A fluorine-containing electrochromic polymer, its preparation method and application

Abstract

The present invention provides a fluorine-containing electrochromic polymer, a preparation method thereof and an application thereof. The fluorine-containing electrochromic polymer has a structure shown in Formula I. In the present invention, by introducing fluorine atoms into the electrochromic polymer and through the interaction between the fluorine atoms and a single alkoxy group with a specific structure on the quinoxaline group, the prepared fluorine-containing electrochromic polymer has excellent properties, and thus the prepared electrochromic device has a lower starting voltage, a lower contrast attenuation rate, a faster response speed and a higher coloring efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochromic materials, and particularly relates to a fluorine-containing electrochromic polymer, a preparation method thereof, and an application thereof. Background Art

[0002] Electrochromism refers to the phenomenon that the optical properties (transmittance, reflectance or absorbance) of a substance change stably and reversibly in the visible light wavelength range under the action of an external electric field or current. In appearance, electrochromism is manifested as a reversible change in color and transparency, and is often used as a passive display device. Although the research on electrochromism has been reported since the 1930s and has made great progress, there are still many problems in terms of theory and practical application. Organic materials with electrochromic properties include viologen, rare earth phthalocyanine, pyrazine, polyaniline, and some conductive organic polymers. Their color change mechanism is relatively complex, mostly involving the gain and loss of electrons, thereby causing different colored reactants and products. In practical applications, the coloring rate (the change in optical density caused by the charge energy injected into the film per unit area), the response characteristics (the change in current with time during the color change process under the action of the working voltage), the storage characteristics (the ability of the film to maintain its characteristics after removing the external electric field), the service life (the number of coloring-fading cycle operations under a specific working voltage), and the mobility of the electrochromic material have all been greatly limited. With the continuous improvement of market requirements and the development of technology, the research on electrochromic materials has become more and more in-depth, and more and more electrochromic materials have been synthesized and applied.

[0003] CN102690646A discloses an electrochromic material and an electrochromic device. The electrochromic material includes a cathode electrochromic material and an anode electrochromic material. The cathode and anode electrochromic materials are subjected to a chemical reaction, and then solidified in an electrolyte to form a gel-like electrochromic material. The electrochromic device includes a glass coated with a transparent conductive film and a substrate coated with a conductive reflective layer, and a gel-like electrochromic material is disposed between the transparent conductive film and the conductive reflective layer. This technical solution adopts the method of grafting the cathode and anode electrochromic materials onto a polymer respectively, and then solidifying in an electrolyte to form a gel-like electrochromic material, which improves the color change stability, avoids the harm caused by electrolyte leakage when the electrochromic device is damaged by external force, and improves the performance of the electrochromic material in practical applications.

[0004] CN112500556A discloses a donor - acceptor type electrochromic polymer and its preparation method, electrochromic film and application. The electrochromic polymer is a donor - acceptor type electrochromic polymer, in which indacenodithiophene is the donor, 2,1,3 - benzothiadiazole is the acceptor, and four thiophenes are the bridging units; the preparation method adopts Stille coupling polymerization. The polymer prepared by this coupling polymerization not only has solubility, but also can achieve the preparation of high - purity and high - quality polymer through post - treatment. The electrochromic film is prepared from the polymer, has stable P - doping characteristics, can realize reversible transformation from infrared to transparent under a lower potential drive, and exhibits reasonable optical contrast, fast response rate and good color - change stability, and has potential application value in the field of electrochromics, and can be used in devices such as smart windows, electrochromic displays, and adaptive camouflage.

[0005] In the prior art, the research on electrochromic materials has become more and more in - depth, and the requirements for electrochromic devices have also become higher and higher. In practical applications, the stability of electrochromic devices plays a decisive role, and the three parts that play an important role in its stability are: the electrochromic layer, the electrolyte layer and the ion storage layer. Regarding the mechanism of the optical performance decay of electrochromics, some studies believe that the decay of electrochromics is due to the fact that ion doping is too deep to migrate out of the film, and reducing the oxidation potential can effectively avoid this situation. In addition, the redox process of electrochromics will cause changes in the stacking state of electrochromic materials, resulting in the color - change decay of electrochromic materials.

[0006] Therefore, how to provide an electrochromic material with a lower oxidation potential and a lower contrast decay has become an urgent technical problem to be solved at present. Summary of the Invention

[0007] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a fluorine - containing electrochromic polymer and its preparation method and application. In the present invention, through the design of the structure of the electrochromic polymer, by introducing fluorine atoms into the electrochromic polymer, and through the interaction between fluorine atoms and a single alkoxy group with a specific structure on the quinoxaline group, the prepared fluorine - containing electrochromic polymer has excellent properties. Thus, the prepared electrochromic device has a lower starting voltage, a lower contrast decay rate, a faster response speed and a higher coloring efficiency, and is suitable for fields such as smart windows and military camouflage.

[0008] To achieve this purpose, the present invention adopts the following technical solutions:

[0009] In the first aspect, the present invention provides a fluorine - containing electrochromic polymer, and the fluorine - containing electrochromic polymer has a structure shown in Formula I:

[0010]

[0011] Wherein, R1 and R2 are each independently selected from any one of a hydrogen atom, a C2-C20 acyl group, and a C1-C20 linear or branched alkyl group;

[0012] R3 and R4 are each independently a C1-C18 linear or branched alkyl group;

[0013] a, b, and c are all integers greater than 0;

[0014] n is an integer from 3 to 100.

[0015] In the present invention, through the design of the structure of the fluorine-containing electrochromic polymer, by introducing fluorine atoms into the electrochromic polymer, and through the interaction between the fluorine atoms and a single alkoxy group (i.e., a branched alkoxy group) with a specific structural formula on the quinoxaline group, the prepared electrochromic polymer has excellent properties. Thus, the prepared electrochromic device has a low starting voltage, a low contrast attenuation rate, a fast response speed, and a high coloring efficiency, and is applicable to fields such as smart windows and military camouflage.

[0016] Fluorine atoms have a high electronegativity and a small atomic radius. In the present invention, by introducing fluorine atoms into the electrochromic polymer, the properties of the polymer can be effectively regulated without causing unnecessary steric hindrance. In the present invention, a donor-acceptor type random block copolymer is formed by copolymerizing fluorinated quinoxaline with thiophene compounds. Since quinoxaline has a high degree of conjugation, a polymer with a dense molecular packing can be formed. By introducing fluorine atoms on quinoxaline, the electron-withdrawing ability of the unit is further enhanced, which can effectively adjust the band gap of the copolymer and lower its oxidation potential; by introducing a single alkoxy group on quinoxaline, the solubility of the polymer can be improved. In the present invention, through the interaction between the fluorine atoms in the polymer and the single alkoxy group on the quinoxaline group, while improving the solubility of the copolymer, it does not cause a large steric hindrance to prevent the entry of doping ions, and a fluorine-containing electrochromic polymer with excellent properties is obtained.

[0017] In the present invention, the C2-C20 can be C2, C4, C6, C8, C10, C12, C14, C16, C18, or C20, etc.

[0018] The C1-C20 can be C1, C2, C4, C6, C8, C10, C12, C14, C16, C18, or C20, etc.

[0019] The C1-C18 can be C1, C2, C4, C6, C8, C10, C12, C14, C16, or C18, etc.

[0020] n can be 3, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100 or the like.

[0021] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the purpose and beneficial effects of the present invention can be better achieved and realized.

[0022] As a preferred technical solution of the present invention, each of R1 and R2 is independently selected from any one of butyryl, hexanoyl, octanoyl, 2-ethylhexanoyl, propyl, butyl, pentyl, hexyl, octyl or dodecyl.

[0023] As a preferred technical solution of the present invention, each of R3 and R4 is independently selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, dodecyl or tridecyl.

[0024] As a preferred technical solution of the present invention, (a + b):c ≥ 5:1 (for example, it can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1 or 12:1, etc.), and preferably (5 - 10):1.

[0025] In the present invention, by controlling the ratio of the sum of the degrees of polymerization of a repeating units and b repeating units (a + b) to the degree of polymerization of c repeating units in the fluorine-containing electrochromic polymer within a specific range, the prepared fluorine-containing electrochromic polymer has excellent properties, and further the prepared electrochromic device has a low starting voltage, good optoelectronic properties and a fast response speed. If the content of the fluorine-containing repeating unit (c repeating unit) in the fluorine-containing electrochromic polymer is too high, that is, the value of (a + b):c is too small, then the optoelectronic properties and response speed of the electrochromic device prepared therefrom are both poor; if the content of the fluorine-containing repeating unit (c repeating unit) in the fluorine-containing electrochromic polymer is too low, that is, the value of (a + b):c is too large, then the response speed of the electrochromic device prepared therefrom is slow and the cycling performance is poor.

[0026] As a preferred technical solution of the present invention, the preparation raw materials of the fluorine-containing electrochromic polymer include compound A, compound B and compound C;

[0027] Compound A is Compound B is Compound C is

[0028] Among them, R1, R2, R3 and R4 have the same protection scope as described above.

[0029] Second aspect, the present invention provides a preparation method of a fluorine-containing electrochromic polymer as described in the first aspect, and the preparation method includes the following steps:

[0030] After mixing the raw materials for preparing the fluorine-containing electrochromic polymer, a polymerization reaction is carried out to obtain the fluorine-containing electrochromic polymer.

[0031] The raw materials for preparing the fluorine-containing electrochromic polymer include compound A, compound B and compound C;

[0032] Compound A is Compound B is Compound C is

[0033] Among them, R1, R2, R3 and R4 have the same protection scope as above.

[0034] The preparation process of the fluorine-containing electrochromic polymer is as follows:

[0035]

[0036] Among them, R1, R2, R3, R4, a, b, c and n have the same protection scope as above.

[0037] As a preferred technical solution of the present invention, the temperature of the polymerization reaction is 160-180 °C, for example, it can be 160 °C, 162 °C, 164 °C, 166 °C, 168 °C, 170 °C, 172 °C, 174 °C, 176 °C, 178 °C or 180 °C, etc.

[0038] Preferably, the time of the polymerization reaction is 4-48 h, for example, it can be 4 h, 8 h, 12 h, 16 h, 20 h, 24 h, 28 h, 32 h, 36 h, 40 h, 44 h or 48 h, etc.

[0039] As a preferred technical solution of the present invention, the polymerization reaction is carried out in the presence of a protective gas;

[0040] Preferably, the protective gas includes nitrogen and argon.

[0041] Preferably, the polymerization reaction is carried out in the presence of an organic solvent.

[0042] It should be noted that the present invention has no special restrictions on the selection of organic solvents, and commonly used organic solvents in the art are applicable. Exemplarily, it includes but is not limited to: N,N-dimethylacetamide (DMAc).

[0043] Preferably, the polymerization reaction is followed by a post-treatment step.

[0044] Preferably, the post-treatment method includes washing, suction filtration, and concentration.

[0045] In a third aspect, the present invention provides an electrochromic device, which includes a first working electrode, an electrochromic layer, an electrolyte layer, an ion storage layer, and a second working electrode arranged in sequence;

[0046] The material of the electrochromic layer is a fluorine-containing electrochromic polymer as described in the first aspect.

[0047] Preferably, the material of the electrolyte layer includes polycarbonate (PC), poly(ethylene glycol) diacrylate (PEGDA), 0.2M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and dimethoxy-2-phenylacetophenone (BDK).

[0048] Preferably, the ion storage layer is poly(3,4-ethylenedioxythiophene)·poly(styrenesulfonate) (PEDOT·PSS) prepared by screen printing.

[0049] Preferably, the first working electrode and the second working electrode can be ITO glass.

[0050] In a fourth aspect, the present invention provides an application of the fluorine-containing electrochromic polymer as described in the first aspect in the preparation of smart windows, military camouflage products, dimming and color-tuning products, and packaging display products;

[0051] Preferably, the process for preparing smart windows, military camouflage products, dimming and color-tuning products, and packaging display products includes a coating or printing process.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] In the present invention, through the design of the structure of the fluorine-containing electrochromic polymer, and further through the interaction between the fluorine atoms on the quinoxaline group and a single alkoxy group with a specific structure, the prepared fluorine-containing electrochromic polymer has excellent properties. Thus, the prepared electrochromic device has a low starting voltage, a low contrast attenuation rate, a fast response speed, and a high coloring efficiency. Its starting voltage is -0.17V to -0.25V, the optical contrast is 25.6% to 36.1%, the contrast attenuation rate is 6.7% to 9.6%, the fading time is 0.8s to 1.3s, the coloring time is 0.7s to 1.8s, and the coloring efficiency is 532.9 cm 2 / C to 739.6 cm 2 / C. The electrochromic device prepared from the fluorine-containing electrochromic polymer provided by the present invention is applicable to fields such as smart windows and military camouflage. Description of the Drawings

[0054] Figure 1 It is a schematic structural diagram of the electrochromic device provided in Application Example 1 of the present invention;

[0055] Figures 2 - 5 They are respectively cyclic voltammetry characteristic curves of the electrochromic devices provided in Application Examples 1-2 and Application Examples 6-7;

[0056] Figures 6 - 9 They are respectively test result diagrams for testing the optical modulation rate and color change response speed of the colored state and faded state of the electrochromic devices provided in Application Examples 1-2 and Application Examples 6-7;

[0057] Figures 10 - 13 They are respectively test result diagrams for testing the stability of the electrochromic devices provided in Application Examples 1-2 and Application Examples 6-7;

[0058] Wherein, 1 - the first working electrode, 2 - the electrochromic layer, 3 - the electrolyte layer, 4 - the ion storage layer, 5 - the second working electrode. Specific Embodiments

[0059] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations of the present invention.

[0060] Example 1

[0061] This example provides a fluorine-containing electrochromic polymer PTQ6-2F and its preparation method, and the preparation method is as follows:

[0062]

[0063] Compound A (0.74 g), compound B (0.68 g), compound C (0.27 g), Pd(OAc)2 (0.035 g), K2CO3 (0.65 g), PivOH (pivalic acid, 0.049 g), and DMAc (7 mL) were added to a 50 mL Schlenk tube. After purging with nitrogen three times, the temperature was raised to 170 °C until reflux occurred. After reacting overnight for 24 h, it was cooled to room temperature. A small amount of chloroform was added to fully dissolve the solid. The reaction solution was slowly poured into 150 mL of continuously stirred methanol solution. Immediately, a solid precipitated, and the liquid tended to become clear and yellowish transparent. 3 g of ethylenediaminetetraacetic acid (EDTA) was added, and the system became a yellowish turbid solution. Stirring was stopped, and filtration was carried out, followed by washing twice with methanol (100 mL) to obtain a purple-black solid (mixed with EDTA). The filtrate was a yellowish turbid solution, which was subjected to Soxhlet extraction with methanol, acetone, n-hexane, and chloroform respectively. The chloroform solution was concentrated by rotary evaporation, slowly dropped into methanol for precipitation, and continuously stirred. Filtration through a filter cloth gave a purple-black solid, the fluorine-containing electrochromic polymer PTQ6-2F (0.98 g, yield 58%).

[0064] Example 2

[0065] This example provides a fluorine-containing electrochromic polymer PTQ8-2F and its preparation method, and the preparation method is as follows:

[0066]

[0067] Compound A (0.74 g), compound B (0.74 g), compound C (0.20 g), Pd(OAc)2 (0.035 g), K2CO3 (0.65 g), PivOH (0.049 g), and DMAc (7 mL) were added to a 50 mL Schlenk tube. After purging with nitrogen three times, the temperature was raised to 170 °C until reflux occurred. After reacting overnight for 24 hours, it was cooled to room temperature. A small amount of chloroform was added to fully dissolve the solid. The reaction solution was slowly poured into 150 mL of continuously stirred methanol solution. Immediately, a solid precipitated, and the liquid tended to become clear and yellowish transparent. 3 g of ethylenediaminetetraacetic acid (EDTA) was added, and the system became a yellowish turbid solution. Stirring was stopped, and filtration was carried out, followed by washing twice with methanol (100 mL) to obtain a purple-black solid (mixed with EDTA). The filtrate was a yellowish turbid solution, which was subjected to Soxhlet extraction with methanol, acetone, n-hexane, and chloroform respectively. The chloroform solution was concentrated by rotary evaporation, slowly dropped into methanol for precipitation, and continuously stirred. Filtration through a filter cloth gave a purple-black solid, the fluorine-containing electrochromic polymer PTQ8-2F (1.02 g, yield 61%).

[0068] Example 3

[0069] This example provides a fluorine-containing electrochromic polymer PTQ7-2F and its preparation method, and the preparation method is as follows:

[0070]

[0071] Compound A (0.74 g), compound B (0.68 g), compound C (0.27 g), Pd(OAc)2 (0.035 g), K2CO3 (0.65 g), PivOH (pivalic acid, 0.049 g), and DMAc (7 mL) were added to a 50 mL Schlenk tube. After purging with nitrogen three times, the temperature was raised to 170 °C until reflux occurred. After reacting overnight for 24 h, it was cooled to room temperature. A small amount of chloroform was added to completely dissolve the solid. The reaction solution was slowly poured into 150 mL of continuously stirred methanol solution. Immediately, a solid precipitated, and the liquid tended to become clear and yellowish transparent. 3 g of ethylenediaminetetraacetic acid (EDTA) was added, and the system became a yellow turbid solution. Stirring was stopped, and filtration was carried out, followed by washing twice with methanol (100 mL) to obtain a purple-black solid (mixed with EDTA). The filtrate was a yellow turbid solution, which was subjected to Soxhlet extraction with methanol, acetone, n-hexane, and chloroform respectively. The chloroform solution was concentrated by rotary evaporation, slowly dropped into methanol for precipitation, and continuously stirred. Filtration through a filter cloth gave a purple-black solid of the fluorine-containing electrochromic polymer PTQ7-2F (0.98 g, yield 58%).

[0072] Example 4

[0073] This example provides a fluorine-containing electrochromic polymer PTQ5-2F and its preparation method. The preparation method is as follows:

[0074]

[0075] The specific preparation method is only different from that of Example 1 in that the addition amount of compound A is 0.63 g, the addition amount of compound B is 0.54 g, and the addition amount of compound C is 0.27 g; other conditions are the same as those in Example 1, and the fluorine-containing electrochromic polymer PTQ5-2F (0.91 g, yield 63%) was prepared.

[0076] Example 5

[0077] This example provides a fluorine-containing electrochromic polymer PTQ10-2F and its preparation method. The preparation method is as follows:

[0078]

[0079] The specific preparation method is only different from that of Example 1 in that the addition amount of compound A is 1.16 g, the addition amount of compound B is 1.22 g, and the addition amount of compound C is 0.27 g; other conditions are the same as those in Example 1, and the fluorine-containing electrochromic polymer PTQ10-2F (1.86 g, yield 70%) was prepared.

[0080] Example 6

[0081] This example provides a fluorine-containing electrochromic polymer PTQ3-2F and its preparation method, and the preparation method is as follows:

[0082]

[0083] Add compound A (0.74 g), compound B (0.48 g), compound C (0.47 g), Pd(OAc)2 (0.035 g), K2CO3 (0.65 g), PivOH (0.049 g), and DMAc (7 mL) into a 50 mL schlenk tube. Replace the air with nitrogen three times, heat to 170 °C until reflux appears, react overnight for 24 h, then cool to room temperature. Add a small amount of chloroform to fully dissolve the solid. Slowly pour the reaction solution into 150 mL of continuously stirred methanol solution. Immediately, a solid precipitates, and the liquid tends to become clear and yellowish transparent. Add 3 g of ethylenediaminetetraacetic acid (EDTA), and the system becomes a yellowish turbid solution. Stop stirring, perform suction filtration, and wash twice with methanol (100 mL) to obtain a purple-black solid (mixed with EDTA). The filtrate is a yellowish turbid solution. Perform Soxhlet extraction with methanol, acetone, n-hexane, and chloroform respectively. Concentrate the chloroform solution by rotary evaporation, slowly drop it into methanol for precipitation, and continuously stir. Filter with a filter cloth to obtain a purple-black solid fluorine-containing electrochromic polymer PTQ3-2F (1.01 g, yield 60%).

[0084] Example 7

[0085] This example provides a fluorine-containing electrochromic polymer PTQ13-2F and its preparation method, and the preparation method is as follows:

[0086]

[0087] The only difference in the specific preparation method from Example 1 is that the addition amount of compound A is 0.74 g, the addition amount of compound B is 0.82 g, and the addition amount of compound C is 0.13 g; other conditions are the same as those in Example 1, and fluorine-containing electrochromic polymer PTQ13-2F (1.11 g, yield 66%) is prepared.

[0088] Comparative Example 1

[0089] This comparative example provides a fluorine-containing electrochromic polymer and its preparation method, and the preparation method is as follows:

[0090]

[0091] The difference from Example 1 is that compound C in Example 1 is replaced with an equimolar amount of Other conditions are the same as those in Example 1.

[0092] Comparative Example 2

[0093] This comparative example provides a fluorine-containing electrochromic polymer and a preparation method thereof. The preparation method is as follows:

[0094]

[0095] The difference from Example 1 is that compound C in Example 1 is replaced with an equimolar amount of Other conditions are the same as those in Example 1.

[0096] Comparative Example 3

[0097] This comparative example provides a fluorine-containing electrochromic polymer and a preparation method thereof. The preparation method is as follows:

[0098]

[0099] The difference from Example 1 is that compound C in Example 1 is replaced with an equimolar amount of Other conditions are the same as those in Example 1.

[0100] Application Example 1

[0101] This application example provides an electrochromic device. The structural schematic diagram is as Figure 1 shown. The electrochromic device includes a first working electrode, an electrochromic layer, an electrolyte layer, an ion storage layer, and a second working electrode arranged in sequence.

[0102] The first working electrode and the second working electrode are ITO glasses;

[0103] The material of the electrochromic layer is the fluorine-containing electrochromic polymer PTQ6-2F;

[0104] The material of the electrolyte layer is a gel polymer electrolyte of polycarbonate (PC), poly(ethylene glycol) diacrylate (PEGDA), 0.2 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and dimethoxy-2-phenylacetophenone (BDK);

[0105] The material of the ion storage layer is poly(3,4-ethylenedioxythiophene)·poly(styrenesulfonate) (PEDOT·PSS).

[0106] The preparation method of the electrochromic device is as follows:

[0107] (1) After cleaning two pieces of ITO glass, they are treated by O-plasma to obtain the first working electrode and the second working electrode;

[0108] (2) Dissolve the fluorine-containing electrochromic polymer PTQ6-2F in xylene to obtain a mixed solution (80 mg / mL), then mechanically filter the mixed solution to remove impurities, and spin-coat it onto one side of the first working electrode by static spin-coating (spin-coat for 6 seconds at 600 rpm and then spin-coat for 30 seconds at 4000 rpm) to obtain an electrochromic layer with an effective area of 2.0×3.0 cm;

[0109] (3) Coat the gel polymer electrolyte composed of polycarbonate (PC), poly(ethylene glycol) diacrylate (PEGDA), 0.2 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and dimethoxy-2-phenylacetophenone (BDK) on the side of the electrochromic layer away from the first working electrode to obtain an electrolyte layer;

[0110] (4) Screen-print poly(3,4-ethylenedioxythiophene)·poly(styrenesulfonate) onto the side of the electrolyte layer away from the electrochromic layer to obtain an ion storage layer;

[0111] (5) Place the second working electrode on the side of the ion storage layer away from the electrolyte layer and seal the edges with double-sided tape to obtain an electrochromic device.

[0112] Application Examples 2-7

[0113] Application Examples 2-7 respectively provide an electrochromic device, which is only different from Application Example 1 in that the material of the electrochromic layer, the fluorine-containing electrochromic polymer PTQ6-2F, is sequentially replaced with the fluorine-containing electrochromic polymers provided in Examples 2-7, and other conditions are the same as those in Application Example 1.

[0114] Use the Chenhua electrochemical workstation CHI660E to test the cyclic voltammetry characteristic curves of the electrochromic devices provided in Application Examples 1-2 and Application Examples 6-7 respectively, and their cyclic voltammetry characteristic curves are as Figures 2 - 5 shown. It can be seen from Figures 2 - 5 that the fluorine-containing electrochromic polymer provided by the present invention has good electrochemical cycling performance and certain charge storage ability.

[0115] Use the Chenhua electrochemical workstation CHI660E and the Lambda 750 spectrophotometer to test the optical modulation rate and color change response speed of the electrochromic devices provided in Application Examples 1-2 and Application Examples 6-7 in the colored state and the bleached state, and their test results are as Figures 6 - 9 shown. It can be seen from Figure 6 , Figure 7 and Figure 8 , Figure 9By comparison, in the present invention, by controlling the ratio of the degree of polymerization of repeating units in the fluorine-containing electrochromic polymer (a + b):c within a specific range, the electrochromic device prepared from this fluorine-containing electrochromic polymer has good optical modulation rate and fast color change response speed.

[0116] Using a Lambda 750 spectrophotometer, the cyclic voltammetry characteristic curves of the electrochromic devices provided in Application Examples 1-2 and Application Examples 6-7 were respectively tested, and the test results are as Figures 10 - 13 shown. From Figure 10 , Figure 11 and Figure 12 , Figure 13 comparison, the electrochromic device prepared from the fluorine-containing electrochromic polymer provided by the present invention has good cycle stability.

[0117] Comparative Application Examples 1-3

[0118] Comparative Application Examples 1-3 respectively provide an electrochromic device. The difference from Application Example 1 is only that the material of the electrochromic layer, the fluorine-containing electrochromic polymer PTQ6-2F, is successively replaced with the fluorine-containing electrochromic polymers provided in Comparative Examples 1-3, and other conditions are the same as those in Application Example 1.

[0119] The performances of the electrochromic devices provided in Application Examples 1-7 and Comparative Application Examples 1-3 were tested, and the test methods are as follows:

[0120] (1) Initial voltage: Test instrument: Electrochemical workstation, Test method: Cyclic voltammetry; Test conditions: 50 mV / s, voltage range: 2000 mV to -2000 mV, number of cycles: 8 cycles, current setting range: 2.5×10 -3 mA, Initial voltage value: The intersection point of the tangent line of the curve and y = 0.

[0121] (2) Maximum absorption wavelength: Test instrument: Lambda750 combined use, Test method: Absorption spectrum, Test conditions: Spectrum range: 400 - 800 nm, Sampling interval: 1 nm, Maximum absorption wavelength value: The transmittance spectra of the colored state and the transmissive state of the above-mentioned devices were respectively tested, and the wavelength with the largest transmittance difference was taken as the maximum absorption wavelength.

[0122] (3) Optical contrast: Test instrument: Electrochemical workstation combined with Lambda750. Test method: Transmittance time spectrum. Test conditions: Electrochemical workstation: Forward voltage: Fading voltage, time: 10 s; Reverse voltage: Coloring voltage, time: 10 s. Lambda750: Wavelength: Maximum absorption wavelength, time: 12 minutes, sampling interval: 0.2 s. Test mode: Transmittance (T%). Value: Transmittance in the fading state - Transmittance in the coloring state.

[0123] (4) Contrast attenuation rate: Test instrument: Function generator + Electrochemical workstation combined with Lambda750. Test method: Perform a step cycle on the function generator and then test the optical contrast. Value: (Optical contrast before cycling - Optical contrast after cycling) / Optical contrast before cycling.

[0124] (5) Fading time: Test instrument: Electrochemical workstation combined with Lambda750. Test method: Transmittance time spectrum. Test conditions: Electrochemical workstation: Forward voltage: Fading voltage, time: 10 s; Reverse voltage: Coloring voltage, time: 10 s. Lambda750: Wavelength: Maximum absorption wavelength, time: 12 minutes, sampling interval: 0.2 s. Test mode: Transmittance (T%). Value: The time required for the change in transmittance to reach 95% of the optical contrast from the fading state to the coloring state.

[0125] (6) Coloring time: Test instrument: Electrochemical workstation combined with Lambda750. Test method: Transmittance time spectrum. Test conditions: Electrochemical workstation: Forward voltage: Fading voltage, time: 10 s; Reverse voltage: Coloring voltage, time: 10 s. Lambda750: Wavelength: Maximum absorption wavelength, time: 12 minutes, sampling interval: 0.2 s. Test mode: Transmittance (T%). Value: The time required for the change in transmittance to reach 95% of the optical contrast from the coloring state to the fading state.

[0126] (7) Coloring efficiency: Test instrument: Electrochemical workstation combined with Lambda750. Test method: Transmittance time spectrum. Test conditions: Electrochemical workstation: Forward voltage: Fading voltage, time: 10 s; Reverse voltage: Coloring voltage, time: 10 s. Lambda750: Wavelength: Maximum absorption wavelength, time: 12 minutes, sampling interval: 0.2 s. Test mode: Transmittance (T%). Value: Using Q / A as the x-axis and (log(T / T c )) as the y-axis, plot a graph and take the slope of the tangent as the coloring efficiency; Q: Current passing through per unit time, A: Effective area of the device, T: Transmittance, T c : Transmittance in the coloring state, T b: Transmittance in the bleached state.

[0127] The performance test results of the electrochromic devices provided in Application Examples 1-5 and Comparative Application Examples 1s-2s are shown in Table 1 below:

[0128] Table 1

[0129]

[0130]

[0131] As can be seen from the content of Table 1, in the present invention, through the design of the structure of the fluorine-containing electrochromic polymer, and further through the interaction between the fluorine atoms on the quinoxaline group and a single alkoxy group with a specific structure, the prepared fluorine-containing electrochromic polymer has excellent properties. Thus, the prepared electrochromic device has a low starting voltage, a low contrast attenuation rate, a fast response speed, and a high coloring efficiency. Its starting voltage is -0.17V to -0.25V, the optical contrast is 25.6% to 36.1%, the contrast attenuation rate is 6.7% to 9.6%, the bleaching time is 0.8s to 1.3s, the coloring time is 0.7s to 1.8s, and the coloring efficiency is 532.9 cm 2 / C to 739.6 cm 2 / C. The electrochromic device prepared from the fluorine-containing electrochromic polymer provided by the present invention is applicable to fields such as smart windows and military camouflage.

[0132] Compared with Example 1, if the content of the fluorine-containing repeating unit in the fluorine-containing electrochromic polymer is too high, the electrochromic device (Application Example 6) prepared therefrom has a low optical contrast, a high contrast attenuation rate, a slow response speed, and a low coloring efficiency; if the content of the fluorine-containing repeating unit in the fluorine-containing electrochromic polymer is too low, the comprehensive performance of the electrochromic device (Application Example 7) prepared therefrom is poor. Thus, it can be seen that in the present application, by controlling the ratio of the sum of the polymerization degrees of the a repeating unit and the b repeating unit (a + b) to the polymerization degree of the c repeating unit in the fluorine-containing electrochromic polymer within a specific range, the response speed, coloring efficiency, and optical contrast of the electrochromic device are improved, and the contrast attenuation rate is reduced.

[0133] Compared with Example 1, if the alkoxy group in the quinoxaline structure of the fluorine-containing electrochromic polymer is a straight-chain alkoxy group (Comparative Example 1), or the fluorine-containing electrochromic polymer does not contain fluorine atoms, or the quinoxaline structure in the fluorine-containing electrochromic polymer has two straight-chain alkoxy groups, the comprehensive performance of the electrochromic device (Application Comparative Examples 1-3) prepared therefrom is poor.

[0134] In summary, in the present invention, through the design of the structure of the fluorine-containing electrochromic polymer, and further through the interaction between the fluorine atoms on the quinoxaline group and a single alkoxy group with a specific structure, the prepared fluorine-containing electrochromic polymer has excellent properties. Thus, the prepared electrochromic device has a low starting voltage, a low contrast attenuation rate, a fast response speed, and a high coloring efficiency, and is applicable to fields such as smart windows and military camouflage.

[0135] The applicant declares that the present invention uses the above embodiments to illustrate the detailed structural features and detailed process flows of the present invention, but the present invention is not limited to the above detailed structural features and detailed process flows, that is, it does not mean that the present invention must rely on the above detailed structural features and detailed process flows to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent replacement of the components selected for the present invention, the addition of auxiliary components, the selection of specific methods, etc., the equivalent replacement of the raw materials of the present invention's products, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A fluorine-containing electrochromic polymer, characterized in that, The fluorine-containing electrochromic polymer has a structure shown in Formula I: Wherein, R1 and R2 are each independently selected from any one of C2-C10 straight-chain or branched-chain alkyl groups; R3 and R4 are each independently C1-C18 straight-chain or branched-chain alkyl groups; a, b, and c are all integers greater than 0; n is an integer from 3 to 100; (a + b):c ≥ 5:

1.

2. The fluorine-containing electrochromic polymer according to claim 1, characterized in that, R1 and R2 are each independently selected from any one of propyl, butyl, pentyl, hexyl, or octyl.

3. The fluorine-containing electrochromic polymer according to claim 1, wherein R3 and R4 are each independently selected from any one of methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, dodecyl, or tridecyl.

4. The fluorine-containing electrochromic polymer according to claim 1, wherein (a + b):c is (5-10):

1.

5. The fluorine-containing electrochromic polymer according to claim 1, characterized in that, The preparation raw materials of the fluorine-containing electrochromic polymer include Compound A, Compound B, and Compound C; The said compound A is Compound B is Compound C is Wherein, R1, R2, R3 and R4 have the same scope of protection as that in claim 1.

6. A preparation method of a fluorine-containing electrochromic polymer according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: After mixing the preparation raw materials of the fluorine-containing electrochromic polymer, a polymerization reaction is carried out to obtain the fluorine-containing electrochromic polymer.

7. The preparation method according to claim 6, characterized in that, The temperature of the polymerization reaction is 160-180 °C.

8. The preparation method according to claim 6, wherein, The time of the polymerization reaction is 4-48 h.

9. The preparation method according to claim 6, characterized in that, The polymerization reaction is carried out in the presence of a protective gas.

10. The preparation method according to claim 6, characterized in that, The polymerization reaction is carried out in the presence of an organic solvent.

11. The preparation method according to claim 6, characterized in that, After the polymerization reaction, a post-treatment step is also included.

12. The preparation method according to claim 6, wherein, The post-treatment method includes washing, suction filtration, and concentration.

13. An electrochromic device, characterized in that, The electrochromic device includes a first working electrode, an electrochromic layer, an electrolyte layer, an ion storage layer, and a second working electrode arranged in sequence; The material of the electrochromic layer is the fluorine-containing electrochromic polymer according to any one of claims 1-5.

14. Use of a fluorine-containing electrochromic polymer according to any one of claims 1-5 in the preparation of smart windows, military camouflage products, dimming and color-tuning products, and packaging display products.

15. The application according to claim 14, wherein The process for preparing smart windows, military camouflage products, dimming and color-tuning products, and packaging display products includes a coating or printing process.

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