LED lightbulbs promise a highly efficient, nontoxic, long-lasting alternative to today's incandescent and halogen lightbulbs. Lighting entire rooms using LEDs has, however, proved both technically challenging and expensive.

Soraa, a startup based in Fremont, California, has developed a new type of LED that it says generates 10 times more light from the same quantity of active material used in other LEDs. The company's first product is a 12-watt bulb that uses 75 percent less energy than a similarly illuminating 50-watt halogen bulb. Company officials would not disclose the cost of the bulb, but say it will pay for itself in less than one year through energy savings.

LEDs contain a semiconducting material that lights up when current passes through it, and are commonly used for low-light applications such as illuminating computer screens.

LEDs are usually made by growing a thin layer of gallium nitride on top of a sapphire, silicon carbide, or silicon substrate.