A kind of columnarene conjugated polymer-based electrochromic material and its preparation method and application

Abstract

The application discloses a kind of based on pillararene conjugated polymer electrochromic material and its preparation method and application. By double OTf pillararene and boric acid reagent through Suzuki reaction, double aromatic ring substituted pillararene compound 2 is obtained;Subsequently, brominated pillararene polymer monomer compound 3 is obtained by reaction with NBS;Final compound 3 and equimolar amount of 3,4-propylenedioxythiophene monomer under alkaline conditions with palladium catalyst polymerization, obtained pillararene conjugated polymer P.The method of the application introduces the structure of pillararene into conjugated polymer electrochromic material for the first time, can be realized at lower voltage color from light yellow to light green, color can be reversible recovery, the electrochromic material responds quickly, contrast is high, and reversibility is high good.The electrochromic device manufactured using the electrochromic material based on pillararene conjugated polymer of the application has more outstanding color-changing performance, greater transmittance and longer service life.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of organic photoelectric materials, and particularly relates to a kind of electrochromic material based on pillararene conjugated polymer and its preparation method and application. BACKGROUND

[0002] Electrochromism refers to the reversible change of optical properties of a material under the action of an external electric field, which is optically manifested as a reversible change in transmittance or reflectance in the visible light range, and is visually manifested as a reversible change in color. Such materials are called electrochromic materials. In recent years, electrochromic technology has been widely used in various aspects of social life, and is widely used in the fields of automobile rearview mirrors, intelligent windows and intelligent display screens.

[0003] In 1980, the discovery of highly conductive polyacetylene revolutionized the traditional understanding that organic polymers were not conductive. Conducting polymers are characterized by easy large-area preparation, low processing cost and light weight, and are also known as conjugated polymers due to their conjugated structure with single and double bonds arranged at regular intervals. Electrochromic materials based on conjugated polymers exhibit fast response speed, high contrast, low energy consumption, and easy structure modification. Among them, polythiophene is considered one of the most promising materials for electrochromic materials due to its easy synthesis, good stability, and easy processing. For polymers such as 3,4-ethylenedioxythiophene (EDOT) and 3,4-propylenedioxythiophene (ProDOT), they are currently the focus of research due to their easy synthesis, high conductivity, good optical transparency, and ability to lower the oxidation potential of the polymer. The current research on polythiophene electrochromic materials has poor solubility due to the rigid structure of the thiophene backbone. Long alkyl chains can be introduced into the thiophene to enhance the solubility of the polythiophene. (Xu P, Murtaza I, Shi J, et al. Highly transmissive blue electrochromic polymers based on thieno[3,2-b]thiophene [J]. Polymer Chemistry, 2016, 7(34):5351-5356.) However, this method has the disadvantage of a complex synthesis process. In contrast, the strategy of introducing pillararene monomers into the polythiophene backbone for copolymerization is simple and fast, and facilitates structure control while increasing the solubility of the conjugated polymer. In addition, research on conjugated polymers based on pillararenes is increasingly widespread, including applications in molecular recognition, sensors, pollutant removal, adsorption separation, artificial light energy capture systems, and heterogeneous catalysis. However, there is no relevant literature on the application of conjugated polymers based on pillararenes in electrochromic materials. SUMMARY

[0004] One of the objectives of this invention is to overcome the poor solubility of organic polymers in the current field of electrochromic materials. By introducing a columnar aromatic hydrocarbon structure into the polymer backbone, the columnar aromatic hydrocarbon can improve the polymer solubility and adjust the polymer optical bandgap, resulting in color-changing materials with richer colors.

[0005] The second objective of this invention is to provide an electrochromic conjugated organic polymer material and its preparation method, as well as to develop the application of columnar aromatic conjugated polymers as electrochromic materials. The method of this invention introduces the columnar aromatic structure into conjugated polymer electrochromic materials for the first time, solving the problem of poor transmittance in existing electrochromic materials or devices.

[0006] The objective of this invention is achieved through the following technical solution:

[0007] This invention provides an electrochromic material based on columnar aromatic conjugated polymers, the structural formula of which is:

[0008]

[0009] Where R is C4-C 10 The straight-chain or branched alkoxy group; n represents the number of repeating units in the main molecule of the conjugated polymer, n>2; the dashed line in the structure represents the columnar aromatic ring structure of the repeating unit of the conjugated polymer.

[0010] Preferably, R is -O(CH2). n CH3, n = 3–9;

[0011] The method of this invention involves a Suzuki reaction of a bis-thiophene ring-substituted columnar aromatic hydrocarbon compound 2 with a boric acid reagent; subsequently, it reacts with NBS to yield a brominated columnar aromatic hydrocarbon polymer monomer compound 3; finally, compound 3 is polymerized with an equimolar amount of a 3,4-propanedioxythiophene derivative monomer under alkaline conditions using a palladium catalyst to obtain the columnar aromatic hydrocarbon conjugated polymer P. The reaction route is as follows:

[0012]

[0013] The preparation method specifically includes the following steps:

[0014] (1) Add 2.5-6 times the molar amount of 2-thiopheneboronic acid (based on compound 1) to a reaction flask, add 4-10 times the molar amount of base (based on compound 1), and then add a mixed solution of organic solvent and water. The volume ratio of organic solvent to distilled water is between 2:1 and 8:1. Under inert gas protection, add 0.01-0.1 times the molar amount of palladium catalyst (based on compound 1), and react at 70-90℃ for 6-24 h. Vacuum concentration is used to remove the solvent, and compound 2 is obtained by column chromatography.

[0015] (2) adding compound 2 and 2-4 times of N-bromosuccinimide (NBS) of compound 2 into one of dichloromethane or tetrahydrofuran solvent, reacting at 0-40℃ in dark for 3-8h, adding 1-3 times of sodium thiosulfate of compound 2, stirring for 0.5-3h, extracting with dichloromethane and drying with anhydrous Na2SO4, removing the solvent by rotary evaporation, and column chromatography to obtain compound 3;

[0016] (3) adding compound 3 and equimolar amount of 3,4-propylenedioxythiophene monomer into high-boiling organic solvent, adding 2-10 times of base of compound 3, and then adding 0.01-0.1 times of palladium catalyst of compound 3 and 0.2-0.6 times of pivalic acid of compound 3, passing inert gas for 10-20min, increasing the temperature to 90-130℃, stirring for 3-12h, after the reaction is completed, precipitating in methanol, filtering to obtain solid, and performing Soxhlet extraction to obtain polymer P.

[0017] Further, the palladium catalyst in step (1) is one of Pd(PPh3)4 or Pd(PPh2)Cl2.

[0018] Further, the base in step (1) includes Na2CO3, K2CO3, KOH or NaOH.

[0019] Further, the organic solvent in step (1) includes chloroform, tetrahydrofuran, toluene or 1,4-dioxane.

[0020] Further, the base in step (3) includes Na2CO3, KOAc, K2CO3, potassium tert-butoxide, KOH or NaOH.

[0021] Further, the palladium catalyst in step (3) is Pd(OAc)2.

[0022] Further, the high-boiling organic solvent in step (3) includes toluene, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

[0023] Further, the inert gas in step (1) and step (3) is argon or nitrogen.

[0024] The columnar arene-based conjugated polymer electrochromic material prepared by the above preparation method can be applied to the preparation of electrochromic devices, such as rearview mirrors of cars, smart windows and smart display screens and the like.

[0025] Compared with the prior art, the present application has the following advantages and gain effects:

[0026] (1) The present application introduces a p-arylene structure on a traditional conjugated polythiophene chain, for the first time to obtain a novel p-arylene conjugated polymer, and applies it to electrochromic materials and devices. The electron-rich cavity structure of p-arylene improves the distribution of the conjugated main chain electron cloud, making the molecule more likely to lose electrons, effectively reducing the band gap of the conjugated molecule, and changing color faster. Secondly, compared with the traditional rigid main chain structure, p-arylene has five benzene ring structures, which has excellent solubility, so that the solubility of the conjugated polymer is improved. Thirdly, in order to increase the diversity of color change, different color-changing groups are usually introduced as side chains, but the synthesis is complex. P-arylene has its unique host-guest properties. The cavity of the p-arylene conjugated polymer can combine with other guest molecules to introduce other electrochromic molecules, which can be physically blended to realize color adjustment, and can be used as a new color adjustment method.

[0027] (2) The electrochromic device prepared by using the p-arylene conjugated polymer shows completely different ultraviolet-visible absorption spectra and color changes before and after the experiment under 0-2.4V voltage. The color changes from light yellow to light green at a lower voltage, and the color can be reversibly recovered. The electrochromic material has rapid response, high contrast and good reversibility. The electrochromic device manufactured by using the electrochromic material based on the p-arylene conjugated polymer has more outstanding color-changing performance, higher transmittance and longer service life. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 It is the nuclear magnetic hydrogen spectrum of the p-arylene conjugated polymer molecule P1 synthesized in Example 1.

[0029] Figure 2 It is the infrared spectrum of the p-arylene conjugated polymer molecule P1 synthesized in Example 1.

[0030] Figure 3 It is the ultraviolet-visible absorption spectrum and fluorescence emission spectrum of the p-arylene conjugated polymer molecule P1 synthesized in Example 1.

[0031] Figure 4 It is the thermogravimetric analysis diagram of the p-arylene conjugated polymer molecule P1 synthesized in Example 1.

[0032] Figure 5 It is the cyclic voltammetry curve of the p-arylene conjugated polymer molecule P1 synthesized in Example 1.

[0033] Figure 6 It is the transmittance spectrum of the electrochromic device based on the p-arylene conjugated polymer molecule P1 synthesized in Example 1 under different voltages. DETAILED DESCRIPTION

[0034] The technical solutions of the present application are further described below in combination with the drawings and specific examples, but the scope of the present application claimed is not limited to the range expressed by the examples.

[0035] Example 1

[0036] The present example provides a preparation method of a columnar arene conjugated polymer-based electrochromic material, comprising the following steps:

[0037] Synthesis of main chain containing columnar [5] arene conjugated polymer (R is 2- ethylhexyloxy), the synthetic route is shown as follows:

[0038]

[0039] The synthesis steps are as follows:

[0040] (1) Synthesis of compound 2:

[0041]

[0042] Compound 1 (2.87g, 3.12mmol), 2-thiophene boronic acid (1.22g, 9.39mmol), potassium carbonate (3.3g, 31.1mmol) were weighed and added to a 50mL two-necked round-bottom flask under argon protection, 20mL of 1,4-dioxane and 2.5mL of water were added to the reaction bottle, and tetrakis(triphenylphosphine)palladium (180mg, 0.156mmol) was added and heated to 90℃ for 6h, and the reaction progress was monitored by TLC. After the reaction was completed, 50mL×3 dichloromethane was added, and 50mL×3 saturated brine was extracted three times, and the dichloromethane phase of the extraction was collected, dried with anhydrous sodium sulfate, and concentrated. A chromatographic column was filled with 300-400 mesh silica gel, and a mixture of petroleum ether, dichloromethane and ethyl acetate (V 石油醚 :V 二氯甲烷 :V 乙酸乙酯 =25:2:1) was used as the eluent for column chromatography, and white powder (compound 2, 1.71g) was obtained, with a yield of 64%.

[0043] NMR hydrogen spectrum data of compound 2: 1H-NMR (400 MHz, CDC13, 298 K) δ (ppm): 7.23-7.22 (dd, 2H), 7.20 (s, 2H), 7.00-6.98 (q, 2H), 6.83-6.82 (dd, 2H), 6.72 (s, 2H), 6.69 (s, 2H), 6.55 (s, 2H), 6.02 (s, 2H), 3.97 (s, 4H), 3.83 (s, 2H), 3.75 (s, 4H), 3.64 (s, 6H), 3.56 (s, 6H), 3.42 (s, 6H), 3.39 (s, 6H).

[0044] (2) Synthesis of compound 3

[0045]

[0046] Compound 2 (0.5 g, 0.58 mmol) was weighed into a 50 mL two-necked round-bottom flask, 15 mL of tetrahydrofuran was added under nitrogen protection, stirred and dissolved, NBS (0.313 g, 1.76 mmol) was dissolved in 10 mL of tetrahydrofuran solution under ice bath condition, slowly added dropwise using a constant pressure dropping funnel, after dropwise addition, the reaction was carried out for 8 h under ice bath condition, and the reaction progress was monitored by TLC. After the reaction was completed, sodium thiosulfate (0.137 g, 0.87 mmol) was added to 10 mL of deionized water to dissolve thoroughly, added to the reaction flask, stirred at room temperature for 1 h, then 50 mL x 3 dichloromethane was added, 50 mL x 3 saturated brine was extracted three times, the dichloromethane phase was collected, dried with anhydrous sodium sulfate, and concentrated. A chromatographic column was packed with 300-400 mesh silica gel, column chromatography was carried out using a mixture of petroleum ether and ethyl acetate (V 石油醚 :V 乙酸乙酯 = 50:1) as eluent, and white powder (compound 3, 0.458 g) was obtained by column chromatography separation with a yield of 78%.

[0047] NMR data of compound 3: 1 H-NMR (400 MHz, CDC13, 298 K) δ (ppm): 7.13 (s, 2H), 6.92-6.91 (d, 2H), 6.74 (s, 2H), 6.73 (s, 2H), 6.56 (s, 2H), 6.49-6.48 (d, 2H), 6.07 (s, 2H), 4.04-4.01 (d, 2H), 3.84-3.77 (m, 4H), 3.77 (s, 4H), 3.69 (s, 6H), 3.59 (s, 6H), 3.49 (s, 6H), 3.41 (s, 6H).

[0048] (3) Synthesis of columnar arene conjugated polymer P1:

[0049]

[0050] Compound 3 (202.4 mg, 0.2 mmol), 3,4-propylenedioxythiophene derivative (82.5 mg, 0.2 mmol), potassium carbonate (55 mg, 0.4 mmol), pivalic acid (6.1 mg, 0.06 mmol) were added into a 25 mL two-necked round bottom flask in turn, 7 mL of anhydrous N,N-dimethylacetamide was added under argon protection, and finally palladium acetate (4.5 mg, 0.02 mmol) was added. The reaction was carried out at 130°C for 3 h, and the reaction progress was monitored by TLC. After the reaction was completed, it was cooled to room temperature, and the obtained mixture was added into 300 mL of a methanol solution. The precipitate was filtered and dried. Soxhlet extraction was carried out with methanol, n-hexane and chloroform in turn. The chloroform-washed solution was collected and concentrated, and dried to obtain a dark brown solid powder (columnar [5] arene conjugated polymer P1, 119 mg), with a yield of 47%.

[0051] Figure 1 The nuclear magnetic resonance hydrogen spectrum of the columnar arene conjugated polymer molecule P1 synthesized in Example 1. Nuclear magnetic resonance hydrogen spectrum data: 1 H-NMR (400 MHz, CDCl3, 298K) δ (ppm): 7.30-7.00 (m, 4H), 6.73-6.18 (m, 10H), 4.21-3.33 (m, 46H), 1.62-0.88 (m, 30H).

[0052] Gel permeation chromatography (GPC) test showed that the number average molecular weight (Mn) of the polymer P1 was 14800 g / mol, and the dispersion coefficient (PDI) was 1.50.

[0053] Figure 2 The infrared spectrum of the columnar arene conjugated polymer molecule P1 synthesized in Example 1. It can be seen that the 3116 cm -1 stretching vibration peak of unsaturated C-H on the thiophene ring and benzene ring, 2990 cm -1 stretching vibration peak of unsaturated C-H on the thiophene ring and benzene ring, 2990 cm -1 stretching vibration peak of unsaturated C-H on the thiophene ring and benzene ring, 2990 cm

[0054] Example 2

[0055] The present example provides a preparation method of an electrochromic material based on a columnar arene conjugated polymer, comprising the following steps:

[0056] Synthesis of a main chain containing columnar [5] arene conjugated polymer (R is 2-ethylhexyloxy), the synthesis route is as shown below:

[0057]

[0058] The synthesis steps are as follows:

[0059] (1) Synthesis of compound 2:

[0060]

[0061] Compound 1 (2.87 g, 3.12 mmol), 2-thiopheneboronic acid (2.40 g, 18.72 mmol), sodium carbonate (3.31 g, 31.2 mmol) were weighed into a 50 mL two-necked round-bottom flask under argon protection, 20 mL of tetrahydrofuran and 5 mL of water were added to the reaction flask, and tetrakis(triphenylphosphine)palladium (180 mg, 0.156 mmol) was added. The reaction was heated to 70°C and reacted for 24 h, and the reaction progress was monitored by TLC. After the reaction was completed, 50 mL of dichloromethane was added, and the mixture was extracted three times with 50 mL of saturated brine. The dichloromethane extract was collected and dried over anhydrous sodium sulfate, and concentrated. The column was packed with 300-400 mesh silica gel, and the mixture of petroleum ether, dichloromethane and ethyl acetate (V 石油醚 :V 二氯甲烷 :V 乙酸乙酯 = 25:2:1) was used as the eluent for column chromatography, and white powder (compound 2, 1.28 g) was obtained, with a yield of 48%.

[0062] (2) Synthesis of compound 3

[0063]

[0064] Compound 2 (0.5 g, 0.58 mmol) was weighed into a 50 mL two-necked round-bottom flask under nitrogen protection, 15 mL of tetrahydrofuran was added, and stirred to dissolve, NBS (0.413 g, 2.32 mmol) was dissolved in 10 mL of tetrahydrofuran solution under ice bath conditions, and added slowly using a constant pressure dropping funnel. After the addition was completed, it was restored to room temperature, and reacted for 4 h at room temperature. The reaction progress was monitored by TLC. After the reaction was completed, sodium thiosulfate (45.9 mg, 0.29 mmol) was dissolved in 5 mL of deionized water, added to the reaction flask, and stirred at room temperature for 0.5 h. Then 50 mL of dichloromethane was added, and the mixture was extracted three times with 50 mL of saturated brine. The dichloromethane extract was collected and dried over anhydrous sodium sulfate, and concentrated. The column was packed with 300-400 mesh silica gel, and the mixture of petroleum ether and ethyl acetate (V 石油醚 :V 乙酸乙酯 = 50:1) was used as the eluent for column chromatography, and white powder (compound 3, 0.352 g) was obtained, with a yield of 60%.

[0065] (3) Synthesis of pillar [5] arene conjugated polymer P1:

[0066]

[0067] Compound 3 (202.4 mg, 0.2 mmol), 3,4-propylenedioxythiophene derivative (82.5 mg, 0.2 mmol), sodium carbonate (64 mg, 0.6 mmol), pivalic acid (12.3 mg, 0.12 mmol) were weighed into a 25 mL two-necked round-bottom flask under argon protection, 10 mL of anhydrous N-methylpyrrolidone was added, and finally palladium acetate (11.2 mg, 0.05 mmol) was added. The reaction was carried out at 90°C for 6 h, and the reaction progress was monitored by TLC. After the reaction was completed, it was cooled to room temperature, and the resulting mixture was added to 300 mL of a methanol solution. The precipitate was filtered and dried. Soxhlet extraction was performed with methanol, n-hexane, and chloroform, respectively. The chloroform-washed solution was collected and concentrated, and dried to obtain a dark brown solid powder (pillar [5] arene conjugated polymer P1, 142 mg), with a yield of 56%.

[0068] Example 3

[0069] The present example provides a preparation method of a pillar arene conjugated polymer-based electrochromic material, comprising the following steps:

[0070] Synthesis of a main chain containing pillar [5] arene conjugated polymer P2 (R is 1-hexyloxy), and the synthesis route is as shown below:

[0071]

[0072] The synthesis steps are as follows:

[0073] (1) Synthesis of compound 2:

[0074]

[0075] Compound 1 (2.87 g, 3.12 mmol), 2-thiophene boronic acid (1.0 g, 7.8 mmol), potassium hydroxide (0.353 g, 6.3 mmol) were weighed into a 50 mL two-necked round-bottom flask under argon protection, 10 mL of tetrahydrofuran and 5 mL of water were added to the reaction flask, and tetrakis(triphenylphosphine)palladium (137 mg, 0.12 mmol) was added. The reaction was heated to 72°C for 12 h, and the reaction progress was monitored by TLC. After the reaction was completed, 50 mL of dichloromethane was added, and the mixture was extracted with 50 mL of saturated brine three times. The dichloromethane extract was collected, dried with anhydrous sodium sulfate, and concentrated. A chromatographic column was packed with 300-400 mesh silica gel, and a mixed solution of petroleum ether, dichloromethane, and ethyl acetate (V 石油醚 :V二氯甲烷 : V 乙酸乙酯 Column chromatography separation was performed with petroleum ether and ethyl acetate mixed solution (V

[0076] (2) Synthesis of compound 3

[0077]

[0078] Compound 2 (0.5 g, 0.58 mmol) was weighed into a 50 mL two-necked round-bottom flask, 15 mL of tetrahydrofuran was added under nitrogen protection, stirred and dissolved, NBS (0.214 g, 1.2 mmol) was weighed into 8 mL of tetrahydrofuran solution under ice bath conditions, slowly added dropwise using a constant pressure dropping funnel, and after the addition was completed, it was restored to room temperature, heated to 40°C for 3 h, and the reaction progress was monitored by TLC. After the reaction was completed, sodium thiosulfate (280 mg, 1.74 mmol) was added to 15 mL of deionized water to dissolve thoroughly, added to the reaction flask, stirred at room temperature for 3 h, then 50 mL x 3 dichloromethane, 50 mL x 3 saturated brine was extracted three times, the dichloromethane phase was collected, dried with anhydrous sodium sulfate, and concentrated. A chromatographic column was packed with 300-400 mesh silica gel, and column chromatography separation was performed with petroleum ether and ethyl acetate mixed solution (V 石油醚 : V 乙酸乙酯 = 50:1) as eluent to obtain white powder (compound 3, 0.270 g) with a yield of 46%.

[0079] (3) Synthesis of columnar arene conjugated polymer P2:

[0080]

[0081] Compound 3 (202.4 mg, 0.2 mmol), 3,4-propylenedioxythiophene derivative (82.5 mg, 0.2 mmol), sodium carbonate (64 mg, 0.6 mmol), and pivalic acid (10.2 mg, 0.1 mmol) were sequentially weighed into a 25 mL two-necked round-bottom flask, 10 mL of anhydrous N,N-dimethylacetamide was added under argon protection, and finally palladium acetate (11.2 mg, 0.05 mmol) was added. The reaction was carried out at 120°C for 12 h, and the reaction progress was monitored by TLC. After the reaction was completed, it was cooled to room temperature, and the resulting mixture was added to 300 mL of methanol solution, filtered to obtain a precipitate, and oven dried; Soxhlet extraction was performed with methanol, n-hexane, and chloroform in sequence, the chloroform washed solution was collected and concentrated, and oven dried to obtain dark brown solid powder (columnar [5] arene conjugated polymer P2, 110 mg) with a yield of 43%.

[0082] Example 4

[0083] The columnar arene conjugated polymer molecule P1 synthesized in Example 1 was subjected to UV-visible absorption spectrum test and fluorescence emission spectrum test (concentration was 5 x 10 -6 mol / L, and the solvent was tetrahydrofuran, at room temperature). The normalized superimposed spectrum of the measured UV-visible absorption spectrum and fluorescence emission spectrum is shown in Figure 3 , the maximum absorption wavelength of the UV-visible absorption spectrum was 413 nm, and the strongest emission wavelength of the fluorescence emission spectrum was 525 nm.

[0084] Meanwhile, the columnar arene conjugated polymer molecule P1 synthesized in Example 1 was subjected to thermogravimetric analysis, as shown in Figure 4 , it can be seen that the initial thermal decomposition temperature of the polymer P1 was 372℃, the terminal decomposition temperature was 451℃, and the mass loss reached 30%.

[0085] The solid powder of the polymer material was dissolved in tetrahydrofuran at a concentration of 12.9 mg / mL. After complete dissolution, the solution was spin-coated on ITO conductive glass. The spin-coated uniform film was subjected to 80℃ annealing for 3h to obtain a polymer material film. The ITO glass spin-coated with the columnar arene conjugated polymer material film was used as the working electrode, Ag / AgCl was used as the reference electrode, platinum wire electrode was used as the counter electrode, and tetrabutylammonium perchlorate (0.1 mol / L) tetrahydrofuran solution was used as the electrolyte. The polymer film was subjected to cyclic voltammetry test in the range of -2V-3V voltage in a three-electrode system at a rate of 100 mV / s. As shown in Figure 5 , the cyclic voltammogram was obtained, which had an oxidation peak and two reduction peaks. The initial oxidation potential was 1.24V, and the initial reduction potential was -0.31V. During the voltage change process, the film changed from yellow to light green, and the film changed from light green to light yellow within a few seconds, indicating that the electrochromic material had rapid response and reversibility, and could be applied to electrochromic devices. The columnar arene conjugated polymer molecules P1 and P2 prepared in Example 2 and Example 3 also had rapid response and reversibility, and could also be applied to electrochromic devices.

[0086] Example 5

[0087] A polymer (0.02M) and tetrabutylammonium perchlorate (0.01M) are formulated into a tetrahydrofuran solution, and after being dissolved by stirring, a polymer electrochromic material electrolyte solution is obtained. An electrochromic device is assembled by first taking an ITO conductive glass, and then pasting a certain thickness of double-sided adhesive on the conductive surface to form a cavity to control the thickness of the electrochromic active layer solution. Another ITO glass is taken, and the two ITO glasses are pasted together and tightly attached by applying pressure. Then, the prepared polymer solution is injected into the cavity, and hot melt adhesive is used to seal the four corners to form a liquid electrochromic device.

[0088] By using the ultraviolet-visible absorption spectrum and the electrochromic cycle tester, it is found that the device is slightly yellow under natural light, and displays a light green color under natural light after a 2.4V voltage is applied to both ends. The change curve of the transmittance of the device under ultraviolet-visible absorption under a voltage of 0-2.4V is shown in FIG. 2, and it can be seen that the transmittance of the device between 530nm and 750nm decreases as the voltage applied to both ends increases, and the transmittance change at 680nm reaches more than 50%, and the color changes from light yellow to light green, indicating that the device has color change and electrochromic performance. Figure 6

[0089] The present application is not limited to the above-mentioned optional embodiments, and anyone can derive other various forms of products under the inspiration of the present application, but regardless of any changes in the structure, any technical solution falling within the scope defined by the claims of the present application falls within the protection scope of the present application.​

Claims

1. A columnar arene-conjugated polymer-based electrochromic material, characterized in that, The structural formula is: wherein R is a linear or branched alkoxy group having 4 to 10 carbon atoms; and n represents the number of repeating units of the conjugated polymer host molecule, n > 2; and the dotted line in the structure represents a columnar arene ring structure of the conjugated polymer repeating unit. 10 wherein R is a linear or branched alkoxy group having 4 to 10 carbon atoms; and n represents the number of repeating units of the conjugated polymer host molecule, n > 2; and the dotted line in the structure represents a columnar arene ring structure of the conjugated polymer repeating unit.

2. The method for preparing a columnar arene-conjugated polymer-based electrochromic material according to claim 1, characterized in that, The reaction route is as follows: The high-boiling organic solvent includes toluene, 1,4-dioxane, N,N-dimethylformamide, N,N-dimethylacetamide or N-methylpyrrolidone.

3. The method for preparing an electrochromic material based on a pillar [6]arene-conjugated polymer according to claim 2, characterized in that, The preparation method specifically comprises the following steps: (1) adding compound 1, 2.5-6 times of the molar amount of 2-thiophene boronic acid based on compound 1 into a reaction bottle, adding 4-10 times of the molar amount of a base based on compound 1, then adding a mixed solution of an organic reagent and distilled water, the volume ratio of the organic solvent and the distilled water being between 2:1 and 8:1, adding 0.01-0.1 times of the molar amount of a palladium catalyst based on compound 1 under the protection of an inert gas, and reacting at 70-90 DEG C for 6-24 h, then removing the solvent by rotary evaporation, and performing column chromatography to obtain compound 2; (2) adding compound 2 and 2-4 times of the molar amount of N-bromosuccinimide based on compound 2 into one of dichloromethane or tetrahydrofuran solvent, reacting at 0-40 DEG C in the dark for 3-8 h, adding 1-3 times of the molar amount of sodium thiosulfate based on compound 2, stirring for 0.5-3 h, extracting with dichloromethane and drying over anhydrous Na2SO4, removing the solvent by rotary evaporation, and performing column chromatography to obtain compound 3; (3) adding compound 3 and an equimolar amount of 3,4-propylenedioxythiophene monomer into a high-boiling organic solvent, adding 2-10 times of the molar amount of a base based on compound 3, then adding 0.01-0.1 times of the molar amount of a palladium catalyst based on compound 3 and 0.2-0.6 times of the molar amount of pivalic acid based on compound 3, passing an inert gas for 10-20 min, increasing the temperature to 90-130 DEG C, stirring for 3-12 h, after the reaction is completed, precipitating in methanol, filtering to obtain a solid, and performing Soxhlet extraction to obtain a polymer P, i.e., the electrochromic material based on a pillararene conjugated polymer.

4. The preparation method according to claim 3, characterized in that, The palladium catalyst in step (1) is one of Pd(PPh3)4 or Pd(PPh2)Cl2; and the palladium catalyst in step (3) is Pd(OAc)2.

5. The preparation method according to claim 3, characterized in that, The base in step (1) includes Na2CO3, K2CO3, KOH or NaOH.

6. The preparation method according to claim 3, characterized in that, The organic solvent in step (1) includes chloroform, tetrahydrofuran, toluene or 1,4-dioxane.

7. The preparation method according to claim 3, characterized in that, The base in step (3) includes Na2CO3, KOAc, K2CO3, potassium tert-butoxide, KOH or NaOH.

8. The preparation method according to claim 3, characterized in that, The inert gas in step (1) and step (3) is argon or nitrogen.

9. Use of the electrochromic material based on a pillararene conjugated polymer in claim 1 in the preparation of an electrochromic device.

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