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Electrochromic window with high reflectivity modulation

United States Patent

July 25, 2000
View the Complete Patent at the US Patent & Trademark Office
A multi-layered, active, thin film, solid-state electrochromic device having a high reflectivity in the near infrared in a colored state, a high reflectivity and transmissivity modulation when switching between colored and bleached states, a low absorptivity in the near infrared, and fast switching times, and methods for its manufacture and switching are provided. In one embodiment, a multi-layered device comprising a first indium tin oxide transparent electronic conductor, a transparent ion blocking layer, a tungsten oxide electrochromic anode, a lithium ion conducting-electrically resistive electrolyte, a complimentary lithium mixed metal oxide electrochromic cathode, a transparent ohmic contact layer, a second indium oxide transparent electronic conductor, and a silicon nitride encapsulant is provided. Through elimination of optional intermediate layers, simplified device designs are provided as alternative embodiments. Typical colored-state reflectivity of the multi-layered device is greater than 50% in the near infrared, bleached-state reflectivity is less than 40% in the visible, bleached-state transmissivity is greater than 60% in the near infrared and greater than 40% in the visible, and spectral absorbance is less than 50% in the range from 0.65-2.5 .mu.m.
Goldner; Ronald B. (Lexington, MA), Gerouki; Alexandra (Medford, MA), Liu; Te-Yang (Arlington, MA), Goldner; Mark A. (Cambridge, MA), Haas; Terry E. (Southborough, MA)
Trustees of Tufts College (Medford, MA)
09/ 027,133
February 20, 1998
GOVERNMENT RIGHTS The invention described herein was supported in part with U.S. Government funding under Department of Energy contracts DE-FG02-95ER14578 and DE-FG03-85SF15927. The U.S. Government has certain rights to this invention.