Electrochromic device

• US 6,870,657 B1
• Filed: 10/11/2000
• Issued: 03/22/2005
• Est. Priority Date: 10/11/1999
• Status: Expired due to Term

• Current Assignee: University College Dublin Nat'L University of Ireland
• Original Assignee: University College Dublin
• Inventors: Corr, David, Boschloo, Gerrit, Cummins, David, Fitzmaurice, Donald, Rao, S. Nagaraja
• Primary Examiner(s): Lester, Evelyn A.
• Application Number:
  US10/110,245
• Time in Patent Office: 1,623 Days
• Field of Search: 359265-275, 216/24, 252/583, 252/586, 438/85, 438/86, 438/57, 438/69, 438/150, 438/514, 438/515, 438/532, 438/609, 438/718, 438/722
• US Class Current: 359/273
• CPC Class Codes: C07F 17/02 of metals of Groups 8, 9 or 10 of the Periodic Table
• CPC Class Codes: C07F 5/025 Boronic and borinic acid compounds
• CPC Class Codes: C07F 7/1804 Compounds having Si-O-C linkages Si-O-acyl linkages C07F7/1896
• CPC Class Codes: C07F 9/3808 Acyclic saturated acids which can have further substituents on alkyl
• CPC Class Codes: C07F 9/59 Hydrogenated pyridine rings
• CPC Class Codes: C07F 9/650994 condensed with carbocyclic rings or carbocyclic ring systems
• CPC Class Codes: C07F 9/65335 condensed with carbocyclic rings or carbocyclic ring systems
• CPC Class Codes: C07F 9/6547 condensed with carbocyclic rings or carbocyclic ring systems
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1516 comprising organic material

Abstract

This invention concerns an electochromic device comprising an electrode including a nanostructured metal oxide film, doped to metallic levels of conductivity and optionally modified by chemisorption of an electroactive compound. Such an electrochromic device is suitable for applications where optical modulation is required, such as large area static displays and automatically dimmable rear-view mirrors. The invention also concerns conducting nanostructured metal oxide films and electrodes comprising same and which are suitable for use in the electrochromic device.

Claims

1. An electrochromic device, comprising:

(a) a first electrode comprising a transparent or translucent substrate bearing an electrically conducting coating on an internal face which in turn bears a nanostructured film comprising a conducting or semiconducting metal oxide having an n-type or p-type redox chromophore or an n-type or p-type redox promoter adsorbed thereto, wherein when the metal oxide is a semiconducting metal oxide, one of a n-type redox chromophore and promoter is adsorbed thereto;

(b) a second electrode comprising a transparent or translucent substrate bearing an electrically conducting coating on its internal face which in turn bears a nanostructured film comprising a conducting metal oxide having a p-type or n-type redox promoter or a p-type or n-type redox chromophore adsorbed thereto, wherein when the first electrode comprises an n-type redox chromophore or promoter, the second electrode comprises a p-type redox promoter or chromophore or vice versa; and

(c) an electrolyte intermediate the electrodes.

2. The electrochromic device according to claim 1, wherein the nanostructured film of the first electrode comprises a semiconducting metal oxide having an n-type redox chromophore adsorbed thereto, and the second electrode comprises a conducting metal oxide having a p-type redox promoter adsorbed thereto.

3. The electrochromic device according to claim 1, wherein the semiconducting metal oxide is selected from the group consisting of oxides of titanium, zirconium, hafnium, chromium, molybdenum, tungsten, vanadium, niobium, tantalum, silver, zinc, strontium, iron (Fe²⁺ or Fe³⁺), nickel or a perovskite thereof.

4. The electrochromic device according to claim 1, wherein the first electrode is the cathode and the nanostructured film coated thereon comprises TiO₂ having an n-type redox chromophore selected from the group consisting of the formula I, II or III adsorbed thereto:

wherein R₁ is selected from the group consisting of;

R₂ is selected from C_1-10 alkyl, N-oxide, dimethylamino, acetonitrile, benzyl and phenyl optionally mono- or di-substituted by nitro;

R₃ is C_1-10 alkyl and R₄-R₇ are each independently selected from hydrogen;

C_1-10 alkyl;

C_1-10 alkylene;

aryl or subtituted aryl;

halogen;

nitro; and

an alcohol group;

X is a charge balancing ion which is selected from chloride, bromide, iodide, BF₄—

, PF₆—

, and ClO₄—

; and

n=1-10;

and wherein the second electrode is the anode and the nanostructured film coated thereon comprises SnO₂;

Sb having a p-type redox promoter absorbed thereto, said redox promoter being selected from the group consisting of the formula IV, V, VI or VII;

wherein X in formula V is S or O and R₆-R₁₀ are each independently selected from the following;

wherein R₁₁ is C_1-10 alkyl and R₁₂-R₁₅ are each independently hydrogen;

C_1-10 alkyl;

C_1-10 alkylene;

optionally substituted aryl;

halogen;

nitro;

or an alcohol group; and

n=1-10.

5. The electrochromic device according to claim 1, wherein the first and second electrodes are formed from a glass or plastics material, preferably glass coated with fluorine doped tin oxide or indium tin oxide.

6. The electrochromic device according to claim 1, wherein the first and second electrodes are spaced apart by a distance of up to 5 mm.

7. The electrochromic device according to claim 1, wherein the electrolyte is in liquid form and comprises at least one electrochemically inert salt in solution in a solvent.

8. The electrochromic device according to claim 7, wherein the electrochemically inert salt in a solution in a solvent comprises lithium perchlorate in γ

-butyrolactone.

9. The electrochromic device according to claim 1, wherein the semiconducting metal oxide is selected from the group consisting of TiO₂, WO₃, MoO3, ZnO and SnO₂.

10. The electrochromic device according to claim 1, wherein the first and second electrodes are spread apart at a distance of from about 50 μ

m to about 5 mm.

11. An electrochromic device comprising:

(a) a first electrode comprising a transparent or translucent substrate bearing an electrically conducting coating on an internal face which in turn bears a nanostructured film comprising a conducting or semiconducting metal oxide having an n-type or p-type redox chromophore adsorbed thereto, wherein when the metal oxide is a semiconducting metal oxide, an n-type redox chromophore is adsorbed thereto;

(b) a second or counter electrode comprising a transparent or translucent substrate bearing an electrically conducting coating on an internal face which in turn bears a nanostructured film comprising a conducting metal oxide without an electroactive compound adsorbed thereto; and

(c) an electrolyte intermediate the electrodes.

12. The electrochromic device according to claim 11, wherein the nanostructured film of the first electrode comprises a semiconducting metal oxide having an n-type redox chromophore adsorbed thereto, which is selected from the group consisting of compounds of the following general formulae I-III:

wherein R₁ is selected from the group consisting of;

R₂ is selected from C_1-10 alkyl, N-oxide, dimethylamino, acetonitrile, benzyl and phenyl optionally mono- or di-substituted by nitro;

R₃ is C_1-10 lkyl and R₄-R₇ are each independently selected from hydrogen;

C_1-10 alkyl;

C_1-10 alkylene;

aryl or substituted aryl;

halogen;

nitro; and

an alcohol group;

X is a charge balancing ion which is selected from chloride, bromide, iodide, BF₄—

, PF₆—

, and ClO₄—

, and

n=1-10.

13. A process for preparing an electrochromic device having a first electrode comprising a transparent or translucent substrate bearing an electrically conducting coating on an internal face which in turn bears a nanostructured film comprising a conducting or semiconducting metal oxide having an n-type or p-type redox chromophore or an n-type or p-type redox promoter adsorbed thereto, wherein when the metal oxide is a semiconducting metal oxide, one of a an n-type redox chromophore and promoter is adsorbed thereto;

a second electrode comprising a transparent or translucent substrate bearing an electrically conducting coating on its internal face which in turn bears a nanostructured film comprising a conducting metal oxide having a p-type or n-type redox promoter or a p-type or n-type redox chromophore adsorbed thereto, wherein when the first electrode comprises an n-type redox chromophore or promoter, the second electrode comprises a p-type redox promoter or chromophore or vice versa; and

an electrolyte intermediate the electrodes, the process comprising;

(a) providing conducting or semiconducting nanostructured metal oxide films;

(b) modifying the resulting films by chemisorption of an electroactive compound of the p- or n-type;

(c) applying the modified films to the internal face of the first and second electrodes; and

(d) adding an electrolyte so that it is disposed between the electrodes.

14. The process according to claim 13, wherein the conducting or semiconducting metal oxide films are treated by exposure to a water plasma stream prior to chemisorption of the electroactive compound.