Nanowires could boost solar cell efficiency
REUTERS/Jose Manuel Ribeiro
Solar panels have great potential to harness a powerful, renewable form of energy. But there's one problem: They just aren't hairy enough.
That could soon change. Two teams of researchers have independently come up with a way of using nanowires – which, as the name suggests, are microscopically small wires – to more effectively conduct the electrons that are knocked loose from materials on the surface of the silicon solar cell as sunlight strikes it. Current thin-film photovoltaic cells are basically just a flat surface that provide no direct conduit for the electrons to get to the electrode. But by making the surfaces hairy – that is, by adding nanowires to the surface of the cell – you can provide millions of defined pathways for the electrons, making the panel more efficient.
One technique, developed by researchers at UC San Diego, "grows" the nanowires directly onto a cheap conductive surface made of indium tin oxide. The nanowires are then coated with an organic polymer. The scientists hope that this method will allow the solar nanowires to grow on curved surfaces, such as rooftops or cars. Newswise reports that this method could deliver six to seven times a much energy as conventional panels. “By growing nanowires directly on an untreated electrode surface, you can start thinking about incorporating millions or billions of nanowires in a single device. I think this is where the field is eventually going to end up,” says lead engineer Clint Novotny. “But I think we are at least a decade away from this becoming a mainstream technology.”