Electrochromic compound capable of switching between red system and transparent state and preparation method and application thereof
A novel electrochromic compound with high contrast and fast switching times is developed through specific synthesis and film formation, addressing low contrast and slow response issues in red-to-transparent materials, suitable for electronic price tags.
Patent Information
- Application Number
- CN202510467246.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-15
- Publication Date
- 2025-07-15
AI Technical Summary
The existing solution-transparent electrochromic materials have low contrast and slow response time.
The electrochromic compound was prepared by arylation polycondensation reaction of 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane and 3,6-dibromodyridazine under the protection of an inert gas, and an electrochromic compound was prepared and sprayed on ITO glass to form an electrochromic film that can be switched in the red-transparent state.
It achieves high optical contrast and fast response time, with optical contrast of 34.84%, coloring time of 0.91s, fading time of 0.45s, good cycle stability, and is suitable for electronic price tag field.
Smart Images
Figure CN120309899A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the field of chemical materials, and particularly relates to an electrochromic compound capable of switching between a red series and a transparent state, a preparation method and an application thereof, and an electrochromic film capable of switching between a red series and a transparent state. Background Art
[0002] Electrochromic materials are a class of functional materials that can reversibly change their optical properties (such as color, light transmittance, etc.) under the action of an external electric field, and have broad application prospects in the fields of smart windows, anti-glare rearview mirrors, display devices, etc. According to different chemical compositions, electrochromic materials can be divided into inorganic materials (such as WO3, NiO, etc.) and organic materials (such as viologens, conductive polymers, etc.). Among them, organic electrochromic materials have become a research hotspot in recent years due to their strong molecular structure designability, rich colors, fast response speed and other advantages.
[0003] Among organic electrochromic materials, solution-processable electrochromic materials have received extensive attention because they can be prepared in large areas through low-cost and high-efficiency film-forming processes such as spraying. At present, the solution-processable electrochromic material system based on the red-transparent state switching is relatively complete, but there are few materials that can switch between red and transparent with high contrast and low response time. Therefore, it is necessary to develop an electrochromic compound that can switch between a red series and a transparent state and has good performance for preparing an electrochromic material that can switch between red and transparent. Summary of the Invention
[0004] In order to solve the problems of low contrast and slow response time of the solution-processable electrochromic materials that can switch between a red series and a transparent state in the prior art, the present invention provides a solution-processable electrochromic compound capable of switching between a red series and a transparent state and having excellent optical and electrochromic properties, a preparation method and an application thereof, and an electrochromic film capable of switching between a red series and a transparent state.
[0005] The technical solution adopted by the present invention is: an electrochromic compound capable of switching between a red series and a transparent state, and the compound is shown in Formula I:
[0006]
[0007] The present invention also provides a preparation method of the electrochromic compound, including:
[0008] 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepin shown in Formula II and 3,6-dibromopyridazine shown in Formula III are subjected to an arylation polycondensation reaction to prepare the electrochromic compound;
[0009]
[0010] Preferably, the preparation method includes: under the protection of an inert gas, mixing the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine, 3,6-dibromopyridazine, potassium carbonate, pivalic acid, Pd(OAc)2, and anhydrous DMAc, reacting at 120-140 °C for 15-17 h, and subjecting the reaction solution to post-treatment to obtain the electrochromic compound.
[0011] Preferably, the molar ratio of 3,6-dibromopyridazine to 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 1-1.1:1, preferably 1:1.
[0012] Preferably, the molar ratio of potassium carbonate to 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 2-3:1, preferably 2.5:1.
[0013] Preferably, the molar ratio of pivalic acid to 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 0.01-0.1:1, preferably 0.04:1.
[0014] Preferably, the molar ratio of Pd(OAc)2 to 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 0.01-0.05:1, preferably 0.02:1.
[0015] Preferably, the added volume of anhydrous DMAc is 30-40 mL / g based on the mass of 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine, preferably 34 mL / g.
[0016] Preferably, the post-treatment method is: adding the reaction solution to methanol, performing suction filtration, washing the filter cake with methanol, extracting the product from the filter cake successively with methanol, acetone, petroleum ether, and chloroform, and rotary evaporating the solvent from the product extracted by chloroform to obtain the electrochromic compound.
[0017] The present invention also provides the use of the chromic compound in preparing an electrochromic film that can switch between a red series and a transparent state. The use includes: dissolving the electrochromic compound in an organic solvent, and then spraying it on the conductive surface of ITO glass to form a film, so as to prepare an electrochromic film that can switch between a red series and a transparent state.
[0018] The present invention also provides an electrochromic film that can switch between a red series and a transparent state. The electrochromic film is prepared by the following method: the electrochromic compound is dissolved in an organic solvent, and then sprayed on the conductive surface of ITO glass to form a film, so as to obtain the electrochromic film that can switch between a red series and a transparent state.
[0019] Beneficial effects of the present invention: The electrochromic compound that can switch between two colors provided by the present invention presents a red color in a neutral state, and the color finally presents a transparent state as the applied voltage increases. The optical contrast of the electrochromic compound at a wavelength of 536nm is 34.84%, the coloring time is 0.91s, and the fading time is 0.45s; the optical contrast of the electrochromic film obtained after 1000 cycles at a step voltage of 0V and 1.2V can maintain 79.69% of the initial contrast, which is an excellent solution-processable electrochromic material that can switch between red and transparent colors, and is expected to be used in the field of electronic price tags. BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Figure 1 The invention provides a synthesis route for an electrochromic material that can switch between a red series and a transparent state.
[0021] Figure 2 This is a CV curve of the electrochromic film switchable between the red series and transparent states provided in Example 2 of the present invention.
[0022] Figure 3 This is a graph of the ultraviolet-visible absorption spectra of the electrochromic film switchable between the red series and transparent state provided in Example 2 of the present invention at different voltages.
[0023] Figure 4 The response time of the electrochromic film switchable between the red series and transparent state provided in Example 2 of the present invention in the 536nm band.
[0024] Figure 5 This is a dynamic test of the electrochromic film that can switch between the red series and transparent state provided in Example 2 of the present invention in different wavelength bands.
[0025] Figure 6 The chromaticity of the electrochromic film switchable between the red series and transparent state provided in Example 2 of the present invention at different voltages. Detailed Embodiments
[0026] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. In the embodiments of the present invention, the methods used are conventional methods unless otherwise specified, and the reagents used can be obtained from commercial channels.
[0027] Example 1 Synthesis of Compound pDQ (Formula I)
[0028] Weigh 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (Formula II) (440.68 mg, 1.0 mmol), 3,6-dibromopyridazine (237.88 mg, 1.0 mmol), anhydrous potassium carbonate (345 mg, 2.5 mmol), pivalic acid (4.09 mg, 0.04 mmol) and Pd(OAc)2 (4.53 mg, 0.02 mmol) and add them to a 15 mL Schlenk tube. Under nitrogen protection, add 15 mL of anhydrous DMAc and react at 130 °C for 15 h, then cool to room temperature. Add the reaction solution to 300 ml of methanol, filter it with a Buchner funnel, and wash the filter cake with methanol. Wrap the filter cake with filter paper and extract the polymers with different degrees of polymerization using a Soxhlet extractor. During this process, change the solvents with different dissolution abilities. The order of solvent use is methanol, acetone, petroleum ether, chloroform. Finally, rotate and evaporate the solvent from the chloroform-extracted part to obtain compound pDQ (Formula I).
[0029] Example 2 Preparation of Electrochromic Film
[0030] Add 45 mg of the compound pDQ (Formula I) prepared in Example 1 to a 10 ml beaker, add 3 ml of chloroform to it respectively, shake to mix the solution evenly, then filter it using a microporous filter with a pore size of 0.45 μm. Then, use a spin coater to spin coat a film on the conductive surface of a 25 * 40 mm ITO glass (parameter settings: 1000 rpm / min, spin coating time 1 min) to obtain an electrochromic film.
[0031]
Performance Test of Electrochromic Film
[0032] Perform the following tests on the electrochromic film prepared in Example 2.
[0033] 1. Electrochemical tests
[0034] The electrochemical tests were carried out using a Chenhua 660 electrochemical workstation. The parameter settings were as follows: CV mode, scan rates of 50 mV / s, 100 mV / s, 200 mV / s, 300 mV / s, and 500 mV / s, and a scan range of 1.2 V to 0 V. As Figure 2 shown, the electrochromic films prepared from compound pDQ (Formula I) all had electrochemical responses within this scan range, and their CV curves showed quasi-reversible redox behavior.
[0035] 2. Optical and electrochromic performance tests
[0036] The optical and electrochromic performance tests were carried out by using a Chenhua 660 electrochemical workstation in combination with a Shimadzu UV1800 ultraviolet-visible spectrophotometer. The test results are as Figure 3 , 4 and 5 shown.
[0037] As Figure 3 shown, the maximum absorption peak of the film in the neutral state (0.0 V) was 536 nm; as the voltage continued to increase, the original absorption peak gradually disappeared, and a double-absorption characteristic appeared in the visible light region (the trough of the absorption curve appeared between 500 and 600 nm); as the voltage was further increased, there were no obvious absorption peaks in the absorption curves of the three films in the visible light region.
[0038] As Figure 4 and Figure 5 shown, the optical contrast and cycle stability of the film were tested in the wavelength range of the maximum absorption peak. It was found that the optical contrast of pDQ at a wavelength of 536 nm was 34.84%, the coloring time was 0.91 s, and the fading time was 0.45 s; after 1000 cycles under the step voltage of 0 V and 1.2 V, the optical contrast of this material could maintain 79.69% of the initial contrast.
[0039] 3. Chromaticity tests
[0040] As Figure 6 shown, at 0 V, the film presented a red color, and as the voltage continued to increase, the three films finally presented a transparent state.
[0041] The embodiments described above are only used to describe the preferred embodiments of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, various deformations and improvements made by those of ordinary skill in the art to the technical solutions of the present invention should all fall within the protection scope of the present invention.
Claims
1. An electrochromic compound that can be switched between a red color system and a transparent state, characterized in that, The compound is shown in Formula I:
2. The preparation method of the electrochromic compound according to claim 1, characterized in that, Including: The electrochromic compound is prepared by the arylation polycondensation reaction of 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine shown in Formula II and 3,6-dibromopyridazine shown in Formula III; 3. The method according to claim 2, characterized in that, Including: Under the protection of inert gas, the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine, 3,6-dibromopyridazine, potassium carbonate, pivalic acid, Pd(OAc)2, and anhydrous DMAc are mixed and reacted at 120-140 °C for 15-17 h. After post-treatment of the reaction solution, the electrochromic compound is obtained.
4. The method according to claim 3, wherein The molar ratio of the 3,6-dibromopyridazine to the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 1-1.1:
1.
5. The method according to claim 3, wherein The molar ratio of the potassium carbonate to the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 2-3:
1.
6. The method according to claim 3, characterized in that, The molar ratio of the pivalic acid to the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 0.01-0.1:
1.
7. The method according to claim 3, wherein The molar ratio of the Pd(OAc)2 to the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine is 0.01-0.05:1; and / or The added volume of the anhydrous DMAc is 30-40 mL / g based on the mass of the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine.
8. The method according to claim 3, characterized in that, The method of the post-treatment is: adding the reaction solution into methanol, filtering by suction, washing the filter cake with methanol, extracting the product from the filter cake successively with methanol, acetone, petroleum ether, and chloroform, and rotary evaporating the solvent of the product extracted by chloroform to obtain the electrochromic compound.
9. The application of the electrochromic compound according to claim 1 or the electrochromic compound prepared by the method according to any one of claims 2-8 in the preparation of an electrochromic film capable of switching between a red system and a transparent state.
10. An electrochromic film that can be switched between a red color system and a transparent state, characterized in that, The electrochromic film is prepared by the following method: dissolving the electrochromic compound according to claim 1 or the electrochromic compound prepared by the method according to any one of claims 2-8 in an organic solvent, and then spraying and forming a film on the conductive surface of ITO glass to obtain an electrochromic film capable of switching between a red system and a transparent state.