Electrochromic tin oxide

• US 6,084,701 A
• Filed: 02/24/1999
• Issued: 07/04/2000
• Est. Priority Date: 12/26/1995
• Status: Expired due to Fees

• Current Assignee: Monsanto Company (Bayer AG)
• Original Assignee: Monsanto Company (Bayer AG)
• Inventors: Coleman, James P.
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Spector, David N.
• Application Number:
  US09/256,829
• Time in Patent Office: 496 Days
• Field of Search: 359/265-274
• US Class Current: 359/273
• 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: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1523 comprising inorganic material
• CPC Class Codes: H01B 1/08 oxides
• CPC Class Codes: Y10T 428/2982 Particulate matter [e.g., sphere, flake, etc.]

Abstract

Tin oxide doped with an electrochromically effective amount of a metal, e.g. antimony or niobium, which provides a color change when the doped tin oxide is exposed to an electrochemical potential in the presence of mobile ions. Particles of electrochromic doped tin oxide, e.g. coated on a white or pastel pigment substrate, have a contrast ratio greater than 1.2, where contrast ratio is a measure of electrochromic functionality of a material and is the ratio of reflectance of the material in an oxidized state to the color of the material in a reduced state and where color is a photodiode measurement of the value of light reflected off the oxidized or reduced material from a constant source of light shining on the material. Such doped tin oxide-containing particles are useful as electrochromic material in display devices.

Claims

1. An electrochromic device comprising a layer of electrochromic material in contact with an ion-supplying electrolyte layer and conductors for applying an electrical potential across an interface between said layer of electrochromic material and said ion-supplying electrolyte layer, where in said electrochromic material comprises doped tin oxide particles.

2. A device according to claim 1 wherein said electrochromic material comprises antimony-doped, tin oxide particles on a substrate of or in admixture with a white or pastel pigment.

4. A device according to claim 1, wherein said electrochromic material comprises niobium-doped tin oxide particles on a substrate of or in admixture with a white or pastel pigment.

3. A method of producing an electrochromic contrast ratio greater than 1.2 by applying an electrochemical potential to doped tin oxide particles in contact with mobile ions.