Composition for electrochromic element having light transparency, high flexibility, and high moisture resistance, and method for manufacturing electrochromic member

Abstract

The present invention relates to a composition for an electrochromic element having improved light transmittance and elasticity, and a method for producing an electrochromic member. The composition for an electrochromic device according to an embodiment of the present invention includes a light-transmitting polymer resin, a plasticizer, and an electrochromic material.

Description

[Technical Field]

[0001] The present invention relates to a composition for an electrochromic element having optical transparency, high flexibility, and high moisture resistance, and a method for producing an electrochromic member. [Background technology]

[0002] An electrochromic element contains an electrochromic material and changes color depending on the voltage applied from the outside. Various materials such as polymer compounds and metal oxides are used as the electrochromic material, and the color changes reversibly depending on the voltage applied to the electrodes.

[0003] Recently, the application of such color-changing elements has been expanding, including smart window systems that block outside views and sunlight, and automotive glass that displays information such as maps and text.

[0004] Conventional electrochromic devices have a problem of electrolyte leakage due to the use of liquid electrochromic materials, which limits their use as flexible displays.

[0005] Recently, solidified water-based electrolytes have been developed, but they have the problem of requiring an additional protective layer to prevent water from easily evaporating. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Korean Patent Registration No. 10-2078481 Summary of the Invention [Problem to be solved by the invention]

[0007] An object of the present invention is to provide a composition for an electrochromic element and a method for producing an electrochromic member which have improved light transmittance and stretchability.

[0008] It also has a long life and excellent durability.

[0009] In addition, the flexibility and stretchability of the material make it applicable to a variety of fields.

[0010] Furthermore, the manufacturing method is simple, which allows for increased production efficiency and reduced manufacturing costs. [Means for solving the problem]

[0011] The composition for an electrochromic device according to an embodiment of the present invention includes a light-transmitting polymer resin, a plasticizer, and an electrochromic material.

[0012] The electrochromic material may be diheptyl viologen dihexafluorophosphate, and the content of the electrochromic material may be 5 to 20 parts by weight based on 100 parts by weight of the polymer resin.

[0013] The electrochromic material may be represented by the following Chemical Formula 1.

[0014] [ka]

[0015] The composition may further contain an ionic liquid having a content of 100 to 200 parts by weight based on 100 parts by weight of the polymer resin.

[0016] The electrochromic material may be ethyl viologen dibis(trifluoromethanesulfonyl)imide, and the content of the electrochromic material may be 5 to 14 parts by weight based on 100 parts by weight of the polymer resin.

[0017] The ethyl viologen dibis(trifluoromethanesulfonyl)imide can be represented by the following Chemical Formula 2.

[0018] [ka]

[0019] An electrochromic element according to an embodiment of the present invention includes a first electrode, a second electrode, and an electrochromic element layer that changes color in response to a voltage applied between the first electrode and the second electrode, and the electrochromic element layer includes the composition for an electrochromic element described above.

[0020] A method for manufacturing an electrochromic member according to an embodiment of the present invention includes the steps of dissolving a polymer resin, a plasticizer, an ionic liquid, and an electrochromic material in a solvent to prepare a mixed solution, and removing the solvent from the mixed solution.

[0021] The electrochromic substance may be diheptyl viologen dihexafluorophosphate, and a method for preparing the electrochromic substance may include preparing a solution of 1,1'-diheptyl-4,4'-bipyridinium dibromide in a solvent and adding NH4PF6 to the solution.

[0022] The electrochromic material may be ethyl viologen dibis(trifluoromethanesulfonyl)imide, and a method for preparing the electrochromic material may include preparing a solution of ethyl viologen dibromide in a solvent, and adding lithium bis(trifluoromethanesulfonyl)imide to the solution. [Effects of the Invention]

[0023] The composition for an electrochromic element and the method for manufacturing an electrochromic member according to the embodiments of the present invention may have improved light transmittance and flexibility.

[0024] It also has a long life and excellent durability.

[0025] In addition, the flexibility and stretchability of the material make it applicable to a variety of fields.

[0026] Furthermore, the manufacturing method is simple, which allows for increased production efficiency and reduced manufacturing costs. [Brief explanation of the drawings]

[0027] [Figure 1] FIG. 10 is a diagram showing the results of cyclic voltammetry measurements when the electrochromic substances are DHV[PF6]2, DBV[PF6]2, and DEV[PF6]2. [Figure 2] FIG. 10 is a diagram showing the measurement results of light absorptance when the electrochromic materials are DHV[PF6]2, DBV[PF6]2, and DEV[PF6]2. [Figure 3] Photographs showing the degree of color development depending on the potential when the electrochromic materials are DHV[PF6]2, DBV[PF6]2, and DEV[PF6]2. [Figure 4] FIG. 10 is a diagram showing experimental results of light transmittance when the electrochromic materials are DHV[PF6]2, DBV[PF6]2, and DEV[PF6]2. [Figure 5] FIG. 1 shows the optical density versus charge density analysis results for electrochromic materials DHV[PF6]2, DBV[PF6]2, and DEV[PF6]2. [Figure 6] FIG. 1 shows the results of repeated coloring / bleaching cycle experiments when the electrochromic materials are DHV[PF6]2, DBV[PF6]2, and DEV[PF6]2. [Figure 7] FIG. 1 is a Nyquist diagram showing the results of an impedance experiment when the electrochromic material is EV[TFSI]2. [Figure 8] FIG. 1 shows the results of tensile strength-strain measurements where the electrochromic material is EV[TFSI]2. [Figure 9] FIG. 1 shows the results of a compressive load test where the electrochromic material is EV[TFSI]2. [Figure 10] FIG. 1 shows the results of an evaporation test where the electrochromic material is EV[TFSI]2. [Figure 11] FIG. 1 shows the results of cyclic voltammetry measurements in which the electrochromic material is EV[TFSI]2. [Figure 12] FIG. 1 shows the measurement results of light absorptance when the electrochromic material is EV[TFSI]2. [Figure 13] FIG. 10 shows the experimental results of light transmittance when the electrochromic material is EV[TFSI]2. [Figure 14] FIG. 1 shows optical density versus charge density analysis results where the electrochromic material is EV[TFSI]2. DETAILED DESCRIPTION OF THE INVENTION

[0028] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. However, the embodiments of the present invention may be modified into various other forms, and the scope of the present invention is not limited to the embodiments described below. Furthermore, the embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art. Therefore, the shapes and sizes of elements in the drawings may be exaggerated for clarity, and elements denoted by the same reference numerals in the drawings are the same elements. Furthermore, the same reference numerals are used throughout the drawings for parts having similar functions and actions. Furthermore, throughout the specification, the term "comprising" a certain element does not mean excluding other elements, but means that the term may further include other elements, unless otherwise specified.

[0029] Composition for electrochromic elements The composition for an electrochromic device according to an embodiment of the present invention includes a light-transmitting polymer resin, a plasticizer, and an electrochromic material.

[0030] The polymer resin forms a basic body from a composition for an electrochromic device. The polymer resin may have optical transparency, flexibility, and elasticity when cured with a plasticizer. To this end, the polymer resin may be at least one of polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyurethane (PU), polymethyl methacrylate (PMMA), polydimethylsiloxane (PDMS), polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), polyethylene oxide (PEO), polyimide (PI), and polyethylene terephthalate (PET). In particular, polyvinyl chloride (PVC) can be used to achieve high optical transparency, flexibility, and elasticity.

[0031] A plasticizer is a substance that plasticizes a polymer resin. The plasticizer is not particularly limited, but may be DBA (dibutyl adipate). DBA may be represented by the following Chemical Formula 3:

[0032] [ka]

[0033] The content of the plasticizer may be 700 to 1200 parts by weight, preferably 800 to 1000 parts by weight, based on 100 parts by weight of the polymer resin. If the content of the plasticizer is too low, crystals may easily form in the manufactured color-changing element member, and if the content of the plasticizer is too high, mechanical properties may be reduced.

[0034] An electrochromic material is a material that changes its color by changing the wavelength of absorption depending on an externally applied voltage. In an embodiment of the present invention, the electrochromic material may be preferably diheptyl viologen dihexafluorophosphate or ethyl viologen dibis(trifluoromethanesulfonyl)imide.

[0035] The diheptyl viologen dihexafluorophosphate is represented by DHV[PF6]2 and is represented by the following chemical formula 4. The diheptyl viologen dihexafluorophosphate can realize a blue or cyan color when a voltage is applied. By limiting the electrochromic material in this way, it is possible to maintain high light transmittance of the electrochromic element layer while controlling the light transmittance depending on the voltage, thereby accurately realizing a color.

[0036] [ka]

[0037] The ethyl viologen dibis(trifluoromethanesulfonyl)imide is represented by EV[TFSI]2 and is represented by the following chemical formula 5. The ethyl viologen dibis(trifluoromethanesulfonyl)imide can realize a blue or cyan hue when a voltage is applied. By limiting the electrochromic material in this way, it is possible to maintain high light transmittance of the electrochromic element layer while controlling the light transmittance depending on the voltage, thereby accurately realizing a color.

[0038] [ka]

[0039] The content of the electrochromic material may be 5 to 20 parts by weight based on 100 parts by weight of the polymer resin. If the electrochromic material is diheptyl viologen dihexafluorophosphate, the content of the electrochromic material may be preferably 14 to 17 parts by weight.

[0040] When the electrochromic material is ethyl viologen dibis(trifluoromethanesulfonyl)imide, the content of the electrochromic material is preferably 8 to 13.5 parts by weight, more preferably 11 to 13.5 parts by weight. If the content of the electrochromic material is too low, it is difficult to control the light transmittance, and the color may not be accurately realized. If the content is too high, crystals may form in the electrochromic layer, resulting in uneven color change.

[0041] In one embodiment, the composition for an electrochromic device may further include an ionic liquid. An ionic liquid is generally a substance that can improve the mobility of ions and electrons while remaining in a non-volatile liquid state at temperatures below 100°C. Various ionic liquids may be used, but 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM-TFSI) is preferred. By limiting the ionic liquid to this, the light transmittance of the electrochromic device layer can be maintained at a high level. The EMIM-TFSI may be represented by the following Chemical Formula 6:

[0042] [ka]

[0043] The content of the ionic liquid may be 100 to 200 parts by weight, preferably 150 to 170 parts by weight, based on 100 parts by weight of the polymer resin. If the content of the ionic liquid is too high, light transmittance may decrease.

[0044] In one embodiment, the composition for an electrochromic device may further include an anode redox compound. The anode redox compound may be one of ferrocene and dimethylferrocene, preferably dimethylferrocene. The dimethylferrocene may be represented by the following Formula 7:

[0045] [ka]

[0046] The content of the anode redox compound may be 1 to 5 parts by weight, preferably 1 to 7 parts by weight, based on 100 parts by weight of the polymer resin.

[0047] Electrochromic element An electrochromic element according to an embodiment of the present invention includes a first electrode, a second electrode, and an electrochromic element layer that changes color in response to a voltage applied between the first electrode and the second electrode, and the electrochromic element layer includes the composition for an electrochromic element described above.

[0048] The first and second electrodes may be any electrode commonly used in electrical devices, but may be made of ITO glass or ITO-PEN, which has optical transparency, flexibility, and stretchability.

[0049] The electrochromic element layer may contain the composition for electrochromic elements described above, and may be prepared in an appropriate size and thickness using the composition for electrochromic elements according to the preparation method described below.

[0050] Manufacturing method of electrochromic member A method for manufacturing an electrochromic member according to an embodiment of the present invention includes the steps of dissolving a polymer resin, a plasticizer, an ionic liquid, and an electrochromic material in a solvent to prepare a mixed solution, and removing the solvent from the mixed solution.

[0051] The polymer resin, plasticizer, and ionic liquid mixed in the step of preparing the mixed solution are the same as those described above.

[0052] In this step, if the electrochromic material is diheptyl viologen dihexafluorophosphate, the method for preparing the electrochromic material may include preparing a solution of 1,1'-diheptyl-4,4'-bipyridinium dibromide in a solvent and adding NH4PF6 to the solution. The 1,1'-diheptyl-4,4'-bipyridinium dibromide may be represented by DHV(Br).

[0053] The solvent is a liquid capable of dissolving 1,1'-diheptyl-4,4'-bipyridinium dibromide, preferably water. In this step, 1,1'-diheptyl-4,4'-bipyridinium dibromide is added to water and stirred to completely dissolve.

[0054] The step of adding NH4PF6 to the solution can be carried out by slowly adding NH4PF6 dropwise onto the 1,1'-diheptyl-4,4'-bipyridinium dibromide solution.

[0055] Then, the reaction can be carried out at room temperature to produce DHV[PF6]2, followed by removing the solvent, washing and drying, and finally producing DHV[PF6]2.

[0056] In this step, if the electrochromic material is ethyl viologen dibis(trifluoromethanesulfonyl)imide, the electrochromic material can be prepared by preparing a solution of ethyl viologen dibromide in a solvent and adding lithium bis(trifluoromethanesulfonyl)imide to the solution. The ethyl viologen dibromide is represented by EV(Br)2 and is represented by the following chemical formula 8:

[0057] [ka]

[0058] The solvent is a liquid capable of dissolving ethyl viologen dibromide, preferably water. In this step, ethyl viologen dibromide is added to water and stirred to completely dissolve.

[0059] The step of adding lithium bis(trifluoromethanesulfonyl)imide can be carried out by slowly dropping lithium bis(trifluoromethanesulfonyl)imide onto the ethyl viologen dibromide solution. The lithium bis(trifluoromethanesulfonyl)imide is represented by LiTFSI and is represented by the following Formula 9:

[0060] [ka]

[0061] Then, the reaction can be carried out at room temperature to produce EV[TFSI]2, which can then be finally produced by removing the solvent, washing, and drying.

[0062] The solvent used in the step of preparing the mixed solution may be a polar organic solvent, which easily dissolves polymer resins such as PVC. The polar organic solvent may be any one of dioxane, tetrahydrofuran (THF), acetone, dimethyl sulfoxide (DMSO), dimethylformamide (DMF), and 1-methyl-2-pyrrolidone (NMP).

[0063] The content of the plasticizer added in this step may be 700 to 1200 parts by weight, the content of the ionic liquid may be 100 to 200 parts by weight, and the content of the electrochromic material may be 5 to 20 parts by weight, preferably 5 to 14 parts by weight, based on 100 parts by weight of the polymer resin. Also, an anode redox compound may be further added in an amount of 1 to 7 parts by weight, preferably 1 to 5 parts by weight, based on 100 parts by weight of the polymer resin.

[0064] After this step, a solvent removal step is performed. This step can be performed by leaving the mixed solution of various materials at room temperature for a long period of time, or using a dryer if necessary. This step can also be performed on a film or mold to produce a desired shape and thickness.

[0065] Manufacturing example: Electrochromic material DHV[PF 6 ] 2 , DBV[PF 6 ] 2 , DEV[PF 6 ] 2 Manufacturing To prepare the electrochromic material DHV[PF6]2, 0.2 g of DHV(Br)2 (manufactured by TCI) was dissolved in 40 ml of water, followed by dissolving 0.19 g of NH4PF6 in another 40 ml of water. Next, an aqueous solution of NH4PF6 was added dropwise to the DHV(Br)2 solution. The mixed solution was then left at 25°C for 24 hours to produce DHV[PF6]2. The mixed solution was filtered under reduced pressure, washed with distilled water, and then dried in a vacuum oven at 80°C for 24 hours.

[0066] To prepare the electrochromic material DBV[PF6]2, 0.2 g of DBV(Br)2 (benzyl viologen dichloride) manufactured by Alfa Aeser was dissolved in 40 ml of water, and 0.2389 g of NH4PF6 was added dropwise to the solution to achieve a molar ratio of DBV(Br)2 to NH4PF6 of 1:3. The mixed solution was then left at 25°C for 24 hours to produce DBV[PF6]2. The mixed solution was filtered under reduced pressure, washed with distilled water, and then dried in a vacuum oven at 80°C for 24 hours.

[0067] To prepare the electrochromic material DEV[PF6]2, 0.2 g of DEV(Br)2 (1,1'-diethyl-4,4'-bipyridinium dibromide) was dissolved in 40 ml of water, and 0.34 g of NH4PF6 was added dropwise. The mixture was then left at 25°C for 24 hours to produce DEV[PF6]2. The mixture was filtered under reduced pressure, washed with distilled water, and then dried in a vacuum oven at 80°C for 24 hours.

[0068] Manufacturing example: Electrochromic material EV [TFSI] 2 Manufacturing 0.2 g of EV(Br)2 was dissolved in 40 ml of water, and 0.34 g of LiTFSI was dissolved in another 40 ml of water. The LiTFSI solution was then added dropwise to the EV(Br)2 solution so that the molar ratio of EV(Br)2 to LiTFSI was 1:3. The mixed solution was then left at 25°C for 24 hours to produce EV[TFSI]2. The mixed solution was filtered under reduced pressure, washed with distilled water, and dried in a vacuum oven at 80°C for 24 hours.

[0069] Manufacturing example: DHV[PF 6 ] 2 , DBV[PF 6 ] 2 , DEV[PF 6 ] 2 Manufacturing electrochromic materials using Example 1 0.3424 g of PVC (Scientific Polymer Products) as a polymer resin, 3.0816 g of DBA (TCI) as a plasticizer, 0.5478 g of EMIMTFSI (io-li-tec) as an ionic liquid, 0.0333 g of DHV[PF6]2 (previously prepared) as an electrochromic material, and 0.0111 g of dimethylferrocene (TCI) as an anode redox compound were mixed in THF as a solvent. The mixed solution was then poured into a glass dish and dried at room temperature for 3 days to evaporate the solvent.

[0070] Example 2 The procedure of Example 1 was repeated except that 0.0416 g of DHV[PF6]2 and 0.0138 g of dimethylferrocene were used.

[0071] Example 3 The procedure for preparation was the same as in Example 1, except that 0.0499 g of DHV[PF6]2 and 0.0166 g of dimethylferrocene were used.

[0072] Example 4 The procedure of Example 1 was repeated except that 0.0583 g of DHV[PF6]2 and 0.0194 g of dimethylferrocene were used.

[0073] Comparative Example 1 The procedure of Example 1 was repeated except that 0.0325 g of DBV[PF6]2 (previously prepared) and 0.0111 g of dimethylferrocene were used instead of DHV[PF6]2.

[0074] Comparative Example 2 The procedure of Example 2 was repeated except that 0.0406 g of DBV[PF6]2 (previously prepared) and 0.0138 g of dimethylferrocene were used instead of DHV[PF6]2.

[0075] Comparative Example 3 The procedure for Example 3 was the same as in Example 1, except that 0.0487 g of DBV[PF6]2 (previously prepared) and 0.0166 g of dimethylferrocene were used instead of DHV[PF6]2.

[0076] Comparative Example 4 The procedure of Example 1 was repeated except that 0.0130 g of DEV[PF6]2 (previously prepared) and 0.0055 g of dimethylferrocene were used instead of DHV[PF6]2.

[0077] Comparative Example 5 The same procedure as in Comparative Example 4 was carried out to prepare the polymer, except that 0.0196 g of DEV[PF6]2 and 0.008 g of dimethylferrocene were used.

[0078] Comparative Example 6 The same procedure as in Comparative Example 4 was carried out to prepare the polymer, except that 0.0261 g of DEV[PF6]2 and 0.0111 g of dimethylferrocene were used.

[0079] Manufacturing example: EV[TFSI] 2 Manufacturing of electrochromic elements using Example 5 0.3424 g of PVC (Scientific Polymer Products) as a polymer resin, 3.0816 g of DBA (TCI) as a plasticizer, 0.5478 g of EMIMTTFSI (io-li-tec) as an ionic liquid, 0.02 g of EV[TFSI]2 (previously prepared) as an electrochromic material, and 0.0055 g of dimethylferrocene (TCI) as an anode redox compound were added to 25 ml of THF solvent and mixed. Next, the mixture was poured into a glass dish and dried at room temperature for 3 days to evaporate the solvent.

[0080] Example 6 The procedure for preparation was the same as in Example 1, except that 0.03 g of EV[TFSI]2 and 0.0083 g of dimethylferrocene were used.

[0081] Example 7 The procedure for preparation was the same as in Example 1, except that 0.04 g of EV[TFSI]2 and 0.0111 g of dimethylferrocene were used.

[0082] Example 8 The procedure for preparation was the same as in Example 1, except that 0.045 g of EV[TFSI]2 and 0.01244 g of dimethylferrocene were used.

[0083] Comparative Example 7 The procedure for preparation was the same as in Example 1, except that 0.050 g of EV[TFSI]2 and 0.01383 g of dimethylferrocene were used.

[0084] Comparative Example 8 The production was carried out in the same manner as in Example 1, except that EV[TFSI]2 was not added.

[0085] Manufacturing example: Manufacturing of electrochromic elements The electrochromic member prepared above was placed on ITO glass, 100 μm thick spacers were placed around the edge of the electrochromic member, and then the top was covered with another ITO glass. The electrochromic elements prepared in this manner were defined as Examples D1 to D4 corresponding to Examples 1 to 4, Examples E5 to E8 corresponding to Examples 5 to 8, Comparative Examples D1 to D6 corresponding to Comparative Examples 1 to 6, and Comparative Examples E7 and E8 corresponding to Comparative Examples 7 and 8, respectively.

[0086] Experimental example: Visual inspection Examples 1 to 8 and Comparative Examples 1 to 8 were visually inspected to check for any abnormalities. In the cases of Comparative Examples 3, 6, and 7, it was confirmed that crystals had formed inside.

[0087] Experimental Example: Cyclic Voltammetry Measurement (1) 20mVs using a potentiometer (biologics, SP240) -1Current / potential curves were obtained by cyclic voltammetry for Examples D1 to D4 and Comparative Examples D1 to D6 under the conditions shown in Figure 1. Figure 1 shows the results of this experiment. It can be seen that Examples D1 to D4 show clearer changes in current than the comparative examples, and that Examples D3 and D4 in particular show clearer changes in current.

[0088] Experimental example: Measuring light absorption rate For Example D4, Comparative Example D2, and Comparative Example D5, measurements were taken in the range of 400 to 800 nm using a UV-Vis Spectrometer (Perkin Elmer, Lambda 465). Figure 2(a) shows the experimental results for Example D4, Figure 2(b) shows the experimental results for Comparative Example D2, and Figure 2(c) shows the experimental results for Comparative Example D5. Referring to Figure 2, it can be seen that Example D4 had the highest absorptance at a wavelength of 606 nm, and that the light absorptance was adjusted depending on the applied voltage. For the Comparative Example, the light absorptance was higher around 606 nm than at other wavelengths, but the difference in absorption was not as great as that of the Examples.

[0089] Experimental example: Color development experiment A voltage ranging from 0 V to -1.4 V was applied to Example D4, Comparative Example D2, and Comparative Example D5, and the change in hue was observed. Figure 3 shows the results of this experiment. Referring to Figure 3, in the case of Example D4, the control of hue depending on the applied voltage was most clear, and it was a deeper blue color than the comparative examples.

[0090] Experimental Example: Light Transmittance Experiment (1) The transmittance of light at a wavelength of 606 nm was measured for Examples D1 to D4 and Comparative Examples D1 to D6. The change in light transmittance was observed while coloring and bleaching were performed by applying and removing voltage. Figure 4 shows the results of this experiment. Referring to Figure 4, the Examples showed a greater change in light transmittance than the Comparative Examples, and among the Examples, Examples D3 and D4 showed a greater change in light transmittance than the other Examples.

[0091] Experimental Example: Optical Density vs. Charge Density Analysis (1) The relationship between optical density and charge density was analyzed for Examples D1 to D4 and Comparative Examples D1 to D6 at 606 nm and -1.0 V to determine the coloring efficiency (η). Figure 8 shows the experimental results. Referring to Figure 5, it can be seen that the Examples have higher coloring efficiency (η) than the Comparative Examples, with Examples 6 to 8 showing particularly large increases in coloring efficiency (η), with Examples D3 to D4 showing the largest increases among the Examples.

[0092] Experimental example: Light transmittance experiment using repeated coloring and bleaching cycles For Example D4 and Comparative Examples D2 and D5, voltage was repeatedly applied to repeatedly color and bleach the film, and the transmittance of light with a wavelength of 606 nm was measured for 40,000 seconds. The change in light transmittance was observed during the coloring and bleaching process by applying and removing voltage. Figure 6 shows the results of this experiment, with (a) the results for Example D4, (b) the results for Comparative Example D2, and (c) the results for Comparative Example D5. Referring to Figure 6, it can be seen that Example D4 maintained a constant light transmittance during the cycle, while Comparative Examples D2 and D5 experienced a decrease in light transmittance.

[0093] Experimental example: Measurement of impedance characteristics The electrochromic members prepared in Examples 5 to 8 and Comparative Example 8 were placed between platinum electrodes, and impedance spectra were measured using an impedance spectrometer. Figure 7 is a Nyquist diagram showing the experimental results. Referring to Figure 7, it can be seen that there is no significant difference in characteristics between Example 5 and Comparative Example 8, but that Example 8 has improved characteristics compared to Comparative Example 8.

[0094] Experimental example: Tensile strength-strain measurement Measurements were performed on Examples 5 to 8 and Comparative Example 8 using a universal testing machine (UTM, Tinius Olsen, H5KT) in accordance with ASTM D638 type V. Figure 8 shows the experimental results. Referring to Figure 8, it can be seen that the Examples have significantly higher tensile strength than Comparative Example 8, and that Examples 6 to 8 are particularly superior.

[0095] Experimental example: Compression load test Examples 5 to 8 and Comparative Example 8 were each cut to a thickness of 3 mm and a width and length of 10 mm, and were subjected to compression at a speed of 10 mm / min using a compression load tester. Figure 9 shows the results of this experiment. Referring to Figure 9, it can be seen that the Examples have superior compression characteristics compared to Comparative Example 8.

[0096] Experimental example: Evaporation test The samples from Examples 5 to 8 and Comparative Example 8 were cut to a certain size, and the weights of the samples were measured while maintaining them at room temperature for 30 days under conditions of 20 to 27°C and 19 to 40% RH. Figure 10 shows the results of this experiment. Referring to Figure 10, it can be seen that there was no change in weight even when the content of the electrochromic material increased.

[0097] Experimental Example: Cyclic Voltammetry Measurement (2) 20mVs using a potentiometer (biologics, SP240) -1 Current / potential curves were obtained by cyclic voltammetry for Examples E5 to E8 under the conditions shown in Figure 11. The results are shown in Figure 11. It can be seen that the higher the content of the electrochromic material, the more pronounced the change in current.

[0098] Experimental example: Measuring light absorption rate For Example E8, measurements were taken in the range of 400 to 800 nm using a UV-Vis Spectrometer (Perkin Elmer, Lambda 465). Figure 12 shows the results of this experiment. Referring to Figure 12, it can be seen that the absorbance is highest at a wavelength of 606 nm, and that the light absorbance is controlled by the applied voltage.

[0099] Experimental Example: Light Transmittance Experiment (2) The transmittance of light at a wavelength of 606 nm was measured for Examples E5 to E8. The change in light transmittance was observed while coloring and bleaching were performed by applying and removing voltage. Figure 13 shows the results of this experiment. Referring to Figure 13, it can be seen that the higher the electrochromic material content, the greater the change in light transmittance, and that Examples E7 and E8 showed particularly excellent changes in light transmittance.

[0100] Experimental Example: Optical Density vs. Charge Density Analysis (2) The relationship between optical density and charge density was analyzed for Examples E5 to E8 at 606 nm and -1.0 V to determine the coloring efficiency (η). Figure 14 shows the experimental results. Referring to Figure 14, it can be seen that the higher the content of electrochromic material, the higher the coloring efficiency (η), with the increase in coloring efficiency (η) being particularly noticeable for Examples E6 to E8.

[0101] The present invention is not limited by the above-described embodiments and the accompanying drawings, but is limited by the appended claims. Therefore, various substitutions, modifications, and changes can be made by a person skilled in the art without departing from the technical spirit of the present invention as defined in the claims, and such changes are also within the scope of the present invention.

Claims

1. a light-transmitting polymer resin; A plasticizer, an electrochromic material; the polymer resin is polyvinyl chloride; the electrochromic material is diheptyl viologen dihexafluorophosphate or ethyl viologen dibis(trifluoromethanesulfonyl)imide; When the electrochromic material is diheptyl viologen dihexafluorophosphate, the content of the electrochromic material is 14 to 17 parts by weight based on 100 parts by weight of the polymer resin; When the electrochromic material is ethyl viologen dibis(trifluoromethanesulfonyl)imide, the content of the electrochromic material is 11 to 13.5 parts by weight based on 100 parts by weight of the polymer resin; The diheptyl viologen dihexafluorophosphate is represented by the following chemical formula 1: 【Chemical 1】 The ethyl viologen dibis(trifluoromethanesulfonyl)imide is represented by the following chemical formula 2: 【Chemistry 2】 Composition for electrochromic elements.

2. 2. The composition for an electrochromic device according to claim 1, further comprising an ionic liquid having a content of 100 to 200 parts by weight based on 100 parts by weight of the polymer resin.

3. 2. The composition for an electrochromic device according to claim 1, further comprising an anode redox compound in an amount of 1 to 7 parts by weight based on 100 parts by weight of the polymer resin.

4. A first electrode; A second electrode; An electrochromic element comprising: an electrochromic element layer that changes color in response to a voltage applied by the first electrode and the second electrode, the electrochromic element layer comprising the composition for electrochromic elements according to claim 1 .

5. dissolving a polymer resin, a plasticizer, an ionic liquid, and an electrochromic material in a solvent to prepare a mixed solution; removing the solvent from the mixed solution; the polymer resin is polyvinyl chloride; the electrochromic material is diheptyl viologen dihexafluorophosphate or ethyl viologen dibis(trifluoromethanesulfonyl)imide; When the electrochromic material is diheptyl viologen dihexafluorophosphate, the content of the electrochromic material is 14 to 17 parts by weight based on 100 parts by weight of the polymer resin; When the electrochromic material is ethyl viologen dibis(trifluoromethanesulfonyl)imide, the content of the electrochromic material is 11 to 13.5 parts by weight based on 100 parts by weight of the polymer resin; The diheptyl viologen dihexafluorophosphate is represented by the following chemical formula 3: 【Chemistry 3】 The ethyl viologen dibis(trifluoromethanesulfonyl)imide is represented by the following chemical formula 4: 【Chemistry 4】 Method for manufacturing electrochromic members.

6. The electrochromic material is diheptyl viologen dihexafluorophosphate, and the electrochromic material is prepared by the following method: preparing a solution of 1,1'-diheptyl-4,4'-bipyridinium dibromide in a solvent; and The solution was added with NH ４ PF ６ and adding a step of:

7. The electrochromic material is ethyl viologen dibis(trifluoromethanesulfonyl)imide, and the electrochromic material is prepared by the following method: preparing a solution of ethyl viologen dibromide in a solvent; and adding lithium bis(trifluoromethanesulfonyl)imide to the solution; The method for producing the electrochromic member according to claim 5 , comprising:

8. In the step of preparing the mixed solution, The content of the plasticizer is 700 to 1200 parts by weight based on 100 parts by weight of the polymer resin, The method for manufacturing an electrochromic member according to claim 5, wherein the content of the ionic liquid is 100 to 200 parts by weight.

9. In the step of preparing the mixed solution, 6. The method for manufacturing an electrochromic member according to claim 5, further comprising adding an anode redox compound having a content of 1 to 7 parts by weight based on 100 parts by weight of the polymer resin.

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