Continuing on yesterday’s improving-solar-panels beat, today we learn of a new process that can quickly create a solar surface that barely reflects any light and can clean itself. And the innovation comes from sunny Finland, of course.
Researchers at Aalto University (a recently formed conglomeration of three older Universities) created a new method — using deep reactive ion etching — for fabricating a pyramid-shaped nanostructure on a silicon surface. The silicon wafer, once etched, can then be used to create a stamp, making further wafer fabrication an easy additional step.
Generally, the smooth silicon surfaces used in solar cells reflect a lot of the light that hits them, lowering their efficiency. The shaped surfaces, though, barely reflect any light at all.
Water and particle accumulation on solar cell surfaces also increase the reflectivity, so the researchers went a step further. They coated the surface with a “low surface energy fluoropolymer,” which made it ultrahydrophobic. Water droplets that hit a solar cell with such a coating would quickly roll off, carrying dust and other particles with them. There are other strategies for dust removal on solar cells — including one that was developed for use on Mars, of all places — but no matter what the method it’s clear that keeping a cell clean will boost its efficiency by an enormous amount.
According to the researchers’ paper, which was published in the journal Advanced Materials: “High-throughput fabrication of low-cost self-cleaning surfaces, which suppress the reflection of light over a wide spectral range, is expected to have applications ranging from chemical analysis of drugs and biomolecules to photovoltaics.”
POSTED BY: Dave Levitan / Fri, November 05, 2010
(Image via Aalto University)