From imitation leather to humanoid robots. How does organic electronics work?

Electronics made from carbon, not silicon, can lead to a new generation of medical devices, sensors and perhaps even robots. Materials such as graphene may soon appear in electronic devices and lead to completely new forms of “chemical” computing and information storage. We tell you what organic electronics are, how it works and how this field of research will improve not only consumer devices, but also healthcare.

What is Organic Electronics?

It is an electronics industry that uses organic materials to make circuits and other electronic devices, mostly with a number of advantages over traditional inorganic materials that everyone is familiar with. This is a fairly new area, but its possibilities are endless and the results are already impressive.

Traditional electronics are based on solid silicon, which is used to create semiconductors. They are inorganic (that is, they do not contain carbon). On the contrary, organic electronics use molecules based on carbon – either small molecules or polymers, which are long chains of molecules. Almost all biological molecules are organic compounds, but also substances derived from hydrocarbons such as petrochemicals, oils and plastics. Many people may think of polymers in particular as non-conductive – for example, plastic polymers are used to insulate copper wires. But some organic polymers and molecules can conduct electricity.

How do they differ from traditional silicon based electronics?

Organic compounds have some advantages over non-organic compounds. They are lightweight, can be flexible and transparent – all very different from classic silicon technology. Their production can also be cheaper.

Why does organic electronics cause so much excitement?

There are so many organic compounds and a great variety of functional groups (atom clusters with their distinctive properties). Their electronic properties become very easy to configure by adding functional groups. Some functional groups give away electrons, and some give away electrons, so by combining them, scientists can very accurately adjust the necessary properties. For example, you can adjust the fluorescence for light-emitting diodes.

How did the new kind of electronics come into being?

Organic electronics appeared in the 1950s, when H. Inokuchi and his colleagues discovered the first conducting organic molecule. From this discovery, it was discovered that organic molecules can be semiconductors, a term commonly used for silicon, germanium and other similar elements. It turns out that organic semiconductors have several advantages over traditional semiconductors.

Organic semiconductors

В. Helfrich and WG Schneider, in turn, discovered that organic molecules can emit light. This property was first discovered in an anthracene molecule. The only drawback was that this effect required a high voltage, which made the discovery and possible future developments extremely ineffective. Then, in the 1980s, three scientists – Heeger, McDiarmid and Shirakawa – made conductive polymers, for which they won the Nobel Prize in Chemistry in 2000. A few years later, it was discovered that perylentetracarbon dianhydride – PTCDA, a molecule of organic dye that is still used in automotive paints, has semiconductor properties.

Another important milestone was the discovery of organic light-emitting diodes – OLED – semiconductor devices made of organic compounds that effectively emit light when electric current passes through them. This device was invented in 1987 by Ching Tang and Stephen Van Slyke of Kodak. The device could radiate light with a voltage of only 5 volts and it changed the display industry forever.

Where is this kind of electronics used now and what is its future?

According to Professor Andreas Hirsch, Head of the Department of Organic Chemistry at the Friedrich-Alexander University in Erlangen-Nuremberg, Germany, electronics made of carbon, not silicon, can lead to a new generation of medical devices, sensors and perhaps even robots.

“Probably most people will use screen technology. Organic LEDs (OLEDs) are now quite common in cell phones, and you can also buy TVs with them. But even before that, liquid crystal devices (LCDs), which can be considered a kind of organic electronics, have been used in many applications for years,” explains Hirsch in an interview for Richard Gray, Horizon.

“I’m convinced that in 50 years or so, you’ll see a lot more robots that look organic, they can perform functions that metal-based robots can’t,” the scientist says.

The range of applications of organic electronics

Organic electronics has a wide range of applications. Four of them can be called the most promising: displays, photovoltaic and transistor technologies and biomedicine.

Displays

OLED (Organic Light Emitting Diodes) is an innovative technology developed by Ching Tang and Stephen Van Slyke. OLEDs consist of an organic film that uses the property of phosphorescence to generate its own light instead of using backlighting. Phosphorescence is radiation due to the excitation of electrons that lasts for a long period of time. You may have noticed this in wrist watches and dials that glow in the dark.

Namsan Seoul Tower 1F- OLED Tunnel

Phosphorescence is a special type of photoluminescence. Unlike fluorescent, phosphorescent substances do not emit absorbed energy immediately. More remission time is associated with “forbidden” energy transitions in quantum mechanics.

The work of OLED is quite simple. The organic film consists of two layers: an emitting and a conductive one. There are holes at the border between the two layers. The emitting layer emits electrons, and the recombination of electrons and holes leads to the generation of photons that make up light.

Two types of OLED – with passive and active matrix

-The passive matrix OLED (PMOLED) has cathode strips and anode strips, they are perpendicular to each other. The intersections form pixels from which light is emitted. The external circuits supply current to the selected anode and cathode bands, determining which pixels will be on and which will remain off. The brightness depends on the value of the applied current. Their disadvantage is that they consume a lot of power and are therefore used in small screens such as PDAs (Personal Digital Assistant) and MP3 players.

-The second type of OLED is OLED with Active Matrix (AMOLED). AMOLED also has complete cathode, organic material and anode layers, but the anode layer overlaps the thin film transistor (TFT) matrix. The TFT array is a circuit that determines which pixels are included to form an image.

AMOLED consumes much less power than PMOLED because the TFT array requires less power than external circuits. As a result, it is suitable for large displays such as computer monitors, TVs and electronic billboards.

In turn, OLEDs have many advantages over LCD displays (liquid crystal displays). Traditional LCD displays are made up of many parts. Liquid crystals do not have their own backlight, so they use backlighting. In addition, the display designs have reflector sheets for improved brightness, diffuser sheets for light separation and uniform distribution, a bottom polarizer and top polarizer, a color filter for creating color light and of course liquid crystals, which are key elements. This dramatically increases the thickness of the screen.

Quantum light-emitting diodes (QLEDs) are in a different direction. They contain polarizers and color filters. They also need illumination because quantum dots cannot emit their own light. As a result these displays become too thick. OLEDs are slim, produce more absolute black than QLED and work better in dim light because each pixel is illuminated individually. OLED screens can be very thin. However, most companies and consumers choose OLED displays for their smartphones.

Photoelectric applications

Organic photovoltaic devices are mainly organic solar cells. As a photovoltaic material, polymers are usually used. One of the main advantages of using organic materials to produce solar cells is that the “optical absorption coefficient” of organic molecules is high, so large amounts of light can be absorbed by a small amount of material, usually about hundreds of nanometers. In addition, they are very flexible and much thinner than their silicon counterparts. While the current OPV (Organic Photovoltaic) technology boasts a conversion efficiency of over 10%, reaching even 12%, some researchers predict that organic solar cells will achieve 15-20% efficiency. They can also be rolled out and even composted.

And although we live in an increasingly electronic world, access to this world is limited. It is estimated that 1.3 billion people do not have access to electricity, and many rely on kerosene, batteries or diesel generators. Because of cheaper production costs, organic electronics promises not only to change the way people use technology, but also to increase its use for people who do not have access to the electricity grid.

The main disadvantage of organic photovoltaic cells is the low efficiency compared to inorganic photovoltaic cells such as silicon solar cells. But to solve this problem, research is being conducted and new materials are being discovered every day that can revolutionize the solar energy industry.

Flexible printed organic transistors

Transistors are the fundamental building blocks of modern electronic devices that either amplify signals or operate as switches. Organic Field Effect Transistor (OFET) is a field effect transistor that contains conductive electrodes, organic semiconductor and dielectric. Its special feature is that it uses very little power to patrol a very high current and also acts as a good switch. Such transistors are manufactured by printed circuits using organic dyes on a flexible basis. Special care is taken to ensure that no contaminants get into the material, as this can negatively affect the conductivity of the material.

Printed circuit using OFET
Yasunori Takeda et al/Wikimedia, licenced under CC BY 4.0

Over the past few years, interest in OFET has grown tremendously and there are reasons for it. OFET can compete with amorphous silicon (a-Si) in its characteristics. As a result, there is now an increased interest in the industrial use of OFET for applications that are currently incompatible with a-Si or other inorganic transistor technologies. One of their main technological advantages is that all layers of OFET can be applied and structured at room temperature, making them ideally suited for low-cost, large area electronic devices on flexible substrates. Silicon needs to be heated to high temperatures above 40 °C in order to cast it into a mould. However, it is too early to talk about the wide spread OFET because of imperfect technology.

Biomedicine

Another important application of organic electronics is medicine. For example, for the treatment of blindness using a retinal chip that is implanted in the eye. The device registers the light signals coming into the eye and converts them into electrical signals, which are sent to the brain. Electrodes coated with organic dyes transmit electrical signals to the receptor cells in the eye.

The composition must be biocompatible. The choice of suitable materials and a mixture of components is crucial. Right now, this has allowed patients with blindness to perceive light and darkness, the outlines of objects, sometimes even letters and facial expressions. The scientists’ goal is that the device not only has a high resolution, but also a good performance. This is a great example of how technology and medicine work together to improve people’s lives.

The Future of New Electronics

The field of organic electronics in the future will continue to develop in ways that are unimaginable today. Some ideas have already been implemented, such as OLED smartphones, TVs and inexpensive solar panels that are installed on rooftops in rural areas. In the future, folding smartphones will become more common, and, for example, electronic skin, which by its tactile sensitivity imitates human skin, will require more time for development. Other predictions are not yet possible, because the application possibilities are diverse and cover many areas – medical and biomedical research, energy and the environment, communications and entertainment, home and office furniture, clothing and personal accessories and much more.

Organic electronics can also make the production, use and disposal of electronics more environmentally friendly. Scientists and engineers are looking for ways to make new electronics more energy efficient than today’s silicon-based designs.

What are the benefits of using organic electronics for electronic production?

1. New opportunities

Organic materials have unique properties that cannot be achieved with silicon-based electronics. Their properties include sensitivity, biocompatibility and flexibility. Sounding is the use of electronic devices to determine chemical or biological substances in the environment or on the human body.

Scientists envision biosensors that not only determine glucose levels in people with diabetes, but also actually distribute the appropriate insulin dose at the right time. Not only are organic electronic materials more chemically compatible with biological systems than silicon-based devices; they also give the substance flexibility, extensibility and mechanical “softness.

Together, these properties create potential for innovative bioelectronic sensors that can match the curvature and moving parts of the human body.

2. Energy Efficiency

As scientists and engineers continue to improve the synthesis and characterization of organic materials for use in electronics, they hope that the use of such materials will lead to more energy-efficient electronic displays, lighting fixtures and other devices.

For example, it is necessary to make organic solar cells more efficient so that they can be used in places such as Northern Europe and most of Russia, where nights are very long and there are only short periods of sunlight, especially in winter.

Engineers are trying to create devices from organic materials that last longer, are recyclable or maybe even biodegradable. Methods of producing organic electronics will also become more energy efficient, reducing the number of steps and methods to recover lost heat.

3. Less waste, more safety

The use of organic materials to create electronic devices gives hope that future electronics manufacturing methods will rely on fewer raw materials, and it will be safer.

Materials can be saved by relying on less wasteful processes such as printing. Materials are added to structures or devices layer by layer as they are created, unlike centrifugation, which involves the removal of materials and disposal of excess.

In addition to using fewer materials, chemists are looking for ways to use safer materials. For example, many polymers require carcinogenic solvents. Some solvents are not even allowed in the EU printing industry because of their toxicity.

4. Sustainable electronics

Creating more environmentally friendly electronic products is not only about creating more “greener” solar panels or other devices, but also about using more “greener” production methods. Environmental sustainability should be applied at every stage of the production cycle, from obtaining raw materials to waste disposal. Organic materials can channel electronics into the future in a more environmentally sustainable way than is possible in today’s electronic world.

Finally, “green electronics” implies that the electronics themselves are durable. The universal nature of organic electronics, combined with the promises this field makes for environmental and social sustainability, points the way to a very long lasting set of technologies.

Market situation

According to Allied Market Research, by 2027 the organic electronics market will reach $ 159.1 billion with an average annual growth rate of 21.0%. Growth in demand due to the introduction of sustainable technologies and the need for organic electronics to develop the latest technologies has driven growth in the global organic electronics market. Based on materials, the semiconductor segment accounted for the largest share in 2019. Depending on the region, the Asia Pacific market had the lion’s share in 2019.

In addition, this week a large report “Volume, share, growth and report until 2020-2028” was released. According to this report, in the forecast period, the global market for organic electronics will only grow. This research report looks at the market landscape and prospects for its development in the near future. After studying the key companies, the report focuses on new participants contributing to market growth. Most companies in the global organic electronics market are currently mastering new technological trends in the market.

Finally, researchers shed light on various ways to identify strengths, weaknesses, opportunities and threats that are affecting the growth of the global organic electronics market.

Some of the key players operating in this market include such companies as Fujifilm Dimatix, AU Optronics, BASF, Bayer MaterialScience, H.C. STARCK, DuPont, Koninklijke Philips, LG Display, Sumitomo, Merck, AGC Seimi Chemical, Novaled, Samsung Display, Sony, Universal Display, Heliatek, Evonik and others.

What in the end?

Over the past few decades, the field of organic electronics has clearly achieved tremendous success: Many devices are already on the market and many prototypes are under development. This field will continue to grow, changing the way society interacts with technology as chemists, physicists and other scientists and engineers solve research problems. Interdisciplinary research and training programs that bring together scientists and engineers from different fields of knowledge as well as from different sectors of activity (e.g. academia, industry, government) will facilitate the collaborative efforts needed to address these challenges.