It looks as though the puzzle of getting high-energy UV light from an LED has been solved.
These deep UV LEDs emit even shorter wavelengths of light than blue LEDs, and they have promising applications. Nikkiso envisions applications for its deep UV LEDs in three broad fields.
First is the environmental field, where the sterilizing effects of deep UV radiation can be put to use disinfecting water and sewage. This is already done using mercury lamps, but the new LEDs have many advantages: They are smaller and can run on lower voltage, around 5-7 volts. They are far more durable, lasting more than 10,000 hours, compared to around 3,000 to 5,000 hours for mercury lamps. Finally, they do not use toxic mercury.
Could be a pretty big deal if the technology trickles down [heh] to our world. Imagine a UV sterilizer as efficient and reliable as our little UV flashlights.