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Lighting the Dark by Kathleen Cason |
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When a power outage darkened dozens of Northeastern cities this past August, New Yorkers trapped in
subways groped along pitch-black tunnels, hunting for exits. Had William Yen’s invention been
available then, glowing arrows painted on walls might have illuminated the commuters’ paths
to safety.
Yen, the University of Georgia’s Graham Perdue Professor of Physics, has invented and patented a
new breed of glow-in-the-dark pigments or “long-persistence phosphors.” After just a few minutes’
exposure to light, these inorganic compounds emit a bright glow for more than 20 hours ‹ twice the
time of similar substances.
Yen’s invention advances a technology that first appeared more than 2,000 years ago. During the Han
Dynasty, Chinese artists used phosphors to create luminescent paintings. Today
phosphorescent materials have become standard on clocks, watch faces and instrument panels.
These new phosphor technologies offer several advantages over those available in the marketplace.
Yen’s materials are low-cost, non-toxic and come in any color imaginable. (Previously only
green and blue were available.) He can even engineer how long his material will emit light. Plus,
his phosphors do not contain many of the troublesome substances commonly used to make
compounds glow, such as radioactive elements, heavy metals or sulfurs, which smell like rotten eggs
when wet.
“There are many possible applications: emergency signage, paintings, military uses, toys, clothing,
even luminescent nail polish,” said Yen, who is co-editor of the Phosphors Handbook, a technical
manual of phosphor properties and uses.
The uses are limited only by imagination. Phosphors could be added to paints, fabrics or other
materials. Exit signs powered by phosphors would need no electricity, saving money and energy.
Color-coded phosphors added to the plastic sleeves on wires might make maintenance easier in
low-light environments. In fact, Yen’s research group, which includes former graduate students and
postdoctoral fellows, has developed specific uses incorporating these phosphors.
“The worldwide market for phosphor technologies could be around $600 million to $800 million
dollars a year, if not a billion dollars,” said Gennaro Gama, a technology manager for the UGA
Research Foundation.
For more information, contact Gennaro Gama at gjg@ovpr.uga.edu.
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Research
Communications, Office of the VP for Research, UGA
For comments or for information please e-mail the editor: jbp@ovpr.uga.edu To contact the webmaster please email: ovprweb@uga.edu
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