vanadium oxide (V ₂ O ₃ ) or cobalt oxide (CoO), etc., but not limited thereto.

The ion-conducting layer is an all-solid polymer electrolyte layer with relatively high proton-conducting ability, which consists of:

Polymer 100 parts (moles of repeating units)

Lewis acid component 01-80 parts (moles)

The polymer here refers to a polymer that is Lewis basic and has certain transparency in a film state, such as polyvinyl alcohol, polyethylene oxide, polyvinyl pyrrolidone, polyvinyl butyral or polyvinyl tetrazole, etc. But it doesn't stop there.

The Lewis acid component refers to a proton (H ⁺ ), non-volatile inorganic, organic acid or acid salt, such as phosphoric acid, sulfuric acid, phosphotungstic acid or ammonium dihydrogen phosphate, but not limited thereto .

The concrete steps of preparing electrochromic device with sol-gel involved in the present invention are as follows:

(1) Treatment of the glass substrates. There are two glass substrates, and the dust and dirt on the surface of the glass substrates are removed. For example, it can be cleaned with acetone first, then soaked in 10% NaOH solution for 2 hours, washed with water after taking it out, and dried for later use;

(2) To prepare a transparent conductive layer, add a film-forming agent, a pH regulator and a co-solvent in the uniformly dispersed nano-scale metal oxide slurry, the pH value of the slurry is 3-3.5, and it is coated on the treated The surface of two glass substrates is made into a transparent conductive film;

(3) The electrochromic layer and the ion storage layer are respectively prepared on the transparent conductive layers of the two glass substrates by the sol-gel method;

(4) The sol-gel method is used to prepare an all-solid polymer electrolyte layer with high proton conductivity, which can be directly cast on the electrochromic layer based on glass or the ion storage layer based on glass The all-solid polymer electrolyte layer is then dried to form a film, and then compounded with another part. The other part refers to the part of the uncast all-solid polymer electrolyte layer. It is also possible to cast the polymer electrolyte layer on the template first, then form a film, and then It is composited with other partial layers by hot pressing method, that is, it is composited with two parts, the electrochromic layer and the ion storage layer with glass as the base material.

(5) Epoxy resin is used to seal the device. When sealing, pay attention to exposing the transparent conductive layer or leading in and out wires in advance.

Compared with other traditional preparation methods, the method for preparing each layer of an all-solid-state electrochromic device by the sol-gel method proposed by the present invention has the advantages of simple process equipment, no special vacuum coating conditions or other expensive equipment, and low cost. Low temperature, easy to apply and popularize, low process temperature, easy to prepare uniform multi-component oxide film, easy to do quantitatively, and can effectively control the composition and microstructure of the film. Therefore, this process for preparing all-solid-state devices has great advantages in terms of cost and preparation process. All layers of the device are prepared by the sol-gel method and the device assembly based on this preparation process has not been reported in the literature.

Description of drawings

Fig. 1 Schematic diagram of the structure of the electrochromic device and the coloring/fading reaction.

Fig. 2 Visible spectra of the all-solid-state electrochromic device in the coloring and achromatic states at +3V and -3V voltages respectively.

Detailed ways

The following examples are only to further illustrate the present invention in detail, and the present invention should not be limited to the specific and express contents of the following experimental examples without violating the gist of the present invention.

Example 1

Preparation of each layer of the electrochromic device:

(1) Preparation of transparent conductive layer:

The raw materials used are as follows:

Nano-indium tin oxide ethanol paste (20-30nm) Ningxia Dongfang Nonferrous Metals Group

Butanol (analytical grade AR) Shanghai Lingfeng Chemical Reagent Co., Ltd.

Hydrochloric acid (analytical pure AR) Sinopharm Chemical Reagent Co., Ltd.

Silane coupling agent (KH560) Nanjing Hefu Chemical Factory

Silica Sol (FSI) Zhejiang Yuda Chemical Co., Ltd.

Ethanol (analytical pure AR) Sinopharm Chemical Reagent Co., Ltd.

Ethyl Orthosilicate Shanghai Chemical Reagent Purchasing Supply Wulian Chemical Factory

Epoxy Resin (E-51) Zhejiang Jiahua Industrial Co., Ltd.

Maleic acid (analytical pure AR) Sinopharm Chemical Reagent Co., Ltd.

The raw material ratio of the self-made film-forming agent is as follows:

Silane coupling agent (KH560) 25 parts (weight)

Silica sol (FSI) 50 parts (weight)

Ethanol (analytical pure AR) 20 parts (weight)

Tetraethyl silicate 20 parts (weight)

Epoxy resin (E-51) 0.5 parts (weight)

Maleic acid (analytical pure AR) 3 parts (weight)

The raw material ratio of the prepared transparent conductive layer is as follows:

ITO powder evenly dispersed slurry 100 parts (weight)

Film-forming agent 15 parts (weight)

Hydrochloric acid 10 parts (weight)

n-butanol 2 parts (by weight)

Preparation process: Slowly add film-forming agent and co-solvent n-butanol to the nano-indium tin oxide ethanol slurry under magnetic stirring according to the proportion, and adjust the pH value of the system to 3-3.5 with dilute hydrochloric acid. Continue stirring for 1 h to make the slurry evenly mixed. Adopt spin-coating method (uniform glue machine, KW-4A type, Chemat Technology, Inc, USA) the coating of above-mentioned preparation is coated on the glass substrate surface that has been processed, put into baking oven after solvent volatilization at room temperature, at 120 Cure to form a film at ℃.

(2) The preparation of the electrochromic layer refers to the literature method (ozkan E., Tepehan F.Z., Solar Energy Materials & Solar Cells, 2001, 68 265-277)

The raw materials used are as follows:

Tungstic acid (H ₂ WO ₄ ) (analytical pure AR) was provided by Shanghai Chemical Reagent Company.

Citric acid (analytical pure AR) China National Pharmaceutical Group Shanghai Chemical Reagent Company

Hydrochloric acid (analytical pure AR) Sinopharm Chemical Reagent Co., Ltd.

Hydrogen peroxide (analytical pure AR) Yixing Second Reagent Factory

Preparation process: Dissolve tungsten oxide powder in 100ml of high-purity water, ultrasonically disperse for 10 minutes to dissolve, add slightly hot citric acid solution, adjust the pH value to 1, this solution is very easy to gel, according to 10ml (colloid) : 0.6ml (15% H ₂ O ₂ ) was added with hydrogen peroxide to stabilize the sol. Continue ultrasonic dispersion to obtain a colorless and transparent nano-sized WO ₃ .2H ₂ O sol containing citric acid, and form a WO ₃ thin film on the surface of the ITO substrate by a spin coating method. Dry the film in an oven (100°C, constant temperature for 1h), put the dried film into the oven, and perform annealing treatment at 150°C for 2h to obtain an amorphous WO ₃ film. (Strictly control the heating rate during the annealing process, about 2°C/min, otherwise cracks and holes will appear in the film, and the discoloration performance of the film will be seriously affected.)

(3) The preparation of the ion storage layer refers to the literature method (Wang Lianchao, Meng Fanli, Sun Yufeng, Huang Xingjiu, Liu Jinhuai, Journal of Inorganic Materials, 2004, 19(6): 1391-1396):

The raw materials used are as follows:

Nickel acetate (analytical pure AR) Shanghai Runjie Chemical Reagent Co., Ltd.

Sodium Hydroxide Jiangsu Jincheng Reagent Factory (Kunshan)

Ethanol (analytical pure AR) China National Pharmaceutical Group Shanghai Chemical Reagent Company

Ammonia (analytical pure AR) Shanghai Zhenxing Chemical Plant No. 2

Preparation process: Nickel acetate is dissolved in distilled water and ethanol to make nickel alkoxide, and the solution is subjected to alkaline hydrolysis catalytic reaction with NaOH, and then an appropriate amount of stabilizer is added, and a non-flocculating precipitate, homogeneous and translucent, is prepared after thorough stirring Precursor glue. The N ₁ O _x film was formed on the surface of the ITO substrate by the spin coating method, and then dried in an 80°C drying oven for 30 minutes, and then placed in a 500°C muffle furnace for 1 hour, and finally nickel oxide with electrochromic properties was obtained. film.

(4) The preparation of the ion-conducting layer refers to the literature method (Petty-Weeks, Zupancic J.J., Swedo J.R., Solid State Ionics, 1988, 31: 117-125).

The raw materials used are as follows:

Polyvinyl alcohol, the number average molecular weight Mn is 17200, the product of Aldrich company.

85wt% phosphoric acid, product of Shanghai United Chemical Plant.

Preparation process: Weigh a certain amount of polyvinyl alcohol (PVA) and phosphoric acid according to a certain ratio, first dissolve the PVA in deionized water, and stir with a magnetic stirrer at a constant temperature of 90-105°C until the PVA is completely dissolved and becomes transparent. Uniform viscous liquid, then add phosphoric acid, continue to stir at constant temperature for 2 hours, mix evenly, use the method of casting film to form a film on the polytetrafluoroethylene board, after vacuum drying, you can get the all-solid polymer non-aqueous sub-conductive film.

(5) Assembly of all-solid-state electrochromic devices: the above-prepared ion-conducting layer material can be directly cast on the electrochromic layer (or ion storage layer) by scraping, and then dried to form a film, as shown in Figure 1 The method shown is compounded with other layers, and it can also be used to make all-solid film on other templates, and then compound with other layers by hot pressing. Use epoxy resin to seal the device. When sealing, pay attention to make the ITO layer partially exposed or pre-introduce and connect the outgoing wires.

Test of electrochromic device (ECD) performance: adopt 760CTR double-beam ultraviolet-visible spectrophotometer (Shanghai Precision Scientific Instrument Co., Ltd.) to measure the light transmittance of ECD, as shown in Fig. 2 .

Example 2

Preparation of transparent conductive layer:

The raw materials used are as follows:

Aluminum-doped zinc oxide (AZO) (20-30nm) Ningxia Dongfang Nonferrous Metals Group.

The raw material ratio of the prepared transparent conductive layer is as follows:

AZO homogeneously dispersed slurry 100 parts (weight)

Film-forming agent 15 parts (weight)

Hydrochloric acid 10 parts (weight)

n-butanol 2 parts (by weight)

The preparation of the film-forming agent, the preparation process of the transparent conductive layer and the preparation process of other layers and device assembly of the all-solid-state electrochromic device are similar to those shown in Example 1, and the electrochromic performance of the obtained device is similar to that shown in FIG. 2 .

Example 3

Preparation of transparent conductive layer:

The raw materials used are as follows:

Aluminum-doped zinc oxide (AZO) (20-30nm) Ningxia Dongfang Nonferrous Metals Group.

The raw material ratio of the prepared transparent conductive layer is as follows:

AZO homogeneously dispersed slurry 100 parts (weight)

Film-forming agent 15 parts (weight)

Hydrochloric acid 10 parts (weight)

n-butanol 2 parts (by weight)

The preparation of the film-forming agent, the preparation process of the transparent conductive layer and the preparation process of other layers and device assembly of the all-solid-state electrochromic device are similar to those shown in Example 1, and the electrochromic performance of the obtained device is similar to that shown in FIG. 2 .

In above-mentioned embodiment, each component raw material and consumption and the parameter of preparation process are only for describing the representative that the present invention is selected, and in fact a large amount of experiments show, all can obtain above-mentioned similar in the scope of experiment contents part limitation. Electrochromic layers of similar performance and corresponding all-solid-state electrochromic devices.

Claims (6)

1. the preparation method of a full-solid electrochromic device, this device is formed by transparency conducting layer, electrochromic layer, ion conductive layer, ion storage and transparency conducting layer are compound successively, it is characterized in that adopting sol-gel process to prepare transparency conducting layer, electrochromic layer, ion conductive layer and ion storage successively, concrete steps are as follows:

(1) processing of glass baseplate, glass baseplate is 2, removes the dust and the dirt on glass baseplate surface;

(2) the preparation transparency conducting layer adds film forming agent, pH regulator agent and cosolvent in the finely dispersed slurry of nanosize metal oxide powder, and it is coated on treated two glass baseplate surfaces, makes transparent conductive film;

(3) adopt sol-gel process on the transparency conducting layer of two glass baseplates, to prepare electrochromic layer and ion storage layer respectively;

(4) the full solid state polymer electrolyte layer that adopts the sol-gel process preparation to have higher proton conductive ability, direct pouring full solid state polymer electrolyte layer on the ion storage layer of the electrochromic layer of glass baseplate or glass baseplate, drying and forming-film is compound with another part more then; Perhaps earlier at template top casting polyelectrolyte floor, film forming then, reusable heat platen press and other parts layer are compound; Here said another part is meant the part of the full solid state polymer electrolyte of not casting;

(5) adopt the epoxy sealing device, note making the electrically conducting transparent layer segment to expose during sealing or introduce in advance picking out lead;

Wherein, it is as follows that described transparency conducting layer is formed the weight share meter:

100 parts of the homodisperse slurries of nanosize metal oxide powder,

Film forming agent 0.1-80 part,

PH regulator agent 0-50 part,

Cosolvent 0-50 part,

Here, described nanosize metal oxide powder is one or more of tin indium oxide, tin-antiomony oxide, Al-Doped ZnO, titania, and slurry is that above-mentioned metal-oxide powder is scattered in the ethanol and forms, and weight concentration is 20-30%;

Described film forming agent, its composition weight share meter is as follows:

25 parts of silane coupling agents,

Silicasol 50-70 part,

Ethanol 20-60 part,

Ethyl orthosilicate 20-80 part,

Epoxy resin 0.5-1 part,

Maleic acid 2-4 part,

Described pH regulator agent is to be used for the pH value of regulation system and the acidity or the basic component that add in system;

Described cosolvent is the solvent that adds for the rate of volatilization of controlling solvent.

2. preparation method according to claim 1, its feature is being that described electrochromism layer material is tungsten oxide, molybdena, yttrium oxide, polyaniline, polypyrrole, polypyridine or polythiophene.

3. preparation method according to claim 1 is characterized in that described ion storage layer material is nickel oxide, vanadium oxide or cobalt oxide.

4. preparation method according to claim 1 is characterized in that described ion conductive layer consists of:

100 parts in polymkeric substance, by the repetitive molal quantity,

Lewis acid 0.1-80 part, by molal quantity,

The polymkeric substance here is to be polymkeric substance lewis base property, have the transparency under filminess;

Described lewis acid is that proton (H can be provided ⁺), nonvolatile inorganic, organic acid or acidic salt.

5. preparation method according to claim 4 is characterized in that described polymkeric substance is polyvinyl alcohol (PVA), polyoxyethylene, polyvinylpyrrolidone, polyvinyl butyral alcohol or polyvinyl alcohol tetrazole.

6. preparation method according to claim 4 is characterized in that described lewis acid is phosphoric acid, sulfuric acid, phosphotungstic acid or phosphoric acid dihydro amine.

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