Electrochromic thin film with super-long power-off coloring memory time and preparation method thereof

Abstract

The application discloses an electrochromic film with super-long power-off coloring memory time and a preparation method thereof. The film is a titanium dioxide and organic small molecule composite film. The test is completed under a three-electrode system. The three-electrode system comprises a working electrode, an electrolyte, a counter electrode and a reference electrode. The working electrode is a conductive substrate with an electrochromic layer, and the electrochromic layer is a titanium dioxide and organic small molecule composite film. The electrolyte is a 1M LiClO4 / PC solution. The counter electrode is a Pt electrode. The reference electrode is an Ag / AgCl electrode. After the organic small molecules are doped on the titanium dioxide film, the film has excellent performance in cycle stability and coloring efficiency, has greater optical modulation capacity under the same voltage, and has quite excellent performance in power-off coloring memory time, thereby achieving the purpose of energy saving.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of photoelectric materials, and particularly relates to an electrochromic film with super-long discharging coloring memory time based on the synergistic effect of an organic small molecule and titanium dioxide. BACKGROUND

[0002] With the increase of world population and the acceleration of urbanization, the total energy consumption is also rapidly increasing, and global warming and energy crisis accelerate the development of various energy-saving systems and energy-saving products. + Titanium dioxide is a common Li The method for improving the electrochromic performance of titanium dioxide includes doping and loading electrochromic active substances, and some organic small molecules help to increase the electron concentration in titanium dioxide, thereby improving the utilization rate of electrons and accelerating the redox process of titanium dioxide film. SUMMARY

[0003] To solve the above-mentioned technical problems, the application provides an electrochromic film with super-long discharging coloring memory time based on the synergistic effect of an organic small molecule and titanium dioxide, which improves the electrochromic performance of titanium dioxide film through a simple and easy soaking method.

[0004] The technical scheme adopted by the application is as follows: an electrochromic film with super-long discharging coloring memory time, wherein the electrochromic film is provided with an electrochromic layer on a conductive substrate, and the electrochromic layer is a titanium dioxide and organic small molecule composite film; the organic small molecule is H4TBAPy-R, wherein R is selected from OH, X or NO2; and X is halogen.

[0005] Preferably, the organic small molecule is selected from 1,3,6,8-tetrakis (benzoic acid) pyrene (H4TBAPy), hydroxyl-substituted 1,3,6,8-tetrakis (benzoic acid) pyrene (H4TBAPy-OH), halogen-substituted 1,3,6,8-tetrakis (benzoic acid) pyrene (H4TBAPy-X), or nitro-substituted 1,3,6,8-tetrakis (benzoic acid) pyrene (H4TBAPy-NO2).

[0006] A preparation method of an electrochromic film with super-long discharging coloring memory time, comprising the following steps:

[0007] 1) Preparation of titanium dioxide layer: titanium dioxide is printed on a conductive substrate by screen printing, sintered at 500 DEG C for 30 min, and cooled to room temperature to obtain a titanium dioxide film;

[0008] 2)The conductive substrate printed with titanium dioxide film is immersed in an ethanol solution of organic small molecules to obtain a titanium dioxide and organic small molecule composite film.

[0009] Preferably, the concentration of the organic small molecules in step 2) is 0.15 mg mL -1 .

[0010] Preferably, the immersion time in step 2) is 12 h.

[0011] The beneficial effects of the present application are:

[0012] 1、The present application uses organic small molecule composite titanium dioxide to improve the electron utilization rate of the film, accelerate the reduction process of titanium dioxide, and has excellent performance in cycle stability and coloring efficiency. The film has greater optical modulation capacity under the same voltage, especially in the power-off coloring memory time, and achieves the purpose of energy saving.

[0013] 2、The present application has a simple composite film preparation process and easy operation. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is the transmittance change of TiO2@H4TBAPy prepared in Example 1 after applying a voltage of 1~-1.6 V at a UV-visible wavelength of 700 nm.

[0015] Figure 2 is the transmittance change of TiO2@H4TBAPy-OH prepared in Example 2 after applying a voltage of 1~-1.6 V at a UV-visible wavelength of 700 nm.

[0016] Figure 3 is the transmittance change of TiO2@H4TBAPy-Br prepared in Example 3 after applying a voltage of 1~-1.6 V at a UV-visible wavelength of 700 nm.

[0017] Figure 4 is the transmittance change of TiO2@H4TBAPy-NO2 prepared in Example 4 after applying a voltage of 1~-1.6 V at a UV-visible wavelength of 700 nm. DETAILED DESCRIPTION

[0018] In order to highlight the technical advantages and excellent performance of the present application, the following will be further described in combination with the drawings and specific examples. The following specific examples are only for the present application, and the specific implementation process can also be adjusted according to the understanding of the technical personnel and the actual situation.

[0019] Example 1 An electrochromic film (TiO2@H4TBAPy) with super-long power-off coloring memory time

[0020] (I) Preparation method

[0021] 1. Preparation of titanium dioxide film

[0022] A commercial titanium dioxide slurry was used as raw material, and the titanium dioxide was printed on a 10x10 cm 2 FTO glass by screen printing method, sintered at 500°C for 30 min, and cooled to room temperature to obtain a titanium dioxide film.

[0023] 2. Preparation of TiO2@H4TBAPy composite film

[0024] The FTO glass printed with the titanium dioxide film was immersed in an ethanol solution of H4TBAPy with a concentration of 0.15 mg mL -1 , taken out after 12 hours, washed with anhydrous ethanol, and dried at 60°C to obtain a TiO2@H4TBAPy film.

[0025] 3. Preparation of electrolyte

[0026] 1.06 g of LiClO4 was dissolved in 10 mL of PC solution at room temperature under magnetic stirring, and 1 M LiClO4 / PC solution was obtained after complete dissolution.

[0027] (II) Performance test

[0028] The prepared film TiO2@H4TBAPy was used as the working electrode, 1 M LiClO4 / PC solution was used as the electrolyte, Pt electrode was used as the counter electrode, and Ag / AgCl electrode was used as the reference electrode to form a three-electrode system for testing. The applied voltage was 1~-1.6 V. The wavelength was 700 nm in the test in the ultraviolet-visible spectrophotometer. In the present application, the color fading memory time was tested with the optical contrast decay as the original 80%. The transmittance change of the device is shown in Figure 1 , and the color of TiO2@H4TBAPy reached saturation at 4.9%, and then the transmittance decayed to 22.0% at 3000 s.

[0029] Example 2: An electrochromic film (TiO2@H4TBAPy-OH) with super-long power-off coloring memory time

[0030] (I) Preparation method

[0031] 1. Preparation of titanium dioxide film

[0032] The same as example 1.

[0033] 2. Preparation of TiO2@H4TBAPy-OH composite film

[0034] The FTO glass printed with the titanium dioxide film was immersed in an ethanol solution of H4TBAPy-OH with a concentration of 0.15 mg mL -1 After 12 hours, the FTO glass was taken out, washed with anhydrous ethanol, and dried at 60°C to obtain the TiO2@ H4TBAPy-OH film.

[0035] 3. Preparation of the electrolyte

[0036] The same as in Example 1.

[0037] (II) Performance test

[0038] The prepared film TiO2@ H4TBAPy-OH was used as a working electrode, a 1 M LiClO4 / PC solution was used as an electrolyte, a Pt electrode was used as a counter electrode, and an Ag / AgCl electrode was used as a reference electrode to form a three-electrode system for testing. The applied voltage was 1~-1.6 V. The wavelength was 700 nm in the test in the ultraviolet-visible spectrophotometer. In the present application, the color fading memory time was tested with the standard of the optical contrast ratio being 80% of the original. The transmittance change of the device is shown in Figure 2 The color of TiO2@ H4TBAPy-OH reached saturation at 6.3%, and then the transmittance decayed to 22.5% at 3300 s.

[0039] Example 3: An electrochromic film (TiO2@ H4TBAPy-Br) with super-long color fading memory time after power-off

[0040] (I) Preparation method

[0041] 1. Preparation of the titanium dioxide film

[0042] The same as in Example 1.

[0043] 2. Preparation of the TiO2@ H4TBAPy-Br composite film

[0044] The FTO glass printed with the titanium dioxide film was immersed in an ethanol solution of H4TBAPy-Br with a concentration of 0.15 mg mL -1 After 12 hours, the FTO glass was taken out, washed with anhydrous ethanol, and dried at 60°C to obtain the TiO2@ H4TBAPy-Br film.

[0045] 3. Preparation of the electrolyte

[0046] The same as in Example 1.

[0047] (II) Performance test

[0048] The prepared film TiO2@ H4TBAPy-Br is used as a working electrode, 1 M LiClO4 / PC solution is used as an electrolyte, a Pt electrode is used as a counter electrode, and an Ag / AgCl electrode is used as a reference electrode to form a three-electrode system for testing. The applied voltage is 1~1.6 V. The testing is performed in a UV-visible spectrophotometer with a wavelength of 700 nm. In the present application, the coloring power-off memory time is tested with the optical contrast decay as the original 80% as the standard. The transmittance change of the device is shown in Figure 3 As shown in the figure, the color of TiO2@ H4TBAPy-Br reaches saturation at 8.5%, and then the transmittance decays to 24.2% at 3600 s.

[0049] Example 4: An electrochromic film (TiO2@ H4TBAPy-NO2) with super-long power-off coloring memory time

[0050] (I) Preparation method

[0051] 1. Preparation of titanium dioxide film

[0052] The same as example 1.

[0053] 2. Preparation of TiO2@ H4TBAPy-NO2 composite film

[0054] The FTO glass printed with the titanium dioxide film is immersed in an ethanol solution of H4TBAPy-NO2 with a concentration of 0.15 mg mL -1 , and taken out after 12 hours. After washing with anhydrous ethanol and drying at 60°C, the TiO2@ H4TBAPy-NO2 film is obtained.

[0055] 3. Preparation of electrolyte

[0056] The same as example 1.

[0057] (II) Performance test

[0058] The prepared film TiO2@ H4TBAPy-NO2 is used as a working electrode, 1 M LiClO4 / PC solution is used as an electrolyte, a Pt electrode is used as a counter electrode, and an Ag / AgCl electrode is used as a reference electrode to form a three-electrode system for testing. The applied voltage is 1~1.6 V. The testing is performed in a UV-visible spectrophotometer with a wavelength of 700 nm. In the present application, the coloring power-off memory time is tested with the optical contrast decay as the original 80% as the standard. The transmittance change of the device is shown in Figure 4 As shown in the figure, the color of TiO2@ H4TBAPy-NO2 reaches saturation at 10.1%, and then the transmittance decays to 26.2% at 3800 s.

Claims

1. An electrochromic film with an ultra-long power-off color memory time, characterized in that, The electrochromic film is a conductive substrate coated with an electrochromic layer, and the electrochromic layer is a composite film of titanium dioxide and organic small molecules; the organic small molecules are selected from 1,3,6,8-tetra(benzoic acid)pyrene, hydroxy-substituted 1,3,6,8-tetra(benzoic acid)pyrene, halogen-substituted 1,3,6,8-tetra(benzoic acid)pyrene or nitro-substituted 1,3,6,8-tetra(benzoic acid)pyrene.

2. The method for preparing an electrochromic thin film with an ultra-long power-off color memory time as described in claim 1, characterized in that, Includes the following steps: 1) Preparation of titanium dioxide layer: Titanium dioxide was printed on a conductive substrate by screen printing, sintered at 500 °C for 30 min, and cooled to room temperature to obtain titanium dioxide film; 2) The conductive substrate printed with titanium dioxide film is immersed in an ethanol solution of small organic molecules to obtain a composite film of titanium dioxide and small organic molecules.

3. The preparation method according to claim 2, characterized in that: In step 2), the concentration of the small organic molecule is 0.15 mg / mL. -1 .

4. The preparation method according to claim 3, characterized in that: In step 2), the soaking time is 12 hours.

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