 So, a solar cell's job is to convert light from the sun into electrical energy. And in order for us to have access to that electrical energy, we need to wire up the solar cell. But the problem is that the wires on the front of the solar cell actually block some of the incoming light. But as you can see on this device, the wires cover about 5 to 10 percent of the surface and they act like metal mirrors reflecting sunlight away and that light can't be converted to electricity. So in the Tway group we wanted to figure out if there was a way to hide these wires and basically make them invisible to incoming light. So we started by studying a similar structure to solar cells. In this case we had a thin gold film on top of a sheet of silicon. This gold film was riddled with lots of tiny holes that are on the order of a few hundred nanometers. And when you look at this surface initially, you can see that it looks like a shiny golden mirror. So next we immersed the sheet of silicon with the gold wires on it into a chemical solution and within seconds the wires start to sink down into the silicon surface and through each hole in the wire grid pops out a silicon nanopillar. As soon as the nanopillars start popping out, there's a dramatic color change in the surface. It goes from clear to red to dark purple and this indicates that the wires are starting to be hidden from incoming light. When this process is complete, over 97% of light can be absorbed in this material even though gold covers 65% of the surface. So the huge advantage of our design over a conventional solar cell like this one is that we can cover nearly the entire surface with metal. What that means is that we have wires connected to every part of the device and we can therefore extract more electrical power and improve the device's efficiency. This is a huge advantage over conventional designs.