Team claims material can emit light in near-infrared range

The Georgia University scientists say they have created a material that emits a long-lasting, near-infrared glow after a single minute of exposure to sunlight.

Materials that emit visible light after being exposed to sunlight are commonplace and can be found in everything from signs 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.

Zhengwei Pan, associate professor of physics and engineering in the Franklin College of Arts and Sciences and the Faculty of Engineering, said: ‘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.’

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.