Far-ultraviolet LED Designed to Kill Bacteria and Viruses Efficiently Without Harming Humans

A highly efficient LED that is deadly to microbes and viruses but safe for people has been engineered in Japan by three RIKEN physicists. It could one day help countries emerge from the shadows of pandemics by killing pathogens in rooms full of people.

Most LEDs emit visible light, but RIKEN physicists have created an LED that emits in a narrow region in the far ultraviolet that is safe for humans but deadly for viruses and bacteria. 

Ultraviolet germicidal lamps are extremely effective at exterminating bacteria and viruses, and they are routinely used in hospitals to sterilize surfaces and medical instruments.

Such lamps can be made with LEDs, making them energy efficient. But these LEDs use ultraviolet light in a range that damages DNA and thus cannot be used around people. The hunt is on to develop efficient LEDs that shine light within a narrow band of far-ultraviolet light that appears to be both good at disinfecting and safe for people.

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Nanoparticles Help to Produce Rapid, Efficient Hydrogen from Water

UCSC chemists developed a simple method to make aluminum nanoparticles that split water and generate hydrogen gas rapidly under ambient conditions. Aluminum is a highly reactive metal that can strip oxygen from water molecules to generate hydrogen gas. Its widespread use in products that get wet poses no danger because aluminum instantly reacts with air to acquire a coating of aluminum oxide, which blocks further reactions.

For years, researchers have tried to find efficient and cost-effective ways to use aluminum’s reactivity to generate clean hydrogen fuel. A new study by researchers at UC Santa Cruz shows that an easily produced composite of gallium and aluminum creates aluminum nanoparticles that react rapidly with water at room temperature to yield large amounts of hydrogen. The gallium was easily recovered for reuse after the reaction, which yields 90% of the hydrogen that could theoretically be produced from reaction of all the aluminum in the composite.

We don’t need any energy input, and it bubbles hydrogen like crazy. I’ve never seen anything like it,” said UCSC Chemistry Professor Scott Oliver.

Oliver and Bakthan Singaram, professor of chemistry and biochemistry, are corresponding authors of a paper on the new findings, published February 14 in Applied Nano Materials.

The reaction of aluminum and gallium with water has been known since the 1970s, and videos of it are easy to find online. It works because gallium, a liquid at just above room temperature, removes the passive aluminum oxide coating, allowing direct contact of aluminum with water. The new study, however, includes several innovations and novel findings that could lead to practical applications.