Record plastic solar cell efficiency set

WINSTON-SALEM, N.C., April 23 (UPI) -- U.S. scientists reported breaking the record for plastic solar cell efficiency, pushing it to more than 6 percent.

The Wake Forest University scientists achieved the record efficiency for organic or flexible, plastic solar cells by creating "nano-filaments" within light absorbing plastic, similar to the veins in tree leaves. That allows for the use of thicker absorbing layers in the devices, which capture more of the sun's light.

Traditional solar panels are heavy and bulky and convert about 12 percent of the light that hits them to useful electrical power.

Three percent was the highest efficiency ever achieved for plastic solar cells until 2005 when David Carroll, director of the Wake Forest nanotechnology center, announced his group had come close to reaching 5 percent efficiency. Now Carroll said his group has surpassed the 6 percent mark.

"Within only two years we have more than doubled the 3 percent mark," Carroll said. "I fully expect to see higher numbers within the next two years, which may make plastic devices the photovoltaic of choice."

The achievement is to be published in an upcoming issue of the journal Applied Physics Letters.