Zhengwei Pan and colleagues view the world's first single-phosphor, single-emitting-center-converted LED that emits warm white light.

Photos: Courtesy of the University of Georgia

Zhengwei Pan and colleagues view the world's first single-phosphor, single-emitting-center-converted LED that emits warm white light.

Solid-state lighting, which includes semiconductor-based LED, OLED, and PLED lighting technologies, has advanced quickly during the last decade, and now dominates a large portion of the lighting industry. Yet for all its benefits—such as long bulb-life, low energy consumption, and controllability—challenges remain. For example, despite the broad color capabilities of solid-state lighting, achieving a pleasing, warm white light has been a challenge.

“Right now, white LEDs are mainly used in flashlights and in automotive lamps, but they give off a bluish, cool light that people tend to dislike, especially in indoor lighting,” said University of Georgia associate professor Zhengwei Pan in a university press release. Pan and his research team have developed what they believe to be the world’s first warm white LED based on a single light-emitting phosphor. The material, which is a yellow luminescent compound made from europium oxide, aluminum oxide, barium oxide, and graphite powder, produces a warm white light when lit by a blue LED chip.

“Our material achieves a warm color temperature while at the same time giving highly accurate color rendition, which is something no single-phosphor-converted LED has ever been shown to do,” Pan said. The research suggests that LEDs may eventually be accepted much more broadly into interior spaces—territory that is currently challenged based on the color temperature limitations of conventional LEDs.

Blaine Brownell, AIA, is a regularly featured columnist whose stories appear on this website each week. His views and conclusions are not necessarily those of ARCHITECT magazine nor of the American Institute of Architects.