Fabrication of Electrochromic Tungsten Oxide Films
for Optical Modulation
Chi-Ping Li, Robert C. Tenent, Chaiwat Engtrakul, and Colin A. Wolden
Summary: Mesoporous tungsten oxide films that are capable of modulating optical
transmission up to the theoretical limit of 100% in the visible regime
Description: Smart windows are solar control devices that can electronically regulate the flow
of sunlight and heat. The U.S. Department of Energy has estimated that the use of smart
windows could reduce peak electric loads in buildings by 20-30%; however, cost and
unsatisfactory performance are two issues that limit wider adoption of this technology. The
present invention describes a unique chemistry and fabrication approach that produces
mesoporous tungsten oxide films capable of modulating optical transmission up to the
theoretical limit of 100% in the visible regime (>550 nm). The novel process is based on
adopting established sol-gel chemistry to ultrasonic spray deposition (USD). USD is performed
under ambient conditions as opposed to high vacuum sputtering (the standard commercial
process), and as such is more amenable to in-line, high volume, low cost manufacturing.
Main Advantages of this Invention
 100% optical modulation
 Lower production costs
 Fast switching kinetics (75% change
in absolute transmission in 3 sec.)
 Amenable to in-line, high volume
Potential Areas of Application
 Green Engineering
 Window Manufactures
ID number: 14005
Intel ectual Property Status: US utility
Cyclic voltammograms (left) and optical transmission
at 670 nm recorded in registry (right)
patent pending (application #14/700,287)
Publication: C.-P. Li et al., Sol. Ener. Mater. Sol. Cells 2015, 132, 6-14. (Available upon request.)
Opportunity: We are seeking an exclusive or non-exclusive licensee for marketing,
manufacturing, and sale of this technology.
For more information contact:
William Vaughan, Director of Technology Transfer
Colorado School of Mines, 1500 Illinois Street, Guggenheim Hall Suite 314, Golden, CO 80401
Phone: 303-384-2555; e-mail: wvaughan@mines.edu