JPH0726091B2 - Electrochromic display device - Google Patents

Description

The present invention relates to a display device, particularly an electrochromic display device (hereinafter abbreviated as ECD) using an organic electrochromic (EC) material.

Organic ECDs that use organic EC materials are expected to be put to practical use because of the principle advantages such as multicoloring and clear images, but they have not yet been put to practical use. The first of the main reasons is insufficient operational stability. A typical organic ECD that has been proposed and developed is one in which viologen is used as an EC material (Reference Applied Physics Letters (Appl.Phys.Lett.23 (1973), P64)), which operates stably. According to our test results, the OFF repeat life is about 10 ⁵ times, which is insufficient compared to the minimum life required for practical use of 10 ⁶ times.The cause of this operation deterioration is coloring-erasing (ON-OFF).
It is said that this is caused by the reversible incompleteness of the viologen precipitation-redissolution phenomenon that accompanies the above, but its strictness is unknown.
The second reason is that the display color is a single purple color peculiar to the viologen type, and it cannot fully meet the market demand for display color diversification. Further, viologen's purple color is not always suitable as a standard display color, which is one of the reasons why it is not accepted in the market.

It is an object of the present invention to provide a novel organic ECD having a display color suitable for a display device and stable reversible coloring / decoloring operations.

That is, the present invention is an electrochromic display device comprising a solution in which an organic material and a supporting electrolyte capable of electrochemically reversible color development / decoloration are dissolved, and a pair of electrode substrates sandwiching the solution, wherein the organic material is Compound (I) below [In the formula, R represents an alkyl group, an aryl group, an aralkyl group or a cycloalkyl group, and R ₁ and R ₂ represent a hydrogen atom, an alkyl group, a halogen atom or an —OR group, and a ring formed by the —OR group and the R ₂ group. May be formed.

In the substituents R, R ₁ and R ₂ , the alkyl chain and the aryl ring may be substituted. ] It is an electrochromic display device characterized by containing 1 type (s) or 2 or more types.

In the compound (I), the substituent R is a methyl group, an ethyl group, a propyl group, a butyl group, an amyl group, a hexyl group,
Linear or branched alkyl group such as octyl group, dodecyl group, methoxyethyl group, ethoxyethyl group, methoxypropyl group, phenoxyethyl group, chloroethyl group,
Substituted alkyl group such as hydroxyethyl group, phenyl group, methylphenyl group, ethylphenyl group, butylphenyl group, hexylphenyl group, nonylphenyl group, dodecylphenyl group, dimethylphenyl group, chlorophenyl group, methoxyphenyl group, butoxyphenyl Group, aryl group such as hexyloxyphenyl group, benzyl group, methylbenzyl group, phenethyl group, aralkyl group such as α-methylbenzyl group, methoxybenzyl group, chlorobenzyl group, cyclohexyl group, methylcyclohexyl group, cyclopentyl group, butoxy group Cycloalkyl groups such as cyclohexyl groups, R ₁ and R _{2 such} as hydrogen atoms, methyl groups, ethyl groups, butyl groups, linear or branched alkyl groups such as pentyl groups, chloro atoms, fluorine atoms, bromine atoms, etc. Halogen atom Have the abovementioned meaning -O-
As a group which forms a ring with the R group or the —O—R group and the R ₂ group, Specific examples of the substituent include an —O—CH ₂ CH ₂ CH ₂ —O— group.

Next, the present invention will be described together. FIG. 1 is a sectional view showing an example of a display device of the present invention.

In the figure, 1 and 2 are glass substrates, 3 are display electrodes made of ITO (indium tin oxide) film, or tin oxide (SnO ₂ ) film, 4 are ITO, SnO ₂ or metal film such as stainless steel or platinum, or carbon or A counter electrode composed of a film obtained by pressing a mixture of an iron complex and carbon, 5 is an EC solution in which an organic EC material and a supporting salt are dissolved, and 6 is a porous light scatterer such as a ceramic thin plate such as alumina or a polymer thin plate. is there. The electrode substrate is composed of a glass substrate and electrodes. Examples of the porous light scatterer include titanium oxide (TiO ₂ ), alumina (Al
_An insulating or semiconductor white powder such as ₂ O ₃ ) may be used. As the EC solution material, any solvent can be used as long as it has a large polarity and is electrochemically stable. For example, a non-aqueous solvent such as propylene carbonate, dimethylformamide, N-methyl-2-pyrrolidone or the like is used.

Quaternary ammonium and perchlorate ClO ₄ , halogen, fluoroborate BF ₄ , fluorophosphate as supporting salt
Quaternary ammonium salts such as salts with PF ₆ are used,
Used at a concentration of 5 to 1.0 mol /.

Further, examples of the compound represented by the compound (I) include the following.

The compound of general formula (I) is usually used at a concentration of 0.01 to 1.0 mol / mol.

The compound of the general formula (I) can be obtained by, for example, Methoden der Organ.
It can be prepared according to the methods described in ischen Chemie 7 3C, 1979 years (Georg Thieme Verlag publishing).

When the compound of the present invention is used alone as an organic material capable of electrochemically reversible color development / decoloration, a display device can be constructed which develops a color between the display electrode and the counter electrode when the display electrode has a negative voltage. Furthermore, the polarity of the voltage applied to the display electrode is reversed by mixing the compound of the present invention with a compound having a polarity opposite to that of the compound of the present invention, that is, a compound (O-type compound) that develops a hue different from that of the compound of the present invention. It is possible to change the display color by controlling.

As the O-type compound, tetrathiafulvalene (TT
F), pyrazoline derivatives, diphenylamine derivatives, fluorene derivatives and the like are known.

Next, the present invention will be described with reference to examples.

Example 1 A display device provided with a display electrode and a counter electrode was filled with a solution prepared by dissolving tetrabutylammonium iodide in propylene carbonate at a concentration of 0.3 mol / m and compound No. 1 at a concentration of 0.02 mol / m.

When a voltage of 1.5 to 2.0 V is applied between the display electrode and the counter electrode of the display device so that the display electrode side has a negative voltage, the display surface shows a clear red color (λmax505nm) on a white background,
The color disappears when the voltage is OV or the polarity is reversed.

When the repeated coloring / decoloring operation test of this device was conducted,
It showed very high stability.

Examples 2 to 6 In Example 1, except that the compound No. 1 was changed to the following compound, the same procedure as in Example 1 was carried out, and the results shown in the following table were obtained. The operational stability was good.

Example 7 A display device provided with a display electrode and a counter electrode was charged with 0.3 mol of tetrabutylfulborolate in propylene carbonate.
A solution in which 0.02 mol / of compound No. 1 and 0.02 mol / of 2-aminofluorene were dissolved was enclosed.

When a voltage of -1.5 to 2.0 V is applied between the display electrode and the counter electrode of the display device so that the display electrode side has a negative voltage, the display surface shows a clear red color on a white background, and the voltage is 0 V or +0. The color disappeared when about 5V was applied. Further, when a voltage of +1.5 to 2.0 V was applied so that the display electrode had a positive voltage, a blue color was obtained, and when a voltage of about 0 V or -0.5 V was applied, the color rapidly disappeared.

Example 8 A display device having the same configuration as in Example 7 except that 0.02 mol of 4,4'-bis (dimethylamino) diphenylamine was used in place of 2-aminofluorene of Example 7 was used. When applied, the same effects as in Example 7 were obtained except that green color was obtained.

[Brief description of drawings]

The figure shows an embodiment of the present invention. In the figure, 1 and 2 are glass substrates, 3 are display electrodes, 4 are counter electrodes, 5 is EC solution, 6
Is a porous light scatterer.

Claims (1)

[Claims] 1. An electrochromic display device comprising a solution in which an organic material capable of electrochemically reversible color development and decolorization and a supporting electrolyte are dissolved, and a pair of electrode substrates sandwiching the solution, wherein the organic material is An electrochromic display device comprising one or more of the following compounds (I). [In the formula, R represents an alkyl group, an aryl group, an aralkyl group or a cycloalkyl group, R ₁ and R ₂ represent a hydrogen atom, an alkyl group, a halogen atom or an —OR group, and a ring formed by the —OR group and the R ₂ group. May be formed. In the substituents R, R ₁ and R ₂ , the alkyl chain and the aryl ring may be substituted. ]