Separate research teams — one at the University of California at San Diego, the other a consortium of Harvard and three German universities (Jena, Gottingen and Bremen) — have developed methods to dramatically improve the efficiency of solar photovoltaic (PV) cells using nanowires.
The Harvard and German team has developed a technique to bond nanowires with spun glass. The approach is based on a kind of high-tech ‘sandwich,’ where nanowires run between a conductive bottom layer and a metallic top layer, with spun glass between to prevent a short circuit. This allows current to run smoothly along the nanowires and could lead to a completely new class of efficient integrated circuits.
The technique developed by researchers at UC San Diego creates hairy solar cells (though the hairs are visible only at a microscopic level). 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. The nanowires were coated with an organic polymer. This process still faces obstacles, such as the propensity of the polymer layer to degrade when exposed to air.
If either approach can be made to work on a commercial scale, it could lead to solar cells that are smaller, cheaper and easier to install than current versions.