Friday, January 29, 1999 Published at 08:57 GMT
Fluorescent lamps go green
The fluorescent lamp is seen virtually everywhere - now even more uses could be possible
The 30-year search for a new kind of luminescent chemical has ended and means it may be possible to make fluorescent lamps more environmentally friendly.
This means fluorescent lamps, which are more energy efficient, could be used in brake lights, photocopiers and the plasma display screens used for ultra-thin televisions.
Fluorescent lamps light up when an electric current vapourises the liquid mercury in a tube. The energy makes the mercury atoms emit ultra-violet (UV) light which is absorbed by phosphor crystals on the inner walls of the tube. These luminesce, i.e. re-emit the energy as visible light.
The problem with xenon is that the UV light it emits has a shorter wavelength. This is not converted efficiently by conventional phosphors.
One of the team, René Wegh, told BBC News Online they were actively searching for similar ways to produce blue and green light. This would enable them to make white light tubes. He expected the work to take at least five years.
The work is published in Science magazine, in which Alok Srivastava, a chemist with General Electric in New York describes the work as very promising: "It is the first experiment to demonstrate that you can get a practical system out of these ideas."