Two research teams have independently developed methods to produce nanowires that could lead to a dramatic improvement in solar photovoltaic cell efficiency. In both cases, the basic concept is the same, to use nanowires for more efficient conduction of electrons from the collection surface of a solar cell to an electrode.
The first technique, developed by researchers at UC San Diego, creates ‘hairy’ solar cells, only visible at a microscopic level. In fact, the hairs are nanowires, tiny metallic or silicon structures used to complete very small circuits. Researchers were able to grow nanowires directly onto a cheap conductive surface made of indium tin oxide. Nanowires were then coated with an organic polymer.
The second team, a consortium between three German universities (Jena, Gottingen and Bremen) and Harvard, has developed a technique to bond nanowires with spun glass. The approach is based on a kind of high-tech ‘sandwich,’ whereby nanowires are placed between a highly conductive bottom layer and a metallic top one, with spun-on glass forming a ‘spacer layer’ to prevent the circuit from shorting. This means that current can run smoothly along the nanowires and could lead to a completely new class of efficient integrated circuits.
There are still a few teething problems with the San Diego approach, the chief one being that the polymer layer currently degrades when exposed to air. However, if either approach can be made to work on a commercial scale, it could lead to smaller, cheaper and easier to install panels. Perhaps we’ve just moved one small step closer to a solar future.
written by Design, May 25, 2008
written by Ryan, May 30, 2008
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