Flexible electronics, constantly refreshing your perception

At the 2nd International Conference on Flexible Electronics, R&D personnel showed on-site ultra-thin flexible chips that could be crimped and bent at will.

Not long ago, Huawei's first folding screen mobile phone became the focus of hot discussion. How to fold a square, hard, and irreversible screen? In fact, the folding screen is only a kind of flexible screen, which is developed from the accumulation of flexible electronic technology - it will constantly refresh people's cognition and bring a new experience in both shape and function.

In life, flexible electronics can not only fold the screen. In the future, flexible electronics will be developed from the development of daily electronic products such as mobile phones, tablets and TVs to medical, information, energy and national defense. During the second International Conference on Flexible Electronics held recently, the “Spicy Spicy” salon event launched by China Association for Science and Technology focused on the development of flexible electronic technology, and invited many industry experts and scholars to talk about how flexible electronics will change the future of mankind.

"To soften just" to help the Internet of Everything

"Human-computer interaction" is a magical word that vividly explains the process of adapting from human adaptation to computer to computer. At present, scientists are trying to establish a system of information transmission between people and the outside world using flexible electronic devices as a medium.

The concept of flexible electronics can be traced back to the study of organic electronics. Starting in the 1980s, people tried to replace inorganic semiconductors such as silicon with organic semiconductors, so that organic electronic devices have flexible characteristics.

In 2006, the scientific community first proposed the concept of ductile inorganic flexible electrons, and achieved flexibility and ductility in the case of brittle silicon films without changing their electronic properties. Later, some optimized structural designs were derived, which made the electronic device more excellent in mechanical properties and could withstand complex deformations such as stretching, torsion and bending.

In view of the wide variety of folding screen mobile phone products on the market, Shen Yang, deputy dean of the School of Materials Science and Technology of Tsinghua University, believes that the screen folding is mainly due to the flexibility of the display materials. But folding screen phones are not "soft" because there are hundreds of key electronic components in each phone, and these devices are still rigid. "In the future, if the flexibility of these electronic components is high enough, the mobile phone can not only fold in half, but also curl or even fold completely."

"To soften just" to create a new form of electronic device application. "Flexible electronic technology can change the rigid physical form of traditional information devices and systems, and realize information acquisition, processing, transmission, display, and energy flexibility." Feng Xue, director of Tsinghua University's Flexible Electronics Technology Research Center, said that flexible electronics will promote information and The efficient integration of people, objects and the environment helps to build a new era in which everything is connected.

Feng Xue told reporters that flexible electronic technology has been very important applications in the field of biomedical, including non-invasive blood glucose measurement, photoelectric blood oxygen sensor, sciatic nerve electrical signal acquisition, skin-like flexible deformation sensor, carbon nanofiber foam flexible pressure sensor, class A series of flexible medical electronic products such as skin flexible pressure sensors, and so on.

Electronic "band-aid" is not a dream

In science fiction movies, it is common to implant a chip into the human body to achieve a bridge that manipulates human behavior. And if the chip is attached to the skin like a band-aid, it will not cause harm to the human body. Would you accept it? The development of flexible electronics has brought this bold idea into reality – without wounds, it can be applied to medical perception and gain a lot of body signals and data.

“For example, for diabetics, blood glucose monitoring is an important part of the treatment, but the traditional method is to tie the fingers and tie them several times a day. And we can use flexible electronic technology to drive the blood vessels as long as they are attached to the skin surface. Glucose flows and monitors," Feng Xue said.

According to Feng Xue, the flexible electronic technology team of Tsinghua University has designed and mass-produced flexible electronic devices that are inexpensive and capable of monitoring body temperature and ECG information. It is shaped like a band-aid film with a flexible monitoring chip attached to the surface of the human body. It can wirelessly upload physiological indicators to mobile applications or the cloud, allowing users to quickly and easily understand the body information, and can be used repeatedly. Currently, it has passed the national medicine. Supervision Bureau and EU CE certification.

Flexible electronic integrated devices such as these, combined with the development of organic semiconductor and inorganic semiconductor technology, make inorganic semiconductor devices have the characteristics of stretchable, bendable and other deformation characteristics, and at the same time have the high performance and high reliability of traditional inorganic integrated devices and circuits. "Integrated detection of temperature, strain, acceleration and other sensing elements on flexible electronic devices is like 'body networking', which can achieve the acquisition of physical information; in the future, it is necessary to break through the reliable preparation process, dynamic tolerance and other technologies. Challenge.” Chen Xiaodong, a professor at the School of Materials Science and Engineering at Nanyang Technological University in Singapore.

"The stiffness of this new type of electronic device is much smaller than that of human tissue. Therefore, it will not cause discomfort to the human body after being attached to human tissue." Li Yuhang, an associate professor at the Institute of Solid Mechanics, Beijing University of Aeronautics and Astronautics, pointed out that the ductile performance is exactly The unique mechanical properties of flexible electronics, due to the extremely complex surface morphology of human organs and tissues, can not be attached to soft tissues if the device is not malleable, and this is not the case with traditional wires.

According to UN statistics, by the middle of this century, China will have nearly 500 million people over 60 years old. Concerns about human health have become an important direction for future social needs. In particular, real-time monitoring of chronic diseases and infant signs in the elderly has become an important application direction of this new medical device.

"Band-Aid" for measuring blood pressure and blood sugar, clothes for detecting physiological indicators, diapers for monitoring urine, artificial muscles... These intelligent wearable devices will be manufactured by flexible electronic technology. People can also carry out physical health monitoring through telemedicine, reduce medical costs, and benefit the public.

“The use of flexible chip technology can design a lighter, thinner and softer electronic sensing system that can better fit the robot or the human body, and the perception of the environment will become more sensitive.” Flexible Electronics Technology, Global Research Center for Flexible Electronics and Intelligent Technology Wang Bo, head of the R&D team, said that flexible chips will continue to have a profound impact on areas such as artificial intelligence and medical care.

Agglomeration of multidisciplinary wisdom and cooperation

Today, flexible electronic technology has become a research hotspot in the field of electronic technology worldwide. "Australia's research on flexible electronic technology is mainly focused on solar cells, using flexible electronic technology to achieve printing and printing into solar cells and other products." Paul Bourne, a professor at the University of Queensland and a member of the Australian Academy of Sciences, believes that the development of flexible electronic technology requires People from different disciplines learn from each other and seek common ground while reserving differences to promote more cooperation and promote more innovation and research results.

At this conference, the R&D team of the Center for Flexible Electronics and Intelligent Technology Global Research also released two ultra-thin flexible chips that can be arbitrarily crimped and bent. Both chips are less than 25 microns thick and less than a quarter of the diameter of a single hair.

The developer demonstrated the flexible microsystem function consisting of two flexible chips in the field. The two flexible chips are op amp chips and Bluetooth SoC chips, in which the op amp chip can amplify the analog signal, while the Bluetooth SoC chip integrates the processor and Bluetooth wireless communication. Compared with traditional chips, the newly released flexible chip is not only very thin, but also very flexible. Take it between two fingers and gently pinch it, the flexible chip will bend into a curve but will not be damaged.

However, Feng Xue pointed out that the development of flexible electronic technology is still in its infancy, and its biggest feature is the multi-disciplinary intersection, attracting people from different industries and different disciplines, and colliding with each other to provide different ideas and solutions.

In Chen Xiaodong's view, the future flexible sensor will occupy an important position in the development of the 5G era. "The device is made into a bendable and extendable state. It has no feeling on the body and the arm, and can present all the data about the human body. This is the higher realm and pursuit of scientists for future flexible sensors."

In this regard, the Flexible Electronics Technology Collaborative Innovation Center and the Tsinghua University Flexible Electronics Technology Research Center jointly initiated the establishment of the Flex.net Academic Alliance. The alliance integrates the superior resources and innovation power of all parties. The next step is to build a flexible electronic technology industry-university-research ecosystem through co-construction, sharing and sharing, and vigorously promote flexible electronic technology from laboratory to industrialization. (Reporter Guo Jingyuan)