A method for preparing an electrochromic film using a high polymer and application of the electrochromic film in an electrochromic device

Abstract

This invention belongs to the technical field of electrochromic devices, specifically relating to a method for preparing electrochromic thin films using polymers and the application of these films in electrochromic devices. Materials used to prepare the electrochromic thin films include gum arabic powder and P2W. 18 The material is prepared by spin-coating the material with deionized water in a mass ratio of 0.1:1:5, 0.15:1:5, 0.2:1:5, 0.25:1:5, or 0.3:1:5. The electrochromic film is prepared by spin-coating the material onto the surface of FTO glass, and then assembled with blank FTO glass to fabricate an electrochromic device. The electrochromic film provided by this invention utilizes the abundant hydroxyl groups on gum arabic powder to form a hydrogen-bonded cross-linked network while simultaneously immobilizing P2W. 18 This can prevent P2W 18 It detaches during cycling, thereby improving the cycling stability of electrochromic devices. Furthermore, gum arabic powder, as a natural polymer material, offers significant environmental advantages when used in electrochromic films.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrochromic devices, and particularly relates to a method for preparing an electrochromic film by using a high polymer and application of the electrochromic film in an electrochromic device. BACKGROUND

[0002] With the continuous growth of the world population and the accelerated urbanization process, the total energy consumption is showing a vigorous upward trend. Global warming and innovation opportunities in the energy field are driving the innovation and development of various energy-saving systems and low-carbon products. This green development momentum is becoming an increasingly strong engine for global sustainable development. As a cathode color-changing material, polyoxometalate has good redox activity, strong light modulation capability, high chemical stability and ultraviolet stability, and can also be used as an electron storage body to produce color changes without changing the structure. It has been widely studied in the field of electrochromism. However, polyoxometalate can be dissolved in most polar solvents and easily fall off the substrate, with poor cycle stability. Moreover, most of the cross-linking agents currently studied are chemical drugs, which pose environmental problems. Therefore, it is urgent to develop an environmentally friendly polyoxometalate-based electrochromic film and electrochromic device with high cycle stability. SUMMARY

[0003] In view of the above problems, the present application provides a method for preparing an electrochromic film by using a high polymer and application of the electrochromic film in an electrochromic device. The abundant hydroxyl groups on gum arabic powder (GA) form a hydrogen-bonded cross-linked network while fixing P2W 18 , so that the electrochromic performance of P2W 18 is maximized.

[0004] To achieve the above-mentioned purposes, the technical scheme adopted by the present application is as follows:

[0005] A method for preparing an electrochromic film by using a high polymer, gum arabic powder and P2W 18 are dissolved in deionized water in a mass ratio, and then spin-coated on the surface of FTO glass; the mass ratio of the gum arabic powder, P2W 18 and deionized water is 0.1:1:5, 0.15:1:5, 0.2:1:5, 0.25:1:5 or 0.3:1:5.

[0006] Further, the above-mentioned method for preparing an electrochromic film by using a high polymer specifically comprises the following steps:

[0007] 1) gum arabic powder and P2W 18 are dissolved in deionized water in a mass ratio;

[0008] 2) the solution obtained in step 1) is spin-coated on the surface of FTO glass;

[0009] 3) After spin coating, dry at 80℃ for 10min to prepare electrochromic film on FTO glass surface.

[0010] Further, in step 2), the spin coating is first at 1000r / min for 10s, and then at 2000r / min for 20s.

[0011] Further, in step 3), the thickness of the electrochromic film is 300nm.

[0012] The application of the electrochromic film prepared by the method in any one of the above in electrochromic device.

[0013] Further, the electrochromic device is a "sandwich" structure composed of FTO glass loaded with electrochromic film as working electrode, ion transport liquid as electrolyte, and blank FTO glass as counter electrode.

[0014] Further, the ion transport liquid is an organic electrolyte solution containing Li + .

[0015] Preferably, the ion transport liquid is LiClO4 / PC electrolyte.

[0016] Further, the LiClO4 / PC electrolyte is a solution of lithium perchlorate dissolved in propylene carbonate (PC) to prepare a Li + concentration of 1M solution.

[0017] The beneficial effects of the present application are:

[0018] 1. The gum arabic powder used in the present application is a natural polysaccharide extracted from acacia trees, acacia trees and other plants, which is a highly branched complex structure connected by multiple monosaccharides. The structure is rich in functional groups such as hydroxyl and carboxyl groups, which form hydrogen bond cross-linking network with metal ions to fix polyoxometalate and prevent polyoxometalate from falling off during the cycle. In addition, in the solution, the gum arabic molecules are in random coiled conformation, which can fully stretch and interact with the surrounding water molecules, so that the gum arabic powder has good solubility and dispersibility, and can form a uniform solution or colloid in the system. Moreover, the gum arabic powder has a certain surface activity, which can reduce the surface tension of the liquid, promote the adsorption of polyoxometalate on the interface and form a stable film, thereby improving the cycle stability and light modulation range of the electrochromic device.

[0019] 2. The material used for preparing the electrochromic film in the present application adopts gum arabic powder, P2W 18and deionized water, by using the rich hydroxyl group on gum arabic powder to form a hydrogen bond crosslinking network while fixing P2W 18 , P2W 18 is prevented from falling off in the cycle process, thereby improving the cycle stability of the electrochromic device.

[0020] 3、Gum arabic powder as a natural polymer material, applied in electrochromic film to assemble electrochromic device with application value, has very obvious environmental protection advantage. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 is the full spectrum diagram of the electrochromic device prepared in Example 1 under ultraviolet visible light 400-800nm and different applied voltages.

[0022] Figure 2 is the full spectrum diagram of the electrochromic device prepared in Example 2 under ultraviolet visible light 400-800nm and different applied voltages.

[0023] Figure 3 is the full spectrum diagram of the electrochromic device prepared in Example 3 under ultraviolet visible light 400-800nm and different applied voltages.

[0024] Figure 4 is the full spectrum diagram of the electrochromic device prepared in Example 4 under ultraviolet visible light 400-800nm and different applied voltages.

[0025] Figure 5 is the full spectrum diagram of the electrochromic device prepared in Example 5 under ultraviolet visible light 400-800nm and different applied voltages.

[0026] Figure 6 is the long-term cycle stability test diagram of the electrochromic device prepared in Example 1 under ultraviolet visible light 600nm and two-electrode system with applied voltage-2v~2v.

[0027] Figure 7 is a schematic diagram of the electrochromic device of the present application, wherein 1 and 2 are FTO glass, 3 is an electrochromic film, and 4 is LiClO4 / PC electrolyte. DETAILED DESCRIPTION

[0028] Example 1

[0029] 1. An electrochromic film material, comprising gum arabic powder, P2W 18 and deionized water, the mass ratio of gum arabic powder, P2W 18 and deionized water is 0.2:1:5.

[0030] 2. A method for preparing an electrochromic film using a polymer, comprising the following steps:

[0031] 1) According to the mass ratio of gum arabic powder, P2W 18 and deionized water is 0.2:1:5, gum arabic powder and P2W 18 are dissolved in deionized water;

[0032] 2) The solution obtained in step 1) is spin-coated on the surface of FTO glass, and the spin-coating is first carried out at a speed of 1000 r / min for 10 s, and then at a speed of 2000 r / min for 20 s;

[0033] 3) After spin-coating, dry at 80°C for 10 min to prepare an electrochromic film on the surface of FTO glass. The thickness of the prepared electrochromic film is 300 nm.

[0034] 3, The FTO glass loaded with the electrochromic film obtained is used as a working electrode, and a blank FTO glass is used as a counter electrode to assemble an electrochromic device, and LiClO4 / PC electrolyte is injected in the middle, as shown in Figure 7 . The LiClO4 / PC electrolyte is a solution with a Li + concentration of 1M prepared by dissolving lithium perchlorate in propylene carbonate (PC).

[0035] 4, Full spectrum test: The electrochromic device prepared in Example 1 is tested in the full spectrum of ultraviolet-visible light 400-800 nm under different voltages, as shown in Figure 1 , the ΔT of the electrochromic device prepared in Example 1 is 78% (-1.6v~1.6v) (ΔT is the difference between the transmittance T of the bleached state and the transmittance T of the colored state).

[0036] Example 2

[0037] 1. An electrochromic film material, comprising gum arabic powder, P2W 18 and deionized water, the mass ratio of gum arabic powder, P2W 18 and deionized water is 0.1:1:5.

[0038] 2. A method for preparing an electrochromic film using a polymer, comprising the following steps:

[0039] 1) According to the mass ratio of gum arabic powder, P2W 18 and deionized water is 0.1:1:5, gum arabic powder and P2W 18 are dissolved in deionized water;

[0040] 2) The solution obtained in step 1) is spin-coated on the surface of FTO glass, and the spin-coating is first performed at a speed of 1000 r / min for 10 s, and then at a speed of 2000 r / min for 20 s;

[0041] 3) After spin-coating, the film is dried at 80°C for 10 min to obtain an electrochromic film on the surface of FTO glass.

[0042] 3) The FTO glass loaded with the electrochromic film obtained in step 2) is used as a working electrode, and a blank FTO glass is used as a counter electrode to assemble an electrochromic device, and LiClO4 / PC electrolyte is injected therebetween, as shown in Figure 7 The LiClO4 / PC electrolyte is a solution of lithium perchlorate in propylene carbonate (PC) with a concentration of 1M. +

[0043] 4) Full spectrum test: The electrochromic device prepared in Example 2 is subjected to full spectrum test under ultraviolet-visible light of 400-800 nm and different voltages, as shown in Figure 2 The ΔT of the electrochromic device prepared in Example 2 is 65% at -1.6V-1.6V (ΔT is the difference between the transmittance T in bleached state and the transmittance T in colored state).

[0044] Example 3

[0045] 1) An electrochromic film material, comprising gum arabic powder, P2W 18 and deionized water, wherein the mass ratio of gum arabic powder, P2W 18 and deionized water is 0.15:1:5.

[0046] 2) A method for preparing an electrochromic film by using a polymer, specifically comprising the following steps:

[0047] 1) Gum arabic powder and P2W 18 are dissolved in deionized water according to the mass ratio of gum arabic powder, P2W 18 and deionized water of 0.15:1:5.

[0048] 2) The solution obtained in step 1) is spin-coated on the surface of FTO glass, and the spin-coating is first performed at a speed of 1000 r / min for 10 s, and then at a speed of 2000 r / min for 20 s;

[0049] 3) After spin-coating, the film is dried at 80°C for 10 min to obtain an electrochromic film on the surface of FTO glass.

[0050] ​3, the FTO glass loaded with the electrochromic film obtained as the working electrode and the blank FTO glass as the counter electrode are assembled into an electrochromic device, and LiClO4 / PC electrolyte is injected in the middle, as shown in Figure 7 + The LiClO4 / PC electrolyte is a solution of lithium perchlorate in propylene carbonate (PC) prepared into a Li

[0051] 4, full spectrum test: the electrochromic device prepared in Example 3 is subjected to full spectrum test under ultraviolet visible light 400-800nm and different voltages, as shown in Figure 3 The ΔT of the electrochromic device prepared in Example 3 is 65.6% at -1.6v-1.6v (ΔT is the difference between the transmittance T of the bleached state and the transmittance T of the colored state).

[0052] Example 4

[0053] 1, an electrochromic film material, comprising gum arabic powder, P2W 18 and deionized water, and the mass ratio of gum arabic powder, P2W 18 and deionized water is 0.25:1:5.

[0054] 2, a method for preparing an electrochromic film by using a high polymer, specifically comprising the following steps:

[0055] 1) according to the mass ratio of gum arabic powder, P2W 18 and deionized water is 0.25:1:5, gum arabic powder and P2W 18 are dissolved in deionized water;

[0056] 2) the solution obtained in step 1) is spin-coated on the surface of FTO glass, and the spin-coating is first carried out at a speed of 1000r / min for 10s, and then at a speed of 2000r / min for 20s;

[0057] 3) after spin-coating, dry at 80℃ for 10min to prepare an electrochromic film on the surface of FTO glass. The thickness of the electrochromic film prepared is 300nm.

[0058] 3, the FTO glass loaded with the electrochromic film obtained as the working electrode and the blank FTO glass as the counter electrode are assembled into an electrochromic device, and LiClO4 / PC electrolyte is injected in the middle, as shown in Figure 7 + The LiClO4 / PC electrolyte is a solution of lithium perchlorate in propylene carbonate (PC) prepared into a Li

[0059] ​​4. Full-spectrum testing: The electrochromic device prepared in Example 4 was subjected to full-spectrum testing in the ultraviolet-visible light range of 400-800 nm under different applied voltages, such as... Figure 4 As shown, the electrochromic device prepared in Example 4 has a ΔT of 72.8% in the range of -1.6V to 1.6V (ΔT is the difference between the transmittance T in the faded state and the transmittance T in the colored state).

[0060] Example 5

[0061] 1. An electrochromic thin film material, comprising gum arabic powder and P2W 18 And deionized water, gum arabic powder, P2W 18 The mass ratio of water to deionized water is 0.3:1:5.

[0062] 2. A method for preparing electrochromic thin films using polymers, specifically comprising the following steps:

[0063] 1) According to gum arabic powder, P2W 18 The mass ratio of gum arabic powder to deionized water is 0.3:1:5. 18 Soluble in deionized water;

[0064] 2) Spin-coat the solution obtained in step 1) onto the FTO glass surface. When spin-coating, first spin at 1000 r / min for 10 s, and then spin at 2000 r / min for 20 s.

[0065] 3) After spin coating, the film was dried at 80°C for 10 min to obtain an electrochromic film on the FTO glass surface. The thickness of the obtained electrochromic film was 300 nm.

[0066] 3. Using the obtained FTO glass loaded with the electrochromic film as the working electrode and blank FTO glass as the counter electrode, an electrochromic device is assembled, with LiClO4 / PC electrolyte injected in between. Figure 7 As shown. The LiClO4 / PC electrolyte is prepared by dissolving lithium perchlorate in propylene carbonate (PC). + A solution with a concentration of 1M.

[0067] 4. Full-spectrum testing: The electrochromic device prepared in Example 5 was subjected to full-spectrum testing in the ultraviolet-visible light range of 400-800 nm under different applied voltages, such as... Figure 5 As shown, the electrochromic device prepared in Example 5 has a ΔT of 66.2% in the range of -1.6V to 1.6V (ΔT is the difference between the transmittance T in the faded state and the transmittance T in the colored state).

[0068] Depend on Figures 1-5It can be seen that Example 1 has higher optical contrast at the same color-changing voltage compared to Examples 2-5, while the cyclic stability test is performed on Example 1, and Figure 6 It can be seen that by utilizing the abundant hydroxyl groups on gum arabic powder to form a hydrogen-bonding crosslinking network while fixing P2W 18 , the polyacid P2W 18 is prevented from falling off during the cycle, thereby improving the cyclic stability of the electrochromic device.

Claims

1. A method for preparing an electrochromic thin film using a high polymer, characterized by, Gum arabic powder and P2W 18 dissolved in deionized water, and then spin-coated on the surface of FTO glass; the mass ratio of the gum arabic powder, P2W 18 and deionized water is 0.1:1:5, 0.15:1:5, 0.2:1:5, 0.25:1:5, or 0.3:1:

5.

2. The method for preparing electrochromic thin films using polymers according to claim 1, characterized in that, Specifically comprising the following steps: 1) Gum arabic powder and P2W 18 dissolved in deionized water; 2) spin coating the solution obtained in step 1) on the surface of FTO glass; 3) drying the spin-coated product at 80°C for 10 min to obtain an electrochromic film on the surface of FTO glass.

3. The method for preparing electrochromic thin film using high polymer according to claim 2, characterized in that, In step 2), the spin coating is first performed at a speed of 1000 r / min for 10 s, and then at a speed of 2000 r / min for 20 s.

4. The method for preparing electrochromic thin films using polymers according to claim 2, characterized in that, In step 3), the electrochromic film has a thickness of 300 nm.

5. Use of the electrochromic film prepared by the method of any one of claims 1-4 in an electrochromic device.

6. Use according to claim 5, characterized in that, The electrochromic device is a "sandwich" structure composed of FTO glass loaded with the electrochromic film as a working electrode, an ion transport liquid as an electrolyte, and blank FTO glass as a counter electrode.

7. Use according to claim 6, characterized in that, The ion transport liquid is an organic electrolyte solution containing Li + PF6.

8. Use according to claim 7, characterized in that, The ion transport liquid is LiClO4 / PC electrolyte.

9. Use according to claim 8, characterized in that, The LiClO4 / PC electrolyte is prepared by dissolving lithium perchlorate in propylene carbonate to form a Li + solution having a concentration of 1 M.

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