Electrochromic medium composition and application thereof

Abstract

The invention discloses an electrochromic medium composition and application thereof.The electrochromic medium composition comprises at least one anode electrochromic material and at least one cathode electrochromic material, and the cathode electrochromic material comprises viologen derivatives. The viologen derivative is fluorenyl viologen prepared by introducing fluorene into a viologen structure, the compound can show different coloring states under different voltages, the compound is matched with a ferrocene derivative, a red and blue mixed coloring state can be realized, and the color of the viologen derivative is improved. Or the compound, dimethyl dihydrophenazine and a ferrocene derivative are matched, so that a neutral gray coloring state can be realized, and the application value of the compound in the field of electrochromism is greatly expanded.

Description

Technical Field

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

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

[0003] The purpose of the present invention is to provide an electrochromic medium composition and its application in order to overcome the defects of the above-mentioned prior art.

[0004] The present invention solves the technical problem by adopting the following technical solutions.

[0005] The present invention provides an electrochromic medium composition, comprising 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:

[0006] Formula I 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 - For I - Br - , Cl - 、ClO4 - 、BF4 - PF6 - 、SbF6 - or TFSI - Any one of .

[0007] The present invention provides an application of the electrochromic medium composition in preparing an electrochromic film or an electrochromic device.

[0008] The present invention has the following beneficial effects: The present invention provides an electrochromic medium composition and its application. The electrochromic medium composition provided by the present invention comprises at least one anode electrochromic material and a cathode electrochromic material, wherein the cathode electrochromic material comprises a viologen derivative, wherein the viologen derivative is a "fluorenyl viologen" prepared by introducing "fluorene" into the viologen structure, and such compounds can show different coloring states under different voltages and have good color change characteristics, so that they show great application value in the field of electrochromism. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0010] Figure 1 A synthesis path diagram of the cathode electrochromic material in an embodiment of the present invention; Figure 2 This is a UV-visible spectrum of the electrochromic device composed of the electrochromic medium 2 measured at 1.4V~1.6V. DETAILED DESCRIPTION

[0011] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be described clearly and completely below. If the specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be purchased commercially.

[0012] An electrochromic medium composition and its application provided by an embodiment of the present invention are described in detail below.

[0013] In a first aspect, an embodiment of the present invention provides an electrochromic medium composition, comprising 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:

[0014] Formula I 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 - For I - Br -, Cl - 、ClO4 - 、BF4 - PF6 - 、SbF6 - or TFSI - Any one of .

[0015] The embodiment of the present invention provides an electrochromic medium composition, including at least one anode electrochromic material and a cathode electrochromic material. During the electrochromic process, when the electrochromic device is powered on, the cathode electrochromic material migrates to the negative electrode to obtain electrons, and the anode electrochromic material migrates to the positive electrode to lose electrons. At this time, the color of the material or the absorption peak changes greatly, showing a color change, which is the so-called electrochromism. The electrochromic medium composition provided by the embodiment of the present invention, the cathode electrochromic material of which includes a viologen derivative, and the viologen derivative is a series of "fluorenyl viologen" prepared by introducing "fluorene" into the viologen molecule. The "fluorenyl viologen" has a variety of coloring states, which can achieve color changes under different voltages, showing good application potential.

[0016] In some optional embodiments, R1 and R2 in the viologen derivative are each independently a C1-C15 alkoxy group or a C1-C15 aryl group.

[0017] In some optional embodiments, the anode electrochromic material includes phenazine derivatives and ferrocene derivatives. Phenazine derivatives include but are not limited to 5,10-dimethyl-5,10-dihydrophenazine, 5,10-diethyl-5,10-dihydrophenazine and 5,10-dibenzyl-5,10-dihydrophenazine, and ferrocene includes but is not limited to dinuclear ferrocene, trinuclear ferrocene, tetranuclear ferrocene, pentanuclear ferrocene and derivatives thereof.

[0018] In some optional embodiments, the anode electrochromic material is 5,10-dihydro-5,10-dimethylphenazine or ferrocene. The electrochromic device composed of ferrocene and fluorenyl viologen shows red at low voltage, and as the voltage continues to increase, it shows a "red and blue mixed" color, and finally the blue signal covers the red. By combining ferrocene, dimethyldihydrophenazine and fluorenyl viologen, a "neutral gray" color with equal contributions of yellow, red and blue can be achieved at a suitable voltage, achieving full coverage of the electrochromic device in visible light.

[0019] In some optional embodiments, the molar ratio of the anode electrochromic material to the cathode electrochromic material is 1:(0.5-1.5). Optionally, the molar ratio of the anode electrochromic material to the cathode electrochromic material can be any value between 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 1:(0.5-1.5) or a range between any two values. By adjusting the ratio of the cathode electrochromic material to the anode electrochromic material, the depth of coloring of the electrochromic medium composition can be adjusted so that the electrochromic device can achieve a color effect from red to blue.

[0020] In some optional embodiments, the concentration of the cathode electrochromic material in the electrochromic medium composition is 1mM-100mM, preferably 10mM-50mM. Optionally, the concentration of the cathode 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 1mM-100mM or a range value between any two values, 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.

[0021] In some optional embodiments, the concentration of the anode electrochromic material in the electrochromic medium composition is 1mM-100mM, preferably 10mM-50mM. Optionally, the concentration of the anode 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 1mM-100mM or a range value between any two values, 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.

[0022] In some optional embodiments, the electrochromic medium composition further contains at least one of a solvent, an ultraviolet absorption stabilizer, a thickener and a buffer solution.

[0023] In some optional embodiments, the electrochromic medium composition is obtained by mixing at least one anodic electrochromic material and one cathodic electrochromic material.

[0024] In a second aspect, an embodiment of the present invention provides a use of the above-mentioned electrochromic medium composition in preparing an electrochromic film or an electrochromic device.

[0025] In some optional embodiments, the electrochromic device is electrochromic dimming glass.

[0026] The present invention will be further described below in conjunction with the embodiments.

[0027] The electrochromic medium composition provided by the embodiment of the present invention includes at least one anode electrochromic material and one cathode electrochromic material.

[0028] By adjusting the ratio and concentration of the cathode electrochromic material and the anode electrochromic material, the depth of coloring can be controlled. Preferably, the concentration of the cathode electrochromic material is 1mM-100mM, preferably 10mM-50mM, which can be selected according to the contrast requirement in the visible light range; the concentration of the anode electrochromic material is 1mM-100mM, preferably 10mM-50mM, which can be selected according to the contrast requirement in the visible light range.

[0029] The anode electrochemical material is 5,10-dihydro-5,10-dimethylphenazine or ferrocene.

[0030] The cathode electrochromic material includes a viologen derivative, and the structural formula of the viologen derivative is shown in Formula I:

[0031] Formula I 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 - For I - Br - , Cl - 、ClO4 - 、BF4 - PF6 - 、SbF6 - or TFSI - Any one of .

[0032] The synthesis path diagram of the cathode electrochromic material in the embodiment of the present invention is as follows Figure 1 shown.

[0033] in: In the C alkylation process, X' is Cl, Br or I, the amount of NaOH used is 2 eq ~2.2 eq, the amount of R1X' used is 1 eq, the amount of R2X' used is 1 eq ~1.05 eq, and 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.

[0034] During the coupling process, the amount of pyridine-4-boronic acid used is 2 eq ~2.2 eq, the amount of K2CO3 used is 2 eq, and the amount of palladium catalyst used is 0.01 eq ~0.02 eq.

[0035] During N-alkylation, X - Cl - Br - or I - , R3X dosage is 1 eq ~1.05 eq, R4X dosage is 1 eq ~1.05 eq. - For ClO4 - 、BF4 - PF6 - 、SbF6 - or TFSI - When the reaction is carried out, the product in step 3 needs to be dissolved in water, and an excess of LiClO4, LiBF4, LiPF6, NaSbF6 or LiTFSI aqueous solution is added, and then the precipitated precipitate is filtered and dried.

[0036] Synthesis Example 1: The structural formula of compound 1 is shown below: .

[0037] The preparation of compound 1 comprises the following steps: Step 1: Synthesis of intermediate 1 In a two-necked round-bottom flask, 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. 2.18 g of ethyl bromide was slowly added dropwise, and the reaction progress was monitored by thin layer chromatography. When the raw materials reacted completely, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phases were extracted with dichloromethane and combined. The organic phase was then distilled under reduced pressure to obtain a 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: .

[0038] Step 2: Synthesis of Intermediate 2 In a two-necked round-bottom flask, 3.8 g of intermediate 1 and 2.46 g of pyridine-4-boric acid were dissolved in 100 mL of a mixed solvent of dioxane / water = 5:1. After nitrogen bubbling for 15 min, 116 mg of tetrakistriphenylphosphine palladium was added and reacted at 100 °C for 12 h. When the raw materials reacted completely, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phases were extracted with dichloromethane and combined. The organic phase was then distilled under reduced pressure to obtain a 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: .

[0039] Step 3: Synthesis of Intermediate 3 In a two-necked round-bottom flask, 3.77 g of intermediate 2 and 2.84 g of iodomethane were dissolved in 50 mL of DMF and reacted at 80°C for 12 h. When the raw materials reacted completely, the reaction was cooled to room temperature and 200 mL of dichloromethane was added to precipitate a large amount of powder. 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). The structural formula of intermediate 3 is shown below: .

[0040] Step 4: Synthesis of compound 1 6.6 g of intermediate 3 and 10 g of LiClO4 were dissolved in two 30 mL portions of deionized water, respectively. The two were then mixed to precipitate a large amount of light yellow solid. The precipitate was filtered and washed three times with deionized water to complete the purification of compound 1 (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).

[0041] Synthesis Example 2: The structural formula of compound 2 is shown below: .

[0042] The preparation of compound 2 comprises the following steps: Step 1: Synthesis of intermediate 4 In a two-necked round-bottom flask, 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 reaction progress was monitored by thin layer chromatography. When the raw materials reacted completely, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phases were extracted with dichloromethane and combined. The organic phase was then distilled under reduced pressure to obtain a 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: .

[0043] Step 2: Synthesis of intermediate 5 In a two-necked round-bottom flask, 3.52 g of intermediate 4 and 2.46 g of pyridine-4-boric acid were dissolved in 100 mL of a mixed solvent of dioxane / water = 5:1. After nitrogen bubbling for 15 min, 116 mg of tetrakistriphenylphosphine palladium was added and reacted at 100 °C for 12 h. When the raw materials reacted completely, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phases were extracted with dichloromethane and combined. The organic phase was then distilled under reduced pressure to obtain a crude product, which 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 as follows: .

[0044] Step 3: Synthesis of intermediate 6 In a two-necked round-bottom flask, 3.48 g of intermediate 5 and 2.84 bromoethane were dissolved in 50 mL of DMF and reacted at 80°C for 12 h. When the raw materials reacted completely, the reaction was cooled to room temperature and 200 mL of dichloromethane was added to precipitate a large amount of powder. 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: .

[0045] Step 4: Synthesis of compound 2 5.66 g of intermediate 6 and 10 g of LiTFSI were dissolved in two 30 mL portions of deionized water, respectively. The two were then mixed to precipitate a large amount of light yellow solid. The precipitate was filtered and washed three times with deionized water to complete the purification of compound 1 (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).

[0046] Synthesis Example 3: The structural formula of compound 3 is shown below: .

[0047] The preparation of compound 3 comprises the following steps: Step 1: Synthesis of intermediate 7 In a two-necked round-bottom flask, 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 materials reacted completely, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phases were extracted with dichloromethane and combined. The organic phase was then distilled under reduced pressure to obtain a 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 shown below: .

[0048] Step 2: Synthesis of intermediate 8 In a two-necked round-bottom flask, 4.12 g of intermediate 7 and 2.46 g of pyridine-4-boric acid were dissolved in 100 mL of a mixed solvent of dioxane / water = 5:1. After nitrogen bubbling for 15 min, 116 mg of tetrakistriphenylphosphine palladium was added and reacted at 100 °C for 12 h. When the raw materials reacted completely, the reaction was cooled to room temperature, 200 mL of water was added, and the organic phases were extracted with dichloromethane and combined. The organic phase was then distilled under reduced pressure to obtain a crude product, which 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: .

[0049] Step 3: Synthesis of intermediate 9 In a two-necked round-bottom flask, 4.08 g of intermediate 8 and 2.84 bromoethane were dissolved in 50 mL of DMF and reacted at 80°C for 12 h. When the raw materials reacted completely, the reaction was cooled to room temperature and 200 mL of dichloromethane was added to precipitate a large amount of powder. 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 shown below: .

[0050] Step 4: Synthesis of compound 3 6.26 g of intermediate 9 and 10 g of LiClO4 were dissolved in two 30 mL portions of deionized water, respectively. The two were then mixed to precipitate a large amount of light yellow solid. The precipitate was filtered and washed three times with deionized water 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).

[0051] Example 1 The embodiment of the present invention provides an electrochromic medium composition (referred to as electrochromic medium 1), the solvent used in the electrochromic medium is propylene carbonate solution (PC). Specifically, the electrochromic material composition is shown in Table 1 below: Table 1

[0052] Example 2 The present embodiment provides an electrochromic medium composition (referred to as electrochromic medium 2), the solvent used in the electrochromic medium is propylene carbonate solution (PC). Specifically, the electrochromic material composition is shown in Table 2 below: Table 2

[0053] Example 3 The embodiment of the present invention provides an electrochromic medium composition (referred to as electrochromic medium 3), the solvent used in the electrochromic medium composition is propylene carbonate solution (PC). Specifically, the electrochromic material composition is shown in Table 3 below: Table 3

[0054] Comparative Example 1 The present embodiment provides an electrochromic medium composition (referred to as electrochromic medium 4), the solvent used in the electrochromic medium composition is propylene carbonate solution (PC). Specifically, the electrochromic material composition is shown in Table 4 below: Table 4

[0055] Comparative Example 2 The embodiment of the present invention provides an electrochromic medium composition (referred to as electrochromic medium 5), the solvent used in the electrochromic medium is propylene carbonate solution (PC). Specifically, the electrochromic material composition is shown in Table 5 below: Table 5

[0056] Application Examples Two pieces of 40mm*40mm*0.4mm ITO-coated glass were glued together at different positions. The thickness of the device box was 125 microns. The above materials were mixed into a solution and filled into the prepared electrochromic device by vacuum filling. Voltage was applied at both ends to measure the L, a*, and b* values ​​from 0.8V to 1.7V. The results are shown in Tables 6 and 7 below: Table 6

[0057] Table 7

[0058] It should be noted that the L value, a* value and b* value in the Lab color space represent the brightness, red-green color and yellow-blue color, respectively. The larger the L value, the higher the brightness of the color. When a*>0, it means that the color is red, and the larger the a* value, the more red the color is; when a*<0, it means that the color belongs to the green series, and the smaller the a* value, the more green the color is. When b*>0, it means that the color is yellow, and the larger the b* value, the more yellow the color is; when b*<0, it means that the color is blue, and the smaller the b* value, the more blue the color is.

[0059] As can be seen from the above Tables 6 and 7: From the test results of Examples 1 and 2, the a* values ​​of the two electrochromic systems first increase and then decrease. When the a* value is the largest, it begins to decrease after increasing the voltage, and the b value begins to decrease at the same time. This shows that the color state of compound 1 changes from red to blue. From the test results of Comparative Examples 1 and 2, when the voltage is added to a certain value, the color of the ethyl viologen system is stable and there is no similar effect. It can be seen from the test results of Example 3 that the voltage increases from 0.8, the system gradually transitions from yellow to orange, and is neutral gray at 1.5V, and becomes blue-green when the voltage is further increased.

[0060] Furthermore, the UV-visible spectrum of the electrochromic device composed of medium 2 at 1.4V~1.6V was tested, see Figure 2 Since the molar extinction coefficient of ferrocene is very low, Figure 2 It can be basically considered as the chromatogram of compound 1. Figure 2 As shown, at 1.4 V, the absorption of compound 1 is mainly distributed around 500 nm. When the voltage continues to increase, the absorption of compound 1 at 660 nm is significantly enhanced, which is consistent with the results of the above tests.

[0061] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An electrochromic medium composition, characterized in that: It 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 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 - For I - Br - , Cl - 、ClO4 - 、BF4 - PF6 - 、SbF6 - or TFSI - Any one of .

2. The electrochromic medium composition according to claim 1, characterized in that: R1 and R2 in the viologen derivative are independently C1-C15 alkoxy or C1-C15 aryl.

3. The electrochromic medium composition according to claim 1, characterized in that: The anode electrochromic material includes phenazine derivatives and ferrocene derivatives.

4. The electrochromic medium composition according to claim 3, characterized in that: The anode electrochromic material is 5,10-dihydro-5,10-dimethylphenazine or ferrocene.

5. The electrochromic medium composition according to claim 1, characterized in that: The molar ratio of the anode electrochromic material to the cathode electrochromic material is 1:(0.5-1.5).

6. The electrochromic medium composition according to claim 1, characterized in that: The concentration of the cathode electrochromic material in the electrochromic medium composition is 1 mM-100 mM.

7. The electrochromic medium composition according to claim 1, characterized in that: The concentration of the anode electrochromic material in the electrochromic medium composition is 1 mM-100 mM.

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

9. Use of the electrochromic medium composition according to any one of claims 1 to 8 in the preparation of an electrochromic film or an electrochromic device.

10. The use according to claim 9, characterized in that: The electrochromic device is electrochromic dimming glass.

Images