JP5062712B2 - Polymer material, method for producing the same, and electrochromic device - Google Patents

Description

  The present invention relates to a polymer material having electrochromic characteristics, a method for producing the same, and an electrochromic device using the polymer material. More specifically, the present invention relates to a polymer material that can easily control color development and decoloring by controlling electric potential, a method for producing the same, and an electrochromic device using the same.

  Research on optical devices such as light control elements and display elements using materials having electrochromic properties has been actively conducted. Such materials include inorganic materials typified by tungsten oxide, organic materials typified by viologen, and conductive polymer materials.

  When these materials are applied to optical devices such as light control elements and display elements, it is desirable that these materials can be easily switched between coloring and decoloring. However, with inorganic materials and organic materials, good color erasure (transparency) can be obtained, but color development is poor. On the other hand, with the conductive polymer material, good color development can be obtained, but decolorization (transparency) is poor. This is because the conductivity of the conductive polymer material is based on the π electron conjugated system. That is, the non-doped conductive polymer material has strong light absorption, and the polymer itself has a deep yellow, red, green, or indigo color.

  There is a technique of an electrochromic display element using a conductive polymer material that solves such a problem of decoloring (see Patent Document 1). The technique described in Patent Document 1 includes a first transparent electrode, a graft conductive polymer layer provided in contact with the first transparent electrode, an electrolyte layer in contact with the graft conductive polymer layer, An electrochromic display element having a second electrode having a graft conductive polymer layer and an electrolyte layer sandwiched between the transparent electrode and the transparent electrode is disclosed. The graft conductive polymer layer is formed by bonding a conductive polymer material as a main chain and a conjugated molecular pendant through a metal or metal ion.

By the conjugated molecular pendant, the conductive polymer material changes the binding state of intrinsic π electrons or changes the π-π ^* transition energy. Thereby, the light absorption region by the conductive polymer material is moved to the short wavelength side or the long wavelength side, and the light absorption in the visible light region is suppressed to an inconspicuous level. As a result, the conductive polymer material can be transparent.

JP 2004-20928 A

The graft conductive polymer layer described in Patent Document 1 is synthesized by electrolytic polymerization of a monomer. Such a graft conductive polymer layer has a problem that once it is synthesized, it is difficult to process it again. Electrochromic polymeric materials that are easy to process are desirable.
Accordingly, an object of the present invention is to provide a polymer material that can be easily controlled in color development and decoloring by controlling the electric potential and can be processed, a method for producing the same, and an electrochromic device using the same. That is.

  A further object of the present invention is to provide a polymer material capable of easily controlling and processing a plurality of coloring and decoloring by controlling the potential, a method for producing the same, and an electrochromic device using the same. That is.

  The spacer may be an aryl group or an alkyl group.

The aryl group is
You may select from the group which consists of Formula (2)-Formula (5).

The polymer material for an electrochromic device represented by the formula (6) according to the present invention includes first to Nth (N is an integer of 2 or more) bisterpyridine derivatives and first to Nth (N is 2 or more). And a first to N-th (N is an integer of 2 or more) counter anions,

Here, M ¹ ,..., M ^N (N is an integer of 2 or more) are different first to Nth metal ions, and R ¹ ,..., R ^N (N is an integer of 2 or more) are: All are the same, all different, or partly the same, containing carbon atoms and hydrogen atoms, or spacers directly connecting terpyridyl groups, R ¹ ₁ ,..., R ¹ _N , R ² ₁ ,. ² _N , R ³ ₁ ,..., R ³ _N , R ⁴ ₁ ,..., R ⁴ _N (N is an integer of 2 or more) are all the same, all different, or partly the same hydrogen atom, aryl group or Each of n ¹ ,..., ^{N N} is an integer of 2 or more representing the degree of polymerization, and the first to Nth counter anions are all the same, all different, or partly the same, This achieves the above object.

Wherein R ^1, ..., spacers R ^N are each an aryl group, or an alkyl group.

The aryl group is
You may select from the group which consists of Formula (2)-Formula (5).

  The spacer may be an aryl group or an alkyl group.

The aryl group is
You may select from the group which consists of Formula (2)-Formula (5).

The method for producing the polymer material according to the present invention includes the first to N-th (N is an integer of 2 or more) bisterpyridine derivatives represented by formula (8) and the first to N-th (N is 2 or more). and respective metal salt of the metal ion M ¹ ~M ^N integer), a step of refluxing respectively with acetic acid and methanol,

Here, M ¹ ,..., M ^N (N is an integer of 2 or more) are different first to N-th metal ions, and R ¹ ,..., R ^N (N is an integer of 2 or more) are: All are the same, all different, or partly the same, containing carbon atoms and hydrogen atoms, or spacers directly connecting terpyridyl groups, R ¹ ₁ ,..., R ¹ _N , R ² ₁ ,. ² _N , R ³ ₁ ,..., R ³ _N , R ⁴ ₁ ,..., R ⁴ _N (N is an integer of 2 or more) are all the same, all different, or partly the same hydrogen atom, aryl group or ^{N 1} ,..., ^{N N} are each an integer of 2 or more representing the degree of polymerization, and the first to N-th (N is an integer of 2 or more) obtained in the step and the step of refluxing, respectively. Mixing the reactants in order to achieve the above objective.

Wherein R ^1, ..., spacers R ^N are each an aryl group, or an alkyl group.

The aryl group is
You may select from the group which consists of Formula (2)-Formula (5).

  The electrochromic device according to the present invention includes a first transparent electrode substrate, a second transparent electrode substrate, and the polymer material positioned between the first transparent electrode substrate and the second transparent electrode substrate. This achieves the above object.

  In the polymer material according to the present invention, charge transfer occurs between the metal ion M and the bisterpyridine derivative which is a ligand. By controlling the potential, metal ions can easily change their valence, so that they can be changed from a predetermined color to ideal transparency. A desired color can be obtained by changing the combination of the metal ion and the ligand, or the combination of the metal ion and the counter anion. Moreover, since the polymer material according to the present invention is soluble in a solvent, it can be processed after synthesis of the polymer material.

  Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1)
FIG. 1 is a schematic diagram of a polymer material according to Embodiment 1. FIG.
The polymer material 100 according to the present invention includes a bisterpyridine derivative that is a ligand, a metal ion, and a counter anion, and is represented by the formula (1). Formula (1) is a plurality of repeating units 110.

Here, M is a metal ion, R is a spacer containing a carbon atom and a hydrogen atom or directly connecting a terpyridyl group, and R ¹ , R ² , R ³ and R ⁴ are all the same, All are different or partially the same hydrogen atom, aryl group or alkyl group. n is an integer of 2 or more representing the degree of polymerization.

  The metal ions are selected from the group consisting of iron ions, cobalt ions, nickel ions and zinc ions. These ions can not only change the valence by a redox reaction, but also have different redox potentials in the polymer material 100.

  The spacer R is, for example, an aryl group or an alkyl group. Thereby, since the angle of the terpyridyl group of the polymeric material 100 can be set arbitrarily, the material design of the polymeric material 100 is attained. The aryl group or alkyl group may further contain an oxygen atom or a sulfur atom. Oxygen atoms and sulfur atoms have a modification ability, which is advantageous for the material design of the polymer material 100.

The aryl group is preferably an aryl group selected from the group consisting of formulas (2) to (5). Thereby, since a ligand becomes a clear and rigid skeleton, a good polymer material thin film can be obtained when a polymer material is applied.

  The counter anion is selected from the group consisting of acetate ions, boron tetrafluoride ions, polyoxymetalates, and combinations thereof. Thereby, the charge of the metal ions is compensated, and the polymer material 100 is electrically neutralized.

When R ¹ , R ² , R ³ and R ⁴ are an aryl group or an alkyl group other than a hydrogen atom, examples thereof include a methyl group, an ethyl group, an n-butyl group, a t-butyl group, a phenyl group, and a toluyl group. However, it is not limited to these. Moreover, these aryl groups or alkyl groups may further have a substituent. Such substituents include, for example, alkyl groups such as methyl, ethyl, and hexyl groups, alkoxy groups such as methoxy and butoxy groups, and halogen groups such as chlorine and bromine.

  In the polymer material 100, electron movement occurs between the ligand and the metal ion, and colors such as blue and red are generated. Since the charge transfer speed varies depending on the combination of the ligand and the metal ion, a desired color can be obtained by appropriately combining the ligand and the metal ion. This rate of charge transfer can also be controlled by changing the counter anion.

  Specifically, when iron ion is selected as the metal ion and acetate ion is selected as the counter anion, blue to purple color can be developed, and when the acetate ion is changed to polyoxymetalate, the color changes from blue to purple to dark blue (indigo). Change. Further, when cobalt ion is selected as the metal ion and acetate ion is selected as the counter anion, reddish brown can be developed, and when the acetate ion is changed to polyoxymetalate, the color can be changed from reddish brown to blue. Such a change in color development depends on the charge transfer rate, and it is desirable to examine the charge transfer rate by various combinations in advance.

  In the polymer material 100, the inventors of the present invention control the potential of the polymer material 100 to change the valence of metal ions and cause a redox reaction (that is, the polymer material 100 has electrochromic properties). Have been found). As a result, it has been found that the rate of charge transfer between the ligand and the metal ion changes, and the color of the polymer material 100 is erased. In particular, when polyoxymetalate is selected as the counter anion, the potential range in which oxidation-reduction occurs can be widened, so that control of color development and decoloration is easy.

  In addition, since the polymer material 100 is a polymer electrolyte, it is soluble in a solvent such as water and methanol, and can be further processed after the polymer material 100 is synthesized.

Next, the manufacturing method of the polymeric material 100 by this invention is demonstrated for every process.
Step S110: A bisterpyridine derivative represented by the formula (7) and a metal salt are refluxed in acetic acid and methanol.

Here, R is a spacer containing a carbon atom and a hydrogen atom, or directly connecting a terpyridyl group, and R ¹ , R ² , R ³ , and R ⁴ are all the same, all different, or partly the same. A hydrogen atom, an aryl group or an alkyl group. n is an integer of 2 or more representing the degree of polymerization.

The spacer R is, for example, an aryl group or an alkyl group. The aryl group or alkyl group may further contain an oxygen atom or a sulfur atom. The aryl group is preferably an aryl group selected from the group consisting of formulas (2) to (5). Thereby, when providing a polymer material, a good polymer material thin film is obtained.

When R ¹ , R ² , R ³ and R ⁴ are an aryl group or an alkyl group other than a hydrogen atom, examples thereof include a methyl group, an ethyl group, an n-butyl group, a t-butyl group, a phenyl group, and a toluyl group. However, it is not limited to these. Moreover, these aryl groups or alkyl groups may further have a substituent. Such substituents include, for example, alkyl groups such as methyl, ethyl, and hexyl groups, alkoxy groups such as methoxy and butoxy groups, and halogen groups such as chlorine and bromine.

The metal salt is selected from the group consisting of one metal ion selected from the group consisting of iron ions, cobalt ions, nickel ions and zinc ions, and acetate ions, boron tetrafluoride ions, polyoxymetalates and combinations thereof. Combination with counter anion.

  In step S110, acetic acid and methanol can function as a solvent for the bisterpyridine derivative and the metal salt, respectively. For example, the reflux is performed at a temperature of 150 ° C. for 24 hours, but is not limited thereto. The reflux conditions vary depending on the selected spacer and metal salt, but those skilled in the art can easily conceive the conditions.

  After step S110, the mixture obtained by reflux may be heated. The solvent is evaporated by heating to a powder. The powder has, for example, a color such as purple and is in a reduced state. Since such powder is easily dissolved in methanol, it is easy to handle.

(Embodiment 2)
In the first embodiment, an example in which the type of metal ion contained in the polymer material 100 is one type has been described. In the present invention, the number of types of metal ions contained in the polymer material is not limited. In Embodiment 2, a polymer material containing two or more metal ions will be described.

FIG. 2 is a schematic diagram of a polymer material according to the second embodiment.
The polymer material 200 according to the present invention includes a bisterpyridine derivative that is a ligand, first to Nth metal ions, and first to Nth counter anions, and is represented by Formula (6). Here, N is an integer of 2 or more.

In FIG. 2, element 210 comprises a bisterpyridine derivative, a first metal ion M ¹ ,
A first counter anion, and element 220 includes a bisterpyridine derivative, an Nth metal ion ^MN, and an Nth counteranion. The polymeric material 200 is composed of the element 21
The degree of polymerization of 0 and element 220 is at least 2 respectively.

In Formula (6), M ¹ ,..., M ^N (N is an integer of 2 or more) are different first to Nth metal ions, and R ¹ ,..., R ^N (N is an integer of 2 or more). ) Are all the same, all different, or partly the same, a carbon atom and a hydrogen atom, or a spacer directly connected to a terpyridyl group, R ¹ ₁ ,..., R ¹ _N , R ² ₁ , , R ² _N , R ³ ₁ ,..., R ³ _N , R ⁴ ₁ ,..., R ⁴ _N (N is an integer of 2 or more) are all the same, all different, or partly the same hydrogen atom, Each of n ¹ ,..., ^{N N} is an integer of 2 or more representing the same or different degree of polymerization, and the first to Nth counter anions are all the same, all different, or one Parts are identical.

  The first to Nth metal ions are each selected from the group consisting of iron ions, cobalt ions, nickel ions, and zinc ions. Since these metal ions have different rates of charge transfer between each metal ion and the ligand, the color development by each metal ion can be different.

  Therefore, the polymer material 200 can perform a plurality of colors by appropriately combining differently colored metal ions. Note that the first to Nth metal ions are not limited to the above metal ions as long as the charge transfer rates are different.

  These metal ions have different redox potentials. Therefore, one polymer material 200 can easily control a plurality of coloring and decoloring by a potential.

The spacers R ¹ ,..., R ^N are each an aryl group or an alkyl group. The aryl group or alkyl group may further contain an oxygen atom or a sulfur atom. The aryl group is preferably an aryl group selected from the group consisting of formulas (2) to (5), as in the first embodiment. Thereby, since a ligand becomes a clear and rigid skeleton, a good polymer material thin film can be obtained when a polymer material is applied.

  The first to Nth counter anions are selected from the group consisting of acetate ions, boron tetrafluoride ions, polyoxymetalates, and combinations thereof. Thereby, the charge of the metal ion is compensated, and the polymer material 200 is electrically neutralized.

R ¹ ₁ , ..., R ¹ _N , R ² ₁ , ..., R ² _N , R ³ ₁ , ..., R ³ _N , R ⁴ ₁ , ..., R ⁴ _N is an aryl group or alkyl group other than a hydrogen atom. Examples include, but are not limited to, methyl group, ethyl group, n-butyl group, t-butyl group, phenyl group, and toluyl group. Moreover, these aryl groups or alkyl groups may further have a substituent. Such substituents include, for example, alkyl groups such as methyl, ethyl, and hexyl groups, alkoxy groups such as methoxy and butoxy groups, and halogen groups such as chlorine and bromine.

As described above, the polymer material 200 includes the element 210 having a degree of polymerization of two or more and the element 220 having a degree of polymerization of two or more. Since the polymer material 200 includes a plurality of metal ions, a plurality of colors can be generated based on the speed of charge transfer between each metal ion and the ligand. Further, since the oxidation-reduction potentials of metal ions are different, only the color based on a specific metal ion can be developed by controlling the potential. Since a plurality of colors can be produced from one material, it can be advantageous in shortening the time required for manufacturing the device and reducing the cost. Further, since the polymer material 200 is a polymer electrolyte, it is soluble in a solvent such as water or methanol, and can be further processed after the synthesis of the polymer material 200.

Next, the manufacturing method of the polymeric material 200 by this invention is demonstrated for every process.
Step S210: Each of the first to Nth (N is an integer of 2 or more) bisterpyridine derivatives represented by Formula (8) and each of the first to Nth (N is an integer of 2 or more) metal salts Are refluxed in acetic acid and methanol, respectively.

Here, R ¹ ,..., R ^N (N is an integer of 2 or more) are all the same, all different, or partly the same, containing carbon atoms and hydrogen atoms, or directly connecting a terpyridyl group R ¹ ₁ , ..., R ¹ _N , R ² ₁ , ..., R ² _N , R ³ ₁ , ..., R ³ _N , R ⁴ ₁ , ..., R ⁴ _N (N is an integer of 2 or more) Are all the same, all different, or partly the same hydrogen atom, aryl group or alkyl group, and n ¹ ,..., ^{N N} are each an integer of 2 or more representing the same or different degree of polymerization.

The spacers R ¹ ,..., R ^N are each an aryl group or an alkyl group. The aryl group or alkyl group may further contain an oxygen atom or a sulfur atom. The aryl group is preferably an aryl group selected from the group consisting of formulas (2) to (5), as in the first embodiment. Thereby, since a ligand becomes a clear and rigid skeleton, a good polymer material thin film can be obtained when a polymer material is applied.

R ¹ ₁ , ..., R ¹ _N , R ² ₁ , ..., R ² _N , R ³ ₁ , ..., R ³ _N , R ⁴ ₁ , ..., R ⁴ _N is an aryl group or alkyl group other than a hydrogen atom. Examples include, but are not limited to, methyl group, ethyl group, n-butyl group, t-butyl group, phenyl group, and toluyl group. Moreover, these aryl groups or alkyl groups may further have a substituent. Such substituents include, for example, alkyl groups such as methyl, ethyl, and hexyl groups, alkoxy groups such as methoxy and butoxy groups, and halogen groups such as chlorine and bromine.

  Each of the first to Nth metal salts includes a metal ion selected from the group consisting of iron ion, cobalt ion, nickel ion and zinc ion, acetate ion, boron tetrafluoride ion, polyoxymethacrylate, and these A combination with a counter anion selected from the group consisting of combinations.

  In Step S210, as in Step S110 of Embodiment 1, acetic acid and methanol can function as a solvent for the bisterpyridine derivative and the metal salt. For example, the reflux is performed at a temperature of 150 ° C. for 24 hours, but is not limited thereto. The reflux conditions vary depending on the selected spacer and metal salt, but those skilled in the art can easily conceive the conditions.

  Step S220: The first to Nth reactants obtained in step S210 are mixed. The mixing conditions may be stirring at room temperature for at least 2 hours. Each of the first to Nth reactants may be mixed in different proportions, or may be mixed in equal amounts. It goes without saying that the color intensity for a specific color can be changed by the amount of the mixture. By mixing, the plurality of elements 210 and the plurality of elements 220 are coupled in a self-aligning manner as shown in FIG.

  After step S220, the obtained mixture may be heated. The solvent is evaporated by heating to a powder. The powder has, for example, a color in which a plurality of colors are mixed, and the contained metal ions are in a reduced state.

  The polymer material 200 can also be manufactured by the same method except that two or more metal ions constituting the metal salt are selected in step S110 of the first embodiment. As described above, when a plurality of metal salts are used as starting materials in advance, the same kind of metal ions are condensed in a self-aligned manner by reflux.

(Embodiment 3)
Next, an electrochromic element using the polymer materials 100 and 200 obtained in Embodiments 1 and 2 will be described.
FIG. 3 is a schematic diagram of an electrochromic device according to the third embodiment.
The electrochromic element 300 includes a first transparent electrode 310, a polymer material 320 positioned on the first transparent electrode 310, and a second transparent electrode 330 positioned on the polymer material 320. The electrochromic device 300 may further include a polymer solid electrolyte 340 between the first transparent electrode 310 and the polymer material 320.

The first transparent electrode 310 and the second transparent electrode 330 are arbitrary as long as they are transparent conductive films, but are an SnO ₂ film, an In ₂ O ₃ film, or an ITO film that is a mixture of In ₂ O ₃ and SnO _2. Is preferred. The first transparent electrode 310 and the second transparent electrode 330 can be formed on a transparent substrate such as a glass substrate by any physical or chemical vapor deposition method.

  The polymer material 320 is the polymer material 100 or 200 described in the first embodiment or the second embodiment. Application of the polymer material 320 onto the first transparent electrode 310 can be performed, for example, by spin coating, dip coating, or the like.

  The polymer solid electrolyte 340 is formed by dissolving an electrolyte in a matrix polymer and may have a colorant to improve contrast. Note that this is unnecessary when there is no need to improve contrast.

Next, the operation of the electrochromic element 300 will be described.
The first transparent electrode 310 and the second transparent electrode 330 are connected to a power source, and apply a predetermined voltage to the polymer material 320 and the polymer solid electrolyte 340. Thereby, the oxidation-reduction of the polymer material 320 can be controlled.

  In the case where the polymer material 320 is the single polymer material 100 of Embodiment 1, color development and decoloration may be controlled by oxidizing and reducing metal ions in the polymer material 100. In the case where the polymer material 320 is a plurality of polymer materials 100 of Embodiment 1, a plurality of coloring and decoloring can be controlled by separately controlling the potential of each of the plurality of polymer materials 100. .

  When the polymer material 320 is the polymer material 200 of Embodiment 2, color development and decoloration can be controlled by oxidizing and reducing a plurality of metal ions in the polymer material 200, respectively. Compared with the case where a plurality of polymer materials 100 according to Embodiment 1 are used as the polymer material 320, the coating operation of the polymer material 320 is performed once, which is simple. A plurality of such elements 300 may be combined and arranged in a matrix.

  Next, examples will be described, but it should be noted that the present invention is not limited to the examples.

In a 100 ml two-neck flask, 1,4-bisterpyridinebenzene (30 mg, 0.054 mol) as a ligand was dissolved in 25 ml of acetic acid while heating. Next, 5 ml of a methanol solution containing iron acetate (9.39 mg, 0.054 mol) as a metal salt was added to the two-necked flask. The mixture was heated to reflux in a nitrogen atmosphere at 150 ° C. for 24 hours.
After the reflux, the reaction solution in the two-necked flask was transferred to a petri dish and dried in the air to obtain a purple powder polymer material (hereinafter referred to as FeMEPE). The yield of the powder was 90%.

The electrochemical response of FeMEPE was examined using a cyclic voltammogram measuring device CV50W (manufactured by BAS, Japan). The working electrode for measurement was adjusted by dropping 20 μl of methanol in which FeMEPE (1 mg, 0.5 ml) was dissolved into each of the GCE (glassy carbon) electrode and the ITO electrode, and drying. A Pt counter electrode was used as a counter electrode, and Ag / Ag ⁺ / ACN / TBAP was used as a reference electrode. Both electrodes are BAS
It was made. The voltage was applied in the range of -0.2 V to 1.5 V, and the voltage pulling speed was 0.1 V / s. The results are shown in FIG.

  Next, the color change of FeMEPE was visually observed. The ITO electrode was used as a sample. A voltage was applied to the FeMEPE through the ITO film, and the change in color development was confirmed. The results are shown in FIG.

  Next, using a UV-VIS-NIR spectrometer (UV3150, Shimadzu, Japan) while applying a predetermined voltage (0 V, 0.8 V and 1.0 V) to the sample used for visual observation, In the transmission mode, the ultraviolet / visible absorption spectrum was measured in the wavelength range of 400 nm to 800 nm. The results are shown in FIG.

  Next, the rate of change between coloring and decoloring of the sample and switching characteristics (electrochromic characteristics) were measured. As with the UV / VIS absorption spectrum measurement, a predetermined voltage (0 V and 1.0 V) was repeatedly applied to the sample using a UV-VIS-NIR spectrometer (UV3150, Shimadzu, Japan) to develop and erase the color. The change rate with color and the change in absorbance during color development were examined. The results are shown in FIG.

Since it is the same as that of Example 1 except having used cobalt acetate (9.56 mg, 0.054 mol) as a metal salt, description is abbreviate | omitted. The obtained polymer material is hereinafter referred to as CoMEPE.
The electrochemical response of CoMEPE was examined in the same manner as in Example 1. The voltage was applied in the range of −0.7 V to 0.8 V, and the voltage pulling speed was 0.1 V / s. The results are shown in FIG.

  In the same manner as in Example 1, an ultraviolet-visible absorption spectrum of CoMEPE was measured while applying predetermined voltages (0 V, 0.2 V, and 0.4 V). Next, predetermined voltages (0 V and 0.4 V) were repeatedly applied to CoMEPE, and the change rate between color development and decoloration and switching characteristics were examined. The respective results are shown in FIGS. 9 and 10 and will be described in detail.

A methanol solution (250 μl) in which FeMEPE (0.5 mg) obtained in Example 1 was dissolved was mixed with a methanol solution (250 μl) in which CoMEPE (0.5 mg) obtained in Example 2 was dissolved. . The mixing was performed by stirring for 2 hours at room temperature in a beaker. The obtained mixed solution is referred to as CoMEPE-FeMEPE.
In the same manner as in Examples 1 and 2, while applying a predetermined voltage (0 V, 0.3 V, 0.6 V, 0.8 V, and 1.0 V), the ultraviolet-visible absorption spectrum of CoMEPE-FeMEPE was changed from a wavelength of 420 nm to It measured in the range of 780 nm. The results are shown in FIG.

  Next, in the same manner as in Examples 1 and 2, a predetermined voltage (0 V and 1.0 V) was repeatedly applied to CoMEPE-FeMEPE, and the rate of change between coloring and decoloring at absorption wavelengths of 520 nm and 580 nm, respectively. And the switching characteristic was investigated. The results are shown in FIG.

In a 100 ml two-necked flask, 1,4-bisterpyridinebenzene (60 mg, 0.108 mol) as a ligand was dissolved in 50 ml of acetic acid while heating. Next, 10 ml of a methanol solution containing iron acetate (9.39 mg, 0.054 mol) and cobalt acetate (9.56 mg, 0.054 mol) as metal salts was added to the two-necked flask. Since other than this is the same as the first and second embodiments, the description thereof is omitted. A red-violet polymer material (hereinafter referred to as CoMEPE′-FeMEPE ′) was obtained.
As in Examples 1 to 3, while applying predetermined voltages (0 V, 0.6 V, 0.8 V, and 1.0 V), the UV-visible absorption spectrum of CoMEPE′-FeMEPE ′ was set at a wavelength of 420.
The measurement was performed in the range of nm to 780 nm. The results are shown in FIG.

FIG. 4 is a view showing a cyclic voltammogram of FeMEPE.
A current peak indicating redox at 0.77 V was observed for both the ITO electrode and the carbon electrode. The peak seen when subtracting from -0.2 V to +1.5 shows oxidation, and the peak seen when subtracting from +1.5 V to -0.2 V shows reduction. This oxidation is attributed to the iron ions in FeMEPE becoming divalent to trivalent, and the reduction is attributed to the iron ions becoming trivalent to divalent. In any of the electrodes, the peak current values indicating oxidation and reduction were the same value, and thus it was found that the oxidation / reduction of FeMEPE occurred reversibly. The reason why the peak current value differs between the ITO electrode and the carbon electrode is because the size (area) of the electrode is different. In addition, although such insertion was repeated 500 times, it confirmed that all showed the same result. Thereby, it turned out that obtained FeMEPE does not show the fatigue by voltage application.

FIG. 5 is a diagram showing changes in the color development of FeMEPE.
In the reduced state, the region 500 showed a purple color (the left diagram in FIG. 5). When 0V to 1.3V was applied to FeMEPE and pulled, an oxidation reaction occurred when 0.7V was applied to FeMEPE, and the purple color in region 500 disappeared and was colorless (corresponding to region 510). (Right figure in FIG. 5). When 1.3 V to 0 V was again applied to FeMEPE and pulled, when 0.7 V was applied to FeMEPE, a reduction reaction occurred and a purple color (region 500) was displayed (the left diagram in FIG. 5). In this way, color development and decoloration were confirmed visually.

FIG. 6 is a diagram showing an ultraviolet / visible absorption spectrum of FeMEPE.
Based on the result of FIG. 4, the applied voltage was set to 0 V (reduction state), 0.8 V (oxidation reduction reaction state), and 1.0 V (oxidation state). The absorption spectrum at 0 V showed a clear peak at a wavelength of 580 nm. This peak corresponds to the purple color of FeMEPE observed in FIG. The purple color is due to the rate of charge transfer from Fe ²⁺ ions to the ligand in FeMEPE.

The absorption spectrum at 0.8 V showed a peak at a wavelength of 580 nm, but the peak intensity was lower than that at 0 V. This is because the oxidation reaction occurred in the vicinity of 0.8 V as described with reference to FIG. Specifically, when 0.8 V is applied, Fe ²⁺ ions and Fe ³⁺ ions are mixed in FeMEPE, and the rate of charge transfer from Fe ²⁺ ions to the ligand that contributed to purple color development. And the rate of charge transfer from the Fe ³⁺ ion to the ligand. Thereby, the peak intensity of purple color development was lowered.

The absorption spectrum at 1.0 V showed no absorption at a wavelength of 580 nm. That is, FeMEPE did not show a purple color and was colorless. Since FeMEPE is completely oxidized when 1.0 V is applied, all iron ions in FeMEPE are Fe ³⁺ ions. Therefore, since there was no charge transfer from the Fe ²⁺ ion to the ligand that contributed to purple color development, the color was erased.

  From this, it was shown that the peak intensity can be changed, that is, the purple color intensity can be changed by controlling the voltage (potential) applied to FeMEPE. Further, since the control voltage is about 1V, it can be practical.

FIG. 7 is a diagram showing switching characteristics of peak intensity at a wavelength of 580 nm. It was found that the rate constant required for the absorbance at the wavelength of 580 nm to reach 0 (that is, decoloring) when the applied voltage was switched from 0 V to 1.0 V was 6.5 × 10 ⁻² / s. Similarly, when the applied voltage was switched from 1.0 V to 0 V, the rate constant required for the absorbance at a wavelength of 580 nm to reach a predetermined value (that is, color development) was also 6.5 × 10 ⁻² / s.

  Also from this, color development / decoloration occurs reversibly, and the color development / decoloration change is very fast. Such speed can be comparable to conventional electrochromic materials.

  Further, it was found that even when the voltage was switched 500 times, the absorbance at 580 nm (that is, the purple color intensity) did not change and the fatigue characteristics were good.

FIG. 8 is a diagram showing a cyclic voltammogram of CoMEPE.
The figure shows the result of applying CoMEPE to the ITO electrode. Unlike FeMEPE, a current peak showing redox at 0.20 V was observed. The peak seen when subtracting from -0.5 V to +0.3 shows oxidation, and the peak seen when subtracting from +0.3 V to -0.5 V shows reduction. Similar to FeMEPE, this oxidation is caused by the fact that cobalt ions in CoMEPE are changed from divalent to trivalent, and the reduction is caused by changing the cobalt ions from trivalent to divalent.

  In any of the electrodes, the peak current value indicating oxidation and reduction is the same value, so that it was found that oxidation and reduction of CoMEPE occurred reversibly as well as FeMEPE. It was visually confirmed that CoMEPE developed reddish brown in the reduced state of CoMEPE and disappeared in the oxidized state.

FIG. 9 is a diagram showing an ultraviolet / visible absorption spectrum of CoMEPE.
Based on the result of FIG. 8, the applied voltage was set to 0 V (reduction state), 0.2 V (oxidation reduction reaction state), and 0.4 V (oxidation state). The absorption spectrum at 0 V showed a clear peak at a wavelength of 520 nm. This peak corresponds to the reddish brown coloration of CoMEPE observed visually. The reddish brown color is due to the rate of charge transfer from the Co ²⁺ ion to the ligand in CoMEPE.

The absorption spectrum at 0.2 V showed a weaker peak at a wavelength of 520 nm than that observed at 0 V. This is because an oxidation reaction occurred near 0.2V. In detail, when 0.2 V is applied, Co ²⁺ ions and Co ³⁺ ions are mixed in CoMEPE, and the charge transfer from the Co ²⁺ ions to the ligand contributes to reddish brown color development. There is a rate and a rate of charge transfer from the Co ³⁺ ion to the ligand. As a result, the peak intensity of the reddish brown color was lowered.

  In addition, compared with FeMEPE, the peak intensity at the time of oxidation reduction of CoMEPE (when 0.2 V is applied) is smaller than the peak intensity at the time of oxidation reduction of FeMEPE of Example 1 (when 0.8 V is applied). This is because the degree of coloring of CoMEPE is small.

The absorption spectrum at 0.4 V showed no absorption at a wavelength of 520 nm.
That is, CoMEPE showed no reddish brown color and was colorless. Since CoMEPE is completely oxidized when 0.4 V is applied, all cobalt ions in CoMEPE are Co ³⁺ ions. Therefore, since there was no charge transfer from the Co ²⁺ ion to the ligand that contributed to reddish brown color development, the color was erased.

  From this, it was shown that the peak intensity can be changed, that is, the reddish brown color intensity can be changed by controlling the voltage (potential) applied to CoMEPE. In addition, since the redox potential of FeMEPE and the redox potential of CoMEPE are different, different color development can be easily achieved in an element in which each single layer film is combined.

FIG. 10 is a diagram showing switching characteristics of peak intensity at a wavelength of 520 nm. It was found that the rate constant required for the absorbance at the wavelength of 520 nm to reach 0 when the applied voltage was switched from 0 V to 0.4 V was 2.0 × 10 ⁻² / s. Similarly, the rate constant required for the absorbance at the wavelength of 520 nm to reach a predetermined value by switching the applied voltage from 0 V to 0.4 V was also 2.0 × 10 ⁻² / s.

  This also indicates that the rate of change between color development and color erasure is slower than that of FeMEPE and needs to be improved, but it is advantageous in device design that color development and color erasure occur reversibly at a different oxidation-reduction potential from FeMEPE. possible.

  Further, it was found that the absorbance at 520 nm (that is, the reddish brown color intensity) did not change even when such voltage switching was performed a plurality of times, and the fatigue characteristics were also good.

FIG. 11 is a diagram showing an ultraviolet / visible absorption spectrum of CoMEPE-FeMEPE.
The potential of CoMEPE-FeMEPE is set to 0 V (reduced state for both Co and Fe), 0.3 V (Co redox reaction state and Fe reduced state), 0.6 V (Co oxidized state and Fe reduced state), 0.8 V (Co The ultraviolet and visible absorption spectra were measured by changing the oxidation state and the Fe redox reaction state) and 1.0 V (both Co and Fe were in the oxidation state). It was visually confirmed that the color of CoMEPE-FeMEPE changed from reddish purple, bluish purple, blue and colorless according to the change in potential.

  When 0 V was applied, CoMEPE-FeMEPE developed a reddish purple color. The absorption spectrum at 0 V showed clear peaks at a wavelength of 520 nm and a wavelength of 580 nm. These peaks correspond to the respective peaks of FeMEPE and CoMEPE described in FIGS. 6 and 9, and it was found that both Co and Fe are in a reduced state. Since CoMEPE-FeMEPE has peaks at a wavelength of 520 nm (corresponding to reddish brown color) and a wavelength of 580 nm (corresponding to purple colored color), it was recognized as red purple by human eyes. From this, it was found that the obtained CoMEPE-FeMEPE contained CoMEPE and FeMEPE in a state where each was maintained.

  When 0.3 V was applied, CoMEPE-FeMEPE developed a blue-violet color. The absorption spectrum at 0.3 V showed a weaker peak at a wavelength of 520 nm than that observed at 0 V. This is because an oxidation reaction of Co occurred in the vicinity of 0.3V. On the other hand, the peak intensity at a wavelength of 580 nm was not different from that of 0V. This also shows that only Co in CoMEPE-FeMEPE has undergone an oxidation reaction.

When 0.6 V was applied, CoMEPE-FeMEPE developed a purple color. In the absorption spectrum at 0.6 V, the peak at a wavelength of 520 nm disappears, and it is understood that all Co ions in CoMEPE-FeMEPE are Co ³⁺ ions. On the other hand, the peak intensity at a wavelength of 580 nm did not change from that of 0V and 0.3V.

  CoMEPE-FeMEPE developed a purple color when 0.8 V was applied. The absorption spectrum at 0.8 V maintained the state where the peak at the wavelength of 520 nm disappeared, and still showed a clear peak although it was lower than the peak intensity at the wavelength of 580 nm in the absorption spectra of 0 V, 0.3 V and 0.6 V. This suggests that the oxidation reaction of Fe starts near 0.8V.

  When 1.0 V was applied, CoMEPE-FeMEPE developed a light purple color. In the absorption spectrum at 1.0 V, the peak at a wavelength of 520 nm was maintained in an extinguished state, and the absorbance was almost zero. On the other hand, the peak intensity at a wavelength of 580 nm was remarkably reduced as compared with those at 0 V, 0.3 V, 0.6 V and 0.8 V. This suggests that although the oxidation reaction of Fe is not completely completed even in the vicinity of 1.0 V, it corresponds to a redox potential.

  Since the redox potentials of CoMEPE and FeMEPE also differ in the composite, by controlling the potential applied to the composite, the desired color development / extinction of reddish brown, purple, or a mixed color of these (red purple) can be achieved. Enable color.

FIG. 12 is a diagram showing switching characteristics of peak intensities at a wavelength of 520 nm and a wavelength of 580 nm.
FIG. 12A shows the switching characteristics of peak intensity at a wavelength of 520 nm. 1.0V and 0V were repeatedly applied to CoMEPE-FeMEPE several times, and the change in peak intensity at a wavelength of 520 nm was measured. For reference, the results of the same measurement performed on the CoMEPE obtained in Example 2 are also shown.

  In the case of CoMEPE alone, it was found that dielectric breakdown occurs when 1.0 V is applied. On the other hand, the composite showed electrochromic without dielectric breakdown even when 1.0 V was applied. This is understood to be because Co became more stable by coexisting with Fe.

When the applied voltage is switched from 0 V to 1.0 V, the rate constant required for the absorbance at the wavelength of 520 nm to be minimized (that is, decoloring) may be 2.0 × 10 ⁻² / s as in FIG. I understood. Similarly, when the applied voltage was switched from 0 V to 1.0 V, the rate constant required for the absorbance at a wavelength of 520 nm to reach a predetermined value (that is, color development) was also 2.0 × 10 ⁻² / s. From this, it was found that color development / decoloration occurred reversibly, and the color development / decoloration change was not different from that of CoMEPE alone even in the composite.

  Further, it was found that even when such voltage switching was performed a plurality of times, the absorbance at a wavelength of 520 nm did not change and the fatigue characteristics were good.

FIG. 12B shows switching characteristics of peak intensity at a wavelength of 580 nm. For reference, the results of FIG. 7 are also shown. When the applied voltage was switched from 0 V to 1.0 V, the rate constant at which the absorbance at a wavelength of 580 nm was minimized was 5.0 × 10 ⁻³ / s. This corresponded to 7.7% of the rate constant of FeMEPE alone. It shows that the oxidation rate of iron became slow by becoming a composite. From this, a slight peak was detected at a wavelength of 580 nm in the spectrum when 1.0 V was applied in FIG. 11 (application exceeding the Fe oxidation-reduction potential) because the oxidation rate of iron was significantly reduced. Can be understood. Absorbance at a wavelength of 580 nm is not completely zero. This is because switching of the switching voltage is forcibly performed in 400 seconds, and it should be understood that the absorbance becomes 0 when applied for a longer time.

  Further, even when such voltage switching was performed a plurality of times, the absorbency at a wavelength of 580 nm did not change, and the fatigue characteristics were good.

  From the above results, the CoMEPE-FeMEPE obtained in Example 3 is not a random arrangement of CoMEPE and FeMEPE, but is a block copolymer composed of 1,4-bis (terpyridine) benzene, iron and balt. I understood.

FIG. 13 is a diagram showing an ultraviolet / visible absorption spectrum of CoMEPE′-FeMEPE ′.
The potential of CoMEPE′-FeMEPE ′ is set to 0 V (reduced state for both Co and Fe), 0.6 V (Co oxidized state and Fe reduced state), 0.8 V (Co oxidized state and Fe redox reaction state) and 1.0 V. (Both Co and Fe were changed to oxidation states, and ultraviolet and visible absorption spectra were measured. According to the change in potential, the coloration of CoMEPE′-FeMEPE ′ was reddish purple and bluish purple as in CoMEPE-FeMEPE of Example 3. It was visually confirmed that the color changed from purple to colorless.

  When 0 V was applied, CoMEPE'-FeMEPE 'developed a reddish purple color as in CoMEPE-FeMEPE. The absorption spectrum at 0 V showed a clear peak at a wavelength of 580 nm and a slightly broad peak at a wavelength of 520 nm. A broad peak at a wavelength of 520 nm and a clear peak at a wavelength of 580 nm correspond to the respective peaks of FeMEPE and CoMEPE described with reference to FIGS. 6 and 9, and it was found that both Co and Fe are in a reduced state. The reason why the peak at a wavelength of 520 nm is broader than that in FIGS. 9 and 11 is that the ratio of CoMEPE in CoMEPE′-FeMEPE ′ is smaller than that in FeMEPE. Similar to FIG. 11, CoMEPE′-FeMEPE ′ has a peak at a wavelength of 520 nm (corresponding to reddish brown color) and a wavelength of 580 nm (corresponding to purple colored color), so that it is recognized as red purple by human eyes. The obtained CoMEPE′-FeMEPE ′ was found to contain CoMEPE and FeMEPE in a state in which each was maintained.

When 0.6 V was applied, CoMEPE′-FeMEPE ′ developed a purple color. In the absorption spectrum at 0.6 V, the peak at a wavelength of 520 nm disappeared, but the absorbance did not completely become zero. This is presumably because Co ions in CoMEPE′-FeMEPE ′ are oxidized to Co ³⁺ ions, but the oxidation rate of Co is significantly reduced. On the other hand, the peak intensity at a wavelength of 580 nm was not different from that of 0V.

  CoMEPE'-FeMEPE 'developed a light blue color when 0.8 V was applied. The absorption spectrum at 0.8 V maintained the state where the peak at a wavelength of 520 nm disappeared, and the absorbance was zero. On the other hand, the peak intensity at a wavelength of 580 nm was significantly reduced as compared with 0 V and 0.6 V. This suggests that the oxidation reaction of Fe starts near 0.8V.

When 1.0 V was applied, CoMEPE′-FeMEPE ′ was colorless. In the absorption spectrum at 1.0 V, the peak at the wavelength of 520 nm maintained the disappearance state, and the peak at the wavelength of 580 nm almost disappeared.
Since the redox potentials of CoMEPE and FeMEPE also differ in the composite, by controlling the potential applied to the composite, the desired color development / extinction of reddish brown, purple, or a mixed color of these (red purple) can be achieved. Enable color.

The electrochromic material according to the present invention can be applied to any device utilizing its color development and decoloration, and specifically can be applied to display elements, light control elements, and electronic paper.

3 is a schematic diagram of a polymer material according to Embodiment 1. FIG. FIG. 5 is a schematic diagram of a polymer material according to Embodiment 2. FIG. 6 is a schematic diagram of an electrochromic element according to a third embodiment. The figure which shows the cyclic voltammogram of FeMEPE. The figure which shows the color change of FeMEPE. The figure which shows the ultraviolet and visible absorption spectrum of FeMEPE. The figure which shows the switching characteristic of the peak intensity in wavelength 580nm. The figure which shows the cyclic voltammogram of CoMEPE. The figure which shows the ultraviolet and visible absorption spectrum of CoMEPE. The figure which shows the switching characteristic of the peak intensity in wavelength 520nm. The figure which shows the ultraviolet and visible absorption spectrum of CoMEPE-FeMEPE. The figure which shows the switching characteristic of the peak intensity in wavelength 520nm and wavelength 580nm. The figure which shows the ultraviolet and visible absorption spectrum of CoMEPE'-FeMEPE '.

Explanation of symbols

300 Electrochromic device 310 First transparent electrode 320 Polymer material 330 Second transparent electrode 340 Polymer solid electrolyte

Claims (10)

First to Nth (N is an integer of 2 or more) bisterpyridine derivatives, First to Nth (N is an integer of 2 or more) metal ions, and First to Nth (N is an integer of 2 or more) A polymer material for an electrochromic device represented by the formula (6) including a counter anion of:

Here, M ¹ ,..., M ^N (N is an integer of 2 or more) are different first to Nth metal ions, and R ¹ ,..., R ^N (N is an integer of 2 or more) are: All are the same, all different, or partly the same, containing carbon atoms and hydrogen atoms, or spacers directly connecting terpyridyl groups, R ¹ ₁ ,..., R ¹ _N , R ² ₁ ,. ² _N , R ³ ₁ ,..., R ³ _N , R ⁴ ₁ ,..., R ⁴ _N (N is an integer of 2 or more) are all the same, all different, or partly the same hydrogen atom, aryl group or Each of n ¹ ,..., ^{N N} is an integer of 2 or more representing the degree of polymerization, and the first to N-th counter anions are all the same, all different, or partly the same. Polymer material. Wherein R ^1, ..., spacers R ^N are each an aryl group or an alkyl group, the polymer material according to claim 1. The aryl group is

The polymer material according to claim 2, which is selected from the group consisting of formula (2) to formula (5). Wherein the metal ion ^M 1 ~M ^N of the respective Bicester pyridine derivative of the first to N shown in (8) (N is an integer of 2 or more), (the N integer of 2 or more) first to N Each of the metal salts is refluxed in acetic acid and methanol, respectively,

Here, M ¹ ,..., M ^N (N is an integer of 2 or more) are different first to N-th metal ions, and R ¹ ,..., R ^N (N is an integer of 2 or more) are: All are the same, all different, or partly the same, containing carbon atoms and hydrogen atoms, or spacers directly connecting terpyridyl groups, R ¹ ₁ ,..., R ¹ _N , R ² ₁ ,. ² _N , R ³ ₁ ,..., R ³ _N , R ⁴ ₁ ,..., R ⁴ _N (N is an integer of 2 or more) are all the same, all different, or partly the same hydrogen atom, aryl group or An alkyl group, and n ¹ ,..., ^{N N} are each an integer of 2 or more representing the degree of polymerization;
And a step of mixing the first to Nth reactants (N is an integer of 2 or more) obtained in the respective refluxing steps. Wherein R ^1, ..., spacers R ^N are each an aryl group or an alkyl group, The method of claim 4. The aryl group is

6. The method according to claim 5, wherein the method is selected from the group consisting of formula (2) to formula (5).   The polymer according to any one of claims 1 to 3, wherein the polymer is located between the first transparent electrode substrate, the second transparent electrode substrate, and the first transparent electrode substrate and the second transparent electrode substrate. An electrochromic device including a material. Including a first transparent electrode substrate, a second transparent electrode substrate, and a polymer material positioned between the first transparent electrode substrate and the second transparent electrode substrate,
The polymer material is represented by the formula (1) including a bisterpyridine derivative, a metal ion, and a counter anion.

Here, M is the metal ion, R is a spacer containing a carbon atom and a hydrogen atom, or directly connecting a terpyridyl group, and R ¹ , R ² , R ³ and R ⁴ are all the same. Electrochromic devices, which are all different or partially the same hydrogen atom, aryl group or alkyl group, and n is an integer of 2 or more representing the degree of polymerization.   The electrochromic device according to claim 8, wherein the spacer is an aryl group or an alkyl group. The aryl group is

The electrochromic device according to claim 9, which is selected from the group consisting of formula (2) to formula (5).