 I'm not saying anything new if I tell you that sooner or later we're going to run out of fossil fuels. Running out of renewable energy will certainly change our daily lives as well as future generations. We have a renewable energy at glance to all of us, which is the sun. The sun raises every morning and if we don't take this energy efficiently, it laughs forever. So here we have a chance to gain renewable energy sources for our sustainable electricity consumption. If we look now at the energy of the sun that raises on all the earth's surface, we find out that most of the areas get more than 7 kilowatt-hour per unit square meter. This is about the third of a person in the Western world uses energy every day. So if we get solar cell devices that are very efficient, we will be able to be completely independent from other sources. Today, most efficient solar cells are called multi-junction solar cells because they use every color of the sun in a very efficient way to convert it into electricity. However, these devices use up very scarce elements such as gallium and indium. The question here now is do we have enough gallium and indium on the earth crust so that this technology can be available to all of us? Looking at all the resources that we have, is it realistic to use these high efficient solar cells for all of us and for everywhere in the planet? So we have to look at the availability of the elements on the earth crust and the most abundant elements are oxygen and hydrogen, mostly in the form of water. This is why the earth is called the blue planet. So now we can take this as a base to compare how much indium we have in our earth crust. And it turns out that the volume is not very huge. So we compare it to the whole earth crust. In fact, indium we have like two times the Halley comet. You will convene with me that this is a very small volume. So we will have to rationalize the use of this precious metal for the very precious solar cells. So the question is how we can do this? And what we can do is just to rationalize the use by going from bulk semiconductor wafers to nanoscale materials. So the idea here is to reduce the amount that we use in each device so the overall use is reduced too. These nanostructures are filamentary crystals with a diameter that is about 50 times less than a normal human hair. You will convene that this sparse array of nanostructures, in fact, uses much less material than a bulk semiconductor wafer. The question here is how can this sparse array of nanostructures have the same functionality as a bulky material? And it turns out that these nanostructures, thanks to their special shape and size, have very special properties when it turns to the absorption of the solar light. In fact, they absorb light not only from the sun impinging directly on them but also from the area around them. And it's thanks to this property that when we build a device we can have these filaments sparse next to each other because also they will be able to absorb light also in the empty space around them because these filaments act as concentrating lens, concentrating light all around them. The result is that we will reduce the amount of material used by a factor of a thousand and also the efficiency will be increased. So overall what we can see is that we can save a large amount of materials and by this we can save in the amount of the cost that this solar cell technology is costing us today. I can further illustrate this reduction in cost with an example. So imagine now that one of these very expensive solar cells that we can have in the market is the cost of a high-end car. So now we can reach from the bulk semiconductor technology to nanostructures and the cost would be reduced directly to the price of a pair of diamond rings. But we must do more. In fact, we have to look for materials that contain elements that are much more abundant than the earth crust, for example, like phosphorensic. Using this device that initially was so expensive will turn into the price of the weekly expenditure of a family. So I hope you will come in with me that I see a very bright feature for the solar cell technology. Thanks to the utilization of nanostructures and thanks also to their special properties when it turns to the absorption of the solar light. Thanks for your attention.