 Here is Memo Garcia. Hey guys, great turnout today. Thank you. So I'll give you a little bit of background. Actually, Delia Milliron, who is one of the co-inventors of this technology, was supposed to give a talk, and she emailed me this morning because she just came back from Germany saying, hey, I'm a little tired, I don't think I give the talk. So do you mind giving the talk for me? And being a nerd myself, well, of course. Why wouldn't I like to spend my Sunday night with a bunch of other nerds talking about science? Science is great. I've been in science for a long time. So what I'm going to talk to you guys about today, clearly, smarter smart windows. So what does that really entail? All of us take advantage about windows. We don't, you know, we see windows every day. We don't really think about them. They're just kind of there, give us great views, kind of keep us warm during the day. But we could really make these windows from being dumb to being smart. But before we start talking about that, let's take a step back and let's look at the sun. So the sun provides us all the energy in the Earth. And the amount of energy that comes from the sun, this can be divided into three forms. The first amount of energy that we all kind of know of is ultraviolet. So ultraviolet basically allows polyd here to get tanned. If there's no ultraviolet light, all the Guido's would be looking like vampires, and we wouldn't be able to turn nice and dark. But this is a small portion of the sun's energy. It's only about 5%. The second kind of largest portion of light is a visible light. The light that you and I see with our eyes, it allows us to look through windows and allows us to look at different colors in the rainbow. This is about 43%. And the last portion of the sun is a near infrared portion of light. This is the heat that you and I feel in our skin. So if we're standing right outside and we feel that nice warmth, that comes from the near infrared portion of light. Now, when we're looking at a building and the sunlight's coming through, there's a few things that occur. You could either get the sun's energy into a building the long way, where you could use a solar cell and convert that into some form of electricity, and then use that electricity, place it into some form of light, and light up your room. Well, this is really inefficient. If you look at the amount of energy that came directly from the sun, at the end, you're only about using 2% of the sun's energy. That's really ineffective. Now, if we just have a window and we allow all that energy to go into the building, we could at least use about 30% to light the building. And this is pretty nice. But when you do that, what ends up happening is it can change. These windows are dumb. The environment changes. It gets cloudy. We really want to optimize the amount of energy that goes into a building. And one way of doing that is by taking these dumb windows that have a certain time of day really, really brightness. I know all of you guys have made this kind of face, especially when you're driving towards San Francisco around 530. You can't really see through your window. Into these smart windows where you can dim the brightness of the sun and allow it to make yourself a little happy and comfortable inside the building. Everybody knows these little memes. I like memes, so you're going to be seeing memes around here. Me gusta is really good. You're so bright. I love this guy. So how do we actually make these windows smart? And how do we control the amount of visible light that enters a building? Well, there's different ways of doing it. We do it with what's called electrochromic windows or electrochromism. So a typical electrochromic window is kind of designed like this. You have two pieces of glass and you have two materials attached to each piece of glass. These materials are essentially electrodes. So you have a counter electrode on one end and a working electrode. In the middle, we have an electrolyte. So this material, basically, it's a current barrier. It allows ions to go through the material, but it doesn't allow electricity to go through the material. But when you apply a small voltage across the window, you drive from the current electrode into the working electrode. And when you do that, it changes the optical properties of the material. So you essentially make it go from completely transparent to something that's dark and controls light. The great thing about this is it's completely reversible. So if you switch the polarity of the film, you're able to drive the current back and the film turns nice and transparent. So now that we have control of the light that goes through the window, we're able to use it to modify the conditions inside of a building. If it's too bright, let's dim it. If there's clouds outside, let's make it nice and transparent so it's much like it come into the building. And the great thing about this is that you really use a small amount of voltage so a typical 5-volt battery can control these windows. And the amount of energy that's required to turn it on is minimal to none. One light bulb is about 100 watts. We use less than a watt to turn these windows on. So you're still able to save a lot of energy by maximizing the amount of light that goes into the actual building. Now, it's great that we're able to control the visible portion of light, but we want to make these as smart as possible. And in order to make it really, really smart, we have to regulate the visible light. We also want to control the heat. And today, all the materials and all the window coatings that make smart windows out there cannot do this. So a core team of myself and a few other folks, there's a few people here, wanted to think about how can we actually make a window where you can control both the heat and the light. And in this case, instead of just getting savings and natural light from getting natural light into the building and reducing the artificial lighting, you're able to also control the amount of air conditioning and heating that you can use in the building. So this seems like a big task, but when you have a lot of nerds in the room and you start having a little brainstorming, well, cool ideas come out. So when I talked about essentially why we wanted to do this, I'm going to put this a little bit into perspective. So in the United States, about 63% of all the energy that we consume come from heating, cooling, and lighting a building. That's a lot of energy. A lot of energy. And if we really add up the amount of money that we spend doing this, it's equivalent to $40 billion a year. I bet a lot of these people didn't realize how much money and how much energy is spent in looking at these buildings. So why are we doing this? Why can't we just make use of something that's free that we see every single day, the sunlight, and make these kind of windows out there? So the first thing that we wanted to do when we were thinking about, well, how can we actually control the heat? Well, let's look at the essence of a material. So don't get too scared. I'm going to show you guys a plot. This plot is a plot of the transmission through the film as a function of wavelength, and it's split up into two regions. So these colors didn't come out through the perspective, but the visible portion is between 400 and 700, and the near and far portion is between about 700 and 2500. So when we started kind of browsing the catalog of materials that are available, there's a commonly formed material called transparent conducting oxide materials. So these materials are visibly transparent, but can't conduct electricity. Now, one known fact that I thought was really interesting when I started looking at these, these coatings, transparent conducting oxide materials, are actually put inside of all the refrigerators at supermarkets. So if you ever wonder why the refrigerator doesn't fog up, it's because they drive a little bit of current into these coatings, and it actually warms up that fogging. It keeps it nice and transparent. I thought that was cool, and since you guys are nerds, I'm pretty sure you guys will like something like that. So since it's electrically conductive, it actually allows you to absorb light in the near and far portion of the wavelength, and how does it do that? So the fact that it's electrically conductive means that there's a lot of free electrons in the material that are able to move, and when you drive current, it allows you to continue to drive electricity through the material. Now, when these free electrons come in contact with light, they collectively oscillate. Now, the frequency that they oscillate at absorbs the energy that's being hit on by the light, and that's how you're able to essentially absorb light in the near and far portion. The location or the frequency of the light absorption is dependent on the number of free electrons that you have in the material. So if you could control the number of electrons in the material, you could essentially control where you're going to be absorbing light through the film. And the beauty of it is that you could do this while still maintaining full visibility. So you're only looking at the heat portion of light. So we said, great, we have a material candidate. Let's make a film. So we started thinking about it, well, how are we going to make the film? Is the film just going to be completely flat? Or are we going to have some kind of texture, some kind of size inside of it? So when we started really considering it, we put the two next to each other and we consider, okay, well, what's going to happen if we put it in the same architecture that we were talking about, that two electrodes with electrolyte barrier? I'm going to only show you about half of that device just so we could get the point. But in the normal case, you're going to have these three electrons inside the material. In this case, you have a thin film and in this case, we're going to have nano crystal. Oh, the sexy signs were nano. Everything is nano nowadays. But we'll see why it's nano in a second. So when you drive a potential across the film, in this case, you form a negative bias, you're able to bring in electrons from the counter electrode. The number of electrons that you could put inside depended on the balance of charge you get from the electrolyte. So in this world, everything wants to be balanced. You want to have equal negatives and equal positives on both sides. So in order to get as much electrons in there, you want these ions to come and balance out that charge, but they only balance out at the interface of the material and the electrolyte. In a thin film case, the amount of area at the interface is really, really small. But in a nano crystal case, you're able to really pack a lot of material for the same volume, and it gives you a lot of surface area. So like my little friend over here says, so going nano gives you more surface area? Well, it sure does. And the fact that it gives you more surface area allows you to jam pack a lot more of electrons because you're able to have a lot more interface that you could balance the charge out. And by doing this, you could really extend the amount of range that you could move that frequency of light inside the film. Now, if you do the opposite and now switch the polarity, then you could really remove all the electrons. In this case, you can't really remove a lot because, well, the other side has a small amount of surface area. But in the nano crystal case, if your counter electrode is also nano crystal, you could remove a lot more electrons. So you're really expanding the range to see that you can move. So we say, great. Now we know what material we want to use. We want to know how we want to make the material. How do we actually do it now? So before I talk about that, I guess I want to kind of give you guys a point of perspective. What is nano? Well, nano, this is an example of a nano particle. It's about five nanometers in diameter. If you want to look at how thick this is compared to a piece of hair, it's 20,000 times smaller than a piece of hair. So it's really, really, really tiny. Holds about 5,000 atoms. So, I mean, that's a small amount of that. I mean, big atoms, but it's still a small amount. Now, if you compare it to an ant, it's about one million times smaller than an ant. So in order to really get an effective amount of electrical charge into the actual material, you have to make them really, really small. So how do we make them? Well, this is where the chemistry comes into play. What we wanted to do is we wanted to use a unique method of chemistry that's called wet chemistry. So what I'm going to show you here is basically a pot. Think of it as a pot. This pot is going to be filled with a liquid. In the liquid, what you want to do is you want to mix in different kind of salts. You're going to mix a salt that's going to make the core of the material, and you're going to mix in what we consider a dopant, the material that's going to be incorporated into the core nanocrystal. We incorporate this dopant because every dopant that you put into the core material gives you an extra free electron. So essentially you're able to pack a lot of electrons in there before you even put it in the device so you can control the amount of electrons that you start off with. When you mix these salts into this pot and you start to heat it up, what ends up happening is that the salts start to interact. And inside of it, we add these organic arms, or basically organic molecules. These organic molecules start to bind on the surface of the core material, and they essentially help the growth of the nanocrystals, and they also help the suspension of the nanocrystals. So in the end, when you have these nanocrystals completely formed at the size and shape that you like, these arms allow it to stay and swim stably inside the solution. So now you have a very nice, stable solution of little nanocrystals that are bumping each other and flying inside there. So when you have this ink full of material, you take this ink and you... Well, the beauty of using this colloidal method of chemistry is that you could control the size of the nanocrystals really, really nice. So shown here the same material at different sizes. How do you control the size? Well, you can control the size by using different arms. Some arms allow it to grow faster than other, or you can control the size by changing the temperature. Heat it a little bit higher, you're able to get bigger nanocrystals, or you can essentially just heat it at the same temperature but wait a little bit longer so it continues to form and form and form. So this gives you as a chemist a lot of freedom to control the morphology of the material that you want to use. Second of all, they're crystalline. So these are high-resolution transmission electron microscopes and these are essentially lattices of atoms put together. So just to give you guys a perspective, you're actually looking at the lattices of atoms aligned together. This is beautiful. To me, when I look at these images, I just think, wow. I don't know. It makes me kind of get a little quiet. Okay. So the beauty of this is that you can also control the amount of dopants that you want to put in there. How do you do that? Well, you just essentially control the amount of salt of dopant you put in the pot. Say you're making spaghetti. You want it really salty, add more salt. You're going to give you free electrons. You just add more dopant salt in the center. And so when you do this, you're essentially able to control where you want the starting point of absorption to start before you do it. So shown here is the optical density. So it's going to be the inverse of the transmission, essentially the amount of absorption that you get as a function of wavelength. So to remind you guys again, visible light is from 400 to 750. So you want this to be at zero. You don't want to absorb any light there. And near for a portion is from 750 to 2500. Here we have different percentages of that dopant that we incorporate. The more dopant you put in, the closer you get to the visible portion of light. And this is because you're able to put more electrons into the starting material. In an ideal situation, you want this to be as close to visible as possible so that when you start adding and removing electrons, you can get a wider range of absorption in the full near and far portion of light without affecting the visible portion. So now that we have these beautiful inks and these nice nanocrystals at the right electron concentration that we want to start off with, how do we make the windows themselves? So we take that ink and in lab, what we do is we dispense it on a piece of glass and we spin it really, really fast. As you spin it, the forces spread the liquid across the film and eventually cause all the liquid to dry. So what you have left behind is a nice uniform film of stacked nanocrystals. So this is a top-down image of the nanocrystals and this is a cross-section of the film. So you can see the film is really nice and uniform and this is actually an image of one of the coatings with a picture behind it. So you can see it's extremely transparent and you can see completely through it. And if you look at the morphology of how it looks on the film, essentially you have the core material in the center with all those organic molecule arms on the surface kind of separating the way that they stack. So these arms, they're beautiful in terms of forming and keeping the nanocrystals in suspension, but now they're nuisance. Why are they a nuisance? Well, they're organic. Organics really do not like to conduct electricity. So I want to bring in electrons from the bottom into the film. I have to get rid of these organics. So this kind of posed a challenge for us for a while and we had to think about a unique way to get rid of these organics without really messing up the film. So one technique that we came up with is replacing them with really, really small molecules that can be decomposed by heating at small temperatures. So we soak these films in a solution of formic acid. So formic acid is the same kind of organic molecule that binds to the surface, but it has a small chain. So it's a little tiny arm. Now they're like midget arms. When you put these midget arms and heat them at roughly 200 degrees Celsius, which is a small temperature, you're able to decompose them and now the core material touches each other. So you have now a really conductive porous network of nanocrystals inside of a film. Now we're excited. Now we could actually do stuff. So this sounds like it's pretty easy, but it took me about a year to do. So now that we have these beautiful things, we put them in the electrochemical cells, we drive a potential across them, and Success Kit came out really, really happy. We're able to maintain only a 3% change in visible transparency. It's pretty transparent, but we're able to block at least 50% of the sun's energy, which is what we wanted to do. So it was great. And not only did we do this, but we did this with materials that are really, really cheap, aluminum and zinc. So when you look at the cost of making these things, dramatically cheap. It's a good starting point, right? But it's not the ultimate goal. The ultimate goal is to make the heat and the visible light. So how do we do that? And why do we want to do this? So this is kind of a little cartoon of depicting my image of a universal window. So on a hot, cloudy, cold day, you want both the heat and the visible light to go in. Now, in a kind of, you know, kind of hot day, but it's slightly part of the overcast. I'm from Texas, and there's a lot of these days in Houston. You want all the light to come in, so you don't have to use your artificial lighting, but you want to block the heat out. And in a really, really hot day, like somewhere in Phoenix or in Arizona, you want to block both the near fray or the heat portion, and you want to block some of the visible light to make sure that that glare doesn't make you uncomfortable in the face. Well, you wanted to think about how can we do this in a novel and unique way? Well, there's materials out there that allow you to control the visible portion of light without really affecting the near and fray portion. So again, this is a plot of the transmittance through the film as a function of wavelength. From 400 to 800 is a visible portion. So you see it starts to change. There's a slight change in the near and fray, but get what you get. So we wanted to say, hey, how can we use these materials and incorporate them in our nanocrystal inks? So a core staff of other teams, same kind of team, sat down in a room and we started thinking, well, hey, we have these beautiful nanocrystals with these really organic ligands on the surface, these organic molecules on the surface. Can we replace them with metal clusters that can make that other material and have it all stable in a solution so that when you spin it into a film, you have all these nanocrystals embedded in a material that can allow you to have in a matrix that'll allow you to control the visible portion of light. So we went off and tried it out. So the chemistry that we came up with is stripping the surface. This little step right here is a really unique step. In nanocrystal science, it's really hard to keep these nanocrystals surface bare without organic molecules that's still stable inside of a solution. So we came up with a chemistry. This NObO4 is a chemical compound that just strips off the organics but still keeps it nice and charged so it can be balanced inside the solution. Then we threw in our little metal clusters and had the metal clusters get stuck on the surface of the nanocrystals. So at the end, what ends up happening is we have these nanocrystals that have these metal clusters on the surface of a stable water ink. So now not only are we using an ink, but it's a water. It's cheap. It's cheap and it's not hazardous. So you have a beautiful ink. Oops. You have a beautiful ink that's cheap, made out of cheap materials, and when it's spinned down, it has a nice matrix of nanocrystals that are bare and a matrix that's going to help you do the visible portion of light. So if you look at images of them that pop down in a cross-section, this is a top-down image of the actual film. You see all the little nanocrystals in there? All the little gap spaces are matrix material, and this image, to me, is beautiful. This is another cross-sectional transmission electron microscopy. If any of you guys have ever worked with microscopes or electron microscopes, you would appreciate this. We're lucky enough that we have the world's best microscopes next to our lab, so we're able to show them some of our samples and we took a nice cross-section. But these nanocrystals are about four nanometers in size. I mean, this is tiny stuff. Anyhow. So once we put them in there and we assemble them in the device that I showed you guys earlier, we start off at four volts and we apply a small potential. As you apply a small potential, you start to absorb the near and far portion of light. So essentially the nanocrystals start to get electrons injected inside and you're able to switch the amount of frequency from those electron oscillations. At a certain threshold, you reach a point where you start to absorb the visible portion of light. And the beauty of this is that you do it by just controlling the voltage. So imagine you have a little lever in your building and you just swivel it over and you start to control the light and you start to control the heat. That, my friend, is amazing. Now this isn't the greatest transmission, but that's because it was our first shot. So to me, this is another success kit. Unfortunately, I forgot to put them on here. So we start thinking, okay, now we know how to do it, how can we make better performance? So the next step that we want to do is, hey, well, let's control the number of nanocrystals versus the volume of matrix. So we start off here at zero percent, basically no nanocrystals in just the visible portion. As you start to add a little bit more nanocrystals, you start to get a little bit more near infrared. And then we saw this weird thing, 34 percent, you start to get an enhancement in the visible portion. Whoa, that wasn't expected. We just expected it to start absorbing a little bit more near infrared. As you start to add more, you get a little bit more near infrared and you start getting a little less of the visible because there's no more matrix. And then at a certain point, you have basically no matrix and almost all nanocrystals. 34 percent mark are able to get some near infrared, but you're able to get a lot more visible. Well, that's a shocking thing. We wanted to look into that. So we did. So shown here are actual examples of the windows. This is in the completely transparent state and this is after it's been blocked. And this one has the beauty 34 percent that I was mentioning earlier. This is just a film of the pure matrix. Absolutely no nanocrystals. So if you look at it, it's a lot darker. But the thicknesses are exactly the same. So when we started looking a little bit at the science, instead of having the nanocrystals be completely interfacial in all reality, the way that they look is they diffuse. They start to merge with the matrix. So you have this boundary that enhances the optical properties of the material. This is something new. And this was something we didn't expect works out for us. You need less material and you get better performance. I just want to kind of highlight that for a second. So, now that we were able to do that, well, what's the next step? Well, the next step is, hey, I showed you the window. It's only an inch by an inch. I can't call that a window, I guess. So how do you make that into a commercial perspective? Well, that's where I am today. So most of this work was stuff that I did for my PhD. I just finished this past May. And Delia, the person who was going to give the talk to myself, are founding a company to move forward on trying to commercialize this and trying to get this as large as possible and improve performance. So instead of going from a material discovery, we want to see them on all the buildings on-site. And so with that, I'll open up the floor with some questions, but before I do that, I have to give a pitch for the lab that we use because this is...Nerds are going to appreciate this building. This is a wonderful building. This building is the molecular foundry. It's a nano institute in the Valley National Laboratory, state-of-the-art, about seven years old. There's six floors. And these floors overlook the bay, by the way, so you guys would be a little jealous because you have the best views of the bay. Each one of these floors are dedicated to different forms of nanoscience. The sixth floor focuses on organic and macromolecular science. The fifth floor talks about biological nanoscience. The floor that we worked on was inorganic nanostructures. The third floor focuses on theory, the stuff that we do. The second floor is nanofab, so we have a clean room, and you can see little bunnies like you see in the Intel commercials doing their stuff on lithography. And the bottom floor has all the crazy imaging techniques and electron microscopes. The beauty of this building is that anybody in the general public can apply to use this facility for free. So when you're trying to have a cool idea and you have no way of using any equipment, you send the proposal in. There's a committee that reviews it, and if they like your idea, you have access for a year for free. And the DOE, what it gets is it allows you to expand science with really cool ideas. If you're a company, what you get is you're able to have access to get to a certain point where you can start getting financing from venture capitalists or different people from angel investors that are inside there. This, to me, is the next generation of stuff. And if you think Mitt Romney's going to do this, please. All of this are like waiting, waiting for Obama to get elected so he could keep moving on there. I've had so much interaction as a graduate student with a lot of industrial partners and people, and I've learned so much about, hey, go from a core basic science to something that can practically be used and change the world. That's the things that I like, and that's kind of the direction that I want to keep going. So there's my little pitch. I just want to give you guys that little pitch. That's kind of our view. A little jealous. With that, I'll leave the floor open for any questions.