Modern photovoltaic solar panels are not very efficient converting solar energy into electricity. They need to convert solar energy, which is inherently alternating current [AC], into direct current [DC], which then requires further electronics, an inverter, to convert DC back into AC to connect to the power grid. Seeing as solar panels today have maximum efficiency of 20%, there is clearly plenty of room for improvement.
Typical silicon solar panels are only reactive to a small part of the spectrum. Scientists and researchers have turned to nanotechnology to try and find a solution to the solar efficiency problem. Recently, we took a look at nano-antennae that are tuned to specific wavelengths of light to take advantage of more of the solar spectrum. One problem with this method, though, is that the nano-antennae need to get closer together in order to be more effective.
By combining two nanotechnology methods, nanowire growth and atomic layer deposition [ALD] researchers at University of Connecticut [UConn] have been able to bring the individual electrodes, the nano-antennae, within 1.5nm. Using ALD, copper atoms were deposited on the nano-antennae, making them highly reactive when exposed to sunlight.
Because the nano-antennae are reactive to more of the spectrum, they can convert, theoretically, up to 70% solar efficiency. Before combining ALD with nanowire synthesis, researchers were only able to get nano-antennae within 10nm, still much too far away to be effective.