Bistable Electrochemical Mirror

• US 20150146276A1
• Filed: 11/21/2014
• Published: 05/28/2015
• Est. Priority Date: 11/22/2013
• Status: Active Grant

• Current Assignee: Industry-Academic Cooperation Foundation Yonsei University
• Original Assignee: Yonsei University
• Inventors: Kim, Eunkyoung, Park, Chihyun, Shin, Hai jin
• Granted Patent: US 9,383,619 B2
• Time in Patent Office: Days
• US Class Current: 359/270
• CPC Class Codes: G02F 1/1506 caused by electrodeposition, e.g. electrolytic deposition of an inorganic material on or close to an electrode
• CPC Class Codes: G02F 1/155 Electrodes

Abstract

The present invention relates to a switchable infrared ray-visible ray reflection electrochemical mirror having high electrochemical stability and bistability, in which a stripping phenomenon of a metal thin film can be prevented and bistability can be improved through a process of increasing electrochemical stability of a reflective film from an electrode composition and an ionic liquid electrolyte composition having various compositions. In the proposed electrochemical mirror apparatus, since the metal thin film formed by electric reduction is not stripped from a transparent electrode through a surface treatment process, a more stable apparatus can be provided, and even though a voltage is not applied to the metal thin film, the thin film is prevented from being oxidized by using an optimized ionic liquid electrolyte, thus providing the effective electrochemical mirror apparatus where the metal thin film is continuously maintained.

Claims

1. An electrochemical mirror comprising:

a first transparent electrode;

a second transparent electrode disposed to be spaced apart from the first transparent electrode;

an electrolyte layer positioned between the first transparent electrode and the second transparent electrode and containing metal ions which are capable of being electrodeposited; and

a surface-treated layer formed on a surface of the first transparent electrode or the second transparent electrode.

2. The electrochemical mirror of claim 1, wherein the electrochemical mirror has a transistor-type structure, and comprises:

a substrate;

a first transparent electrode formed on the substrate;

a second transparent electrode disposed to be spaced apart from the first transparent electrode;

an electrolyte layer positioned between the first transparent electrode and the second transparent electrode and containing metal ions which are capable of being electrodeposited;

a dielectric substance layer formed between the electrolyte layer and the second transparent electrode; and

a surface-treated layer formed on a surface of the first transparent electrode or the second transparent electrode.

3. The electrochemical mirror of claim 1, wherein the surface-treated layer is formed by treating the surface of the first transparent electrode or the second transparent electrode by oxygen plasma to form a hydroxy group on the surface of the electrode and then reacting the hydroxy group with silane.

4. The electrochemical mirror of claim 3, wherein the silane is represented by the following Chemical Formula 1:

R—

(CH₂)_n—

Si—

X₃  

 

[Chemical Formula 1]

in the aforementioned Chemical Formula,

R is a mercapto group, a halogen group, an alkyl group having 1 to 20 carbon atoms, a mercaptoalkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms, an arylalkyl group having 1 to 20 carbon atoms, an alkylaryl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms,

n is 0 to 20, and

X is a mercapto group, a halogen group, an alkyl group having 1 to 20 carbon atoms, a mercaptoalkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, an aryl group having 1 to 20 carbon atoms, an arylalkyl group having 1 to 20 carbon atoms, an alkylaryl group having 1 to 20 carbon atoms, or an alkoxy group having 1 to 20 carbon atoms.

5. The electrochemical mirror of claim 1, wherein the metal ions which are capable of being electrodeposited are one kind or more selected from silver, gold, magnesium, nickel, bismuth, chromium, copper, calcium, strontium, and aluminum.

6. The electrochemical mirror of claim 1, wherein the electrolyte layer includes a halogenated salt.

7. The electrochemical mirror of claim 6, wherein the halogenated salt is one kind or more selected from tetrabutylammonium bromide (TBABr), tetraethylammonium bromide (TEABr), 1-ethyl-3-methylimidazolium bromide (EMIMBr), 1-methyl-4-hexylimidazolium bromide (MHIMBr), 1-butyl-4-ethylimidazolium bromide (BEIMBr), 1-butyl-4-hexylimidazolium bromide (BHIMBr), 1-butyl-4-dodecylimidazolium bromide (BDIMBr), and 1-benzyl-3-methylimidazolium bromide (BMIMBr).

8. The electrochemical mirror of claim 1, wherein the electrolyte layer includes one kind or more compounds selected from a copper compound, a calcium compound, and a strontium compound.

9. The electrochemical mirror of claim 1, wherein the electrolyte layer includes an ionic liquid electrolyte.

10. The electrochemical mirror of claim 9, wherein the ionic liquid electrolyte includes one kind or more selected from the following Chemical Formulas 2 and 3 as a cation;

and one kind or more selected from halogen, a halogen compound, and an imide compound as an anion;

11. The electrochemical mirror of claim 1, wherein an incident angle of light reflected by a mirror layer formed by electrodeposition of the metal ions is 0°

to 90°

that is vertical to the transparent electrode.

12. The electrochemical mirror of claim 1, wherein a voltage applied to the electrochemical mirror is less than ±

3 V.

13. The electrochemical mirror of claim 1, wherein transmittance of the electrochemical mirror to a visible ray region in a transparency state is 80% or more, and reflectance to the visible ray region and a near-infrared ray region in a mirror state is 80% or more.

14. The electrochemical mirror of claim 1, wherein reflectance of the electrochemical mirror is maintained even though 1,000 cycles or more of switching is performed, and the electrochemical mirror has a memory effect where reflectance is maintained even after an applied voltage is removed.

15. The electrochemical mirror of claim 1, wherein the transparent electrode is capable of being applied to a glass, polyethylene terephthalate (PET), or flexible substrate.

16. The electrochemical mirror of claim 1, wherein the electrolyte layer includes an ionic gel-phase electrolyte.

17. The electrochemical mirror of claim 16, wherein the ionic gel-phase electrolyte includes one kind or more polymers selected from polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), polyvinylbutyral (PVB), and polyethylene glycol-polypropylene glycol-polyethylene glycol (PEG-PPG-PEG);

and an ionic liquid.