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.
Now investigators at University of California, Santa Barbara, led by material scientists Kristin A. Denault and Michael Cantore, have devised an alternative means of creating high-power white light by using a different excitation source -- a laser diode in combination with inorganic phosphors, instead of the traditional LEDs.
Their laser-based lighting options are high in efficiency and high in performance metrics, according to their study, which is described in the journal AIP Advances, which is produced by AIP Publishing.
"We found two ways to create high-intensity ‘cool’ white light, explained Denault. "In one we used a blue laser diode and yellow-emitting phosphor powder with a luminous flux of 252 lumens, which is comparable to current high-brightness white LEDs. For our second method, we used a near-ultra-violet laser diode and a combination of red-, green-, and blue-emitting phosphors."
They also achieved a variety of other color temperatures with high color rendition, broadening the range of applications for these new lights, she said.
The article, "Efficient and stable laser-driven white lighting" by Kristin A. Denault, Michael Cantore, Shuji Nakamura, Steven P. DenBaars, and Ram Seshadri appears in the journal AIP Advances. See: http://dx.doi.org/10.1063/1.4813837
ABOUT THE JOURNAL
AIP Advances is a fully open access, online-only, community-led journal. It covers all areas of applied physical science. With its advanced web 2.0 functionality, the journal puts relevant content and discussion tools in the hands of the community to shape the direction of the physical sciences. See: http://aipadvances.aip.org
Jason Socrates Bardi | Source: Newswise
Further information: www.aip.org
More articles from Power and Electrical Engineering:
Scientists discover quick recipe for producing hydrogen
09.12.2013 | Deep Carbon Observatory
New Thermoelectronic Generator
04.12.2013 | American Institute of Physics (AIP)
In power electronics systems bonded connections create the central electrical connections between adjoining surfaces.
The quality of these bonded connections is one of the main factors that determines the reliability and availability of drive systems in electric vehicles, and hence constitutes a major design challenge for German auto manufacturers aiming to electrify their vehicles.
Now the partners participating in the RoBE (Robust Bonds in ...
International team of scientists develops new feedback method for optimizing the laser pulse shapes used in the control of chemical reactions
In many ways, traditional chemical synthesis is similar to cooking. To alter the final product, you can change the ingredients or their ratio, change the method of mixing ingredients, or change the temperature or pressure of the environment of the ingredients.
Like an accomplished chef, chemists have become very skilled ...
A genetic defect protects mice from infection with influenza viruses
A new study published in the scientific journal PLOS Pathogens points out that mice lacking a protein called Tmprss2 are no longer affected by certain flu viruses.
The discovery was made by researchers from the Helmholtz Centre for Infection Research (HZI) in Braunschweig in collaboration with colleagues from Göttingen and ...
The Light: Global study gets underway with online user survey
Light has a fundamental impact on our sense of well-being and performance. In cooperation with Zumtobel, a supplier of lighting solutions, Fraunhofer IAO has launched a global user survey of lighting quality in offices. The objective is to identify the best lighting conditions for a variety of spaces and lighting ...
Quantum entanglement, a perplexing phenomenon of quantum mechanics that Albert Einstein once referred to as “spooky action at a distance,” could be even spookier than Einstein perceived.
Physicists at the University of Washington and Stony Brook University in New York believe the phenomenon might be intrinsically linked with wormholes, hypothetical features of space-time that in popular science fiction can provide a much-faster-than-light shortcut from one part of the universe to another.
But here’s the catch: One couldn’t actually ...
09.12.2013 | Materials Sciences
09.12.2013 | Life Sciences
09.12.2013 | Studies and Analyses
05.12.2013 | Event News
04.12.2013 | Event News
12.11.2013 | Event News