Sunlight to night light

A novel material that emits a long-lasting near-infrared glow after just one minute's exposure to sunlight has been developed by US scientists. Zhengwei Pan of the University of Georgia and colleagues claim the new material could be used in new medical diagnostics technology, give the military and law enforcement agencies a "secret" source of illumination and perhaps lead to highly efficient solar cells. A matrix of zinc and gallogermanate into which chromium(III) ions can be intercalated acts as a labyrinthine trap for capturing solar energy releasing it over a 360-hour period as NIR, which can only be seen with "night-vision" cameras.