Solar Cell = LED

The latest news in the field of energy science is a solar cell made of inexpensive organic laminates that can also function as an LED.

Imagine T-shirts that light up, or a beach umbrella that collects solar energy to run a portable TV. How about really cheap solar collectors for the roof?

All this and more could come from cutting-edge research at Cornell that demonstrates a new type of organic semiconductor device which shows electroluminescence and acts as a photovoltaic cell. The device is the first to use an "ionic junction," which researchers say could lead to improved performance. Since organic semiconductors can be made in thin, flexible sheets, they could create displays on cloth or paper.

"Flexible means low-cost fabrication," said George Malliaras, Cornell associate professor of materials science and engineering, in whose laboratory the research was done. And that means another result of the research could be mass-produced, inexpensive solar cells.

The work is described in the Sept. 7 issue of the journal Science in a paper by Cornell graduate researchers Daniel Bernards and Samuel Flores-Torres, Héctor Abruña, the E. M. Chamot Professor of Chemistry and Chemical Biology at Cornell, and Malliaras.

That is the good news. What is the fly in the ointment?

Since the device was created by laminating together materials that are flexible, large quantities could be manufactured very cheaply by feeding two films together from rolls, Malliaras said. The next step, he added, is to try modifying the metal content of the semiconductors to make more efficient materials.

The fly is that the current efficiency of labratory models is not so hot.

However, there is compensation.

"There are tons of materials we can use," he said.

Which means that it is likely with the right combination of materials a commercially viable product is likely. As usual in these things, more study is warranted.