Electrochromic medium compositions and applications thereof

Abstract

The application discloses an electrochromic medium composition and application thereof, and provides the electrochromic medium composition, which comprises at least one anodic electrochromic material and one cathodic electrochromic material, wherein the cathodic electrochromic material comprises a violet derivative prepared by introducing a fluorene into a violet structure, the compound can show different coloring states under different voltages, the compound and a ferrocene derivative are matched to realize a red-blue mixed coloring state, or the compound, dimethyl dihydrophenazine and the ferrocene derivative are matched to realize a neutral gray coloring state, and the electrochromic medium composition greatly expands its application value in the electrochromic field.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electrochromic materials, in particular to an electrochromic medium composition and application thereof. BACKGROUND

[0002] Viologen (1,1'-disubstituted-4,4'-bipyridine) is a common organic small molecule compound with bipyridine molecular structure, which shows obvious color change under voltage driving, has good optical contrast, high coloring efficiency and redox stability, and is widely used as an organic optoelectronic functional material in the field of electrochromism. Although viologen compounds have good electrochemical properties, their colored state is relatively single, usually blue. This greatly limits its application in the field of optoelectronics. SUMMARY

[0003] The present application aims to overcome the defects of the prior art and provides an electrochromic medium composition and application thereof.

[0004] The technical problem of the present application is solved by the following technical scheme.

[0005] The present application provides an electrochromic medium composition, which comprises at least one anodic electrochromic material and one cathodic electrochromic material, and the cathodic electrochromic material comprises a viologen derivative, and the structural formula of the viologen derivative is shown as formula I:

[0006]

[0007] Formula I

[0008] wherein: R1, R2, R3 and R4 are each independently selected from substituted or unsubstituted C1-C15 alkyl, C1-C15 alkoxy, C1-C15 cycloalkyl, C1-C15 aryl, C1-C15 alkenyl and C1-C15 alkynyl, X - is any one of I - , Br - , Cl - , ClO4 - , BF4 - , PF6 - , SbF6 - or TFSI -

[0009] The present application provides an application of the above-mentioned electrochromic medium composition in the preparation of an electrochromic film or an electrochromic device.

[0010] The present application has the following beneficial effects:

[0011] ​The application provides an electrochromic medium composition and application thereof. The electrochromic medium composition provided by the application comprises at least one anodic electrochromic material and one cathodic electrochromic material, and the cathodic electrochromic material comprises a viologen derivative, the viologen derivative is a fluorenyl viologen prepared by introducing a fluorene into a viologen structure, the compound can exhibit different coloring states under different voltages, has good color change characteristics, and has great application value in the field of electrochromism. BRIEF DESCRIPTION OF DRAWINGS

[0012] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed to be used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some of the embodiments of the application, and therefore should not be considered as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0013] Figure 1 Synthesis path diagram of the cathodic electrochromic material in the embodiments of the application;

[0014] Figure 2 UV-visible spectrum diagram of the electrochromic device composed of the electrochromic medium 2 under 1.4V-1.6V. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the embodiments of the application more clear, the technical solutions in the embodiments of the application will be clearly and completely described below. If the specific conditions are not indicated in the embodiments, the conventional conditions or the conditions suggested by the manufacturer are adopted. If the reagents or instruments used are not indicated by the manufacturer, they are all conventional products that can be purchased in the market.

[0016] The electrochromic medium composition and application thereof provided by the embodiments of the application will be specifically described below.

[0017] In a first aspect, the embodiments of the application provide an electrochromic medium composition, which comprises at least one anodic electrochromic material and one cathodic electrochromic material, and the cathodic electrochromic material comprises a viologen derivative, and the structural formula of the viologen derivative is shown as formula I:

[0018]

[0019] Formula I

[0020] wherein R1, R2, R3 and R4 are each independently selected from substituted or unsubstituted C1-C15 alkyl, C1-C15 alkoxy, C1-C15 cycloalkyl, C1-C15 aryl, C1-C15 alkenyl and C1-C15 alkynyl, and X- I - Br - Cl - ClO4 - BF4 - PF6 - SbF6 - or TFSI -

[0021] The embodiment of the present application provides an electrochromic medium composition, which comprises at least one anodic electrochromic material and one cathodic electrochromic material. In the electrochromic process, when the electrochromic device is powered, the cathodic electrochromic material migrates to the negative electrode to obtain electrons, and the anodic electrochromic material migrates to the positive electrode to lose electrons, at this time, the color or absorption peak of the material changes greatly, showing color change, that is, the so-called electrochromism. The electrochromic medium composition provided by the embodiment of the present application comprises a viologen derivative, the viologen derivative is a series of "fluorenyl viologen" prepared by introducing "fluorene" into a viologen molecule, the "fluorenyl viologen" has multiple coloring states, and the color change under different voltages can be realized, and good application potential is shown.

[0022] In some optional embodiments, R1 and R2 in the viologen derivative are each independently C1-C15 alkoxy or C1-C15 aryl.

[0023] In some optional embodiments, the anodic electrochromic material comprises a phenazine derivative and a ferrocene derivative. The phenazine derivative includes but is not limited to 5,10-dimethyl-5,10-dihydrophenazine, 5,10-diethyl-5,10-dihydrophenazine and 5,10-dibenzyl-5,10-dihydrophenazine, and the like, and the ferrocene includes but is not limited to binuclear ferrocene, trinuclear ferrocene, tetranuclear ferrocene, pentanuclear ferrocene and derivatives thereof, and the like.

[0024] In some optional embodiments, the anodic electrochromic material is 5,10-dihydro-5,10-dimethylphenazine or ferrocene. Through the combination of the electrochromic device of the ferrocene and the fluorenyl viologen, a red color is presented at a low voltage, and as the voltage continues to rise, a "red-blue mixed" color is presented, and finally the blue signal covers the red color. Through the combination of the ferrocene, dimethyl dihydrophenazine and fluorenyl viologen, a "neutral gray" color with equal contributions of yellow, red and blue colors can be realized at a suitable voltage, and full coverage of the electrochromic device in the visible light is realized.

[0025] ​In some alternative embodiments, the molar ratio of the anodic electrochromic material to the cathodic electrochromic material is 1:(0.5-1.5). Alternatively, the molar ratio of the anodic electrochromic material to the cathodic electrochromic material can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.3, 1:1.4, 1:1.5, and any value between or any range between any two values of 1:(0.5-1.5). By adjusting the ratio of the cathodic electrochromic material to the anodic electrochromic material, the depth of color of the electrochromic medium composition can be controlled, so that the electrochromic device can present a color effect from red to blue.

[0026] In some alternative embodiments, the concentration of the cathodic electrochromic material in the electrochromic medium composition is 1mM-100mM, preferably 10mM-50mM. Alternatively, the concentration of the cathodic electrochromic material in the electrochromic medium composition can be 1mM, 5mM, 10mM, 20mM, 30mM, 40mM, 50mM, 60mM, 70mM, 80mM, 90mM, 100mM, and any value between or any range between any two values of 1mM-100mM, for example, preferably 10mM-50mM, more preferably 30mM-35mM. The specific concentration can be selected according to the contrast requirement in the visible light range.

[0027] In some alternative embodiments, the concentration of the anodic electrochromic material in the electrochromic medium composition is 1mM-100mM, preferably 10mM-50mM. Alternatively, the concentration of the anodic electrochromic material in the electrochromic medium composition can be 1mM, 5mM, 10mM, 20mM, 30mM, 40mM, 50mM, 60mM, 70mM, 80mM, 90mM, 100mM, and any value between or any range between any two values of 1mM-100mM, for example, preferably 10mM-50mM, more preferably 30mM-35mM. The specific concentration can be selected according to the contrast requirement in the visible light range.

[0028] In some alternative embodiments, the electrochromic medium composition further comprises at least one of a solvent, an ultraviolet absorption stabilizer, a thickening agent, and a buffer solution.

[0029] In some alternative embodiments, the electrochromic medium composition is obtained by mixing at least one anodic electrochromic material and one cathodic electrochromic material.

[0030] In a second aspect, the present application provides a use of the electrochromic medium composition as described above in the preparation of an electrochromic film or an electrochromic device.

[0031] In some alternative embodiments, the electrochromic device is an electrochromic switchable glass.

[0032] The application will be further described in conjunction with the following examples.

[0033] The electrochromic medium composition provided by the embodiments of the application comprises at least one anodic electrochromic material and one cathodic electrochromic material.

[0034] The ratio and concentration of the cathodic electrochromic material and the anodic electrochromic material can be adjusted to control the depth of coloration. Preferably, the concentration of the cathodic electrochromic material is 1 mM-100 mM, preferably 10 mM-50 mM, and the concentration of the anodic electrochromic material is 1 mM-100 mM, preferably 10 mM-50 mM, which can be selected according to the contrast requirement in the visible light range.

[0035] The anodic electrochromic material is 5,10-dihydro-5,10-dimethylphenazine or ferrocene.

[0036] The cathodic electrochromic material comprises a viologen derivative, and the structural formula of the viologen derivative is shown as formula I:

[0037]

[0038] Formula I

[0039] wherein R1, R2, R3 and R4 are each independently selected from substituted or unsubstituted C1-C15 alkyl, C1-C15 alkoxy, C1-C15 cycloalkyl, C1-C15 aryl, C1-C15 alkenyl and C1-C15 alkynyl, and X is any one of I, Br, Cl, ClO4, BF4, PF6, SbF6 or TFSI. - I - , Br - , Cl - , ClO4 - , BF4 - , PF6 - , SbF6 - or TFSI - .

[0040] The synthesis path diagram of the cathodic electrochromic material in the embodiments of the application is shown in Figure 1 .

[0041] wherein:

[0042] In the C-alkylation process, X' is Cl, Br or I, the amount of NaOH is 2 eq ~ 2.2 eq, the amount of R1X' is 1 eq, the amount of R2X' is 1 eq ~ 1.05 eq, R1 and R2 are one or more of C1-C15 alkyl, C1-C15 alkoxy, C1-C15 cycloalkyl, C1-C15 aryl, C1-C15 alkenyl and C1-C15 alkynyl.

[0043] In the coupling process, the amount of pyridine-4-boronic acid is 2 eq ~ 2.2 eq, the amount of K2CO3 is 2 eq, and the amount of palladium catalyst is 0.01 eq ~ 0.02 eq.

[0044] In the N-alkylation process, X - is Cl - , Br - or I - , the amount of R3X is 1 eq ~ 1.05 eq, and the amount of R4X is 1 eq ~ 1.05 eq. When X - is ClO4 - , BF4 - , PF6 - , SbF6 - or TFSI - , the product in step 3 needs to be dissolved in water and an excess amount of aqueous LiClO4, LiBF4, LiPF6, NaSbF6 or LiTFSI solution is added, and the precipitate is filtered and dried.

[0045] Synthesis Example 1: The structural formula of compound 1 is as follows:

[0046] .

[0047] The preparation of compound 1 comprises the following steps:

[0048] Step 1: Synthesis of intermediate 1

[0049] In two round-bottom flasks, 3.24 g of 2,7-dibromofluorene and 0.8 g of sodium hydroxide were dissolved in 100 mL of a mixture of tetrahydrofuran / water=5:1 and stirred at 60°C for 1 h. 2.18 g of bromoethane was slowly added dropwise, and the reaction progress was monitored by thin layer chromatography. When the raw material was completely reacted, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phase was extracted with dichloromethane and combined. Then the organic phase was distilled under reduced pressure to obtain the crude product, which was purified by column chromatography (mobile phase: petroleum ether) to obtain 2.96 g of intermediate 1 (yield 78%). 1H NMR (500 MHz, DMSO-d6): δ 7.79 (d, J = 8.3 Hz, 2H), 7.72(s, 2H), 7.55 (d, J = 7.5 Hz, 2H), 1.89 (q, J = 7.3 Hz, 4H), 0.89 (q, J = 6.7Hz, 6H). The structural formula of intermediate 1 is shown below:

[0050] .

[0051] Step 2: Synthesis of intermediate 2

[0052] In two round bottom flasks, 3.8 g of intermediate 1, 2.46 g of pyridine-4-boronic acid were dissolved in 100 mL of a mixture of dioxane / water = 5:1, and 116 mg of tetrakis triphenylphosphine palladium was added after nitrogen bubbling for 15 min. The reaction was carried out at 100°C for 12 h. When the raw material was completely reacted, the reaction was cooled to room temperature, 200 mL of water was added, extracted with dichloromethane and the organic phase was combined. Then the organic phase was distilled under reduced pressure to obtain the crude product, which was purified by column chromatography (mobile phase: dichloromethane / ethyl acetate = 8 / 1) to obtain 2.67 g of intermediate 2 (yield 71%). 1 H NMR (500 MHz, DMSO-d6): δ 8.71 (d, J=8.2 Hz,4H), 8.09-7.89 (m, 8H), 7.78 (d, J = 7.3 Hz, 2H), 1.91 (q, J = 7.1 Hz, 4H),0.92 (q, J = 6.6 Hz, 6H). The structural formula of intermediate 2 is shown below:

[0053] .

[0054] Step 3: Synthesis of intermediate 3

[0055] In two round bottom flasks, 3.77 g of intermediate 2, 2.84 g of iodomethane were dissolved in 50 mL of DMF, and the reaction was carried out at 80°C for 12 h. When the raw material was completely reacted, the reaction was cooled to room temperature, 200 mL of dichloromethane was added, and a large amount of powder was precipitated. The powder was filtered and washed to obtain 4.88 g of intermediate 3 (yield 74%). 1H NMR (500 MHz, DMSO-d6): δ 9.08 (d, J = 6.9 Hz, 4H), 8.96 (d, J = 7.1 Hz, 4H), 8.09-7.78 (m, 6H), 4.39 (s, 6H), 1.94 (q, J = 7.2 Hz, 4H), 0.95 (q, J = 6.9 Hz, 6H).

[0056] .

[0057] Step 4: Synthesis of compound 1

[0058] Purification of compound 1 was completed by dissolving 6.6 g of intermediate 3 and 10 g of LiClO4 in two portions of 30 mL of deionized water, respectively, then mixing them to precipitate a large amount of light yellow solid, and then filtering the precipitate and washing it with deionized water three times (5.32 g, yield 88%). 1 H NMR (500 MHz, DMSO-d6): δ 9.08 (d, J = 6.9 Hz, 4H), 8.96 (d, J = 7.1 Hz, 4H), 8.09-7.78 (m, 6H), 4.39 (s, 6H), 1.94 (q, J = 7.2 Hz, 4H), 0.95 (q, J = 6.9 Hz, 6H).

[0059] Synthesis Example 2: The structural formula of compound 2 is as follows:

[0060] .

[0061] Preparation of compound 2, comprising the following steps:

[0062] Step 1: Synthesis of intermediate 4

[0063] In two round-bottom flasks, 3.24 g of 2,7-dibromofluorene and 0.8 g of sodium hydroxide were dissolved in 100 mL of a mixed solvent of tetrahydrofuran / water = 5:1 and stirred at 60°C for 1 h. 2.84 g of iodomethane was slowly added dropwise, and the progress of the reaction was monitored by thin layer chromatography. When the raw material was completely reacted, the reaction was cooled to room temperature, 200 mL of water was added, extracted with dichloromethane, and the organic phases were combined. Then the organic phase was distilled under reduced pressure to obtain the crude product, which was purified by column chromatography (mobile phase: petroleum ether) to obtain 2.85 g of intermediate 4 (yield 81%). 1H NMR (500 MHz, DMSO-d6): δ 7.79 (d, J = 8.3 Hz, 2H), 7.72(s, 2H), 7.55 (d, J = 7.5 Hz, 2H), 1.69 (s, 6H). The structural formula of intermediate 4 is shown below:

[0064] .

[0065] Step 2: Synthesis of intermediate 5

[0066] In two round bottom flasks, 3.52 g of intermediate 4, 2.46 g of pyridine-4-boronic acid were dissolved in 100 mL of a mixture of dioxane / water = 5:1, and 116 mg of palladium tetra-triphenylphosphine was added after bubbling nitrogen for 15 min. The reaction was carried out at 100°C for 12 h. When the raw material was completely reacted, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phase was extracted with dichloromethane and combined. Then the organic phase was distilled under reduced pressure to obtain the crude product, and the product was purified by column chromatography (mobile phase: dichloromethane / ethyl acetate = 8 / 1) to obtain 2.40 g of intermediate 5 (yield 69%). 1 H NMR (500 MHz, DMSO-d6): δ 8.71 (d, J = 8.2Hz, 4H), 8.09-7.89 (m, 8H), 7.78 (d, J = 7.3 Hz, 2H), 1.69 (s, 6H). The structural formula of intermediate 5 is shown below:

[0067] .

[0068] Step 3: Synthesis of intermediate 6

[0069] In two round bottom flasks, 3.48 g of intermediate 5, 2.84 g of bromoethane were dissolved in 50 mL of DMF, and the reaction was carried out at 80°C for 12 h. When the raw material was completely reacted, the reaction was cooled to room temperature, 200 mL of dichloromethane was added, and a large amount of powder was precipitated. The powder was filtered and washed to obtain 4.75 g of intermediate 6 (yield 84%). 1 H NMR (500 MHz, DMSO-d6): δ 9.08 (d, J= 6.9 Hz, 4H), 8.96 (d, J = 7.1 Hz, 4H), 8.09-7.78 (m, 6H), 4.51 (q, J = 6.6Hz, 4H), 1.69 (s, 6H), 1.53 (q, J = 6.9 Hz, 6H). The structural formula of intermediate 6 is shown below:

[0070] .

[0071] Step 4: Synthesis of compound 2

[0072] Purification of compound 1 was completed by dissolving 5.66 g of intermediate 6 and 10 g of LiTFSI in two portions of 30 mL of deionized water, respectively, followed by mixing the two to precipitate a large amount of light yellow solid, and then filtering the precipitate and washing it with deionized water three times (8.04 g, yield 81%). 1 H NMR (500 MHz, DMSO-d6): δ 9.08 (d, J = 6.9 Hz, 4H), 8.96(d, J = 7.1 Hz, 4H), 8.09-7.78 (m, 6H), 4.51 (q, J = 6.6 Hz, 4H), 1.69 (s,6H), 1.53 (q, J = 6.9 Hz, 6H).

[0073] Synthesis Example 3: The structural formula of compound 3 is as follows:

[0074] .

[0075] Preparation of compound 3, comprising the following steps:

[0076] Step 1: Synthesis of intermediate 7

[0077] In two round-bottom flasks, 3.24 g of 2,7-dibromofluorene and 0.8 g of sodium hydroxide were dissolved in 100 mL of a mixed solvent of tetrahydrofuran / water = 5:1 and stirred at 60°C for 1 h. 2.5 g of bromomethyl methyl ether was slowly added dropwise, and the reaction progress was monitored by thin layer chromatography. When the raw material was completely reacted, the reaction was cooled to room temperature, 200 mL of water was added, extracted with dichloromethane, and the organic phases were combined. Then the organic phase was distilled under reduced pressure to obtain the crude product, which was purified by column chromatography (mobile phase: petroleum ether) to obtain 3.34 g of intermediate 7 (yield 81%). 1 H NMR (500 MHz, DMSO-d6): δ 7.79 (d, J = 8.3 Hz,2H), 7.72 (s, 2H), 7.55 (d, J = 7.5 Hz, 2H), 3.93 (s, 4H), 3.23 (s, 6H). The structural formula of intermediate 7 is as follows:

[0078] .

[0079] Step 2: Synthesis of intermediate 8

[0080] In two round bottom flasks, 4.12 g of intermediate 7, 2.46 g of pyridine-4-boronic acid were dissolved in 100 mL of a mixture of dioxane / water = 5:1, and 116 mg of tetrakis triphenylphosphine palladium was added after bubbling nitrogen for 15 min. The reaction was carried out at 100°C for 12 h. When the starting material was completely reacted, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phase was extracted with dichloromethane and combined. Then the organic phase was distilled under reduced pressure to obtain the crude product, and the product was purified by column chromatography (mobile phase: dichloromethane / ethyl acetate = 8 / 1) to obtain 2.82 g of intermediate 8 (yield 69%). 1 H NMR (500 MHz, DMSO-d6): δ 8.71 (d, J = 8.2Hz, 4H), 8.09-7.89 (m, 8H), 7.78 (d, J = 7.3 Hz, 2H), 3.93 (s, 4H), 3.23 (s,6H). The structural formula of intermediate 8 is as follows:

[0081] .

[0082] Step 3: Synthesis of intermediate 9

[0083] In two round bottom flasks, 4.08 g of intermediate 8, 2.84 g of bromoethane were dissolved in 50 mL of DMF, and the reaction was carried out at 80°C for 12 h. When the starting material was completely reacted, the reaction was cooled to room temperature, 200 mL of dichloromethane was added, and a large amount of powder was precipitated. The powder was filtered and washed to obtain 5.26 g of intermediate 9 (yield 84%). 1 H NMR (500 MHz, DMSO-d6): δ 9.08 (d, J = 6.9 Hz, 4H), 8.96 (d, J = 7.1 Hz, 4H), 8.09-7.78 (m, 6H), 4.51 (q, J = 6.6Hz, 4H), 3.93 (s, 4H), 3.23 (s, 6H), 1.53 (q, J = 6.9 Hz, 6H). The structural formula of intermediate 9 is as follows:

[0084] .

[0085] Step 4: Synthesis of compound 3

[0086] 6.26 g of intermediate 9 and 10 g of LiClO4 were dissolved in two portions of 30 mL of deionized water, respectively, and then mixed to precipitate a large amount of light yellow solid. The precipitate was filtered and washed with deionized water three times to complete the purification of compound 3 (5.38 g, yield 81%). 1H NMR (500 MHz, DMSO-d6): δ 9.08 (d, J = 6.9 Hz, 4H), 8.96(d, J = 7.1 Hz, 4H), 8.09-7.78 (m, 6H), 4.51 (q, J = 6.6 Hz, 4H), 3.93 (s,4H), 3.23 (s, 6H), 1.53 (q, J = 6.9 Hz, 6H).

[0087] Example 1

[0088] The embodiment of the present application provides an electrochromic medium composition (denoted as electrochromic medium 1), which adopts propylene carbonate solution (PC) as a solvent, and specifically, electrochromic material components are shown in Table 1 below:

[0089] Table 1

[0090]

[0091] Example 2

[0092] The embodiment of the present application provides an electrochromic medium composition (denoted as electrochromic medium 2), which adopts propylene carbonate solution (PC) as a solvent, and specifically, electrochromic material components are shown in Table 2 below:

[0093] Table 2

[0094]

[0095] Example 3

[0096] The embodiment of the present application provides an electrochromic medium composition (denoted as electrochromic medium 3), which adopts propylene carbonate solution (PC) as a solvent, and specifically, electrochromic material components are shown in Table 3 below:

[0097] Table 3

[0098]

[0099] Comparative Example 1

[0100] The embodiment of the present application provides an electrochromic medium composition (denoted as electrochromic medium 4), which adopts propylene carbonate solution (PC) as a solvent, and specifically, electrochromic material components are shown in Table 4 below:

[0101] Table 4

[0102]

[0103] Comparative Example 2

[0104] The embodiment of the present application provides an electrochromic medium composition (denoted as electrochromic medium 5), which adopts propylene carbonate solution (PC) as a solvent, and the electrochromic material component is shown in the following table 5:

[0105] Table 5

[0106]

[0107] Application example

[0108] Two pieces of 40mm*40mm*0.4mm ITO-coated glass are misaligned and spot glued to be attached, the device box thickness is 125 microns, the above-mentioned material is mixed into a solution, and the electrochromic device is filled into the prepared electrochromic device by using a vacuum liquid filling method, and the L, a* and b* values under 0.8V~1.7V are measured. The results are shown in the following table 6 and table 7:

[0109] Table 6

[0110]

[0111] Table 7

[0112]

[0113] It should be noted that the L value, a* value and b* value in the Lab color space respectively represent the brightness, red-green color and yellow-blue color of the color. When L is larger, the brightness of the color is higher. When a*>0, the color is red, and the larger the a* value, the more the color is red. When a*<0, the color belongs to the green system, and the smaller the a* value, the more the color is green. When b*>0, the color is yellow, and the larger the b* value, the more the color is yellow. When b*<0, the color is blue, and the smaller the b* value, the more the color is blue.

[0114] As can be seen from the above table 6 and 7, from the detection results of examples 1 and 2, the a* value of the two electrochromic systems first increases and then decreases, and when the a* value is maximum, the voltage begins to decrease, and the b value begins to decrease. This shows that the compound 1 has a color change from red to blue. From the test results of comparative examples 1 and 2, when the voltage is added to a certain value, the ethyl viologen system has stable color and has no similar effect. The detection results of example 3 can be seen: the voltage starts to increase from 0.8, the system gradually changes from yellow to orange, and at 1.5V, it is neutral gray, and continues to increase the voltage to become blue-green.

[0115] Further, the ultraviolet-visible spectrum of the electrochromic device composed of medium 2 under 1.4V~1.6V is tested, as shown in Figure 2 Because the molar extinction coefficient of ferrocene is very low, the Figure 2The color spectrum can be considered to be substantially that of compound 1. As shown in Figure 2 The absorption of compound 1 is mainly distributed around 500 nm at 1.4 V, and when the voltage continues to rise, the absorption of compound 1 at 660 nm is obviously enhanced, which is consistent with the results of the above test.

[0116] The above merely describes the preferred embodiments of the present application, but is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An electrochromic medium composition, characterized in that: The invention comprises at least one anode electrochromic material and a cathode electrochromic material, wherein the cathode electrochromic material comprises a viologen derivative, and the structural formula of the viologen derivative is shown in Formula I: Formula I The anode electrochromic material is 5,10-dihydro-5,10-dimethylphenazine and ferrocene; The concentration of ferrocene in the electrochromic medium composition is 15 mM; the concentration of 5,10-dihydro-5,10-dimethylphenazine in the electrochromic medium composition is 5 mM; and the concentration of the cathode electrochromic material in the electrochromic medium composition is 20 mM.

2. The electrochromic medium composition according to claim 1, characterized in that: The electrochromic medium composition further contains at least one of a solvent, an ultraviolet absorption stabilizer, a thickener and a buffer solution.

3. The electrochromic medium composition according to claim 2, characterized in that: The solvent is propylene carbonate solution.

4. Use of the electrochromic medium composition according to any one of claims 1 to 3 in the preparation of an electrochromic film or an electrochromic device.

5. The use according to claim 4, characterized in that The electrochromic device is electrochromic dimming glass.

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