 Hello, I'm Dr. Peter Harrocks, Chairman of ID Tech X and always excited to come to the Fraunhofer Institutes which are a massive benefit to Germany and linked all over the world of course and in this particular case we have one Fraunhofer Institute exhibiting a large number of things here at the ID Tech X show and I want to ask for an introduction please. Yeah, thank you. My name is Manuel Gensler from the Fraunhofer Institute of Applied Polymer Research, IAP. We are situated here in Potsdam-Gol and we are doing a lot of topics dealing with fluid processing of thin films like the techniques to apply the films, printing techniques and also from the material side to make OLEDs, to make organic photovoltaics and also to develop new printing techniques such as the electrostatic printing. Alright, so what are we looking at here with these bright colours? So here the bright colours, those are actually quantum dots, cadmium free quantum dots. You mentioned cadmium here which rather surprised me it's been banned in the East Sea, isn't it? Cadmium is in danger of getting banned in the European Union for display applications as well. At the moment there is still an exclusion but this is in danger so there is a huge interest of cadmium free quantum dots and we have great expertise in making indium based cadmium free quantum dots. Like LG and Samsung? Like LG and Samsung who have a great interest but their quantum dots so far are cadmium based. How they told us indium? Already indium? They wrote to us and said they were on indium commercially and so they benefit from the... I thought the ban was coming in in October anyway, we need to do our homework on that I don't know but you're obviously concentrating on indium because it certainly will not be banned. They also have interest and contacts to our technologies because when it comes to the efficiencies indium is still a bit behind cadmium based quantum dots and that's where we're doing material research. Here you see some examples. Those are three different sized indium phosphide quantum dots illuminated by your V-light from the bottom and depending on the size for the larger sizes you get colors in the wet range over the yellow to the green range when you make them really small. Excellent. Now tell me about this multifunctional work that you're displaying here. I'm very interested in the trend away from components in a box to smart materials now with you know car body works going to be a super capacitor as well as photovoltaics and many multi-layer things are coming in and of course you can work at different sizes with different technologies can't you? Very small things you know maybe some 3D printed electronics and then medium sized products in mold structural electronics with TactoTec here and so on and big drones up in the sky and so on that's not going to be either of those it's already is real to real processes and laminations. Where do you come in multifunctional in your terms? What does that mean? So good yeah good good question. So multi functional. Okay yeah let's keep on let's stick to the examples of these these quantum dots. You have the core of the quantum dots which defines the colors of them and so now you can use them for different applications here in the fluids you see them as color converters. Absolutely yes. In a in a fluorescence way you can also make a different shell make the shell smaller to make them electro luminescent and that's what we have here we have the same quantum dots the orange and the green one in an OLED stack which are electro luminescent lighting here. So those multifunctional materials may they will they sometimes appear in devices that are multifunctional using the material for one thing and then another like self-powered piezoelectric energy harvesters used from the same piezoelectric or there's a triboelectric equivalent where you would act as a sensor but you create the power as well it's all same one material is one is it an optical equivalent there where they could be sensors and emitters with the same material or something like that. So the the polymers are usually optimized for for their purpose and emitting polymer has typically other properties than in than in light collecting polymer. So when you want to have a multifunctional device then you need to think of combining this more on a technical point of view by placing them clever. So we had applications we had an OLED in the wet range and a sensor nearby on a strip which could be used as a sensor application then. But to have them have the same material in the same stack for different applications and it's usually something that today not yet know. So your use of the word multifunctional is that the same base material could be when it is customized used for different functions in separate devices. Indeed there's no convergence plan at this point. What else should we be learning about? What other things have you on display today? Yeah so so this this here on this side is also quantum dots and this this is another ID application for the quantum dots. They are their phosphorescent here also illuminated by a bluish UV light and you see probably a barcode application here and this is kind of a security feature. So you have on the one hand a printed barcode which you could have on your on your drug paper and when you scan the barcode you see the whole history of this drug from the producer to the pharmacy store optionally to the to the doctor until you receive it and then you know you have the original drug. Additionally this barcode is printed with a quantum dot which has a very narrow emission bed and this is very difficult to reproduce by possible drug dealers. So only when you have this specific type of quantum dot and if you have the ability to make this you could you could you can print this security feature. That's very exciting isn't it? That's a major problem, a huge problem. That would be wonderful. Tell me about a very different world that you've got displayed behind me above my head of the world of perovskites. Am I right in saying that perovskites have two particular problems which is the practical use of the lid and the life. Tell us about how you address these. Yeah, indeed. So our main focus we had two EU projects where we developed perovskite printing. This was JAOPS and FlexPV and our task of main focus was there the scaling of the perovskite manufacturing from small lab scale to larger size. For example here we have a 15 by 15 perovskite inkjet printed layer which was then cured under a neared atmosphere and has a reasonable closed layer for further application. We could make perovskite solar cells with a size of up to 10 by 10 centimeters which had efficiency between 8 and 10 percent which is already quite good for that large size. When it comes to the problematic of lead these layer of perovskites are extremely thin. If you think of a to place this in a solar module and if you would solder the solar module with lead containing solder paste you would have more lead in the solder paste than in your perovskite module. And in the solar industry still today most of the companies use lead containing solder pastes. That's a relative problem absolutely and you did that in sandwiching glass did you? This is a demonstrator for the printing size. This is not a functioning OPV. This is just one layer sandwiched between glasses so that the perovskite is sealed inside. Of course when using this technology one also has to address the recycling issue. It is not much but of course we are aware that lead is a problem and there are ways by recycling to reduce also this low amount of lead contamination to the environment. That's good news and is this ongoing work where the EU project was finished? I mean ongoing we'd like to see you getting up to flexible and huge areas and low costs and so on. That's something we would really like to continue our work on and we are in the process of further project applications and we hope that we win one of the future calls to continue with work in this direction. There are two directions for instance in the laboratory some people I think claim over 20 percent efficiency so you hope to try to get up to that in practical terms. Is that right? That's right. On the small scale you are still much more efficient than we in the larger scale but we need to make the scale up also in terms of efficiency. With the single perovskite solar cells which we do but also with the application to use them as additional material on top of solar. That's my second point because in the UK where I come from that's starting to go commercial I think the coating to get how much extra efficiency. So as far as I remember they claim that they start from a commercial silicon based solar cell with around 20 percent efficiency and add something like additional 10 percent in the beginning in the early stages now and they say if they... 10 percent to 20 percent is 2 percent. So their plan is to use the perovskite on top of a silicon based solar cell in a tandem stack. So the perovskite... So the solar cell has the issue that it's not very effective in the blue visible spectrum and this will be the job of the perovskite. And then the perovskite will collect mostly the blueish area of the light. The brownish-yellowish part will be transmitted to the silicon based solar cell and then you lower the efficiency of the solar cell because you already captured the blue part of the spectrum but you end up with something like 20 percent plus additional 10 percent and their goal is to achieve to get through the goal of 30 percent efficiency with this tandem stack. It really is 10 percent not 10 percent all of that's right. So 30 percent. That's a huge gain. When they claim if they can get further than 30 percent they can get further what will be ever possible with the silicon solar cells. Do you do... Holy crystal and solar cells. Holy crystal and solar cells. And if they achieve this goal they will be relevant on the market. So you would work on really prodding that with single crystal silicon is that sensible or not? That's a good question. So we are focused solely on the polar... So far we only worked on the perovskite solar cells not on the tandem cells. This was not work. We did. Right. So it's forward of now. And can you say if you would be interested in doing it with single crystal silicon? I mean I read that the Chinese are putting in massive capacity for single crystal silicon and making statements like the polycrystalline silicon will valence off the face of the earth because the single crystal will give you smaller areas or higher efficiency or one way or the other the higher efficiency will give you smaller areas or lower cost or whatever in the total system level. And if it is... Given they are not working on it now but in terms of your dream if you are able to fund and proceed with adding perovskites to the silicon solar cells do you think personally you would work on the polycrystalline? Is it sensible to try to? Is it? Indeed. I think the polycrystalline is still a good opportunity to combine the standard technique which is developed, which is affordable and a logical thing to do. And the coating processes can be done in principle with flexible versions? The things that we developed in this project the inkjet printing is fully compatible with flexible substrates. That's the way why we chose this pathway it's scalable, it's very material effective and it's compatible to many types of substrates. And when you have the perovskite on its own is it ever going to be tightly rollable do you think? We always had the dream of the... It never happened but Samsung issued all sorts of publicity five years ago it's always two years off wasn't it? My Samsung phone I was going to be able to pull it out and I have a big keyboard in photovoltaics and display and twang and it's shot back. I love that, that would be wonderful. I really like that but I don't see it anywhere but it is sometimes tightly rollable devices the problem is actually the transparent conducting electrode isn't it? Yes. What's the impediment with perovskite to do the photovoltaic part of that story? It's the same, you also need the transparent electron of course. Do they exist now do you think? They're tightly rollable, you know less than a millimetre diameter. That's still work to be done, still work in progress. There are advantages with silver nanowires, graphene may also be some solution but I'm not sure if today you could really reach the radius of a millimetre. Do you work on transparent conductive films at all? Yes, we work on them for many flexible OPVs and flexible OLEDs. We did flexible organic photovoltaics with polymer materials on foil. We did similar stuff with flexible OLEDs but in that cases we still used quite brittle high performance top electrodes from evaporation to have which are not bendable in the millimetre range but we are also using solvent processable transparent conductive electrodes such as silver nanowires. Are you in that area as well? They cannot be inkjet printed, at least we haven't found yet a formulation that can be inkjet printed but with other method, late coating for example, you can apply them in a good manner. Are there other possible routes that you're exploring beyond silver nanowires for transparent conductive electrodes that are very flexible, rollable? I don't know. The challenge is to get the good interconnections between the watts and don't making them too long so that they get brittle. So you need to have some flexible, ideally a very conductive polymer material which is flexible, bendable but still has a high enough conductivity. Yeah, absolutely. Because their large area is extremely acute. We keep an eye on the graphene market and there are some companies now who claim they achieved 20 ohms square with a transparency of 70 to 80%. This would be then interesting to test in OBD and OLED applications. And then the challenge would be to get the cost out in large area versions. That would be a real challenge but it doesn't mean it can't be done. I mean absolutely, I think what you're doing is very exciting and with our relative lack of knowledge of what you're doing, what questions should I have asked? What things have I not asked you about? Yeah, so we haven't talked yet about the sjet printing for example. The electrostatic printing which we were awarded for. Absolutely. Tell us too. Can you come around? He's down here. Okay, yeah. Closer? Maybe this way? Can you explain? Yeah, okay. Just looking for the right place to stay. So we just successfully finished the EU project high response and together with our partners we managed to print an active matrix OLED display with a size of 0.5 inch with a resolution of 300 dpi and an amount of approximately 65,000 pixels, each of them 10 micrometer and diameter only. And this wouldn't have been possible by traditional inkjet technology but in this project we were interested in the opportunities of a new technology called electrostatic jetting sjet technology which is shown above here. So we use an ultra fine glass needle which has a metal wire inside and this is connected to a high voltage supply and the counter electrode is below our substrate or the active matrix backplane. And by applying a high voltage field we force the ink out of the nozzle through a tailor cone onto the substrate without any moving parts, without the use of piezo and therefore we can print feature sizes much smaller than the nozzle diameter and by this achieving high resolution printing of organic materials such as p.pss which is shown here with diameters of only 10 micrometer and using this printing technology and printing them into well-defined cavities you'll see 15 micrometer cavities with the droplets which have diameters of 10 micrometers. We finally could print on the active matrix backplane of iMac and TNO the Holtz Center which they provided to us and we were filling the small white dots here with of 10 nanometer diameter each by printing and using a traditional inkjet printer we would just head of droplets that were twice the size but here we were able to hit each and every single pixel finally achieving separate illuminating pixels in the active matrix backplane and the demonstrator was able to show the different logos of the partners one after another because it is a inkjet printed active matrix display and for this one we won here the best academy academic award it's there the price the screen the screen is at the moment at the booth of iMac it's only the way we're going to iMac okay let's go so how far is iMac? we are almost there it's a cool show right? we are here every year in Berlin and it's a really great show so that's the screen here so that's the screen we move the cap this is the printed this is the printed display we printed one of the organic layers by sjet the second layer is spin coated and the third layer is evaluated and this is a top emitting OLED is this the first printed active matrix OLED? no, no, not the first printed active matrix OLED but it is it is the first sjet printed active matrix OLED meaning it is so far the printed OLED with the highest resolution with the smallest pixel size so the highest pixel density printed OLED so due to the back plane it stills having it is 300 ppi the pixels have a pitch of 75 micrometer but the pixel size of only 10 micrometer or diameter shows the capability for future applications and with respect to the pixel size we had a breakthrough and we showed that the breakthrough and resolution will be possible so the breakthrough is it possible to have a printed OLED with all the colors the saturation everything? indeed, so if you go to the post art to take this one so here you see the distance from column to column is 75 micrometer this defines the 300 ppi which our demonstrator had but in the long single columns we have pixel distances of only 25 micrometer and the back plane is ready for RGB it is now the next step to print three different OLED materials namely a red, a green and a blue one one after another so that we have a red, green blue, red, green blue pixel which then make up a full RGB amulet display is that how amulet is usually? no, no, no color amulet, how do you do? normally, there are different ways to do this there are applications where they make them square you have two blues crossing each other and a green one on the other side this way in every line in every column you only have two colors you can get higher resolution in this type of application but there are various kinds of how to organize the pixels here it was the reason to apply them this way was that the back plane is also a special development by our academic partners so it's not a commercial back plane but this has specifically been developed for our project here and in terms of resolution it's also something new for TNO to make their amulet displays in this small size