An electrochromic polymer, its preparation method and application, and high-performance magenta-transparent electrochromic film

Abstract

The present invention belongs to the technical field of electrochromic materials, and provides an electrochromic polymer, a preparation method and application thereof, and a high-performance magenta-transparent electrochromic film. The present invention uses cyclopentathiophene as the D unit and 1,4-dialkoxybenzene as the π unit, prepares an electrochromic polymer by Suzuki reaction, and successfully prepares a high-performance magenta-transparent electrochromic film by spin coating. The film prepared by the present invention exhibits magenta in a neutral state (0V) and is transparent in an oxidized state (1.1V), and has an optical contrast of 56.4% at a wavelength of 532nm, a coloring time of 0.7s, a fading time of 0.6s, and a contrast retention of 84.3% after 1000 cycles. It is a new type of high-performance soluble magenta-transparent electrochromic material with great potential.

Description

Technical Field

[0001] The present invention relates to the technical field of electrochromic materials, in particular to an electrochromic polymer, a preparation method and application thereof, and a high-performance magenta-transparent electrochromic film. Background Art

[0002] In the field of electrochromism, color is a visual representation of a material and an important indicator for evaluating its performance. By adjusting the structure and energy gap of conductive polymers, we can obtain polymers of various colors. In recent years, researchers have made great efforts in designing and preparing soluble cyan, magenta, and yellow (CMY system) electrochromic polymers that can transition from colored to transparent. Among them, many cyan and yellow electrochromic materials with excellent performance have been synthesized and reported, while high-performance soluble magenta-transparent electrochromic materials have rarely been reported. Summary of the Invention

[0003] The purpose of the present invention is to address the deficiencies in the prior art and provide an electrochromic polymer, a preparation method and application thereof, and a high-performance magenta-transparent electrochromic film.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The present invention provides an electrochromic polymer, the structural formula of the electrochromic polymer is:

[0006]

[0007] R1 and R2 are independently one of C1-C30 alkane chains;

[0008] R3 and R4 are independently one of C1-C6 alkane chains;

[0009] n is an integer between 10 and 200.

[0010] The present invention also provides a method for preparing the electrochromic polymer, comprising the following steps:

[0011] Under a protective atmosphere, the first monomer, the second monomer, potassium carbonate, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide and water are mixed and reacted to obtain the electrochromic polymer;

[0012] The structural formula of the first monomer is: The structural formula of the second monomer is:

[0013]

[0014] R1 and R2 are independently one of C1-C30 alkane chains;

[0015] R3 and R4 are independently one of C1-C6 alkane chains.

[0016] Preferably, the molar ratio of the first monomer to the second monomer is 0.5-1.5:0.5-1.5;

[0017] The mass volume ratio of the first monomer, potassium carbonate, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide and water is 1 g: 1-4 g: 0.01-0.2 g: 30-45 mL: 10-15 mL.

[0018] Preferably, the reaction temperature is 110-130° C., and the reaction time is 16-20 h.

[0019] The present invention also provides the use of the electrochromic polymer in preparing a high-performance magenta-transparent electrochromic film.

[0020] The present invention also provides a method for preparing a high-performance magenta-transparent electrochromic film, comprising the following steps:

[0021] The electrochromic polymer is mixed with chloroform to obtain a polymer solution; the polymer solution is spin-coated on a conductive substrate to obtain the high-performance magenta-transparent electrochromic film.

[0022] Preferably, the mass concentration of the polymer solution is 5 to 20 mg / mL.

[0023] Preferably, the spin coating speed is 800-1200 r / s, and the spin coating time is 0.5-1.5 min.

[0024] The present invention also provides a high-performance magenta-transparent electrochromic film prepared by the preparation method of the high-performance magenta-transparent electrochromic film.

[0025] The present invention also provides application of the high-performance magenta-transparent electrochromic film in the field of electrochromism.

[0026] The beneficial effects of the present invention are:

[0027] This invention uses cyclopentabithiophene as the D unit and 1,4-dialkoxybenzene as the π unit to prepare an electrochromic polymer via a Suzuki reaction. A high-performance magenta-transparent electrochromic film was successfully prepared by spin coating. The film exhibits a magenta color in the neutral state (0V) and is transparent in the oxidized state (1.1V). The film exhibits an optical contrast ratio of 56.4% at a wavelength of 532nm, a coloring time of 0.7s, a fading time of 0.6s, and a contrast retention of 84.3% after 1000 cycles. This makes it a promising new high-performance soluble magenta-transparent electrochromic material. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The cyclic voltammograms of the PCPDT-PhO film at different scan rates in Application Example 1 (Potential—voltage, Current—current);

[0029] Figure 2 The UV-visible absorption spectra (Wavelength, Absorbance) of the PCPDT-PhO film at different voltages in Application Example 1 are shown in Figure 1.

[0030] Figure 3 Schematic diagram of the response time of the PCPDT-PhO film in Application Example 1 at 532 nm (Time—time, Transmittance—transmittance);

[0031] Figure 4 Schematic diagram of the stability of the PCPDT-PhO film in Application Example 1 at 532 nm (Time, Transmittance, retain 84.3% after 1000 cycles). DETAILED DESCRIPTION

[0032] The present invention provides an electrochromic polymer, the structural formula of the electrochromic polymer is:

[0033]

[0034] R1 and R2 are independently one of C1-C30 alkane chains;

[0035] R3 and R4 are independently one of C1-C6 alkane chains;

[0036] n is an integer of 10 to 200, preferably 15 to 150, more preferably 20 to 100, and even more preferably 25 to 80.

[0037] The present invention also provides a method for preparing the electrochromic polymer, comprising the following steps:

[0038] Under a protective atmosphere, the first monomer, the second monomer, potassium carbonate, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide and water are mixed and reacted to obtain the electrochromic polymer;

[0039] The structural formula of the first monomer is: The structural formula of the second monomer is:

[0040]

[0041] R1 and R2 are independently one of C1-C30 alkane chains;

[0042] R3 and R4 are independently one of C1-C6 alkane chains.

[0043] In the present invention, the first monomer is prepared by conventional techniques in the art, and the preparation references are as follows: [RSC Adv.2014, 4, 37738-37745], [Adv.Funct.Mater.2012, 22, 2846-2854] and [AdvancedMaterials Research Vols 383-390 (2012) pp7677-7681]; the second monomer is purchased.

[0044] In the present invention, the protective atmosphere is preferably nitrogen.

[0045] In the present invention, the molar ratio of the first monomer to the second monomer is preferably 0.5-1.5:0.5-1.5, more preferably 0.7-1.3:0.7-1.3, and even more preferably 1:1.

[0046] In the present invention, the mass volume ratio of the first monomer, potassium carbonate, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide and water is preferably 1 g:1-4 g:0.01-0.2 g:30-45 mL:10-15 mL, more preferably 1 g:1.5-3.5 g:0.05-0.15 g:35-40 mL:11-14 mL, and more preferably 1 g:2-3 g:0.1-0.12 g:37-38 mL:12-13 mL.

[0047] In the present invention, the reaction temperature is preferably 110-130° C., more preferably 115-125° C., and more preferably 120° C.; the reaction time is preferably 16-20 h, more preferably 17-19 h, and more preferably 18 h.

[0048] In the present invention, after the reaction is completed, the mixture is naturally cooled to room temperature, and the obtained mixture is post-treated to obtain the electrochromic polymer; the post-treatment preferably comprises the following steps: pouring the mixture into methanol, wherein the volume ratio of the mixture to methanol is preferably 1:5 to 25, more preferably 1:10 to 20, and more preferably 1:15; filtering, drying the filter cake obtained by filtration, and after drying, Soxhlet extraction is performed with methanol, acetone, hexane and chloroform in sequence, wherein the amounts of methanol, acetone, hexane and chloroform are conventionally selected by those skilled in the art according to the capacity of the Soxhlet extractor device; finally, the polymer dissolved in the chloroform is collected and spin-dried to obtain the electrochromic polymer.

[0049] The synthesis route of the electrochromic polymer in the present invention is as follows:

[0050]

[0051] The present invention also provides the use of the electrochromic polymer in preparing a high-performance magenta-transparent electrochromic film.

[0052] The present invention also provides a method for preparing a high-performance magenta-transparent electrochromic film, comprising the following steps:

[0053] The electrochromic polymer is mixed with chloroform to obtain a polymer solution; the polymer solution is spin-coated on a conductive substrate to obtain the high-performance magenta-transparent electrochromic film.

[0054] In the present invention, the mass concentration of the polymer solution is preferably 5 to 20 mg / mL, more preferably 10 to 15 mg / mL, and even more preferably 12 to 13 mg / mL.

[0055] In the present invention, the polymer solution is filtered through a Nylon 66 filter and then spin-coated on a conductive substrate; the pore size of the filter is preferably 20-24 μm, more preferably 21-23 μm, and more preferably 22 μm; and the conductive substrate is preferably ITO glass.

[0056] In the present invention, the spin coating rotation speed is preferably 800-1200 r / s, more preferably 900-1100 r / s, and more preferably 1000 r / s; the spin coating time is preferably 0.5-1.5 min, more preferably 0.7-1.3 min, and more preferably 1 min; after the spin coating is completed, it is naturally dried in the air to obtain the high-performance magenta-transparent electrochromic film.

[0057] The present invention also provides a high-performance magenta-transparent electrochromic film prepared by the preparation method of the high-performance magenta-transparent electrochromic film.

[0058] The present invention also provides application of the high-performance magenta-transparent electrochromic film in the field of electrochromism.

[0059] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0060] The second monomer in the embodiment of the present invention, 2,2'-(2,5-dimethoxy-1,4-phenylene)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane, was purchased from Leyan, the website of which is https: / / www.leyan.com / 1338777-82-4.html.

[0061] Example 1

[0062] 1.00g of cyclopentylbithiophene, 0.41g of tetrabutylammonium iodide and 2.73g of 1-Bromodecane was added to a 250 mL two-necked round-bottom flask. Under nitrogen protection, 30 mL of 50% sodium hydroxide solution was added, heated to 75 ° C, and reacted for 6 h. After the reaction, the mixture was extracted with ethyl acetate (the volume ratio of ethyl acetate to the mixture was 1:3), and washed with saturated brine three times. The volume ratio of saturated brine to ethyl acetate used for each wash was 1:3. The organic layers were combined and dried over anhydrous sodium sulfate to obtain a sample. Silica gel with a particle size of 200-300 meshes was added in an amount 1.3 times the mass of the sample. The sample was concentrated and mixed under vacuum. Finally, petroleum ether was used as an eluent and 300-400 mesh silica gel was used as a stationary phase. The mixture was chromatographed to obtain a yellow-brown liquid (tested, the mass was 2.01 g, the yield was 78%), namely 4,4-didecyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene, with the structural formula

[0063] The hydrogen spectrum data is: 1 H NMR (400MHz, CDCl3) δ7.14 (d, J = 4.8Hz, 1H), 6.93 (d, J = 4.9Hz, 1H), 1.87-1.76 (m, 2H), 1.36-0.80 (m, 19H).

[0064] 1.00 g of 4,4-didecyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene was added to a 250 mL round-bottom flask, and then 60 mL of tetrahydrofuran was added. Under light-shielding conditions, 0.81 g of N-bromosuccinimide (added in 3 portions, the mass ratio of the 3 additions being 1:1:1) was added, stirred at 25°C for 90 min, and after the reaction was completed, the reaction solvent was removed by rotary evaporation, and the reaction mixture was extracted with dichloromethane (the volume ratio of dichloromethane to the mixture was 1:3), and washed with saturated brine 3 times, the volume ratio of saturated brine to dichloromethane used for each washing being 1:3. The organic layers were combined and dried over anhydrous sodium sulfate to obtain a sample, and silica gel with a particle size of 200-300 meshes in an amount 1.3 times the mass of the sample was added, and the sample was concentrated and mixed under vacuum. Finally, petroleum ether was used as an eluent and 300-400 mesh silica gel was used as a stationary phase. The mixture was chromatographed on a column to obtain a yellow liquid (tested, the mass was 1.21 g, the yield was 92%), i.e., 2,6-dibromo-4,4-didecyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene, with the structural formula being (first monomer);

[0065] The hydrogen spectrum data is: 1 H NMR (400MHz, CDCl3) δ6.92 (s, 1H), 1.79-1.71 (m, 2H), 1.37-0.80 (m, 19H).

[0066] 0.41 mmol of 2,6-dibromo-4,4-didecyl-4H-cyclopenta[2,1-b:3,4-b']dithiophene (0.25 g, first monomer), 0.41 mmol of 2,2'-(2,5-dimethoxy-1,4-phenylene)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane) (second monomer, structural formula ), 0.6 g potassium carbonate, 0.04 g tetrakis(triphenylphosphine)palladium were added to the reaction tube, and under nitrogen protection, 7.5 mL N, N-dimethylformamide and 2.5 mL deionized water were added, the temperature was raised to 120 ° C, and reflux was maintained for 18 hours. After the reaction was completed, it was naturally cooled to room temperature, and the obtained mixture was poured into methanol (the volume ratio of the mixture to methanol was 1:15), filtered, and the filter cake obtained by filtration was dried. After drying, methanol, acetone, hexane and chloroform were used for Soxhlet extraction in sequence, and the polymer dissolved in chloroform was collected and dried by spin drying to obtain an electrochromic polymer (tested, the mass was 0.22 g, the yield was 86%), marked as PCPDT-PhO, with the structural formula The value of n ranges from 25 to 80.

[0067] The hydrogen spectrum data of the electrochromic polymer obtained in this example are: 1 H NMR (400MHz, CDCl3) δ7.41(s,1H),7.28(s,1H),4.04(s,3H),2.03-1.81(m,2H),1.36-0.76(m,19H).

[0068] Application Example 1

[0069] 10 mg of the PCPDT-PhO prepared in Example 1 was added to a centrifuge tube, chloroform was added, and the mixture was completely dissolved by sonication for 5 min to obtain a polymer solution with a mass concentration of 10 mg / mL. The polymer solution was filtered through a Nylon 66 filter (pore size 22 μm), and then spin-coated on an ITO glass (size 0.9 cm*4 cm) at a spin coater speed of 1000 r / s for 1 min. After the spin coating is completed, the mixture was naturally dried in air to obtain a high-performance magenta-transparent electrochromic film (labeled as PCPDT-PhO film).

[0070] The PCPDT-PhO film was subjected to a performance test. Specifically, 1.935 g of tetrabutylammonium hexafluorophosphate was added to a 50 mL volumetric flask, and the volume was adjusted with 50 mL of acetonitrile. This was used as a blank solution. ITO glass with a PCPDT-PhO film on its surface was used as a working electrode, a platinum wire was used as a counter electrode, and an Ag / AgCl electrode was used as a reference electrode. The electrochromic performance was tested in conjunction with a UV-visible spectrophotometer. The electrochemical workstation was set to a cyclic voltammetry mode, the voltage range was set to 0-1.1 V, and the scan rates were set to 50 mV / s, 100 mV / s, 150 mV / s, 200 mV / s, 250 mV / s, 300 mV / s, and 350 mV / s. The cyclic voltammetry curves of the PCPDT-PhO film in Application Example 1 at different scan rates were obtained, as shown in FIG. Figure 1 As shown; Set the electrochemical workstation to constant potential mode, set the voltage to increase from 0 to 1.1V, each time by 0.1V, and apply the voltage for 15s. Then, use a UV-visible spectrophotometer to in situ record the UV-visible absorption curve of the film at 350nm-1000nm at each voltage, and obtain the UV-visible absorption spectrum of the PCPDT-PhO film in Application Example 1 at different voltages, as shown in FIG. Figure 2 As shown; Set the electrochemical workstation to voltage step mode, set the step voltage to 0-1.1V, use UV-visible spectrophotometer to test the transmittance of the film at the maximum absorption wavelength of 532nm, and obtain the response time schematic diagram of the PCPDT-PhO film in Application Example 1 in the 532nm band, as shown Figure 3As shown; Set the electrochemical workstation to voltage step mode, set the step voltage to 0-1.1V, set 1000 cycles, and use a UV-visible spectrophotometer to test the transmittance of the film at the maximum absorption wavelength of 532nm. The stability diagram of the PCPDT-PhO film in Application Example 1 at 532nm is as shown in FIG. Figure 4 As shown. Figure 1 It can be seen that the initial oxidation potential of PCPDT-PhO is around 0.4V, showing a reversible redox peak, which reflects the good redox activity of PCPDT-PhO polymer and also brings stable redox properties to the polymer film. The peak current intensity of the polymer increases with the increase of scan rate. Figure 2 It can be seen that in the neutral state of 0V, the polymer film is in a high absorption state, with the maximum absorption peak located at 532nm. As the voltage gradually increases, the intensity of the ground state absorption peak gradually weakens. When the voltage reaches 1.1V, the polymer film in the oxidized state shows a high transmittance state in the visible light region (380-780nm). Figure 3 It can be seen that the optical contrast of the polymer at a wavelength of 532 nm is 56.4%, the coloring time is 0.7 s, and the fading time is 0.6 s. Figure 4 It can be seen that the contrast is retained by 84.3% after 1000 cycles, which is a very promising new high-performance soluble fuchsin-transparent electrochromic material.

[0071] As shown in the above examples, the present invention uses cyclopentabithiophene as the D unit and 1,4-dialkoxybenzene as the π unit to prepare an electrochromic polymer via a Suzuki reaction. A high-performance magenta-transparent electrochromic film was successfully prepared by spin coating. The film prepared by the present invention exhibits a magenta color in the neutral state (0V) and is transparent in the oxidized state (1.1V). The optical contrast ratio at a wavelength of 532nm is 56.4%, the coloring time is 0.7s, the fading time is 0.6s, and the contrast ratio retention after 1000 cycles is 84.3%. This makes it a highly promising new high-performance soluble magenta-transparent electrochromic material.

[0072] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, without departing from the principles of the present invention, several improvements and modifications can be made, such as adding some simple groups at the end of the alkyl chain that do not change the electrochromic properties of the original material. These improvements and modifications should also be considered as the scope of protection of the present invention.

Claims

1. An electrochromic polymer, characterized in that The structural formula of the electrochromic polymer is: R1 and R2 are independently one of C1-C30 alkane chains; R3 and R4 are independently one of C1-C6 alkane chains; n is an integer between 10 and 200.

2. The method for preparing the electrochromic polymer according to claim 1, characterized in that: It includes the following steps: Under a protective atmosphere, the first monomer, the second monomer, potassium carbonate, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide and water are mixed and reacted to obtain the electrochromic polymer; The structural formula of the first monomer is: The structural formula of the second monomer is: R1 and R2 are independently one of C1-C30 alkane chains; R3 and R4 are independently one of C1-C6 alkane chains.

3. The method for preparing an electrochromic polymer according to claim 2, wherein: The molar ratio of the first monomer to the second monomer is 0.5-1.5:0.5-1.5; The mass volume ratio of the first monomer, potassium carbonate, tetrakis(triphenylphosphine)palladium, N,N-dimethylformamide and water is 1 g: 1-4 g: 0.01-0.2 g: 30-45 mL: 10-15 mL.

4. The method for preparing an electrochromic polymer according to claim 2 or 3, wherein: The reaction temperature is 110-130° C., and the reaction time is 16-20 hours.

5. Use of the electrochromic polymer according to claim 1 in preparing a high-performance magenta-transparent electrochromic film.

6. A method for preparing a high-performance magenta-transparent electrochromic film, characterized in that: It includes the following steps: The electrochromic polymer according to claim 1 is mixed with chloroform to obtain a polymer solution; the polymer solution is spin-coated on a conductive substrate to obtain the high-performance magenta-transparent electrochromic film.

7. The method for preparing a high-performance magenta-transparent electrochromic film according to claim 6, wherein: The mass concentration of the polymer solution is 5-20 mg / mL.

8. The method for preparing a high-performance magenta-transparent electrochromic film according to claim 6 or 7, wherein: The spin coating speed is 800-1200 r / s, and the spin coating time is 0.5-1.5 min.

9. A high-performance magenta-transparent electrochromic film prepared by the method for preparing a high-performance magenta-transparent electrochromic film according to any one of claims 6 to 8.

10. Use of the high-performance magenta-transparent electrochromic film according to claim 9 in the field of electrochromism.

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