Ultraviolet light can be used to kill bacteria. Currently, LEDs with a large enough band gap to produce ultraviolet radiation with a short enough wavelength to kill bacteria are not available. If they do become available, they may become quite ubiquitous due to their high energy efficiency, relatively low cost, and long service life. Currently, other UV sources are used to sterilize water in Europe and to prevent nosocomial infections in Russian hospitals.
A bunch of them could be activated every time a refrigerator door closes, a bathroom light switch is turned off, or a drinking fountain is not in use. It should not be used while people are around, because it can increase the risk of skin cancer. Their most important function may be the prevention of nosocomial infections in hospitals.
Just as it took a long time to develop the blue LED, it may be quite a while before we start to see deep-UV LEDs. Some may speculate that with time, bacteria may become more resistant to light as they do to antibiotics. Also, it can cause things like paintings and plastic objects to degrade faster than they normally would.
How it Works
Ultraviolet radiation prevents the transcription of DNA by forming pyrimidine dimers and pyrimidinone dimers. Additionally, The amino acids tryptophan, tyrosine, and phenylalanine all contain aromatic ring structures, which absorb UV radiation at 280, 274, and 257 nm. When proteins containing those amino acids are excited by radiation, they may undergo chemical reactions such as cross linking which inactivates them. The same thing can occur with DNA.