Color excursion mitigation in electrochromic devices

• US 10,324,350 B2
• Filed: 09/28/2017
• Issued: 06/18/2019
• Est. Priority Date: 09/30/2016
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Ash, Kevin L., Baumann, Kelvin L.
• Primary Examiner(s): Ben, Loha
• Application Number:
  US15/718,441
• Publication Number:
  US 20180095338A1
• Time in Patent Office: 628 Days
• Field of Search: 359265-275, 345105, 252500, 252582, 252583, 252586, 544347
• CPC Class Codes: B32B 17/10513 Electrochromic layer
• CPC Class Codes: C07D 213/22 containing two or more pyridine rings directly linked together, e.g. bipyridyl
• CPC Class Codes: C07D 241/46 Phenazines
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions
• CPC Class Codes: G02F 1/1514 characterised by the electrochromic material, e.g. by the electrodeposited material
• CPC Class Codes: G02F 1/15165 Polymers
• CPC Class Codes: G02F 1/153 Constructional details
• CPC Class Codes: G02F 1/161 Gaskets; Spacers; Sealing of cells; Filling or closing of cells
• CPC Class Codes: G02F 2001/15145 the electrochromic layer comprises a mixture of anodic and cathodic compounds
• CPC Class Codes: G09G 3/38 using electrochromic devices

Abstract

An electrochromic device includes a chamber defined by a first conductive surface of a first substrate, a second conductive surface of a second substrate, and a sealing member joining the first substrate to the second substrate; an electrochromic medium containing a blue cathodic electroactive compound and up to three anodic electroactive compounds; wherein the electrochromic medium is disposed within the chamber; the anodic electroactive compounds include a green anodic electroactive compound and one or two gray anodic electroactive compounds; and the anodic electroactive compounds include from about 8 mol % to about 15 mol % gray anodic electroactive compounds.

Claims

1. An electrochromic device comprising:

a chamber defined by a first conductive surface of a first substrate, a second conductive surface of a second substrate, and a sealing member joining the first substrate to the second substrate;

an electrochromic medium comprising a blue cathodic electroactive compound and up to three anodic electroactive compounds;

wherein

the electrochromic medium is disposed within the chamber;

the anodic electroactive compounds comprise a green anodic electroactive compound and one or two gray anodic electroactive compounds; and

the anodic electroactive compounds comprise from about 8 mol % to about 15 mol % gray anodic electroactive compounds.

2. The electrochromic device of claim 1, wherein the anodic electroactive compounds comprise one green anodic electroactive compound and two gray anodic electroactive compounds.

3. The electrochromic device of claim 1, wherein the gray anodic electroactive compounds are selected from 2,7-diisobutyl-5,10-dineopentyl-5,10-dihydrophenazine;

2,7-di-2-ethylbutyl-5,10-dineopentyl-5,10-dihydrophenazine;

2,7-di-2-ethylhexyl-5,10-dineopentyl-5,10-dihydrophenazine; and

2,5,7,10-tetraneopentyl-5,10-dihydrophenazine.

4. The electrochromic device of claim 1, wherein the blue cathodic electroactive compound is an alkyl viologen.

5. The electrochromic device of claim 4, wherein the alkyl viologen is selected from 1,1′

-bis-2-ethylhexyl-4,4-bipyridinium tetrafluoroborate, 1,1′

-bis-isobutyl-4,4′

-bipyridinium tetrafluoroborate; and

1,1′

-bis 2-ethyl butyl-4,4′

-bipyridinium tetrafluoroborate.

6. The electrochromic device of claim 1, wherein the green anodic electroactive compound is 5,10-dihydro-5,10-dineopentylphenazine;

5,10-[2(ethyl)butyl]-5,10-dihydrophenazine;

or 5,10-[2(ethyl)hexyl]-5,10-dihydro phenazine.

7. The electrochromic device of claim 1, wherein the molar ratio of a cathodic electroactive compound to the anodic electroactive compounds is about 1:

1 to about 1.1;

1.

8. The electrochromic device of claim 1, further comprising one or more UV stabilizers.

9. The electrochromic device of claim 8, wherein the one or more UV stabilizers are selected from 2-ethyl-2-cyano-3,3-diphenyl acrylate;

(2-ethylhexyl)-2-cyano-3,3-diphenyl acrylate;

2-(2′

-hydroxy-4′

-methylphenyl)benzotriazole;

3-[3-(2H-benzotriazole-2-yl)-5-(1,1-dimethylethyl)-4-hydroxyphenyl]propionic acid pentyl ester;

a composition of C_7-9 branched and linear alkyl esters of 3-(2H-benzotriazol-2-yl)-5-(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid and 1-methoxy-2-propylacetate;

2,4-dihydroxybenzophenone;

2-hydroxy-4-methoxybenzophenone; and

2-ethyl-2′

-ethoxyalanilide.

10. The electrochromic device of claim 1, further comprising an anodic and/or cathodic color-stabilizing redox buffer.

11. The electrochromic device of claim 1, further comprising a cross-linked polymer matrix, a free-standing gel, and/or a substantially non-weeping gel.

12. The electrochromic device of claim 1, wherein the electrochromic device has a clear state and a darkened state and the electrochromic medium maintains a blue-gray color in the darkened state.

13. The electrochromic device of claim 12, wherein the blue-gray color is devoid of a purple hue as observed by the naked eye.

14. The electrochromic device of claim 1, wherein the electrochromic device is an electrochromic aircraft transparency.

15. The electrochromic device of claim 1, wherein the electrochromic device, in a low transmission state, exhibits a u′

-v′

color space where a u′

value is from about 0.15 to about 0.30 and a v′

value is from about 0.30 to about 0.40.

16. The electrochromic device of claim 15, wherein the u′

value is from about 0.18 to about 0.22.

17. A method to minimize or remove purple hue from an electrochromic medium within an electrochromic device in a darkened state, the method comprising adjusting a concentration of gray anodic electroactive compound of the electrochromic medium to from about 8 mol % to about 15 mol % relative to a total molar concentration of anodic electroactive compounds of the electrochromic medium.

18. The method of claim 17, wherein the gray anodic electroactive compound comprises one or more selected from 2,7-diisobutyl-5,10-dineopentyl-5,10-dihydrophenazine;

2,7-di-2-ethylbutyl-5,10-dineopentyl-5,10-dihydrophenazine;

2,7-di-2-ethylhexyl-5,10-dineopentyl-5,10-dihydrophenazine; and

2,5,7,10-tetraneopentyl-5,10-dihydrophenazine.

19. An electrochromic device comprising an electrochromic medium comprising a blue cathodic electroactive compound and up to three anodic electroactive compounds;

wherein;

the anodic electroactive compounds comprise a green anodic electroactive compound and one or two gray anodic electroactive compounds; and

the electrochromic device exhibits, in a low transmission state, a u′

-v′

color space wherein a u′

value is from about 0.15 to about 0.30 and a v′

value is from about 0.30 to about 0.40.

20. The electrochromic device of claim 19, wherein the u′

value is from about 0.18 to about 0.22.