Fiber cells, light pipes — Are they the future of organic PV?
Appearing today, a story I wrote for MIT Technology Review outlines work done at Wake Forest University in North Carolina. Researchers there, led by Prof. David Carroll, have developed a way to make low-cost organic solar cells that have more than double the efficiency of existing organic devices. The idea is to stamp evenly spaced but densely populated polymer fibres onto a substrate. The optical fibres, which protrude from the surface and function like “light pipes”, let sunlight enter from the tip. The sunlight gets trapped and bounces around inside the fibre until it is absorbed by the organic solar cell wrapped around it through a dip-coating process. Carroll has tested the design and found that it improves efficiency by 1.5 times compared to a flat cell design of similar chemistry. But more than that, the sunlight can enter the tips of the fibres at any angle, meaning it can accept sunlight from sunrise to sunset. This contrasts with flat or “planar” cells that must face the sun somewhat directly. Both of these features more than double efficiency.
It’s a fascinating example — and one of hundreds out there — of how innovation is driving real progress in the solar market.
Tyler Hamilton is editor-in-chief of Corporate Knights magazine and a business columnist for the Toronto Star, Canada's largest daily newspaper. In addition to this Clean Break blog, Tyler writes a weekly column of the same name that discusses trends, happenings and innovators in the clean technology and green energy market. This blog is a personal project started in April 2005. It is not an official blog of the newspaper.
