March 21, 08
Researchers Develop Cheap Efficient Hybrid Light LEDs/LECs

Researchers in California have developed a ground breaking new hybrid light (LEC) that will prove cheaper, longer lasting, more energy efficient and is as bright as traditional light emitting diodes (LEDs).

The technology, which blends traditional LEDs with newer light emitting electrochemical cells (LECs) could eventually be used to make cheap hi-definition televisions and other displays that are flat as film.

"Previous studies of LECs have always had problems with lifetime," said Yan Shao, scientist at the University of California, Santa Barbara and a coauthor on the study which appears in this month's issue of Advanced Materials.

"In our papers, we demonstrated for the first time that organic LECs can have a long lifetime; even longer time than organic LEDs."

LECs could spark a lighting revolution since they can be cheaply printed in large rollable films unlike the complicated and relitively expensive manufacture of LEDs. LEDs dim as they get old while LECs actually continue to brighten with age. The Hybrid LECs actually could last about 1000 times longer than standard LED sourced lighting.

Previous LEC models took minutes to reach full illumination, but with the develop of the hybrid light near instant light is now possible.

LEDs use fast and very tiny electrons to create light. LECs create light by rearranging bulkier and slower atoms that have gained or lost an electron, known as ions.

When an electrical switch is flicked on the hybrid light, electrons flow immediately along metal barium and light up the material. After about 20 minutes though a transition occurs. Iron ions separate and start creating light instead of the barium electrons.

"Before the transition it's an LED," said Shao. "After the transition it is an LEC."

Since the hybrid still needs the metal barium it won't be as easy to manufacture as a pure LEC, but "it's not any harder to make than an LED," said Shao.

"They [LECs] will compete with traditional LEDs," said Qibing Pei, a scientist at the University of California, Los Angeles who was not involved in the research. "Traditional LEDs are not suitable for high-resolution information display such as TV sets. The LECs can be."