Having spent over a half-century living under the warm glow of incandescent light bulbs, it's understandable that consumers haven't been keen on adopting the cold bluish light emitted by energy-efficient CFL and LED bulbs. But researchers at the University of Georgia have developed a new single phosphor coating that finally lets LEDs produce that warm nostalgic glow we all know and love.
Past efforts to tweak the colour of light emitted from a blue LED have involved coating it with a mixture of different phosphors to shift its hue towards the warmer end of the colour spectrum. But as the LED heats and cools, its colour can vary over time as the different chemicals respond to the temperature changes. So taking a slightly different approach, the University of Georgia researchers have managed to create a single phosphor that does the same thing, by combining europium oxide, aluminium oxide, barium oxide, and graphite powders in a vacuum furnace heated to 1450C.
The resulting material is able to produce a warm glow when encapsulated around a blue LED, but unfortunately it's not quite ready for primetime just yet. The current manufacturing process is complex and finicky, and the resulting LED bulbs are actually not quite as efficient as what's currently available in stores. But the research certainly has the potential to finally cast LEDs in a better light for consumers. [University of Georgia]