WO2006128807A2

WO2006128807A2 - Material for electrochromic layers

Info

Publication number: WO2006128807A2
Application number: PCT/EP2006/062534
Authority: WO
Inventors: Andreas Kanitz; Wolfgang Roth; Maria Sramek
Original assignee: Siemens Aktiengesellschaft
Priority date: 2005-05-31
Filing date: 2006-05-23
Publication date: 2006-12-07
Also published as: WO2006128807A3

Abstract

The invention relates to a material for electrochromic layers based on a pH-active colour change. Said material is an integral part of a formulation which, being introduced into an organic electronic component such as a display, exhibits a reversible colour change when a current is applied thereto. The service life of said formulation is substantially increased by a betaine chromophore applied according to said invention.

Description

Description / Description

Material for electrochromic layers

The invention relates to a material for electrochromic layers based on a pH-activated color change.

Electrochromic displays based on organic materials normally comprise an active electrochromic layer, which in the case of a display is located between electrodes arranged perpendicular to one another. Essential components of the active layer are a redox system and a pH-active dye. By applying a voltage, the concentration ratio of the redox partners to each other in the material is shifted. In this reaction protons and / or ions are released or bound in the material, which has an effect on the pH. When a voltage is applied to the material, the shift in the equilibrium of the redox partners on the two electrodes is in the opposite direction. As a result, the pH of one of the electrodes rises while it sinks on the counter electrode. Via a pH dye, the change in the pH value is then converted into a color change of the material and the application of the voltage is made visible.

It is known from WO 02 / 075441A2 and WO 02/075442 A1 that a pasty formulation, which represents the electrochromic system, is located between the electrodes. The composition of this electrochromic system comprises as essential constituents a polymer as a solid electrolyte, a conducting salt, a redox system, TiO 2 as a white pigment, a solvent and a dye. This is usually a pH indicator.

A disadvantage of this material (or "the formulation" called) is the use of the conductive salt, which is usually inorganic conductive salt, eg NaCl, Na ₂ SÜ ₄ or more organic tetraalkylammonium salts with anions such as BF ₄ ^" or PF ₆ ^" , has only limited solubility in the components used for the formulation, such as the polymer component and its solvent, so that aggregation of the conductive salt and / or failure of the conductive salt may occur. This limits the function of the conducting salt in the electrochromic cell. The life of an electrochromic electronic device is largely determined by the function of the conductive salt, because the usable switching cycles can only be realized if the material is still fully functional. Among other things, the aggregation of the conductive salt causes the display to fail.

The object of the present invention is therefore to provide a material for a formulation of an electrochromic active layer in an organic electronic component, such as in a display, which has an extended life compared to the prior art, wherein the component in the electrochromic material, the Conducting salt functionality that is so bound or soluble in the material that it neither aggregates nor precipitates.

The object of the invention and solution of the problem is a material for a formulation of an electrochromic active layer of an electronic component comprising at least one polymeric solid electrolyte, a redox system, a white pigment and a solvent, wherein the functionality of the conductive salt in the salt-free material is.

Conducting salt functionality may be included in a betaine, for example. A betaine is characterized by the presence of both a cationic and an anionic charge center in the molecule. The use of an organic betaine, ie a zwitterion, allows dispensing with the addition of conductive salt, since the electroactive material itself can take over the function of the conducting salt via the betaine function. Not only can this reduce the number of components in the formulation material but also provide improved formulation stability and improved display life become. This is due to the fact that "chromophore and conductive salt" are basically in the immediate vicinity, which severely restricts, if not avoids, the electrolyte salt aggregation (ion diffusion and segregation effects) in the electric field.

According to an advantageous embodiment, a basic structural element such as an amino group and an acidic structural element such as a carboxy group or sulfonic acid group will simultaneously be present in the material.

According to a preferred embodiment, organic dye betaines, particularly preferably deprotonatable methine dye betaines of the following type are used:

The color change in this system is from methine dye betaine to merocyanine.

Methine dye - betaine merocyanine bathochromic hypsochromium

For the remainders the following applies:

R ¹ can be H, alkyl (branched or unbranched Cl to ClO) or aryl (preferably phenyl), R and R independently of one another are alkyl (branched or unbranched Cl to ClO), aryl (preferably phenyl), an alkylene structure bridged with Y ¹ and / or Y ² [(CH ₂ ) ₃ , (CH ₂ ) 4 or C (CH ₃ ) ₂ -CH = C (CH ₃ ) -],

R ³ and R ^{3 *} independently of one another are H, alkyl (branched or unbranched Cl to ClO), aryl (preferably phenyl) or both are bonded via an oxygen atom or sulfur atom, X ¹ and X ² independently of one another represent -0- , -S-, -Se-, a vinylene grouping (-CH = CH-) or a benzanelated vinylene grouping,

Y and Y are independently -CH =, - (C-)

Alkyl) = (branched or unbranched Cl to ClO), -C-aryl = (preferably phenyl) or -N =, Z is a) a Monomethingruppierung, for example -N =, -CH = or - (CR ⁴ ) = where R ^{4 is,} for example, CN, alkyl (branched or unbranched Cl to ClO), aryl (preferably phenyl)

b) a trimethine grouping, for example -CH = CH-CH = or

(Quadrainat)

c) a Pentamethingruppierung, for example

with R equal to Cl or substituted by an ln (4-dimethylaminopyridine) radical

and An ^~ stands for any anion that has either one

Alkylenspacer (branched or unbranched Cl to ClO) with the substituents R ¹ or R ² or R ^{2 *} or R ³ or R ^{3 *} or by direct substitution on an aromatic structural element of the methine dye is bonded, so that a salt-like methine dye -Betaine is formed, these are preferably ne ω-Alkylsulfonatgruppierung (branched or unbranched Cl to ClO) or an ω-alkylcarboxylic acid grouping (branched or unbranched Cl to ClO).

The methine dye betaines suitable for the material must be condensed from previously synthesized and appropriately substituted synthons.

In the following, the invention will be further defined by means of selected examples, which represent embodiments of the invention.

1 production of a model according to the invention

Betaine Chromophors 1)

Synthons: a) N-heptylaminophenol-3 - from heptyl bromide, 3-aminophenol and NaHCC> ₃ b) N-heptyl-N-2-hydroxyethyl-amino-phenol-3

from N-heptylaminophenol-3 and oxirane c) 4- (N-heptyl-N-2-hydroxyethyl-amino) -2-hydroxy-nitrosobenzene hydrochloride - from N-heptyl-N-2-hydroxyethyl-amino-phenol 3, propanolic HCl and isoamyl nitrite d) 1-naphthylammonium N-4-butylsulfonate

- from 1-naphthylamine and butane sultone e) phenoxazine synthesis - from 4- (N-heptyl-N-2-hydroxyethyl-amino) -2-hydroxy-nitrosobenzene hydrochloride and 1-naphthylammonium N-4-butylsulfonate 2 Preparation of a usable electrochromic material with a betainic chromophore according to the invention

To prepare the formulation, the following components are mixed in the amount indicated: TiC> 2 (Ig), polyethylene oxide (Ig), durohydroquinone (0.028 g), duroquinone (0.018 g), propylene carbonate (3 ml) and the prepared betaine Chromophore (0.06g). All ingredients are mixed thoroughly after mixing together using a speed mixer.

3 Preparation of an electrochromic cell

The paste-like formulation obtained is applied according to the prior art in the case of a display between intersecting electrodes. When a voltage is applied, a color change is observed. With the formulation, a 3 times higher number of switching cycles can be achieved than with known systems.

The material according to the invention avoids the addition of a conducting salt to an electrochromic material, so that a display based on organic materials without conducting salt can be formed, whereby a lot of critical points such as corrosion of the electrodes, aggregation of the conducting salt and more solvable.

The material is part of a formulation which, when applied to an organic electronic device such as a display, exhibits a reversible color change upon application of a voltage. The lifetime of such formulations is considerably increased with the betaine chromophore used according to the invention.

Claims

claims

A material for a formulation of an electrochromic active layer of an electronic component comprising at least one polymeric solid electrolyte, a redox system, a white pigment and a solvent, wherein the functionality of the conductive salt is contained in the salt-free material.

The material of claim 1, wherein the material includes a component having a betaine structure.

3. Material according to claim 2, wherein the component with the betaine structure in addition to the Leitsalzfunktion also includes the dye functionality.

A material according to any one of the preceding claims wherein the betaine is a deprotonatable methine dye betaine.

5. Material according to one of the preceding claims, wherein the betaine-containing component is a component of the following type:

For the remainders the following applies: R ¹ can be H, alkyl (branched or unbranched Cl to ClO) or aryl,

R and R independently of one another are alkyl (branched or unbranched Cl to ClO), aryl, an alkylene structure bridged with Y ¹ and / or Y ² [- (CH ₂ ) 3 -, - (CH ₂ ) 4 or -C (CH ₃ ) ₂ -CH = C (CH ₃ ) -],

R ³ and R ^{3 *} independently of one another are H, alkyl (branched or unbranched Cl to ClO), aryl or both are bonded via an oxygen atom or sulfur atom, X ¹ and X ² independently of one another are -O-, -S -, -Se-, a vinylene grouping (-CH = CH-) or a benzanelierte vinylene grouping,

Y and Y independently of one another are -CH =, - (C-alkyl) = (branched or unbranched Cl to ClO), -C-aryl = o- of -N =,

Z is d) a monomethine moiety, for example -N =, -CH = or - (CR ⁴ ) =, where R ^{4 is,} for example, CN, alkyl (branched or unbranched Cl to ClO), aryl

e) a trimethine grouping, for example -CH = CH-CH = or

(Quadrainat)

f) a Pentamethingruppierung, for example

with R equal to Cl or R substituted by an LN- (4-dimethylaminopyridine) radical

and

An ^" stands for any anion which either via an alkylene spacer (branched or unbranched Cl to ClO) with the substituents R ¹ or R ² or R ^{2 *} or R ³ or R ^{3 *} or by direct substitution of a aromatic structural element of the methine dye is bound, so that a salt-like Methine dye betaine, such as an ω-alkyl sulfonate moiety (branched or unbranched Cl to ClO) and / or an ω-alkylcarboxylic acid moiety (branched or unbranched Cl to ClO).

6. Material according to claim 5, wherein at least one of the aryl radicals is a phenyl radical.

7. Use of a betaine chromophore in an electrochromic electronic component.

8. Use of a material according to any one of the preceding claims 1 to 6 for the construction of an electrochromic layer in a display.

9. Display, comprising at least two intersecting electrodes and an intermediate electrochromic layer, wherein the electrochromic active layer comprises a Betainchromophor according to any one of claims 1 to 6.