An electrochromic material, a preparation method and application thereof

Abstract

This invention provides an electrochromic material, its preparation method, and its application. The structural formula of the electrochromic material is shown below: AR1 is a group represented by R1 or R3; AR2 is a group represented by R2 or R6; AR3 is selected from any one of R3, R4, and R5; AR4 is a group represented by R2; n is the degree of polymerization, and n is 4–35. This invention uses an arylation polycondensation process to prepare four high-performance solution-processable electrochromic materials: TTP, TEP, TPP, and PBP3P. Using these electrochromic materials as raw materials, high-performance patterned electrochromic camouflage devices are prepared using mask spraying. Nylon filter membranes with different pore sizes are introduced into the device structure to adjust the device's transmittance and achieve better camouflage effects.

Description

Technical Field

[0001] This invention relates to the field of electrochromic materials technology, and in particular to an electrochromic material, its preparation method, and its application. Background Technology

[0002] The application of electrochromic materials in military camouflage has become a research hotspot. Among them, solution-processable electrochromic materials, as a type of organic electrochromic material, have attracted widespread attention due to their diverse and simple film-forming methods. Currently, the electrochromic performance of solution-processable electrochromic materials and devices used in military camouflage is relatively poor.

[0003] Chinese patent literature discloses "an electrochromic material and its preparation method, and an electrochromic device and its preparation method," publication number CN102952538A. This electrochromic material comprises an n-type electrochromic material, a p-type electrochromic material, a polymer matrix, and a first solvent. The n-type electrochromic material is a viologen compound. The n-type and p-type electrochromic materials are embedded in the polymer matrix to form a gel-like electrochromic material. This invention obtains a gel-like electrochromic material by embedding the n-type and p-type electrochromic materials into a polymer matrix. However, the electrochromic performance of this material is still relatively poor when applied in the field of military camouflage and needs further improvement. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide an electrochromic material, its preparation method, and its application, in order to solve the problem of poor electrochromic performance of existing solution-processable electrochromic materials and devices used in military camouflage.

[0005] To achieve the above and other related objectives, the present invention provides an electrochromic material, the structural formula of which is shown below:

[0006]

[0007] Where AR1 is the group represented by R1 or R3;

[0008] AR2 is a group represented by R2 or R6;

[0009] AR3 is selected from any one of the groups represented by R3, R4, and R5;

[0010] AR4 is the group represented by R2;

[0011] n is the degree of polymerization, which refers to the number of repeating units that appear consecutively in the polymer molecular chain, and n ranges from 4 to 35.

[0012] The structural formulas of the groups represented by R1, R2, R3, R4, R5, and R6 are shown below:

[0013]

[0014] Preferably, AR1 is the group represented by R1, AR2 is the group represented by R2, AR3 is the group represented by R5, x, y, z, and w are all 1; n is 20 to 35, and the structural formula of the electrochromic material is shown in Formula I:

[0015]

[0016] More preferably, the electrochromic material TTP shown in Formula I has an optical contrast of 34.08% in the 535nm wavelength range, a coloring time of 0.77s, and a fading time of 0.87s.

[0017] Preferably, AR1 is the group represented by R1, AR2 is the group represented by R2, AR3 is the group represented by R4, x, y, z, and w are all 1; n is 10 to 20, and the structural formula of the electrochromic material is shown in Formula II:

[0018]

[0019] More preferably, the electrochromic material TEP shown in Formula II has an optical contrast ratio of 40.27% in the 545nm wavelength range, a coloring time of 0.90s, and a fading time of 0.64s.

[0020] Preferably, AR1 is the group represented by R1, AR2 is the group represented by R2, AR3 is the group represented by R3, x, y, z, and w are all 1; n is 15 to 25, and the structural formula of the electrochromic material is shown in Formula III:

[0021]

[0022] More preferably, the electrochromic material TPP shown in Formula III has an optical contrast of 45.52% in the 540nm wavelength range, a coloring time of 0.65s, and a fading time of 0.38s; after undergoing 3000 cycles at step voltages of 0V and 0.9V, the optical contrast of the three materials can maintain 60.92%, 87.83%, and 68.52% of the initial contrast, respectively.

[0023] Preferably, AR1 is the group represented by R3, AR2 is the group represented by R6, AR3 is the group represented by R3, x, y, and z are all 1, w is 3, and n is 4 to 8. The structural formula of the electrochromic material is shown in Formula IV.

[0024]

[0025] More preferably, the electrochromic material PBP3P shown in Formula IV has an optical contrast of 43.56% in the 640nm wavelength range, a coloring time of 0.90s, and a fading time of 0.56s; after undergoing 3000 cycles at step voltages of 0V and 1.0V, the optical contrast of the three electrochromic films can maintain 88.25% of the initial contrast.

[0026] The present invention also provides a method for preparing an electrochromic material (TTP) of Formula I, using N,N-bis(4-bromophenyl)-4-butylaniline of Formula V, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane-heptene of Formula VI and 2,5-dibromothiophene of Formula VII as raw materials, and reacting them at 110-135°C under a protective atmosphere to generate the electrochromic material of Formula I;

[0027]

[0028] Preferably, under nitrogen protection, N,N-bis(4-bromophenyl)-4-butylaniline, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane-heptene, 2,5-dibromothiophene, potassium carbonate, tervastatinic acid, appropriate amount of Pd(OAc)2 and anhydrous DMAc are added to a Schlenk tube and reacted at 130°C for 15-17 h. After post-treatment, the electrochromic material TTP shown in Formula I is obtained.

[0029] Preferably, the molar ratio of 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiopheno[3,4-B][1,4]dioxane-heptene to N,N-bis(4-bromophenyl)-4-butylaniline is 2:1.

[0030] Preferably, the molar ratio of 2,5-dibromothiophene to N,N-bis(4-bromophenyl)-4-butylaniline is 1:1.

[0031] Preferably, the molar ratio of anhydrous potassium carbonate to N,N-bis(4-bromophenyl)-4-butylaniline is (4-6):1.

[0032] Preferably, the molar ratio of tervastatin to N,N-bis(4-bromophenyl)-4-butylaniline is (0.01-0.1):1.

[0033] Preferably, the molar ratio of Pd(OAc)2 to N,N-bis(4-bromophenyl)-4-butylaniline is (0.01-0.05):1.

[0034] Preferably, the volume of anhydrous DMAc added is 40-80 mL / g, based on the mass of N,N-bis(4-bromophenyl)-4-butylaniline.

[0035] Preferably, the post-reaction processing method is as follows: the reaction solution is added to methanol, the mixture is filtered using a Buchner funnel, the filter cake is washed with methanol, the filter cake is wrapped with filter paper and extracted with a Soxhlet extractor to extract polymers of different degrees of polymerization. During this process, solvents with different solubilities are changed, and the order of solvent use is methanol, acetone, petroleum ether, and chloroform. The solvent is removed by rotary evaporation of the chloroform-extracted portion to obtain the electrochromic material TTP shown in Formula I.

[0036] The present invention also provides a method for preparing an electrochromic material (TEP) of Formula II, using N,N-bis(4-bromophenyl)-4-butylaniline of Formula V, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane-heptene of Formula VIII and 2,5-dibromo-3,4-vinyldioxothiophene of Formula VIII as raw materials, reacting them at 110-135°C under a protective atmosphere to generate the electrochromic material of Formula II;

[0037]

[0038] Preferably, under nitrogen protection, N,N-bis(4-bromophenyl)-4-butylaniline, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiopheno[3,4-B][1,4]dioxane-heptene, 2,5-dibromo-3,4-vinyldioxothiophene, potassium carbonate, tervastatinic acid, appropriate amount of Pd(OAc)2 and anhydrous DMAc are added to a Schlenk tube and reacted at 130°C for 15-17 h. After post-treatment, the electrochromic material TEP shown in Formula II is obtained.

[0039] Preferably, the molar ratio of 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiopheno[3,4-B][1,4]dioxane-heptene to N,N-bis(4-bromophenyl)-4-butylaniline is 2:1.

[0040] Preferably, the molar ratio of 2,5-dibromo-3,4-vinyldioxythiophene to N,N-bis(4-bromophenyl)-4-butylaniline is 1:1.

[0041] Preferably, the molar ratio of anhydrous potassium carbonate to N,N-bis(4-bromophenyl)-4-butylaniline is (4-6):1.

[0042] Preferably, the molar ratio of tervastatin to N,N-bis(4-bromophenyl)-4-butylaniline is (0.01-0.1):1.

[0043] Preferably, the molar ratio of Pd(OAc)2 to N,N-bis(4-bromophenyl)-4-butylaniline is (0.01-0.05):1.

[0044] Preferably, the volume of anhydrous DMAc added is 40-80 mL / g, based on the mass of N,N-bis(4-bromophenyl)-4-butylaniline.

[0045] Preferably, the post-reaction processing method is as follows: the reaction solution is added to methanol, the mixture is filtered using a Buchner funnel, the filter cake is washed with methanol, the filter cake is wrapped with filter paper and extracted with a Soxhlet extractor to extract polymers of different degrees of polymerization, during which solvents with different solubilities are changed, and the order of solvent use is methanol, acetone, petroleum ether, and chloroform. The solvent is removed by rotary evaporation of the chloroform-extracted portion to obtain the electrochromic material TEP shown in Formula II.

[0046] The present invention also provides a method for preparing an electrochromic material (TPP) of Formula III, using N,N-bis(4-bromophenyl)-4-butylaniline of Formula V, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane-heptene of Formula VI and 6,8-dibromo-3,4-dihydro-3,3-dimethyl2H-thieno[3,4-b][1,4]dioxane-hepten of Formula IX as raw materials, and reacting them at 110-135°C under a protective atmosphere to generate the electrochromic material of Formula III;

[0047]

[0048] Preferably, under nitrogen protection, N,N-bis(4-bromophenyl)-4-butylaniline, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane, 6,8-dibromo-3,4-dihydro-3,3-dimethyl2H-thieno[3,4-B][1,4]dioxane, potassium carbonate, terpentine, appropriate amount of Pd(OAc)2 and anhydrous DMAc are added to a Schlenk tube and reacted at 130°C for 15-17 h. After post-treatment, the electrochromic material TPP shown in Formula III is obtained.

[0049] Preferably, the molar ratio of 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiopheno[3,4-B][1,4]dioxane-heptene to N,N-bis(4-bromophenyl)-4-butylaniline is 2:1.

[0050] Preferably, the molar ratio of the 6,8-dibromo-3,4-dihydro-3,3-dimethyl2H-thiopheno[3,4-B][1,4]dioxane to N,N-bis(4-bromophenyl)-4-butylaniline is 1:1.

[0051] Preferably, the molar ratio of anhydrous potassium carbonate to N,N-bis(4-bromophenyl)-4-butylaniline is 4 to 6:1.

[0052] Preferably, the molar ratio of tervastatin to N,N-bis(4-bromophenyl)-4-butylaniline is (0.01-0.1):1.

[0053] Preferably, the molar ratio of Pd(OAc)2 to N,N-bis(4-bromophenyl)-4-butylaniline is (0.01-0.05):1.

[0054] Preferably, the volume of anhydrous DMAc added is 40-80 mL / g, based on the mass of N,N-bis(4-bromophenyl)-4-butylaniline.

[0055] Preferably, the post-reaction processing method is as follows: the reaction solution is added to methanol, the mixture is filtered using a Buchner funnel, the filter cake is washed with methanol, the filter cake is wrapped with filter paper and extracted with a Soxhlet extractor to extract polymers of different degrees of polymerization. During this process, solvents with different solubilities are changed, and the order of solvent use is methanol, acetone, petroleum ether, and chloroform. The solvent is removed by rotary evaporation of the chloroform-extracted portion to obtain the electrochromic material TPP shown in Formula III.

[0056] The present invention also provides a method for preparing an electrochromic material (PBP3P) of Formula IV, wherein 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxin-6-yl)benzo[c][1,2,5]thiazole of Formula X, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxane-heptene of Formula VI, and 6,8-dibromo-3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxane-heptene of Formula XII are reacted to generate the electrochromic material of Formula IV.

[0057]

[0058] Preferably, under nitrogen protection, 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxin-6-yl)benzo[c][1,2,5]thiazole, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxane-heptene, 6,8-dibromo-3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxane-heptene, potassium carbonate, terpentine, appropriate amount of Pd(OAc)2 and anhydrous DMAc are added to a Schlenk tube and reacted at 130°C for 3-8 h. After post-treatment, the electrochromic material PBP3P shown in Formula IV is obtained.

[0059] Preferably, the molar ratio of the 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiopheno[3,4-b][1,4]dioxane-heptene to 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiopheno[3,4-b][1,4]dioxane-6-yl)benzo[c][1,2,5]thiazole is 1:1.

[0060] Preferably, the molar ratio of 6,8-dibromo-3,3-bis((((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiopheno[3,4-b][1,4]dioxane-heptene to 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiopheno[3,4-b][1,4]dioxane-6-yl)benzo[c][1,2,5]thiazole is 2:1.

[0061] Preferably, the molar ratio of potassium carbonate to 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxon-6-yl)benzo[c][1,2,5]thiazole is (3-5):1.

[0062] Preferably, the molar ratio of the tervastatinic acid to 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxon-6-yl)benzo[c][1,2,5]thiazole is (0.01~0.1):1.

[0063] Preferably, the molar ratio of Pd(OAc)2 to 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxon-6-yl)benzo[c][1,2,5]thiazole is (0.01~0.05):1.

[0064] Preferably, the volume of anhydrous DMAc added is 40-80 mL / g based on the mass of 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxon-6-yl)benzo[c][1,2,5]thiazole.

[0065] Preferably, the post-reaction processing method is as follows: the reaction solution is added to methanol, the mixture is filtered using a Buchner funnel, the filter cake is washed with methanol, the filter cake is wrapped with filter paper and extracted with a Soxhlet extractor to extract polymers of different degrees of polymerization. During this process, solvents with different solubilities are changed, and the order of solvent use is methanol, acetone, petroleum ether, and chloroform. The solvent is removed by rotary evaporation of the chloroform-extracted portion to obtain the electrochromic material PBP3P shown in Formula IV.

[0066] The present invention also provides an application of the above-mentioned electrochromic material in the preparation of electrochromic devices.

[0067] This invention provides a method for preparing an electrochromic device, comprising the following steps:

[0068] Electrochromic materials (TTP) shown in Formula I, (TEP) shown in Formula II, and (TPP) shown in Formula III are respectively sprayed onto transparent conductive electrodes to prepare electrochromic films that can switch between red, yellow-green and high-transparency states as working electrodes.

[0069] Electrochromic materials (PBP3P) shown in Formula IV are sprayed onto a transparent conductive electrode to prepare an electrochromic film that can switch between green and high-transparency states, serving as the counter electrode.

[0070] TTP and PBP3P, TEP and PBP3P, and TPP and PBP3P are assembled into electrochromic devices that switch between red, yellow-green and green tones, respectively, and are called TTP-PBP3P, TEP-PBP3P and TPP-PBP3P.

[0071] This invention provides a method for fabricating a high-performance patterned electrochromic camouflage device, comprising the following steps:

[0072] Electrochromic materials (TTP) shown in Formula I, (TEP) shown in Formula II, and (TPP) shown in Formula III are sequentially masked and sprayed onto the same transparent conductive electrode to prepare a patterned electrochromic film that can switch between red, yellow-green and high-transparency states as a working electrode.

[0073] A patterned electrochromic film capable of switching between green and high-transparency states was prepared by spraying the electrochromic material (PBP3P) shown in Formula IV onto a transparent conductive electrode as a counter electrode.

[0074] When fabricating a sandwich-structured electrochromic device, nylon filter membranes with different pore sizes are added to the electrolyte layer to prepare a high-performance patterned electrochromic camouflage device.

[0075] More preferably, the transparent electrode is selected from any one of ITO glass, ITO-PET, and ITO-PEN.

[0076] More preferably, the pore size of the nylon filter membrane is selected from any one of 10μm, 50μm, 100μm and 200μm.

[0077] As described above, the present invention has the following beneficial effects: four high-performance solution-processable electrochromic materials, TTP, TEP, TPP and PBP3P, were prepared using an arylization polycondensation process; high-performance patterned electrochromic camouflage devices were prepared using the above electrochromic materials as raw materials and by means of mask spraying; and nylon filter membranes with different pore sizes were introduced into the device structure to adjust the device transmittance to achieve a better camouflage effect. Attached Figure Description

[0078] Figure 1 Synthesis routes for four solution-processable electrochromic materials.

[0079] Figure 2 The CV curves are for four electrochromic thin films.

[0080] Figure 3 The images show the UV-Vis absorption spectra of four electrochromic films at different voltages.

[0081] Figure 4 The response times of four electrochromic thin films are given at different wavelengths.

[0082] Figure 5 Stability tests were conducted on four types of electrochromic thin films at different wavelengths.

[0083] Figure 6 Photographs of four electrochromic films at different voltages.

[0084] Figure 7 The chromaticity of four electrochromic films at different voltages is shown.

[0085] Figure 8 The CV curves are for three high-performance electrochromic devices that switch between red, yellow-green, and green tones.

[0086] Figure 9 The images show the UV-Vis absorption spectra of three high-performance electrochromic devices that switch between red, yellow-green, and green tones at different voltages.

[0087] Figure 10 The response time of three high-performance electrochromic devices that switch between red, yellow-green and green tones was tested at 650 nm.

[0088] Figure 11 Stability testing of three high-performance electrochromic devices that switch between red, yellow-green, and green at 650 nm.

[0089] Figure 12 Photographs of three high-performance electrochromic devices that switch between red, yellow-green, and green tones at different voltages.

[0090] Figure 13 The colorimetric properties of three high-performance electrochromic devices that switch between red, yellow-green, and green at different voltages.

[0091] Figure 14 The transmittance curves of nylon filter membranes with different pore sizes were obtained by adding them to three high-performance electrochromic devices that switch between red, yellow-green and green series at ±1V.

[0092] Figure 15 Photographs taken at ±1V of three high-performance electrochromic devices that switch between red, yellow-green, and green tones, with nylon filter membranes of different pore sizes added.

[0093] Figure 16 Photographs of patterned electrochromic camouflage devices at different voltages. Detailed Implementation

[0094] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention.

[0095] It should be noted that the process equipment or apparatus not specifically mentioned in the following embodiments are all conventional equipment or apparatus in the art.

[0096] Furthermore, it should be understood that the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, does not preclude the existence of other method steps before or after the combined steps, or the insertion of other method steps between these explicitly mentioned steps, unless otherwise stated. It should also be understood that the combined connection relationship between one or more devices / apparatus mentioned in this invention does not preclude the existence of other devices / apparatus before or after the combined devices / apparatus, or the insertion of other devices / apparatus between these explicitly mentioned devices / apparatus, unless otherwise stated. Moreover, unless otherwise stated, the numbering of each method step is merely a convenient tool for identifying each method step, and not for limiting the order of the method steps or limiting the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0097] The specific synthesis methods of the electrochromic materials in Examples 1 to 4 of this application are as follows: Figure 1 The synthesis route diagrams for the four solution-processable electrochromic materials shown are presented.

[0098] Example 1: Synthesis of TTP(Ⅰ)

[0099] N,N-bis(4-bromophenyl)-4-butylaniline (229.5 mg, 0.5 mmol), 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane-heptene (440 mg, 1 mmol), 2,5-dibromothiophene (120.97 mg, 0.5 mmol), anhydrous potassium carbonate (345 mg, 2.5 mmol), terpentine (4.09 mg, 0.04 mmol), and Pd(OAc)2 (4.53 mg, 0.02 mmol) were weighed and added to a 15 mL Schlenk tube. Under nitrogen protection, 15 mL of anhydrous DMAc was added, and the reaction was carried out at 130 °C for 15 h. The mixture was then cooled to room temperature.

[0100] The reaction solution was added to 300 ml of methanol, filtered using a Buchner funnel, and the filter cake was washed with methanol. The filter cake was then wrapped with filter paper and extracted with a Soxhlet extractor to extract polymers of different degrees of polymerization. During the extraction process, solvents with different solubilities were changed. The order of solvent use was methanol, acetone, petroleum ether, and chloroform. Finally, the solvent was removed by rotary evaporation of the chloroform extract to obtain TTP as shown in Formula I, where n is 20 to 35.

[0101] Example 2: Synthesis of TEP(II)

[0102] Weigh N,N-bis(4-bromophenyl)-4-butylaniline (229.5 mg, 0.5 mmol), 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane-heptene (440 mg, 1 mmol), 2,5-dibromo-3,4-vinyldioxothiophene (150 mg, 0.5 mmol), anhydrous potassium carbonate (345 mg, 2.5 mmol), terpentine (4.09 mg, 0.04 mmol), and Pd(OAc)2 (4.53 mg, 0.02 mmol) into a 15 mL Schlenk tube. Under nitrogen protection, add 15 mL of anhydrous DMAc and react at 130 °C for 16 h. Then cool to room temperature. The reaction solution was added to 300 ml of methanol, filtered using a Buchner funnel, and the filter cake was washed with methanol. The filter cake was then wrapped with filter paper and extracted with a Soxhlet extractor to extract polymers of different degrees of polymerization. During the extraction process, solvents with different solubilities were changed. The order of solvent use was methanol, acetone, petroleum ether, and chloroform. Finally, the solvent was removed by rotary evaporation of the chloroform-extracted portion to obtain TEP as shown in Formula II, where n is 10 to 20.

[0103] Example 3: Synthesis of TPP(Ⅲ)

[0104] N,N-bis(4-bromophenyl)-4-butylaniline (229.5 mg, 0.5 mmol), 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-B][1,4]dioxane (440 mg, 1 mmol), 6,8-dibromo-3,4-dihydro-3,3-dimethyl2H-thieno[3,4-B][1,4]dioxane (171 mg, 0.5 mmol), anhydrous potassium carbonate (345 mg, 2.5 mmol), terpentine (4.09 mg, 0.04 mmol), and Pd(OAc)2 (4.53 mg, 0.02 mmol) were weighed and added to a 15 mL Schlenk tube. Under nitrogen protection, 15 mL of anhydrous DMAc was added, and the reaction was carried out at 130 °C for 17 h. The mixture was then cooled to room temperature. The reaction solution was added to 300 ml of methanol, filtered using a Buchner funnel, and the filter cake was washed with methanol. The filter cake was then wrapped with filter paper and extracted with a Soxhlet extractor to extract polymers of different degrees of polymerization. During the extraction process, solvents with different solubilities were changed. The order of solvent use was methanol, acetone, petroleum ether, and chloroform. Finally, the solvent was removed by rotary evaporation of the chloroform-extracted portion to obtain TPP as shown in Formula III, where n is 15–25.

[0105] Example 4: Synthesis of PBP3P(Ⅳ)

[0106] Weigh out 4,7-bis(3,3,-dimethyl-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxin-6-yl)benzo[c][1,2,5]thiazole (250.33 mg, 0.5 mmol), 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiophene[3,4-b][1,4]dioxane-heptene (220.34 mg, 0.5 mmol), and 6,8-dibromo-3,3-bis(((2-ethylhexyl)) (Oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane-heptene (598.48 mg, 1 mmol), anhydrous potassium carbonate (345 mg, 2.5 mmol), terpentine (4.09 mg, 0.04 mmol), and Pd(OAc)₂ (4.53 mg, 0.02 mmol) were added to a 15 mL Schlenk tube. Under nitrogen protection, 15 mL of anhydrous DMAc was added, and the reaction was carried out at 130 °C for 5 h. The mixture was then cooled to room temperature. The reaction solution was added to 300 mL of methanol, filtered through a Buchner funnel, and the filter cake was washed with methanol. The filter cake was then wrapped in filter paper and extracted with a Soxhlet extractor to obtain polymers of different degrees of polymerization. During the extraction, solvents with different solubilities were changed in the following order: methanol, acetone, petroleum ether, and chloroform. Finally, the chloroform-extracted portion was removed by rotary evaporation to obtain PBP₃P as shown in Formula IV, where n is 4–8.

[0107] Example 5: Preparation of Electrochromic Thin Film

[0108] 15 mg of TTP, TEP, TPP and PBP3P were added to 10 ml sample vials, and 1 ml of chloroform was added to each vial. The mixture was shaken to ensure homogeneity, and then filtered through a 0.45 μm microporous filter. The solutions were then spin-coated onto the conductive surface of 25*40 mm ITO glass using a spin coater (parameter settings: 1000 rpm / min, spin-coating time 1 min) to obtain electrochromic films.

[0109] Example 6: Performance Testing of Electrochromic Thin Films

[0110] 1. Electrochemical testing of TTP, TEP, TPP and PBP3P

[0111] Electrochemical tests were performed using a Chenhua 660 electrochemical workstation with the following parameter settings: CV mode, scan rate of 50 / 100 / 200 / 300 / 500 mV / s, and scan range of 0.0V and 0.9V (TTP, TEP, and TPP), and 0.0V and 1.0V (PBP3P). Figure 2As shown, TTP, TEP, TPP and PBP3P electrochromic films all exhibit electrochemical responses within this scanning range, and their CV curves show quasi-reversible redox behavior. As the scanning speed increases, the peak current also gradually increases, demonstrating that the films have good adhesion to the conductive substrate.

[0112] 2. Optical and electrochromic performance testing of TTP, TEP, TPP and PBP3P

[0113] Optical and electrochromic properties were tested using a Chenhua 660 electrochemical workstation coupled with a Shimadzu UV1800 UV-Vis spectrophotometer. The test results are as follows: Figure 3 , 4 As shown in Figure 5.

[0114] like Figure 3 As shown, the maximum absorption peaks of TTP, TEP, and TPP in the neutral state (0.0V) are 535nm, 545nm, and 540nm, respectively, all exhibiting a reddish hue. With increasing voltage, the original absorption peaks gradually disappear, and they exhibit double absorption characteristics in the visible light region (absorption curve troughs appear between 500 and 600nm), exhibiting a yellowish-green hue. With a voltage reaching 1.0V, the absorption curves of the three films in the visible light region show no obvious absorption peaks, exhibiting high transmittance. PBP3P exhibits double absorption in the neutral state (0.0V), displaying a greenish hue. With increasing voltage, its absorption in the visible light region gradually decreases; at a voltage of 1V, it exhibits high transmittance.

[0115] like Figure 4 and Figure 5 As shown, the optical contrast and cycling stability of TTP, TEP, TPP, and PBP3P films at the maximum absorption peak wavelength were tested. The results showed that TTP maintained an optical contrast of 34.08% at 535 nm with a coloring time of 0.77 s and a fading time of 0.87 s; TEP maintained an optical contrast of 40.27% at 545 nm with a coloring time of 0.90 s and a fading time of 0.64 s; and TPP maintained an optical contrast of 45.52% at 540 nm with a coloring time of 0.65 s and a fading time of 0.38 s. After 3000 cycles at step voltages of 0 V and 0.9 V, the optical contrast of the three materials remained at 60.92%, 87.83%, and 68.52% of their initial contrast, respectively. PBP3P exhibits a green hue in the neutral state, eventually reaching a high-transmittance state as the applied voltage increases. It has an optical contrast ratio of 43.56% in the 640nm wavelength range, a coloring time of 0.90s, and a fading time of 0.56s. After undergoing 3000 cycles at step voltages of 0V and 1.0V, the optical contrast ratio of the film can maintain 88.25% of the initial contrast ratio.

[0116] 3. Colorimetric tests and photographs of TTP, TEP, TPP, and PBP3P

[0117] The color coordinates in the CIE 1976 L*a*b* color space are expressed using a CM-3600d spectrophotometer. For example... Figure 6 and Figure 7 As shown, at 0V, TTP, TEP and TPP appear red, reddish-brown and pink respectively. As the voltage increases, all three films turn yellowish-green and eventually reach a high-transmittance state. At 0V, PBP3P appears green. As the voltage increases, all films reach a high-transmittance state.

[0118] Example 7: Fabrication of Electrochromic Devices

[0119] ITO glass with TTP, TEP, and TPP films on its surface is used as the working electrode, and ITO glass with PBP3P film on its surface is used as the counter electrode. Electrochromic devices with a traditional sandwich structure are assembled into electrochromic devices that switch between red, yellow-green and green series, and are called TTP-PBP3P, TEP-PBP3P and TPP-PBP3P.

[0120] 1. Electrochemical testing of TTP-PBP3P, TEP-PBP3P and TPP-PBP3P

[0121] Electrochemical tests were performed using a Chenhua 660 electrochemical workstation. Parameter settings were: CV mode, scan rate of 50 / 100 / 200 / 300 / 500 mV / s, and scan range of -1.0V and 1.0V. Figure 8 As shown, TTP-PBP3P, TEP-PBP3P and TPP-PBP3P all exhibit electrochemical responses within this scanning range, and their CV curves show quasi-reversible redox behavior.

[0122] 2. Optical and electrochromic properties of TTP-PBP3P, TEP-PBP3P, and TPP-PBP3P were tested using a Chenhua 660 electrochemical workstation coupled with a Shimadzu UV1800 UV-Vis spectrophotometer. The test results are as follows: Figure 9 , 10 As shown in Figure 11.

[0123] like Figure 9As shown, the maximum absorption peaks of TTP-PBP3P, TEP-PBP3P, and TPP-PBP3P in the neutral state (-1.0V) are 535nm, 545nm, and 540nm, respectively, all exhibiting a reddish hue. As the voltage increases, the original absorption peaks gradually disappear, and the absorption peaks belonging to PBP3P gradually appear, thus exhibiting a yellowish-green hue. As the voltage reaches 1.0V, the absorption curves of the three devices in the visible light region exhibit double absorption, appearing green.

[0124] like Figure 10 and Figure 11 As shown, the optical contrast and cycling stability of TTP-PBP3P, TEP-PBP3P, and TPP-PBP3P at the maximum absorption peak wavelength were tested. The results showed that the optical contrast ratios of TTP-PBP3P, TEP-PBP3P, and TPP-PBP3P in the 650nm wavelength range were 17.59%, 16.07%, and 21.13%, respectively; the coloring and fading times were 1.05s / 0.60s, 1.00s / 0.68s, and 0.36s / 0.38s, respectively. After 15,000 cycles, TTP-PBP3P and TPP-PBP3P maintained 132.4% and 90.11% of their original contrast ratios, respectively; after 5,000 cycles, TEP-PBP3P maintained 97.51% of its original contrast ratio.

[0125] 3. Colorimetric tests and photographs of TTP-PBP3P, TEP-PBP3P, and TPP-PBP3P were performed using a CM-3600d spectrophotometer, representing color coordinates in the CIE 1976 L*a*b* color space. For example... Figure 12 and 13 As shown, at -1.0V, TTP-PBP3P and TPP-PBP3P appear red, reddish-brown and magenta respectively. As the voltage increases, both TTP-PBP3P and TPP-PBP3P turn green, while TEP-PBP3P turns yellowish-green.

[0126] Example 8: Preparation of an electrochromic device with a nylon filter membrane added to the electrolyte layer

[0127] ITO glass with TTP, TEP and TPP films on its surface was used as the working electrode and ITO glass with PBP3P film on its surface was used as the counter electrode. According to the sandwich structure, nylon filter membranes with pore sizes of 10μm / 50μm / 100μm / 200μm were added to the electrolyte during the assembly process to assemble electrochromic devices containing nylon filter membranes with different pore sizes.

[0128] Transmittance testing was performed using a Chenhua 660 electrochemical workstation coupled with a Shimadzu UV1800 UV-Vis spectrophotometer. The test results are as follows: Figure 14 As shown in the figure, the results reveal a significant gradient difference in transmittance between the three electrochromic devices containing nylon filter membranes with different pore sizes in the neutral state (-1.0V) and the oxidized state (1.0V). Specifically, the smaller the pore size, the lower the overall transmittance of the electrochromic device, and the smaller the difference in transmittance between the neutral and oxidized states. Figure 15 These are photographs of three devices containing nylon filter membranes with a pore size of 50 μm in the neutral and oxidized states. It can be seen that the area containing the nylon filter membrane has a darker color, which could enhance the camouflage effect.

[0129] Example 9: Fabrication of a high-performance patterned electrochromic camouflage device

[0130] 15 mg of TTP, TEP, TPP, and PBP3P were added to 10 ml sample vials, respectively. 1 ml of chloroform was added to each vial, and the mixture was shaken to ensure homogeneity. The solutions were then filtered using a 0.45 μm microporous filter. Using a spray gun and a perforated metal plate (allowing the solution to pass through), TTP, TEP, and TPP were sequentially sprayed onto the conductive surface of a 25*40 mm ITO glass or ITO-PET conductive film to create different patterns, serving as the working electrodes. Next, using a spray gun and a perforated metal plate (allowing the solution to pass through), PBP3P was sprayed onto the conductive surface of a 25*40 mm ITO glass or ITO-PET conductive film to create a pattern, serving as the counter electrode. Finally, following a sandwich structure, a 50 μm nylon filter membrane was added to the electrolyte during assembly to create a high-performance electrochromic camouflage device.

[0131] like Figure 16 As shown, due to the different oxidation voltages and intermediate colors of TTP, TEP, and TPP, patterned electrochromic camouflage devices can switch between multiple camouflage modes after applying different voltages. Furthermore, flexible devices can be fabricated by changing the conductive substrate. Simultaneously, since TTP, TEP, TPP, and PBP3P are solution-processable electrochromic materials, large-size camouflage devices can be fabricated through spraying.

[0132] The above embodiments are for illustrating the implementation schemes disclosed in this invention and should not be construed as limiting the invention. Furthermore, various modifications listed herein, as well as variations in the methods and compositions of the invention, will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been specifically described in conjunction with various specific preferred embodiments, it should be understood that the invention should not be limited to these specific embodiments. In fact, various modifications as described above that are obvious to those skilled in the art to obtain the invention should be included within the scope of this invention.

Claims

1. An electrochromic material, characterized in that, Its structural formula is shown in Formula I: ； In Formula I: n is the degree of polymerization, and n is 4~35; The preparation method of the electrochromic material is as follows: using N,N-bis(4-bromophenyl)-4-butylaniline as shown in Formula V, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane-heptene as shown in Formula VI and 2,5-dibromothiophene as shown in Formula VII as raw materials, the electrochromic material shown in Formula I is generated by reacting at 110~135℃ under a protective atmosphere; 。 2. An electrochromic material characterized by: Its structural formula is shown in Formula II: ； In Equation II: n is the degree of polymerization, and n is 4~35; The preparation method of the electrochromic material includes the following steps: using N,N-bis(4-bromophenyl)-4-butylaniline as shown in Formula V, 3,3-bis((((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane-heptene as shown in Formula VIII, and 2,5-dibromo-3,4-ethylenedioxothiophene as shown in Formula VIII, the electrochromic material shown in Formula II is generated by reacting at 110~135℃ under a protective atmosphere; 。 3. An electrochromic material characterized by: Its structural formula is shown in Formula III: ； In Formula III: n is the degree of polymerization, and n is 4~35; The preparation method of the electrochromic material includes the following steps: using N,N-bis(4-bromophenyl)-4-butylaniline as shown in Formula V, 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane as shown in Formula VI, and 6,8-dibromo-3,4-dihydro-3,3-dimethyl2H-thieno[3,4-b][1,4]dioxane as shown in Formula IX as raw materials, the electrochromic material shown in Formula III is generated by reacting at 110~135℃ under a protective atmosphere; 。 4. A method for the preparation of an electrochromic material as claimed in claim 2, characterized in that: Using N,N-bis(4-bromophenyl)-4-butylaniline (Formula V), 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thiopheno[3,4-b][1,4]dioxane-heptene (Formula VIII) as raw materials, an electrochromic material of Formula II is generated by reacting at 110-135°C under a protective atmosphere. 。 5. A method of preparing an electrochromic material as claimed in claim 3, characterized in that: Using N,N-bis(4-bromophenyl)-4-butylaniline (Formula V), 3,3-bis(((2-ethylhexyl)oxy)methyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxane-heptene (Formula VI), and 6,8-dibromo-3,4-dihydro-3,3-dimethyl2H-thieno[3,4-b][1,4]dioxane (Formula IX) as raw materials, an electrochromic material of Formula III is generated by reacting at 110-135°C under a protective atmosphere. 。 6. The application of the electrochromic material as described in any one of claims 1 to 3 in the fabrication of electrochromic devices.

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