Electrochromic material and electro-optical device using same

• US 5,080,471 A
• Filed: 04/06/1990
• Issued: 01/14/1992
• Est. Priority Date: 04/06/1990
• Status: Expired due to Term

• Current Assignee: EIC Laboratories, Inc.
• Original Assignee: EIC Laboratories, Inc.
• Inventors: Cogan, Stuart F., Rauh, R. David
• Primary Examiner(s): Hille, Rolf
• Assistant Examiner(s): SAADAT, MAHSHID D
• Application Number:
  US07/506,340
• Time in Patent Office: 648 Days
• Field of Search: 350/357, 429/194, 429/202, 429/209
• US Class Current: 359/275
• CPC Class Codes: C09K 9/00 Tenebrescent materials, i.e. materials for which the range of wavelengths for energy absorption is changed as a result of excitation by some form of energy
• CPC Class Codes: G02F 1/1524 Transition metal compounds

Abstract

An oxidatively coloring electrochromic layer of composition M_y CrO_2+x (0.33≦y≦2.0 and x≦2) where M=Li, Na or K with improved transmittance modulation, improved thermal and environmental stability, and improved resistance to degradation in organic liquid and polymeric electrolytes. The M_y CrO_2+x provides complementary optical modulation to cathodically coloring materials in thin-film electrochromic glazings and electrochromic devices employing polymeric Li⁺ ion conductors.

Claims

1. An electro-optical device comprising a first substrate,

a first electronic contact disposed over said first substrate,

a layer comprised of M_y CrO_2+x where 0.33≦

y≦

2.0, x≦

2, and M=Li, Na, or K, said M_y CrO_2+x coloring on oxidation,

a layer comprised of an electrochromic material, said electrochromic material coloring on reduction,

a Li⁺ ion conducting layer disposed between said M_y CrO_2+x and said reductively coloring electrochromic layer,

said M_y CrO_2+x layer or said reductively coloring electrochromic layer being disposed on said first electronic contact

a second electronic contact disposed over said previous layers

wherein, one or both of said M_y CrO_2+x and said reductively coloring electrochromic material are partially reduced by electro-active lithium, and whereby said electro-active lithium is distributed between said M_y CrO_2+x and said reductively coloring electrochromic layer in a manner determined by the magnitude and polarity of a voltage applied between said electronic contacts, said electro-active lithium distribution determining the optical state of said device.

2. The electro-optical device of claim 1, wherein a second substrate is disposed over said second electronic contact, one or both of said first or second substrates being substantially transparent.

3. The electro-optical device of claim 2, wherein said Li⁺ ion conducting layer is a polymer.

4. The electro-optical device of claim 3, wherein one or both of said M_y CrO_2+x and reductively coloring electrochromic layers are coated with a solid Li⁺ ion conducting layer, said solid Li⁺ ion conducting layer being disposed between said M_y CrO_2+x or reductively coloring electrochromic layer and said polymeric Li⁺ conducting layer.

5. The electro-optical device of claim 1, wherein said reductively coloring electrochromic material is amorphous or crystalline and chosen singly or as a mixture from the group tungsten oxide, molybdenum oxide, and potassium hexatungstate.

6. The electro-optical device of claim 1, wherein said Li⁺ conducting layer is selected from the group consisting of lithium based oxides and glassy lithium ion conductors.

7. The electro-optical device of claim 3, wherein said polymeric Li⁺ ion conductor is selected from the group polyethylene oxide, mixtures of polyvinylpyrrolidone with polyethylene glycol, and polyvinylpyrrolidone with N-methylpyrrolidone or γ

-butyrolactone, all containing dissolved lithium salts.

8. The electro-optical device of claim 1, wherein said electronic contacts are substantially transparent and selected from the group tin-doped indium oxide, antimony-doped tin oxide, or aluminum-doped zinc oxide.

9. The electro-optical device of claim 1, wherein one of said electronic contacts is optically reflective.

10. The electro-optical device of claim 9, wherein said optically reflective contact is selected from the group gold, silver, nickel, aluminum, or chromium.

11. The electro-optical device of claim 6, wherein said Li⁺ ion conductor is a mixture of Li₂ O and B₂ O₃.