"Solar cells are usually grouped in large arrays, often on rooftops, because each cell can generate only a limited amount of power. However, not every building has enough space for a huge expanse of solar panels. Using carbon nanotubes (hollow tubes of carbon atoms), MIT chemical engineers have found a way to concentrate solar energy 100 times more than a regular photovoltaic cell. Such nanotubes could form antennas that capture and focus light energy, potentially allowing much smaller and more powerful solar arrays."