As a modern culture, we crave artificial white lights -- the brighter
the better, and ideally using less energy than ever before. To meet the
ever-escalating demand for more lighting in more places and to improve
the bulbs used in sports stadiums, car headlights and street lamps,
scientists are scrambling to create better light-emitting diodes (LEDs)
-- solid state lighting devices that are more energy efficient than
conventional incandescent or fluorescent light sources.
Just one
thing stands in the way: "droop," the term for a scientific problem
related to LEDs currently in use. Droop refers to the fact that LED
efficiency falls as operating currents rise, making the lights too hot
to power in large-scale applications. Many scientists are working on new
methods for modifying LEDs and making progress toward cooler, bigger
and brighter bulbs.
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| Photograph of bright white light (right) achieved using lasers in combination with phosphors next to an image of the phosphor with no illumination. (Credit: K.Denault/UCSB) |
Credit: aipadvances