New LEDís may offer better way to clean water in remote areas

Deep UV LED - Nanobusiness For the first time, researchers have created light emitting diodes or LEDs on lightweight flexible metal foil. Engineers have developed the foil based on LEDs for portable ultraviolet UV lights that soldiers and others can use to purify drinking water and sterilize medical equipment. Engineers at the Ohio State University are developing the foil based LEDs for these portable lights. Researchers describe how they have designed the LEDs to shine in the high-energy deep end of the UV spectrum. The University will license the technology industry for further development.
Deep UV light is already used by the military, humanitarian organizations and industry for applications ranging from detection of biological agents to curing plastics. The problem is a conventional deep UV lamps are too heavy to carry around. To make deep ultraviolet light now you have to use Mercury lamps. However Mercury is toxic and the lamps are bulky and electrically inefficient. LEDs on the other hand are efficient so to make them safely and cheaply, we can make safe drinking water wherever we need it. Other research groups have fabricated deep UV LEDs at the laboratory scale but only by using pure, rigid single crystal semi conductors as substrates. This is an enormous cost for the industry.
Foil based nanotechnology could enable large-scale production of a lighter cheaper and more environmentally friendly deep UV LED. People have always said that nanophotonics will never be commercially important, because you can't scale them up. Now we can. So we can consider them for large-scale manufacturing. This new development relies on a well-established semiconductor growth technique known as molecular beam epitaxy, in which vaporized elemental materials settle on a surface and self organize into layers or nanostructures. Ohio State researchers uses technique to grow a carpet of tightly packed aluminum gallium nitride wires on pieces of metal foil such as titanium and tantalum.
The individual wires measure about 200 nm tall and 20 to 50 nm in diameter, 1000 times narrower than a human hair and invisible to the naked eye. These nano wires grown on metal foils lit up nearly as brightly as those manufactured on the more expensive and less flexible single crystal silicon. Researchers are working to make the nano wire LEDs even brighter and will try next to grow the wires on foils made from more common metals, including steel and aluminum.