Led by Soo-Young Park, a professor of organic materials for photonics at the Department of Materials Science and Engineering at Seoul National University in Korea, researchers from Seoul National University and University of Valencia in Spain have developed the world’s first pure white LED.

Currently, due to the cost factor, white LEDs are produced by adding fluorescent powder to tint blue LEDs. Many have been trying to develop different practical LED recipes and components, but there is considerable difference in terms of Color Rendering Index (CRI), though it is difficult to achieve high luminous efficacy and CRI simultaneously. By the same token, white LEDs can be produced by adding a particular phosphor material to UV LED. As for the high-cost, high-CRI RGB, white LEDs are achieved by incorporating all three RGB LED chips.

(Credit: the Journal of the American Chemical Society.)

The most notable aspect is that Park and his researchers have engineered a molecule that combines two light-emitting materials, orange and blue, to produce a white light in the visible light spectrum. The molecule consists of two noninteracting chromophores showing excited-state intramolecular proton transfer.

Laboratory studies showed that the new LED has high luminous efficacy, excellent color stability and reproducibility, all of which are features that make it a practical white light source. Park expressed that an ideal material for white-light source should “be cost-effective, stable, and robust, emit over the whole visible spectrum, not suffer from self-absorption, and its pure color should be easily reproducible.”