CN1237146C - Electrochromic material and its preparation method and electrochromic device - Google Patents

Abstract

A method for preparing an electrochromic material, comprising the steps of: forming a transparent conductive film on a transparent substrate, (b) forming a metal film on the transparent conductive film by electroless plating technique, (c) oxidizing the metal film to form a metal oxide film on the transparent conductive film, wherein the metal oxide film generates electrochromic characteristics when a voltage is applied to the metal oxide film.

Description

Electrochromic material and its preparation method and electrochromic device

【Technical field】

The present invention relates to an electrochromic material and a preparation method thereof, in particular to an electrochromic material and a method for manufacturing the electrochromic material using an electroless plating technique .

【Background technique】

An electrochromic material usually includes a transparent substrate, a transparent conductive film formed on the substrate, and a metal oxide film formed on the conductive film. The metal oxide film, such as nickel oxide (nickel oxide) film, produces electrochromic properties when a voltage is applied. The metal oxide film is formed by first depositing a metal film on the conductive film, and then oxidizing the metal film. The metal thin film is generally obtained by a wet process, such as electrochemical deposition, sol-gel techniques and spin-coating techniques, or a dry process, such as vacuum It is produced by vacuum evaporation, sputtering techniques and electrode deposition. The sputtering techniques, such as rf-sputtering and reactive dc magnetronsputtering, require expensive equipment and a considerable space. The sol-gel technique may result in poorer quality metal films due to heating during solvent removal. The electroplating method has poor reproducibility (cyclic ability) and the aging rate of the prepared metal oxide film is fast (only about 300 times of discoloration life).

【Content of invention】

The main purpose of the present invention is to provide a method for producing an electrochromic material using an electroless plating method, which can overcome the shortcomings of the aforementioned prior art; the present invention also provides an electrochromic material, and an electrochromic material. Chromogenic device.

A method for preparing electrochromic materials of the present invention comprises the following steps: (a) forming a transparent conductive film on a transparent substrate to obtain a transparent conductive substrate, (b) electroless plating forming a metal film on the transparent conductive film of the transparent conductive substrate, (c) oxidizing the metal film to form a metal oxide film on the transparent conductive film, when a voltage is applied to the metal oxide film , the metal oxide film will produce electrochromic properties.

The electrochromic material of the present invention is made by the above method. The electrochromic device of the present invention comprises first and second electrode layers spaced apart from each other, an auxiliary electrode layer and an electrochromic layer disposed between the first and second electrode layers, and an electrochromic layer disposed between the first and second electrode layers, and A conductive polymer layer between the auxiliary electrode layer and the electrochromic layer, the electrochromic layer includes the electrochromic material produced by the above method.

【Description of drawings】

Below in conjunction with accompanying drawing and embodiment the present invention is described in detail:

FIG. 1 is a block diagram illustrating sequential steps of a preferred embodiment of the method of the present invention for preparing an electrochromic material.

FIG. 2 is a schematic diagram illustrating an electrochromic device having an electrochromic layer formed by the method of the present invention.

Fig. 3 is a schematic diagram illustrating how to measure the light transmittance and aging condition of the electrochromic material prepared according to the present invention.

Fig. 4 is an ultraviolet spectrum analysis diagram illustrating the change of the light transmittance in the visible light region (300-820nm) of the electrochromic material prepared according to the present invention under different times of electrochromic reactions.

Figure 5 is a current-potential diagram (C.V.diagram), illustrating the current-potential of the electrochromic material prepared according to the present invention under the electrochromic reaction of 1, 100, 500 and 1000 times (cycle) Variety.

【Detailed ways】

Figure 1 is a block diagram illustrating the sequential steps of a preferred embodiment of the method of the present invention. The method comprises the following steps: (a) forming a transparent conductive film on a transparent substrate to obtain a transparent conductive substrate, (b) forming a metal thin film on the transparent conductive film of the transparent conductive substrate by electroless plating On, (c) oxidizing the metal film to form a metal oxide film on the transparent conductive film, and when a voltage is applied to the film, electrochromic properties will be produced.

The metal film is made of nickel. The electroless plating of the metal thin film on the transparent conductive substrate is carried out by using a plating bath (plating bath) having a composition comprising a water-soluble nickel salt, a reducing agent, and optionally, A chelating agent and a buffer. The nickel salt is a compound selected from the following group: nickel sulfate and nickel chloride. The reducing agent is a compound selected from the group consisting of hypophosphitesalt, hydrazine and sodium borohydride. The chelating agent is a compound selected from the following group: sodium citrate hydrate (trisodium citrate dihydrate, molecular formula is Na ₃ C ₆ O ₇ H ₅ ·H ₂ O), tartaric acid, sodium tartrate, citric acid (citric acid) and ammonium chloride (ammonium chloride). The buffering agent is a compound selected from the group consisting of boric acid, maleic acid and itaconic acid. Preferably, the electroless plating operation is performed at a temperature between 40°C and 60°C.

Preferably, the water-soluble nickel salt is nickel sulfate, the reducing agent is sodium hypophosphite, the chelating agent is sodium citrate hydrate, and the buffering agent is boric acid.

Preferably, the transparent substrate is made of a material selected from the group consisting of glass, polyvinyl chloride, polyethylene, polycarbonate, and poly Polyethylene terephthalate.

Preferably, the transparent conductive film is made of a material selected from the following group: indium tin oxide (indium tin oxide, referred to as ITO), antimony tin oxide (antimony tin oxide, referred to as ATO), fluorine tin oxide (fluorine-doped tin oxide, referred to as FTO), and iridium tin oxide (iridium tin oxide, referred to as IRTO). Preferably, the transparent conductive film is made of ITO.

Preferably, the metal oxide film is prepared by heating the metal film above the transparent conductive film at a temperature of 150-450° C. in the presence of oxygen.

Due to the difference in properties between the metal thin film and the conductive thin film, in order to increase the bonding strength between the metal thin film and the conductive thin film, preferably, the transparent conductive substrate can be surface treated before electroless plating. The surface treatment comprises the following steps: (1) degreasing the transparent conductive substrate, (2) sensitizing the transparent conductive film with a sensitizing solution containing a sensitizing agent, (3) The transparent conductive film is activated by using an activation solution containing an activator. The sensitizer is a compound selected from the group consisting of tin chloride and titanium chloride. The activator is a compound selected from the group consisting of palladium chloride and platinum chloride. Preferably, the aforementioned sensitization and activation steps are performed at a temperature between room temperature and 50°C. For example, when tin chloride and palladium chloride are used as the sensitizer and the activator respectively, the tin ions (Sn ²⁺ ) in the sensitization solution will penetrate into the micropores on the surface of the conductive film during the sensitization operation, During the activation operation, the palladium ions will undergo redox with the tin ions, and the reduced palladium will replace the tin ions and be implanted into the micropores.

Preferably, the sensitizer is tin chloride, and the sensitization solution is prepared by dissolving tin chloride in a hydrochloric acid solution.

Preferably, the activator is palladium chloride, and the activation solution is prepared by dissolving palladium chloride in a hydrochloric acid solution.

FIG. 2 illustrates an electrochromic device (ECD) comprising an electrochromic layer 103 of an electrochromic material made according to the method of the present invention. A polymer conductive layer 104, an auxiliary electrode layer (charge-balancing counter electrode layer) 105 and the electrochromic layer 103 are sandwiched between the first and second electrode layers 102, 102a, and are electrically connected (electrically connected) to the first and second electrode layers 102, 102a. The first and second electrode layers 102, 102a are oppositely formed on the first and second glass substrates 101, 101a. When a voltage is applied to the first and second electrode layers 102 and 102a through the potential input 106, the electrochromic layer 103 will undergo electrochemical oxidation and reduction, thereby causing a change in the absorbance of the electromagnetic spectrum, thereby producing coloring (coloring) and decolorization (bleaching) properties.

The following examples will illustrate how the electrochromic material is prepared according to the method of the present invention.

<Example 1>

In this embodiment, a glass substrate and an ITO conductive film are used to make a transparent conductive substrate. The transparent conductive substrate is degreased in a cleaning solution by ultrasonic vibration. The cleaning solution is prepared by dissolving a predetermined amount of surfactant in 50 ml of de-ionized water. Then the transparent conductive substrate was washed with deionized water. The washed transparent conductive substrate was sensitized by using a sensitizing solution comprising 0.5 g of tin chloride (SnCl ₂ ), 0.5 ml of hydrochloric acid and 50 ml of deionized water. The sensitization step is carried out at room temperature for 5 to 50 minutes. Then, the transparent conductive substrate is activated by using an activation solution comprising 0.025 g of palladium chloride (PdCl ₂ ), 0.5 ml of hydrochloric acid and 50 ml of deionized water. The activation step is carried out at room temperature for 2 to 20 minutes. Afterwards, the activated transparent conductive substrate was washed with deionized water, and then the substrate was soaked in a bath containing 1.6g nickel sulfate (NiSO ₄ ·6H ₂ O), 3.61g sodium citrate hydrate, 2.7g ammonium chloride ( NH ₄ Cl) and 0.75g of sodium hypophosphite (NaH ₂ PO ₂ ·H ₂ O) in a bath for electroless plating. The electroless plating step is performed at a temperature of 45 to 85° C. for 0.5 to 20 minutes. The electroless plated substrate was washed with deionized water and then dried. The metal (nickel) plated film on the non-conductive surface on the substrate side was removed using hydrochloric acid. Afterwards, the substrate is calcined (oxidized) at 150-400° C. for 30-120 minutes by heating in the atmosphere, and a nickel oxide film is formed on the ITO conductive film by annealing.

<Example 2>

The experimental procedure of this example is similar to that of Example 1, except that the composition in the electroless plating bath includes 3.0 g of nickel sulfate, 6.0 g of sodium citrate hydrate, 4.0 g of boric acid and 2.0 g of sodium hypophosphite.

<Electrochromic reaction test>

Using a cyclic voltammeter (Cyclic Voltammeter) 301 and an ultraviolet spectrum analyzer (UV Spectrum Analyzer) 303 as shown in Figure 3, the electrochromic material prepared in Example 1 was tested for electrochromic reaction. The prepared electrochromic material is placed in a UV cell (cell) 302 for testing. The UV tank 302 includes a KOH electrolyte solution 4 body, and a pair of opposite electrodes 1 (counterelectrode), a reference electrode 2 (platinum electrode) and a working electrode 3 (working electrode) immersed in the solution, using the electrochromic Material). During the test, by applying a square-wave output voltage of +1.5V to -1.5V and an input voltage, the electrochromic material of the working electrode 3 will perform the following reversible reactions:

(A)

(B)

The generation of NiOOH in the reaction (B) will cause the coloring of the electrochromic material, while the generation of Ni(OH) ₂ will cause the decolorization of the electrochromic material.

As shown in FIG. 4 , the ultraviolet spectrometer uses visible light with wavelengths ranging from 300 to 820 nm to measure the transmittance of the electrochromic material (using a solvent of 1M KOH). The change in light transmittance of the electrochromic material from Ni(OH) ₂ state to NiOOH state, or conversely from NiOOH state to Ni(OH) ₂ state represents the electrochromic property of the electrochromic material. The results show that after the electrochromic material undergoes 1000 electrochromic reactions (B), the transmittance change from NiOOH to Ni(OH) ₂ (decolorization) is similar to the initial electrochromic reaction , which means that the electrochromic material can still maintain good electrochromic ability after 1000 decolorization reactions, without obvious aging phenomenon, and the light transmittance changes in the visible light region are quite obvious. Potential for blackout window materials.

As shown in FIG. 5 , the cyclic voltammeter measures current and potential changes during the electrochromic reaction (B). The results show that after the electrochromic material undergoes 1000 electrochromic reactions, its redox potential shifts little, which means that the aging phenomenon is not obvious after 1000 reactions.

In view of the above, compared with the previous methods, the method of the present invention using electroless plating technology to prepare electrochromic materials is a method with a simpler process and lower cost, and the life of the electrochromic materials prepared by the method of the present invention is longer.

Although the present invention has been explained in detail by means of the above detailed description and preferred embodiments, the present invention should not be construed as being limited by the foregoing embodiments; on the contrary, the present invention covers the technical contents disclosed in the description of this case. equivalent change. Therefore, without departing from the essence of the present invention, all simple equivalent changes made according to the claims of the present invention should fall within the scope covered by the claims of the present invention.

Claims (17)

1. A method for preparing electrochromic materials, characterized in that it comprises the following steps: (a) forming a transparent conductive film on a transparent base material to make a transparent conductive substrate; (b) forming a metal thin film on the transparent conductive film of the transparent conductive substrate by electroless plating; (c) The metal film is oxidized to form a metal oxide film on the transparent conductive film, and when a voltage is applied to the metal oxide film, the metal oxide film will produce electrochromic properties; Wherein, the metal thin film is made of nickel, and the electroless plating of the metal thin film on the transparent conductive substrate is carried out by using a plating bath with a composition comprising a water-soluble nickel salt, a Reducing agent, and optionally, a chelating agent and a buffering agent; the nickel salt is a compound selected from the following group: nickel sulfate, nickel chloride, and combinations thereof; the reducing agent is selected from the following Compounds in the group: hypophosphite, hydrazine, sodium borohydride, and combinations thereof; the chelating agent is a compound selected from the group consisting of sodium citrate hydrate, tartaric acid, sodium tartrate, citric acid, Ammonium chloride, and combinations thereof; the buffer is a compound selected from the group consisting of boric acid, maleic acid, itaconic acid, and combinations thereof; Before performing electroless plating, the following processing steps are further included: (1) degreasing the transparent conductive substrate; (2) sensitizing the transparent conductive film by using a sensitizing solution containing a sensitizer; The transparent conductive film is activated by using an activation solution containing an activator; the sensitizer is a compound selected from the group consisting of tin chloride, titanium chloride, and combinations thereof; the activator is a compound selected from the group consisting of palladium chloride, platinum chloride, and combinations thereof. 2. The method for preparing electrochromic materials as claimed in claim 1, characterized in that: the water-soluble nickel salt is nickel sulfate, the reducing agent is sodium hypophosphite, and the chelating agent is sodium citrate hydrated material, the buffer is boric acid. 3. The method for preparing an electrochromic material as claimed in claim 1, wherein the transparent substrate is made of a material selected from the following group: glass, polyvinyl chloride, Polyethylene, polycarbonate, and polyethylene terephthalate. 4. The method for preparing electrochromic materials as claimed in claim 3, characterized in that: the transparent conductive film is made of a material selected from the following group: indium tin oxide, antimony oxide tin, fluorine tin oxide, and iridium tin oxide. 5. The method for preparing an electrochromic material as claimed in claim 4, characterized in that: the metal oxide thin film is prepared by applying the It is made by heating the metal film above the transparent conductive film. 6. The method for preparing an electrochromic material as claimed in claim 1, characterized in that: the sensitizer is tin chloride, and the sensitizing solution is obtained by dissolving tin chloride in a hydrochloric acid solution Made in. 7. The method for preparing an electrochromic material as claimed in claim 6, wherein the activator is palladium chloride, and the activation solution is obtained by dissolving palladium chloride in a hydrochloric acid solution And made. 8. An electrochromic material prepared by the method of claim 1, comprising a transparent substrate, a transparent conductive film formed on the transparent substrate, and a transparent conductive film formed on the transparent conductive film and when applied with a A metal oxide film with electrochromic properties will be produced when voltage is applied, wherein the metal oxide film is made by electrolessly plating a metal film on the transparent conductive film, and then oxidizing the metal film. 9. The electrochromic material as claimed in claim 8, characterized in that: the metal film is made of nickel, and the electroless plating of the metal film on the transparent conductive substrate is by using a composition The plating bath is carried out, and the composition comprises a water-soluble nickel salt, a reducing agent, and optionally, a chelating agent and a buffer; the nickel salt is a compound selected from the following group: nickel sulfate, Nickel chloride, and combinations thereof; the reducing agent is a compound selected from the following group: hypophosphite, hydrazine, sodium borohydride, and combinations thereof; the chelating agent is selected from the following group Compounds of: sodium citrate hydrate, tartaric acid, sodium tartrate, citric acid, ammonium chloride, and combinations thereof; the buffer is a compound selected from the group consisting of boric acid, maleic acid, itaconic acid, and their combinations. 10. The electrochromic material according to claim 9, characterized in that: the water-soluble nickel salt is nickel sulfate, the reducing agent is sodium hypophosphite, the chelating agent is sodium citrate hydrate, the buffer For boric acid. 11. The electrochromic material according to claim 10, characterized in that: the transparent substrate is made of a material selected from the following group: glass, polyvinyl chloride, polyethylene, polycarbonate esters, and polyethylene terephthalate. 12. The electrochromic material according to claim 11, characterized in that: the transparent conductive film is made of a material selected from the following group: indium tin oxide, antimony tin oxide, fluorine tin oxide , and iridium tin oxide. 13. The electrochromic material as claimed in claim 12, characterized in that: the metal oxide film is formed by coating the metal on the transparent conductive film at a temperature of 150 to 450°C in the presence of oxygen. The film is made by heating. 14. An electrochromic device, comprising first and second electrode layers spaced apart from each other, an auxiliary electrode layer and an electrochromic layer arranged between the first and second electrode layers, and an The polymer conductive layer between the auxiliary electrode layer and the electrochromic layer, the electrochromic layer includes the electrochromic material prepared by the method of claim 1, which includes a transparent substrate, a A transparent conductive film on the substrate and a metal oxide film that produces electrochromic properties when a voltage is applied, the metal oxide film is formed by electrolessly plating a metal film on the transparent conductive film, and then The metal thin film is oxidized. 15. The electrochromic device according to claim 14, wherein the metal thin film is made of nickel, and the electroless plating of the metal thin film on the transparent conductive substrate is by using a The plating bath is carried out, and the composition comprises a water-soluble nickel salt, a reducing agent, and optionally, a chelating agent and a buffer; the nickel salt is a compound selected from the following group: nickel sulfate, Nickel chloride, and combinations thereof; the reducing agent is a compound selected from the following group: hypophosphite, hydrazine, sodium borohydride, and combinations thereof; the chelating agent is selected from the following group Compounds of: sodium citrate hydrate, tartaric acid, sodium tartrate, citric acid, ammonium chloride, and combinations thereof; the buffer is a compound selected from the group consisting of boric acid, maleic acid, itaconic acid, and their combinations. 16. The electrochromic device according to claim 15, characterized in that: the water-soluble nickel salt is nickel sulfate, the reducing agent is sodium hypophosphite, the chelating agent is sodium citrate hydrate, and the buffer For boric acid. 17. The electrochromic device as claimed in claim 16, characterized in that: the metal oxide film is formed on the transparent conductive film at a temperature of 150 to 450°C in the presence of oxygen The metal thin film is heated and made.

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