Lighting Alternatives
24 December 2007, 17:07
Categories: smt-luminescent-light-emit energy
Approximately 20% of global electricity consumption is used only for illumination, and in response to the ever-increasing energy demands, coupled with serious concern for global warming, there has been an immense interest in the generation of light sources that can save electrical energy consumption, reduce operating expenses, and perform better.
Long billed as a “green” product for environmentally conscious consumers, compact fluorescent light bulbs (CFLs) are quickly becoming the norm in household lighting and may soon replace traditional incandescent bulbs altogether. But CFLs’ cool-burning illumination is made possible by a pinch of poison — about five milligrams of mercury sealed inside every glass tube — a potent neurotoxin and long-lived environmental contaminant. Even the small amount present in CFLs poses a problem. When the bulbs break, either in the house or at a waste disposal site, their mercury content is released.
An alternative to these bulbs is highly efficient LEDs, or OLEDs, however it has been difficult to achieve LEDs that provide pure white light. LEDs need high-quality phosphors that are excited by UV; white phosphors can be made by blending semiconducting nanocrystals that have different colored emissions, however these tend to produce tinted, unstable shades of white light. Now researchers from the Indian Institute of Science in Bangalore, and the Indian Association for the Cultivation of Science in Kolkata have developed a new class of white light phosphor that is based on doped semiconducting nanocrystals.
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Posted by: The Editors
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