Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


UGA scientists invent long-lasting, near infrared-emitting material

Implications for medical diagnostics, security and solar energy

Materials that emit visible light after being exposed to sunlight are commonplace and can be found in everything from emergency signage to glow-in-the-dark stickers. But until now, scientists have had little success creating materials that emit light in the near-infrared range, a portion of the spectrum that only can be seen with the aid of night vision devices.

In a paper just published in the early online edition of the journal Nature Materials, however, University of Georgia scientists describe a new material that emits a long-lasting, near-infrared glow after a single minute of exposure to sunlight. Lead author Zhengwei Pan, associate professor of physics and engineering in the Franklin College of Arts and Sciences and the Faculty of Engineering, said the material has the potential to revolutionize medical diagnostics, give the military and law enforcement agencies a "secret" source of illumination and provide the foundation for highly efficient solar cells.

"When you bring the material anywhere outside of a building, one minute of exposure to light can create a 360-hour release of near-infrared light," Pan said. "It can be activated by indoor fluorescent lighting as well, and it has many possible applications."

The material can be fabricated into nanoparticles that bind to cancer cells, for example, and doctors could visualize the location of small metastases that otherwise might go undetected. For military and law enforcement use, the material can be fashioned into ceramic discs that serve as a source of illumination that only those wearing night vision goggles can see. Similarly, the material can be turned into a powder and mixed into a paint whose luminescence is only visible to a select few.

The starting point for Pan's material is the trivalent chromium ion, a well-known emitter of near-infrared light. When exposed to light, its electrons at ground state quickly move to a higher energy state. As the electrons return to the ground state, energy is released as near-infrared light. The period of light emission is generally short, typically on the order of a few milliseconds. The innovation in Pan's material, which uses matrix of zinc and gallogermanate to host the trivalent chromium ions, is that its chemical structure creates a labyrinth of "traps" that capture excitation energy and store it for an extended period. As the stored energy is thermally released back to the chromium ions at room temperature, the compound persistently emits near-infrared light over period of up to two weeks.

In a process that Pan likens to perfecting a recipe, he and postdoctoral researcher Feng Liu and doctoral student Yi-Ying Lu spent three years developing the material. Initial versions emitted light for minutes, but through modifications to the chemical ingredients and the preparation—just the right amounts of sintering temperature and time—they were able to increase the afterglow from minutes to days and, ultimately, weeks.

"Even now, we don't think we've found the best compound," Pan said. "We will continuously tune the parameters so that we may find a much better one."

The researchers spent an additional year testing the material—indoors and out, as well as on sunny days, cloudy days and rainy days—to prove its versatility. They placed it in freshwater, saltwater and even a corrosive bleach solution for three months and found no decrease in performance.

In addition to exploring biomedical applications, Pan's team aims to use it to collect, store and convert solar energy. "This material has an extraordinary ability to capture and store energy," Pan said, "so this means that it is a good candidate for making solar cells significantly more efficient."

The U.S. Office of Naval Research, the National Science Foundation, the American Chemical Society Petroleum Research Fund and the UGA Research Foundation supported the research.

Zhengwei Pan | EurekAlert!
Further information:

More articles from Materials Sciences:

nachricht 3-D-printed structures shrink when heated
26.10.2016 | Massachusetts Institute of Technology

nachricht From ancient fossils to future cars
21.10.2016 | University of California - Riverside

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Etching Microstructures with Lasers

Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.

This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

Greater Range and Longer Lifetime

26.10.2016 | Power and Electrical Engineering

VDI presents International Bionic Award of the Schauenburg Foundation

26.10.2016 | Awards Funding

3-D-printed magnets

26.10.2016 | Power and Electrical Engineering

More VideoLinks >>>