JPH0726089B2 - 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.

An object of the present invention is to provide a novel organic ECD having a display color suitable for a display device, stable reversible coloring / decoloring operation, and low operating voltage.

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 is an alkyl group, an aryl group, an alkoxy group,
Aryloxy group, alkylthio group, arylthio group,
Aralkyloxy group, aralkylthio group, cycloalkyloxy group, cycloalkylthio group or , R ₁ and R ₂ are a hydrogen atom, an alkyl group, an aryl group, a halogen atom, a nitro group or a --COR group, and R ₃ and R ₄ are a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a cycloalkyl group. Represent.

In the substituents R, R ₁ , R ₂ , R ₃ and R ₄ , 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 branched or linear alkyl group such as methyl group, ethyl group, propyl group, butyl group, pentyl group, heptyl group, octyl group, phenyl group, toluyl group, butyl group. Aryl group such as phenyl group, ethoxyphenyl group, butoxyphenyl group, hexyloxyphenyl group, methoxy group, ethoxy group, butoxy group, hexyloxy group, branched or linear alkoxy group such as dodecyloxy group, methoxyethoxy Group, ethoxypropoxy group, hexafluoroisopropoxy group, substituted alkoxy groups such as octafluoropentoxy group, phenoxy group, ethylphenoxy group, butylphenoxy group, pentylphenoxy group, octylphenoxy group, methoxyphenoxy group, butoxyphenoxy group, Chlorfenoki Group, methoxymethylphenoxy group, dimethylphenoxy group, dimethoxyphenoxy group and other aryloxy groups, ethylthio group, propylthio group, butylthio group, hexylthio group and other alkylthio groups, phenylthio group, methoxyphenylthio group, methylphenylthio group, etc. Arylthio group, benzyloxy group, methylbenzyloxy group, ethoxybenzyloxy group, chlorobenzyloxy group, phenethyloxy group, α
An aralkyloxy group such as a methylbenzyloxy group,
Aralkylthio group such as benzylthio group, methylbenzylthio group, methoxybenzylthio group, cyclohexyloxy group, cyclopentyloxy group, butylcyclohexyloxy group, cycloalkyl group such as butoxycyclohexyloxy group, cyclohexylthio group, methylcyclohexylthio group, etc. Cycloalkylthio group, amino group, ethylamino group, diethylamino group, dibutylamino group, hexylamino group, diethanolamino group, anilino group, toluidino group, butylanilino group, hexylanilino group, butoxyanilino group, dimethylanilino group ,
Amino groups such as dimethoxyanilino group, chloranilino group, cyanoanilino group, N-ethylanilino group, benzylamino group, ethylbenzylamino group and cyclohexylamino group, R ₁ and R ₂ are hydrogen atom, methyl group, ethyl group, butyl group Specific examples include an alkyl group such as, a phenyl group, a methylphenyl group, an aryl group such as a dimethylphenyl group, a chlorine atom, a bromine atom, a halogen atom such as a fluorine atom, a nitro group or a -COR group in which R has the above meaning. It can be mentioned as a substituent.

Next, the present invention will be described with reference to the drawings. 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 is a display electrode made of an ITO (indium tin oxide) film or tin oxide (SnO ₂ ) film, and 4 is a metal film such as ITO, SnO ₂ or stainless steel, 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, propylene carbonate, dimethylformamide, N-
A non-aqueous solvent such as methyl-2-pyrrolidone is used.

As the supporting salt, a quaternary ammonium salt such as a salt of quaternary ammonium with ClO ₄ , perchlorate, halogen, fluoroborate BF ₄ , and fluorophosphate PF ₆ is used.
Used at a concentration of 0.05 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 / l.

Compounds of general formula (I) are, for example, Methoden der Org
anischen Chemie 7 3C, 1979 can be prepared according to the method described in (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. Further, the compound of the present invention is mixed with a compound having a polarity opposite to that of the compound of the present invention (O-type compound) that develops a hue different from that of the compound of the present invention when a positive voltage is applied to the display electrode. 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 0.03 mol / m.

When a voltage of 1.2 to 1.5 V is applied between the display electrode and the counter electrode of the display device so that the display electrode side becomes a negative voltage, the display surface shows a vivid blue (λmax596nm) color on the white background.
The color disappears when the voltage is 0 V 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 5 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 6 In a display device provided with a display electrode and a counter electrode, 0.3 mol of tetrabutylfulborolate was added to 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 vivid blue 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 7 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 6 was used. When applied, the same effects as in Example 6 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 is a display electrode, 4 is a counter electrode, 5 is an EC solution, and 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 is an alkyl group, an aryl group, an alkoxy group,
Aryloxy group, alkylthio group, arylthio group,
Aralkyloxy group, aralkylthio group, cycloalkyloxy group, cycloalkylthio group or , R ₁ and R ₂ are a hydrogen atom, an alkyl group, an aryl group, a halogen atom, a nitro group or a -COR group, and R ₃ and R ₄ are a hydrogen atom, an alkyl group, an aryl group, an aralkyl group or a cycloalkyl group. Represent. In the substituents R, R ′, R ₁ , R ₂ , R ₃ and R ₄ , the alkyl chain and the aryl ring may be substituted. ]