Wy艣wietlacz OLED na grafenie fizyk贸w z Uniwersytetu 艁贸dzkiego. Pierwszy w Polsce

Scientists from the Faculty of Physics and Applied Informatics, University of Lodz have created a prototype of a display in OLED technology (the technology using self-contained organic light sources) with a graphene electrode. Thanks to the plasticity and transparency of graphene, it may be a breakthrough in the development of the so-called flexible electronics, enabling the construction of plastic (freely bending) monitors, screens and displays. This is the first such a device in Poland and one of the few worldwide.

Dr hab. Pawe艂 Kowalczyk from the University of Lodz emphasizes:

This is not a theoretical model, but an actual working device. We have managed to create a transparent structure that works with OLEDs, which will enable usage of all flexible electronics solutions in practice.

A unique solution by scientists from Lodz is modification of the graphene layer with rhenium oxide from which the electrode was made.  

Dr Pawe艂 Krukowski explains:

This was necessary because graphene, although 98 percent flexible and transparent, has an inadequate level of the so-called operation of the output, which makes the LED flash. Only when we have added a rhenium oxide layer to the graphene layer, the output work level turned out to be optimal.

Scientists from Lodz are now working on improving their flexible display, examining its operation in detail.

Flexible electronics is the direction of development of, for example, image transmitting devices to ensure maximum plasticity. As a result, rigid, heavy and bulky monitors and OLED displays will be replaced by bending ultra-thin (a few nanometres) screens that virtually any arbitrarily shaped surface (e.g., car windows, building facades, clothes) can be covered with.  The image emitted by them is to equal or even exceed the quality of that of the monitors and displays produced today, in which the brittle indium tin oxide is used to build the electrodes.

Women with LED hair, i.e., graphene works miracles. Interview with the creators of the OLED technology display prototype.

Or maybe we already live in a simulated world, which is a projection so well performed that we cannot distinguish it from reality? There are scientists in the world who are trying to prove this thesis.

We are talking with dr. hab. Pawe艂 Kowalczyk and dr. Pawe艂 Krukowski  from the Faculty of Physics and Applied Informatics at the University of Lodz about flexible monitors, screens, displays and about how they are going to change our lives.

Marcin Kowalczyk: TV sets the size of a ping-pong table, smartphones, tablets, laptops, displays in cars, on household appliances or in virtual reality goggles - recent years have been a time of extraordinary development of devices for transmitting the image. They are everywhere, each of us uses at least a few...

Dr hab. Pawe艂 Kowalczyk: That鈥檚 true, we live in a civilization of mass access to electronic devices that emit high-quality images. More and more often, in the OLED technology, using self-contained organic light sources.

Both of you are scientifically involved in optoelectronics, so who to ask, if not you, what we will watch TV and Netflix series on, what smartphones will we use in 10-15 years?

Pawe艂 Kowalczyk: Interesting issue... The year 1968, Kubrick's film "A Space Odyssey 2001", and devices that are deceptively similar to tablets used by its heroes, immediately come to my mind. Back then it was absolute science fiction, today we use tablets every day.

- This is a vision from fifty years ago, and technologies of today have accelerated significantly...

Pawe艂 Kowalczyk: Exactly, the world is changing faster. I think flexible electronics will dominate the development of display devices. We will be able to cover the most bizarrely shaped surfaces, e.g., corners of buildings with plastic screens; I can imagine, for example, cars that have all the pillars on the inside covered with flexible monitors displaying the image from the outside so that the driver can avoid the danger of blind spots. The displays are already fitted as standard in many car models, and soon their flexible and transparent versions may cover the windows of cars to support the driver and provide entertainment to the passengers.

Dr Pawe艂 Krukowski: Flexible monitors will also appear in the most ordinary glasses. Yes, the kind you are wearing right now. In your free time, for example during a long train ride, you will be able to watch a movie on such monitors glued to the glasses from the inside, read messages, or e-mails...

- And the television?

Pawe艂 Kowalczyk: It will be on everything and everywhere. It will even chase us. No matter where you go, there will be an image from flexible monitors. Is it normal? Healthy? I do not know, we will see鈥

- With the screens going super-flexible, will I be able to roll up the TV set like a sleeping mat and take it on vacation?

Of course. Development is going this way - to always keep these devices with you and for them not to be an obstacle. Imagine that you have a smartphone in your pocket, but for example in the form of a pen, and you take the scrolled screen out of its side. It's much more handy than the current rigid, rectangular smartphones, right?

- Full agreement. But today OLED monitors are already characterized by remarkable image quality, but also by weight, stiffness and bulky nature.

Pawe艂 Krukowski: Flexible systems produced today (for example, bent, so-called spherical TV screens), even if they can be bent, must be covered with a rigid coating, as otherwise they degrade and lose their display properties. And the stiff shell breaks when trying to re-elasticize ... In addition, currently ITO (indium tin oxide) is used as the electrode, which has a basic disadvantage - it is brittle, so it is not suitable for flexible devices. Additionally - ITO is very expensive.

So how will it be possible to achieve lightness, flexibility, not to say: the plasticity of displays and screens that you are talking about?

Pawe艂 Kowalczyk: It is already happening. I am a fan of technological innovations, so I carefully looked at the Samsung Fold smartphone, the first phone with a foldable screen. It decomposes and I have either a mini-tablet or a smartphone. You can open and close such a phone-screen tens of thousands of times and it still works. Motorola also already uses this solution in its models, such as Razor. It may not be fully flexible electronics yet, but the beginning of it.

Pawe艂 Krukowski: Higher-generation flexible displays have been shown at exhibitions and scientific conferences many times. For now, they are not widely available, mainly due to price which is prohibitive for the common user. Therefore, you need to look for ways to produce them cheaper.

- Apparently you are already doing it at the University of Lodz...

Pawe艂 Kowalczyk: We are working with a material called graphene, a crystalline form of carbon that has only two dimensions - width and length, and the thickness of exactly one atom. So it is practically invisible. There is a lot of carbon around, so the assumption is that graphene will be very cheap in the future.

Pawe艂 Krukowski: Graphene is flexible, transparent, and has a light transmittance of 98 percent. It also has this great advantage that it conducts electricity and heat very well, so it is an ideal material to make a flat electrode, which will supply electricity to a flexible monitor.

- So to the millions of LEDs that make up the monitor?

Pawe艂 Kowalczyk: Yes. To LEDs that make up a very high-quality image, drawing it like pixels. Graphene officially appeared in 2004; then the first results of research on it were published, and the creators of graphene received the 2010 Nobel Prize in Physics. Meanwhile, at the University of Lodz, we were already working with this material in 1999. But then it was called "the thin layer of coal". Back then, graphene was underestimated, today it is a super hit in science and electronics. The possibility of using it to produce OLEDs opens up amazing possibilities of flexible electronics. And that's what we're working on.

- Are the results promising?

Pawe艂 Kowalczyk: This year, we have managed to build a working prototype of an OLED display with a graphene electrode at the University of Lodz. This is definitely the first such a device in Poland and one of the few in the world. We have proved that efficient OLEDs based on graphene can be successfully produced, which gives a chance to produce a display in the future.

Pawe艂 Krukowski: However, graphene has an inadequate level of the so-called work of the output, which - if it is optimal - makes the LED flash. That is why we modified it with rhenium oxide, adding its layer to the graphene layer. Nobody in the world has done this before (so far molybdenum oxide was used). It turned out that graphene with the addition of a 3-5 nanometre thick rhenium oxide layer can successfully act as an anode in an OLED, giving it the right amount of energy.

- Was it a breakthrough?

Pawe艂 Kowalczyk: Actually yes. This is the first device in the world to be based on rhenium oxide. And I emphasize: everything we are talking about here is not theoretical models, but real devices. We have created a transparent structure that successfully cooperates with OLEDs, enabling the use of all flexible electronics solutions in practice.

- The product is already here, and how about its possible commercialisation. Do you hope that your solutions will be used in the production of, for example, rolled up TVs or smartphones?

Pawe艂 Kowalczyk: Certainly, although we are only at the beginning of the road. We still have a lot of technical problems to solve. As for the production itself, there is no semiconductor industry in Poland that would allow the production of a matrix according to our idea. We do have rhenium at hand, which is abundant in the copper basin in Lower Silesia.

Pawe艂 Krukowski: And big billions for implementations would be still useful (laughter). For now, we are focusing on researching the device we have created; we want it to work even more efficiently. For example, you can use 20 volts to power it, but who carries a 20 volt battery with them? We need 3 volts, which is the voltage provided by a battery. And this is one of the things we are working on.

- Let's assume that the optimisation is successful, that there will be plastic, flexible displays in the number that currently exist in classic, rigid ones, of which each of us has at least a few at hand. How will this change our environment? Let's fantasize a little more...

Pawe艂 Kowalczyk: (smile) I'm very imaginative, can I? I imagine, for example, that ladies, and maybe also gentlemen, dye their hair... with flexible TV screens, because these ultra-thin plastic systems shining with millions of microscopic diodes can successfully braid human hair. Then each hair is a separate OLED TV screen.

- ??!

Yes, yes, you haven't misheard. A simpler thing is a classic manicure, or maybe not a classic one, because nails, or actually tips, will be OLED monitors that shine like micro tv sets. Let's go further: flexible OLED displays that cover clothes will be a breakthrough in the textile industry.

- Sorry, but how is this supposed to work?

It鈥檚 very simple 鈥 clothes will shine. After all, the technology allows flexible displays to be placed on single fabric fibres and to control the colour of the LEDs. So such clothes will be able to change colour depending, for example, on the mood of the person wearing them. I'm in a good mood today - I'm changing the colour of the dress to green. I'm sad? It's gray. Not only that, thanks to such clothes you can see me well at night, because they shine. So, at least road safety - a value that cannot be overestimated. LED diodes are already widely used as elements of external car lighting. What if the entire hoods of cars were lit, not just the headlights? Thanks to flexible monitors, this will not be a problem.

- Let's go back for a moment to "dyeing" hair with OLEDs, because earlier I was left speechless: do I understand correctly that these screens would be sprayed on hairstyles?

Exactly. People are already working on the so-called printed electronics. We have also tried to do it with one of the companies from Lodz. And if we can print something, why not spray it with a spray? Not only on hairstyles, but also on entire buildings. Flexible electronics is an ocean of possibilities, for example for advertising. We have the Manhattan housing estate in Lodz, which, after applying flexible screens on the facades of skyscrapers, could become one large advertising space or a monitor for showing films.

- Visions like from "Return from the stars" by Lem, or rather like from the dark "Blade Runner" ... Where are the limits of the development of this technology?

- Flexible electronics, like the human mind, offer virtually unlimited possibilities. In the theoretical model, we will be able to cover everything with screens. I will go even further, but I do not know if you will write it: maybe everything is already covered with screens, maybe we live in a world that is just a projection, but so well performed that we are unable to distinguish it from the reality?

- Well, now you have turned my brain inside out ... And in turn now the Matrix movie came to my mind. 

I am quite serious. There are scientists who are already looking for evidence that we live in a simulated world, that we do not really exist, but are in some machine. There is even a reward for proving this thesis. This is probably due to the fact that the quality of the images displayed to us more and more resembles those real ones. Do you remember your first computer games: Atari, that joystick, those squares that keep moving?

I remember. I used to play a little.

It was the beginning. Today, these are games that operate at such a level of realism that comes closer and closer to the reality. And that is only 30 years in the history of computer development. Entering these games, putting on VR goggles, we already feel like in the real world, and yet the resolution will only increase, it will become consistent with the one characteristic of the human eye and we will not actually notice the difference between the game world and the real world.

Five years ago I had the opportunity to test Virtual Reality and "fly a helicopter" over the Matterhorn in goggles, but the image of the Alps was still a bit hazy, indistinct, a bit like in a cinema...

Yes, but now with 700 pixels, VR has entered the 4K resolution level. Is there a difference? And let's take the entire military complex where progress is being made fastest. Imagine a tank covered with screens that make it invisible because the screens transmit the image from behind the tank. And in urban planning and architecture? I can imagine cities or houses that look transparent because they are covered with screens transmitting the image from behind them.

Were they so ugly that it was decided to make them "disappear"?

Yes, "disappear" is a good word. Or, for example, to display forests, fields, meadows on these screen houses...  

One big wall mural: HD to the power of 4K?

Yes! I think we will go this way, that it will happen. The question of money remains. But I think they will find money sooner or later, because someone will surely get a taste of the business here.

The interview was conducted by: Marcin Kowalczyk

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