Chinese scientists say they have developed a new type of light-emitting diode made from inexpensive, plastic-like organic materials.

The researchers said their new LEDs can produce twice as much light as a normal LEDs -- including the type of white light desired for home and office lighting.

"This work is important because it is the realization of rather high-efficiency white emission by a tandem structure," said Dongge Ma who led the research with his colleagues at the Changchun Institute of Applied Chemistry within the Chinese Academy of Sciences.

The researchers said they built their LEDs from organic, carbon-based materials, rather than from more expensive semiconducting materials such as gallium. And they produced, for the first time, an organic white-light LED operating within only a single active layer, rather than several sophisticated layers.

The scientists said they also placed two of the single-layer LEDs together in a tandem unit, thereby achieving even higher efficiency. Their LEDs attained a color-rendering index of nearly 70 -- practically good enough to read by.

The study appears in the Journal of Applied Physics.