Electrochromic system

• US 6,301,038 B1
• Filed: 10/26/1999
• Issued: 10/09/2001
• Est. Priority Date: 02/06/1997
• Status: Expired due to Term

• Current Assignee: Dublin University College, University College Dublin
• Original Assignee: University College Dublin
• Inventors: Cinnscalach, Rachel, Fitzmaurice, Donald, Nagaraja, S. Rao, Enright, Brendan
• Primary Examiner(s): Kelly, Cynthia H.
• Assistant Examiner(s): XU, LING X
• Application Number:
  US09/367,024
• Time in Patent Office: 714 Days
• Field of Search: 359/265, 359/272, 359/270, 428/411.1, 428/457, 428/469, 428/704, 428/702, 428/315.5, 252/582, 252/586
• US Class Current: 359/265
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1516 comprising organic material
• CPC Class Codes: Y10T 428/249978 Voids specified as micro
• CPC Class Codes: Y10T 428/31504 Composite [nonstructural laminate]

Abstract

An electrochromic system with a first electrode disposed on a transparent or translucent substrate and a second electrode, an electrolyte, an electron donor and a nanoporous-nanocrystalline film of a semiconducting metallic oxide having a redox chromophore absorbed thereto being intermediate the first and second electrodes. Such a system has a very rapid electrochromic effect.

Claims

1. A nanoporous-nanocrystalline film comprising a semiconducting metallic oxide having a redox chromophore adsorbed thereto, characterised in that the redox chromophore is a compound of formula II, viz. bis-(2-phosphonoethyl)-4,4′

-bipyridinium dichloride

2. A film according to claim 1, wherein the metallic oxide is an oxide of a metal selected from titanium, zirconium, hafnium, chromium, molybdenum, tungsten, vanadium, niobium, tantalum, silver, zinc, strontium, iron (Fe²⁺ and Fe³⁺) and nickel and perovskites thereof.

3. A film according to claim 2, wherein the metallic oxide is selected from TiO₂, WO₃, MoO₃, ZnO and SnO₂.

4. Use of a nanoporous-nanocrystalline film comprising a semiconducting metallic oxide having a redox chromophore adsorbed thereto, wherein the redox chromophore is bis-(2-phosphonethyl)-4,4′

-bipyridinium dichloride of the formula II given in claim 1, in a method for the manufacture of an electrochromic system, the method comprising the steps of;

(a) providing an electrochromic system comprising a first electrode and a second electrode; and

(b) disposing said nanoporous-nanocrystalline film on said first or second electrode.

5. An electrochromic system comprising:

a first electrode disposed on a transparent or translucent substrate;

a second electrode;

an electrolyte;

an electron donor; and

a nanoporous-nanocrystalline film intermediate the first and second electrodes, wherein said film comprises a semiconducting metallic oxide having a redox chromophore adsorbed thereto, wherein the redox chromophore is bis-(2-phosphonoethyl)-4,4′

-bipyridinium dichloride of the formula II given in claim 1.

6. An electrochromic system according to claim 5, wherein the electrolyte is in liquid form.

7. An electrochromic system according to claim 5, wherein the electrolyte comprises at least one electrochemically inert salt optionally in molten form or in solution in a solvent.

8. An electrochromic system according to claim 7, wherein the salt is selected from hexafluorophosphate, bis-trifluoromethanesulfonate, bis-trifluoromethyl-sulfonylamidure, tetraalkylammonium, dialkyl-1,3-imidazolium and lithium perchlorate or a mixture thereof and/or is a salt in molten form selected from trifluoromethanesulfonate, 1-ethyl,3-methyl imidazolium bis-trifluoromethyl-sulfonylamidure and 1-propyl-dimethyl imidazolium bis-trifluoromethyl-sulfonylamidure or a mixture thereof;

and/or the solvent is selected from acetonitrile, butyronitrile, glutaronitrile, dimethylsulfoxide, dimethylformamide, dimethylacetamide, N-methyloxazolidinone, dimethyl-tetrahydropyrimidinone and δ

-butyrolactone or a mixture thereof.

9. An electrochromic system according to claim 8, wherein the salt is lithium perchlorate.

10. An electrochromic system according to claim 5, wherein the electron donor is a metallocene or a derivative thereof.

11. An electrochromic system according to claim 10, wherein the metallocene is ferrocene.

12. An electrochromic system according to claim 11, wherein the ferrocene is in solution in the electrolyte solvent.

13. Use according to claim 4, wherein the semiconducting metallic oxide of the nanoporous-nanocrystalline film is an oxide of a metal selected from titanium, zirconium, hafnium, chromium, molybdenum, tungsten, vanadium, niobium, tantalum, silver, zinc, strontium, iron (Fe²⁺ and Fe³+) and nickel and perovskites thereof.

14. Use according to claim 13, wherein the semiconducting metallic oxide is selected from TiO₂, WO₃, MoO₃, ZnO and SnO₂.

15. An electrochromic system according to claim 5, wherein the semiconducting metallic oxide of the nanoporous-nanocrystalline film is an oxide of a metal selected from titanium, zirconium, hafnium, chromium, molybdenum, tungsten, vanadium, niobium, tantalum, silver, zinc, strontium, iron (Fe²⁺ and Fe³⁺) and nickel and perovskites thereof.

16. An electrochromic system according to claim 15 wherein the semiconducting metallic oxide is selected from TiO₂, WO₃, MoO₃, ZnO and SnO₂.