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LED phosphors: better red makes brighter white


June 23, 2014
By Anthony Capkun


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June 23, 2014 – Chemists at Ludwig-Maximilians-Universitaet (LMU) in Munich, Germany, say they have developed a type of red phosphor material that “significantly enhances the performance” of white-emitting LEDs.

In cooperation with Dr. Peter Schmidt of Philips Technologie GmbH in Aachen, a team of researchers led by Dr. Wolfgang Schnick has developed a new material for application in LEDs. “With its highly unusual properties, the new material has the potential to revolutionize the LED market,” said Schnick.

The new material is based on the nitride Sr[LiAl3N4]. When doped with an appropriate amount of europium (a rare-earth metal), the compound displays “intensive luminescence over a very narrow range of frequencies in the red band”. The first prototype LEDs incorporating the new material generate 14% more light than conventional white-light LEDs, say the researchers, and boast an “excellent colour rendering index [CRI]”.

“With its unique luminescence properties, the new material surpasses all red-emitting phosphors yet employed in LEDs, and has great potential for industrial applications,” concluded Schnick.

Schmidt and his associates at the Lumileds Development Center Aachen (Philips Technologie GmbH) are currently modifying the synthesis of the new red phosphor to optimize it for large-scale manufacture with the goal of paving the way to the next generation of brighter and more efficient white-emitting LEDs with the best possible CRI.