Category Archives: graphene

A nonvolatile photo-memristor

Credit: by Xiao Fu, Tangxin Li, Bin Caid, Jinshui Miao, Gennady N. Panin, Xinyu Ma, Jinjin Wang, Xiaoyong Jiang, Qing Lia, Yi Dong, Chunhui Hao, Juyi Sun, Hangyu Xu, Qixiao Zhao, Mengjia Xia, Bo Song, Fansheng Chen, Xiaoshuang Chen, Wei Lu, Weida Hu

it took a while to get there but the February 13, 2023 news item on phys.org announced research into extending memristors from tunable conductance to reconfigurable photo-response,

In traditional vision systems, the optical information is captured by a frame-based digital camera, and then the digital signal is processed afterwards using machine-learning algorithms. In this scenario, a large amount of data (mostly redundant) has to be transferred from a standalone sensing elements to the processing units, which leads to high latency and power consumption.

To address this problem, much effort has been devoted to developing an efficient approach, where some of the memory and computational tasks are offloaded to sensor elements that can perceive and process the optical signal simultaneously.

In a new paper published in Light: Science & Applications, a team of scientists, led by Professor Weida Hu from School of Physics and Optoelectronic Engineering, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, China, State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai, China, and co-workers have developed a non-volatile photo-memristor, in which the reconfigurable responsivity can be modulated by the charge and/or photon flux through it and further stored in the device.

A February 13, 2023 Chinese Academy of Sciences press release, which originated the news item, provided more technical detail about the work,

The non-volatile photo-memristor has a simple two-terminal architecture, in which photoexcited carriers and oxygen-related ions are coupled, leading to a displaced and pinched hysteresis in the current-voltage characteristics. For the first time, non-volatile photo-memristors implement computationally complete logic with photoresponse-stateful operations, for which the same photo-memristor serves as both a logic gate and memory, using photoresponse as a physical state variable instead of light, voltage and memresistance. Polarity reversal of photo-memristors shows great potential for in-memory sensing and computing with feature extraction and image recognition for neuromorphic vision.

The photo-memristor demonstrates tunable short-circuit current in a non-volatile mode under illumination. By mimicking the biological functionalities of the human retina and designing specific device structures, the devices can act as neural network for neuromorphic visual processing and implementation of completely photoresponse-stateful logic operations triggered by electrical and light stimuli together. It can support various kinds of sensing tasks with all-in-one sensing-memory-computing approaches. These scientists summarize the operational principle and feature of their device:

“We design[ed] a two-terminal device with MoS2-xOx and specific graphene for three purposes in one: (1) to provide low barrier energy for the migration of oxygen ions; (2) to perform as geometry-asymmetric metal–semiconductor–metal van der Waals heterostructures with multi-photoresponse states; and (3) as an extension of a memristor, this device not only provides tunable conductance, but also demonstrates reconfigurable photoresponse for reading at zero bias voltage.”

“Moreover, the tunable short-circuit photocurrent and photoresponse can be increased to 889.8 nA and 98.8 mA/W, respectively, which are much higher than that of other reconfigurable phototransistors based on 2D materials. To reverse the channel polarity and obtain a gate-tunable short-circuit photocurrent, the channel semiconductor must be thin enough. Thus, it is difficult to use the thick film needed to absorb enough light to get a large signal. In our case, the mechanism of the two-terminal device rearrangement is based on ion migration, which is not limited by the thickness. We can increase the thickness of the film to absorb more photons and get a large short-circuit photocurrent.” they added.

“This new concept of a two-terminal photo-memristor not only enables all-in-one sensing-memory-computing approaches for neuromorphic vision hardware, but also brings great convenience for high-density integration.” the scientists forecast.

Here’s a link to and a citation for the paper,

Graphene/MoS2−xOx/graphene photomemristor with tunable non-volatile responsivities for neuromorphic vision processing by Xiao Fu, Tangxin Li, Bin Caid, Jinshui Miao, Gennady N. Panin, Xinyu Ma, Jinjin Wang, Xiaoyong Jiang, Qing Lia, Yi Dong, Chunhui Hao, Juyi Sun, Hangyu Xu, Qixiao Zhao, Mengjia Xia, Bo Song, Fansheng Chen, Xiaoshuang Chen, Wei Lu, Weida Hu. Light: Science & Applications volume 12, Article number: 39 (2023) DOI: https://doi.org/10.1038/s41377-023-01079-5 Published: 07 February 2023

This paper is open access.

Treating cardiac arrhythmia with light: a graphene tattoo

An April 17, 2023 news item on Nanowerk announced research into a graphene cardiac implant/tattoo,

Researchers led by Northwestern University and the University of Texas at Austin (UT) have developed the first cardiac implant made from graphene, a two-dimensional super material with ultra-strong, lightweight and conductive properties.

Similar in appearance to a child’s temporary tattoo, the new graphene “tattoo” implant is thinner than a single strand of hair yet still functions like a classical pacemaker. But unlike current pacemakers and implanted defibrillators, which require hard, rigid materials that are mechanically incompatible with the body, the new device softly melds to the heart to simultaneously sense and treat irregular heartbeats. The implant is thin and flexible enough to conform to the heart’s delicate contours as well as stretchy and strong enough to withstand the dynamic motions of a beating heart.

Caption: Graphene implant on tattoo paper. Credit: Ning Liu/University of Texas at Austin

An April 17, 2023 Northwestern University news release (also on EurekAlert), which originated the news item, provides more detail about the research, graphene, and the difficulties of monitoring a beating heart, Note: Links have been removed,

After implanting the device into a rat model, the researchers demonstrated that the graphene tattoo could successfully sense irregular heart rhythms and then deliver electrical stimulation through a series of pulses without constraining or altering the heart’s natural motions. Even better: The technology also is optically transparent, allowing the researchers to use an external source of optical light to record and stimulate the heart through the device.

The study will be published on Thursday (April 20 [2023]) in the journal Advanced Materials. It marks the thinnest known cardiac implant to date.

“One of the challenges for current pacemakers and defibrillators is that they are difficult to affix onto the surface of the heart,” said Northwestern’s Igor Efimov, the study’s senior author. “Defibrillator electrodes, for example, are essentially coils made of very thick wires. These wires are not flexible, and they break. Rigid interfaces with soft tissues, like the heart, can cause various complications. By contrast, our soft, flexible device is not only unobtrusive but also intimately and seamlessly conforms directly onto the heart to deliver more precise measurements.”

An experimental cardiologist, Efimov is a professor of biomedical engineering at Northwestern’s McCormick School of Engineering and professor of medicine at Northwestern University Feinberg School of Medicine. He co-led the study with Dmitry Kireev, a research associate at UT. Zexu Lin, a Ph.D. candidate in Efimov’s laboratory, is the paper’s first author.

Miracle material

Known as cardiac arrhythmias, heart rhythm disorders occur when the heart beats either too quickly or too slowly. While some cases of arrhythmia are not serious, many cases can lead to heart failure, stroke and even sudden death. In fact, complications related to arrythmia claim about 300,000 lives annually in the United States. Physicians commonly treat arrhythmia with implantable pacemakers and defibrillators that detect abnormal heartbeats and then correct rhythm with electrical stimulation. While these devices are lifesaving, their rigid nature may constrain the heart’s natural motions, injure soft tissues, cause temporary discomfort and induce complications, such as painful swelling, perforations, blood clots, infection and more.

With these challenges in mind, Efimov and his team sought to develop a bio-compatible device ideal for conforming to soft, dynamic tissues. After reviewing multiple materials, the researchers settled on graphene, an atomically thin form of carbon. With its ultra-strong, lightweight structure and superior conductivity, graphene has potential for many applications in high-performance electronics, high-strength materials and energy devices.

“For bio-compatibility reasons, graphene is particularly attractive,” Efimov said. “Carbon is the basis of life, so it’s a safe material that is already used in different clinical applications. It also is flexible and soft, which works well as an interface between electronics and a soft, mechanically active organ.”

Hitting a beating target

At UT, study co-authors Dimitry Kireev and Deji Akinwande were already developing graphene electronic tattoos (GETs) with sensing capabilities. Flexible and weightless, their team’s e-tattoos adhere to the skin to continuously monitor the body’s vital signs, including blood pressure and the electrical activity of the brain, heart and muscles.

But, while the e-tattoos work well on the skin’s surface, Efimov’s team needed to investigate new methods to use these devices inside the body — directly onto the surface of the heart.

“It’s a completely different application scheme,” Efimov said. “Skin is relatively dry and easily accessible. Obviously, the heart is inside the chest, so it’s difficult to access and in a wet environment.”

The researchers developed an entirely new technique to encase the graphene tattoo and adhere it to the surface of a beating heart. First, they encapsulated the graphene inside a flexible, elastic silicone membrane — with a hole punched in it to give access to the interior graphene electrode. Then, they gently placed gold tape (with a thickness of 10 microns) onto the encapsulating layer to serve as an electrical interconnect between the graphene and the external electronics used to measure and stimulate the heart. Finally, they placed it onto the heart. The entire thickness of all layers together measures about 100 microns in total.

The resulting device was stable for 60 days on an actively beating heart at body temperature, which is comparable to the duration of temporary pacemakers used as bridges to permanent pacemakers or rhythm management after surgery or other therapies.

Optical opportunities

Leveraging the device’s transparent nature, Efimov and his team performed optocardiography — using light to track and modulate heart rhythm — in the animal study. Not only does this offer a new way to diagnose and treat heart ailments, the approach also opens new possibilities for optogenetics, a method to control and monitor single cells with light. 

While electrical stimulation can correct a heart’s abnormal rhythm, optical stimulation is more precise. With light, researchers can track specific enzymes as well as interrogate specific heart, muscle or nerve cells.

“We can essentially combine electrical and optical functions into one biointerface,” Efimov said. “Because graphene is optically transparent, we can actually read through it, which gives us a much higher density of readout.”

The University of Texas at Austin issued an April 18, 2023 news release and as you would expect the focus is on their researchers, Note 1: I’ve removed many but not all of the redundancies between the two news releases; Note 2: A link has been removed,

A new cardiac implant made from graphene, a two-dimensional super material with ultra-strong, lightweight and conductive properties, functions like a classic pacemaker with some major improvements.

A team led by researchers from The University of Texas at Austin and Northwestern University developed the implantable derivative from wearable graphene-based electronic tattoo, or e-tattoo – graphene biointerface. The device, detailed in the journal Advanced Materials, marks the thinnest known cardiac implant to date.

“It’s very exciting to take our e-tattoo technology and use it as an implantable device inside the body,” said Dmitry Kireev, a postdoctoral research associate in the lab of professor Deji Akinwande’s lab at UT Austin who co-led the research. “The fact that is much more compatible with the human body, lightweight, and transparent, makes this a more natural solution for people dealing with heart problems.”

Hitting a beating target

At UT Austin, Akinwande and his team had been developing e-tattoos using graphene for several years, with a variety of functions, including monitoring body signals. Flexible and weightless, their team’s e-tattoos adhere to the skin to continuously monitor the body’s vital signs, including blood pressure and the electrical activity of the brain, heart and muscles.

But, while the e-tattoos work well on the skin’s surface, the researchers needed to find new ways to deploy these devices inside the body — directly onto the surface of the heart.

“The conditions inside the body are very different compared to affixing a device to the skin, so we had to re-imagine how we package our e-tattoo technology,” said Akinwande, a professor in the Chandra Family Department of Electrical and Computer Engineering.  

The researchers developed an entirely new technique to encase the graphene tattoo and adhere it to the surface of a beating heart. …

Here’s a link to and a citation for the paper,

Graphene Biointerface for Cardiac Arrhythmia Diagnosis and Treatment by Zexu Lin, Dmitry Kireev, Ning Liu, Shubham Gupta, Jessica LaPiano, Sofian N. Obaid, Zhiyuan Chen, Deji Akinwande, Igor R. Efimov. Advanced Materials Volume 35, Issue 22 June 1, 2023 2212190 DOI: https://doi.org/10.1002/adma.202212190 First published online: 25 March 2023

This paper is open access.

Mind-controlled robots based on graphene: an Australian research story

As they keep saying these days, ‘it’s not science fiction anymore’.

It’s so fascinating I almost forgot what it’s like to make a video where it can take hours to get a few minutes (the video is a little over 3 mins.) and all the failures are edited out. Plus, I haven’t found any information about training both the human users and the robotic dogs/quadrupeds. Does it take minutes? hours? days? more? Can you work with any old robotic dog /quadruped or does it have to be the one you’ve ‘gotten to know’? Etc. Bottom line: I don’t know if I can take what I see in the video at face value.

A March 20, 2023 news item on Nanowerk announces the work from Australia,

The advanced brain-computer interface [BCI] was developed by Distinguished Professor Chin-Teng Lin and Professor Francesca Iacopi, from the UTS [University of Technology Sydney; Australia] Faculty of Engineering and IT, in collaboration with the Australian Army and Defence Innovation Hub.

As well as defence applications, the technology has significant potential in fields such as advanced manufacturing, aerospace and healthcare – for example allowing people with a disability to control a wheelchair or operate prosthetics.

“The hands-free, voice-free technology works outside laboratory settings, anytime, anywhere. It makes interfaces such as consoles, keyboards, touchscreens and hand-gesture recognition redundant,” said Professor Iacopi.

A March 20, 2023 University of Technology Sydney (UTS) press release, also on EurekAlert but published March 19, 2023, which originated the news item, describes the interface in more detail,

“By using cutting edge graphene material, combined with silicon, we were able to overcome issues of corrosion, durability and skin contact resistance, to develop the wearable dry sensors,” she said.

A new study outlining the technology has just been published in the peer-reviewed journal ACS Applied Nano Materials. It shows that the graphene sensors developed at UTS are very conductive, easy to use and robust.

The hexagon patterned sensors are positioned over the back of the scalp, to detect brainwaves from the visual cortex. The sensors are resilient to harsh conditions so they can be used in extreme operating environments.

The user wears a head-mounted augmented reality lens which displays white flickering squares. By concentrating on a particular square, the brainwaves of the operator are picked up by the biosensor, and a decoder translates the signal into commands.

The technology was recently demonstrated by the Australian Army, where soldiers operated a Ghost Robotics quadruped robot using the brain-machine interface [BMI]. The device allowed hands-free command of the robotic dog with up to 94% accuracy.

“Our technology can issue at least nine commands in two seconds. This means we have nine different kinds of commands and the operator can select one from those nine within that time period,” Professor Lin said.

“We have also explored how to minimise noise from the body and environment to get a clearer signal from an operator’s brain,” he said.

The researchers believe the technology will be of interest to the scientific community, industry and government, and hope to continue making advances in brain-computer interface systems.

Here’s a link to and a citation for the paper,

Noninvasive Sensors for Brain–Machine Interfaces Based on Micropatterned Epitaxial Graphene by Shaikh Nayeem Faisal, Tien-Thong Nguyen Do, Tasauf Torzo, Daniel Leong, Aiswarya Pradeepkumar, Chin-Teng Lin, and Francesca Iacopi. ACS Appl. Nano Mater. 2023, 6, 7, 5440–5447 DOI: https://doi.org/10.1021/acsanm.2c05546 Publication Date: March 16, 2023 Copyright © 2023 The Authors. Published by American Chemical Society

This paper is open access.

Comments

For anyone who’s bothered by this, the terminology is fluid. Sometimes you’ll see brain-computer interface (BCI), sometimes you’ll see human-computer interface, or brain-machine interface (BMI) and, as I’ve now found in the video although I notice the Australians are not hyphenating it, brain-robotic interface (BRI).

You can find Ghost Robotics here, the makers of the robotic ‘dog’.

There seems to be a movement to replace the word ‘soldiers’ with warfighters and, according to this video, military practitioners. I wonder how medical doctors and other practitioners feel about the use of ‘practitioners’ in a military context.

Future firefighters and wearable technology

I imagine this wearable technology would also be useful for the military too. However, the focus for these researchers from China is firefighting. (Given the situation with the Canadian wildfires in June 2023, we have 10x more than the average at this time in the season over the last 10 years, it’s good to see some work focused on safety for firefighters.) From a January 17, 2023 news item on phys.org,

Firefighting may look vastly different in the future thanks to intelligent fire suits and masks developed by multiple research institutions in China.

Researchers published results showing breathable electrodes woven into fabric used in fire suits have proven to be stable at temperatures over 520ºC. At these temperatures, the fabric is found to be essentially non-combustible with high rates of thermal protection time.

Caption: Scientists from multiple institutions address the challenges and limitations of current fire-fighting gear by introducing wearable, breathable sensors and electrodes to better serve firefighters. Credit: Nano Research, Tsinghua University Press

A January 17, 2023 Tsinghua University Press press release on EurekAlert, which originated the news item, provides more technical details,

The results show the efficacy and practicality of Janus graphene/poly(p-phenylene benzobisoxazole), or PBO, woven fabric in making firefighting “smarter” with the main goal being to manufacture products on an industrial scale that are flame-retardant but also intelligent enough to warn the firefighter of increased risks while traversing the flames.

“Conventional firefighting clothing and fire masks can ensure firemen’s safety to a certain extent,” said Wei Fan, professor at the School of Textile Science and Engineering at Xi’an Polytechnic University. “However, the fire scene often changes quickly, sometimes making firefighters trapped in the fire for failing to judge the risks in time. At this situation, firefighters also need to be rescued.”

The key here is the use of Janus graphene/PBO, woven fabrics. While not the first of its kind, the introduction of PBO fibers offers better strength and fire protection than other similar fibers, such as Kevlar. The PBO fibers are first woven into a fabric that is then irradiated using a CO2 infrared laser. From here, the fabric becomes the Janus graphene/PBO hybrid that is the focus of the study.   

The mask also utilizes a top and bottom layer of Janus graphene/PBO with a piezoelectric layer in between that acts as a way to convert mechanical pressures to electricity.

“The mask has a good smoke particle filtration effect, and the filtration efficiency of PM2.5 and PM3.0 reaches 95% and 100%, respectively. Meanwhile, the mask has good wearing comfort as its respiratory resistance (46.8 Pa) is lower than 49 Pa of commercial masks. Besides, the mask is sensitive to the speed and intensity of human breathing, which can dynamically monitor the health of the firemen” said Fan.

Flame-retardant electronics featured in these fire suits are flexible, heat resistant, quick to make and low-cost which makes scaling for industrial production a tangible achievement. This makes it more likely that the future of firefighting suits and masks will be able to effectively use this technology. Quick, effective responses can also reduce economic losses attributed to fires.

“The graphene/PBO woven fabrics-based sensors exhibit good repeatability and stability in human motion monitoring and NO2 gas detection, the main toxic gas in fires, which can be applied to firefighting suits to help firefighters effectively avoiding danger” Fan said. Being able to detect sharp increases in NO2 gas can help firefighters change course in an instant if needed and could be a lifesaving addition to firefighter gear.

Major improvements can be made in the firefighting field to better protect the firefighters by taking advantage of graphene/PBO woven and nonwoven fabrics. Widescale use of this technology can help the researchers reach their ultimate goal of reducing mortality and injury to those who risk their lives fighting fires.

Yu Luo and Yaping Miao of the School of Textile Science and Engineering at Xi’an Polytechnic University contributed equally to this work. Professor Wei Fan is the corresponding author. Yingying Zhang and Huimin Wang of the Department of Chemistry at Tsinghua University, Kai Dong of the Beijing Institute of Nanoenergy and Nanosystems at the Chinese Academy of Sciences, and Lin Hou and Yanyan Xu of Shaanxi Textile Research Institute Co., LTD, Weichun Chen and Yao Zhang of the School of Textile Science and Engineering at Xi’an Polytechnic University contributed to this research. 

This work was supported by the National Natural Science Foundation of China, Textile Vision Basic Research Program of China, Key Research and Development Program of Xianyang Science and Technology Bureau, Key Research and Development Program of Shaanxi Province, Natural Science Foundation of Shaanxi Province, and Scientific Research Project of Shaanxi Provincial Education Department.

Here are two links and a citation for the same paper,

Laser-induced Janus graphene/poly(p-phenylene benzobisoxazole) fabrics with intrinsic flame retardancy as flexible sensors and breathable electrodes for fire-fighting field by Yu Luo, Yaping Miao, Huimin Wang, Kai Dong, Lin Hou, Yanyan Xu, Weichun Chen, Yao Zhang, Yingying Zhang & Wei Fan. Nano Research (2023) DOI: https://doi.org/10.1007/s12274-023-5382-y Published12 January 2023

This link leads to a paywall.

Here’s the second link (to SciOpen)

Laser-induced Janus graphene/poly(p-phenylene benzobisoxazole) fabrics with intrinsic flame retardancy as flexible sensors and breathable electrodes for fire-fighting field. SciOpen Published January 12, 2023

This link leads to an open access journal published by Tsinghua University Press.

Graphene-based nanoelectronics platform, a replacement for silicon?

A December 31, 2022 news item on phys.org describes research into replacing silicon in the field of electronics, Note: Links have been removed,

A pressing quest in the field of nanoelectronics is the search for a material that could replace silicon. Graphene has seemed promising for decades. But its potential has faltered along the way, due to damaging processing methods and the lack of a new electronics paradigm to embrace it. With silicon nearly maxed out in its ability to accommodate faster computing, the next big nanoelectronics platform is needed now more than ever.

Walter de Heer, Regents’ Professor in the School of Physics at the Georgia Institute of Technology [Georgia Tech], has taken a critical step forward in making the case for a successor to silicon. De Heer and his collaborators have developed a new nanoelectronics platform based on graphene—a single sheet of carbon atoms. The technology is compatible with conventional microelectronics manufacturing, a necessity for any viable alternative to silicon.

In the course of their research, published in Nature Communications, the team may have also discovered a new quasiparticle. Their discovery could lead to manufacturing smaller, faster, more efficient and more sustainable computer chips, and has potential implications for quantum and high-performance computing.

A January 3, 2023 Georgia Institute of Technology news release (also on EurekAlert but published December 21, 2022] by Catherine Barzler, which originated the news item, delves further into the work

“Graphene’s power lies in its flat, two-dimensional structure that is held together by the strongest chemical bonds known,” de Heer said. “It was clear from the beginning that graphene can be miniaturized to a far greater extent than silicon — enabling much smaller devices, while operating at higher speeds and producing much less heat. This means that, in principle, more devices can be packed on a single chip of graphene than with silicon.”

In 2001, de Heer proposed an alternative form of electronics based on epitaxial graphene, or epigraphene — a layer of graphene that was found to spontaneously form on top of silicon carbide crystal, a semiconductor used in high power electronics. At the time, researchers found that electric currents flow without resistance along epigraphene’s edges, and that graphene devices could be seamlessly interconnected without metal wires. This combination allows for a form of electronics that relies on the unique light-like properties of graphene electrons.

“Quantum interference has been observed in carbon nanotubes at low temperatures, and we expect to see similar effects in epigraphene ribbons and networks,” de Heer said. “This important feature of graphene is not possible with silicon.”

Building the Platform

To create the new nanoelectronics platform, the researchers created a modified form of epigraphene on a silicon carbide crystal substrate. In collaboration with researchers at the Tianjin International Center for Nanoparticles and Nanosystems at the University of Tianjin, China, they produced unique silicon carbide chips from electronics-grade silicon carbide crystals. The graphene itself was grown at de Heer’s laboratory at Georgia Tech using patented furnaces.

The researchers used electron beam lithography, a method commonly used in microelectronics, to carve the graphene nanostructures and weld their edges to the silicon carbide chips. This process mechanically stabilizes and seals the graphene’s edges, which would otherwise react with oxygen and other gases that might interfere with the motion of the charges along the edge.

Finally, to measure the electronic properties of their graphene platform, the team used a cryogenic apparatus that allows them to record its properties from a near-zero temperature to room temperature.

Observing the Edge State

The electric charges the team observed in the graphene edge state were similar to photons in an optical fiber that can travel over large distances without scattering. They found that the charges traveled for tens of thousands of nanometers along the edge before scattering. Graphene electrons in previous technologies could only travel about 10 nanometers before bumping into small imperfections and scattering in different directions.

“What’s special about the electric charges in the edges is that they stay on the edge and keep on going at the same speed, even if the edges are not perfectly straight,” said Claire Berger, physics professor at Georgia Tech and director of research at the French National Center for Scientific Research in Grenoble, France.

In metals, electric currents are carried by negatively charged electrons. But contrary to the researchers’ expectations, their measurements suggested that the edge currents were not carried by electrons or by holes (a term for positive quasiparticles indicating the absence of an electron). Rather, the currents were carried by a highly unusual quasiparticle that has no charge and no energy, and yet moves without resistance. The components of the hybrid quasiparticle were observed to travel on opposite sides of the graphene’s edges, despite being a single object.

The unique properties indicate that the quasiparticle might be one that physicists have been hoping to exploit for decades — the elusive Majorana fermion predicted by Italian theoretical physicist Ettore Majorana in 1937.

“Developing electronics using this new quasiparticle in seamlessly interconnected graphene networks is game changing,” de Heer said.

It will likely be another five to 10 years before we have the first graphene-based electronics, according to de Heer. But thanks to the team’s new epitaxial graphene platform, technology is closer than ever to crowning graphene as a successor to silicon.

Here’s a link to and a citation for the paper,

An epitaxial graphene platform for zero-energy edge state nanoelectronics by Vladimir S. Prudkovskiy, Yiran Hu, Kaimin Zhang, Yue Hu, Peixuan Ji, Grant Nunn, Jian Zhao, Chenqian Shi, Antonio Tejeda, David Wander, Alessandro De Cecco, Clemens B. Winkelmann, Yuxuan Jiang, Tianhao Zhao, Katsunori Wakabayashi, Zhigang Jiang, Lei Ma, Claire Berger & Walt A. de Heer. Nature Communications volume 13, Article number: 7814 (2022) DOI: https://doi.org/10.1038/s41467-022-34369-4 Published 19 December 2022

This paper is open access.

Graphene goes to the moon

The people behind the European Union’s Graphene Flagship programme (if you need a brief explanation, keep scrolling down to the “What is the Graphene Flagship?” subhead) and the United Arab Emirates have got to be very excited about the announcement made in a November 29, 2022 news item on Nanowerk, Note: Canadians too have reason to be excited as of April 3, 2023 when it was announced that Canadian astronaut Jeremy Hansen was selected to be part of the team on NASA’s [US National Aeronautics and Space Administration] Artemis II to orbit the moon (April 3, 2023 CBC news online article by Nicole Mortillaro) ·

Graphene Flagship Partners University of Cambridge (UK) and Université Libre de Bruxelles (ULB, Belgium) paired up with the Mohammed bin Rashid Space Centre (MBRSC, United Arab Emirates), and the European Space Agency (ESA) to test graphene on the Moon. This joint effort sees the involvement of many international partners, such as Airbus Defense and Space, Khalifa University, Massachusetts Institute of Technology, Technische Universität Dortmund, University of Oslo, and Tohoku University.

The Rashid rover is planned to be launched on 30 November 2022 [Note: the launch appears to have occurred on December 11, 2022; keep scrolling for more about that] from Cape Canaveral in Florida and will land on a geologically rich and, as yet, only remotely explored area on the Moon’s nearside – the side that always faces the Earth. During one lunar day, equivalent to approximately 14 days on Earth, Rashid will move on the lunar surface investigating interesting geological features.

A November 29, 2022 Graphene Flagship press release (also on EurekAlert), which originated the news item, provides more details,

The Rashid rover wheels will be used for repeated exposure of different materials to the lunar surface. As part of this Material Adhesion and abrasion Detection experiment, graphene-based composites on the rover wheels will be used to understand if they can protect spacecraft against the harsh conditions on the Moon, and especially against regolith (also known as ‘lunar dust’).

Regolith is made of extremely sharp, tiny and sticky grains and, since the Apollo missions, it has been one of the biggest challenges lunar missions have had to overcome. Regolith is responsible for mechanical and electrostatic damage to equipment, and is therefore also hazardous for astronauts. It clogs spacesuits’ joints, obscures visors, erodes spacesuits and protective layers, and is a potential health hazard.  

University of Cambridge researchers from the Cambridge Graphene Centre produced graphene/polyether ether ketone (PEEK) composites. The interaction of these composites with the Moon regolith (soil) will be investigated. The samples will be monitored via an optical camera, which will record footage throughout the mission. ULB researchers will gather information during the mission and suggest adjustments to the path and orientation of the rover. Images obtained will be used to study the effects of the Moon environment and the regolith abrasive stresses on the samples.

This moon mission comes soon after the ESA announcement of the 2022 class of astronauts, including the Graphene Flagship’s own Meganne Christian, a researcher at Graphene Flagship Partner the Institute of Microelectronics and Microsystems (IMM) at the National Research Council of Italy.

“Being able to follow the Moon rover’s progress in real time will enable us to track how the lunar environment impacts various types of graphene-polymer composites, thereby allowing us to infer which of them is most resilient under such conditions. This will enhance our understanding of how graphene-based composites could be used in the construction of future lunar surface vessels,” says Sara Almaeeni, MBRSC science team lead, who designed Rashid’s communication system.

“New materials such as graphene have the potential to be game changers in space exploration. In combination with the resources available on the Moon, advanced materials will enable radiation protection, electronics shielding and mechanical resistance to the harshness of the Moon’s environment. The Rashid rover will be the first opportunity to gather data on the behavior of graphene composites within a lunar environment,” says Carlo Iorio, Graphene Flagship Space Champion, from ULB.

Leading up to the Moon mission, a variety of inks containing graphene and related materials, such as conducting graphene, insulating hexagonal boron nitride and graphene oxide, semiconducting molybdenum disulfide, prepared by the University of Cambridge and ULB were also tested on the MAterials Science Experiment Rocket 15 (MASER 15) mission, successfully launched on the 23rd of November 2022 from the Esrange Space Center in Sweden. This experiment, named ARLES-2 (Advanced Research on Liquid Evaporation in Space) and supported by European and UK space agencies (ESA, UKSA) included contributions from Graphene Flagship Partners University of Cambridge (UK), University of Pisa (Italy) and Trinity College Dublin (Ireland), with many international collaborators, including Aix-Marseille University (France), Technische Universität Darmstadt (Germany), York University (Canada), Université de Liège (Belgium), University of Edinburgh and Loughborough.

This experiment will provide new information about the printing of GMR inks in weightless conditions, contributing to the development of new addictive manufacturing procedures in space such as 3d printing. Such procedures are key for space exploration, during which replacement components are often needed, and could be manufactured from functional inks.

“Our experiments on graphene and related materials deposition in microgravity pave the way addictive manufacturing in space. The study of the interaction of Moon regolith with graphene composites will address some key challenges brought about by the harsh lunar environment,” says Yarjan Abdul Samad, from the Universities of Cambridge and Khalifa, who prepared the samples and coordinated the interactions with the United Arab Emirates.    

“The Graphene Flagship is spearheading the investigation of graphene and related materials (GRMs) for space applications. In November 2022, we had the first member of the Graphene Flagship appointed to the ESA astronaut class. We saw the launch of a sounding rocket to test printing of a variety of GRMs in zero gravity conditions, and the launch of a lunar rover that will test the interaction of graphene—based composites with the Moon surface. Composites, coatings and foams based on GRMs have been at the core of the Graphene Flagship investigations since its beginning. It is thus quite telling that, leading up to the Flagship’s 10th anniversary, these innovative materials are now to be tested on the lunar surface. This is timely, given the ongoing effort to bring astronauts back to the Moon, with the aim of building lunar settlements. When combined with polymers, GRMs can tailor the mechanical, thermal, electrical properties of then host matrices. These pioneering experiments could pave the way for widespread adoption of GRM-enhanced materials for space exploration,” says Andrea Ferrari, Science and Technology Officer and Chair of the Management Panel of the Graphene Flagship. 

Caption: The MASER15 launch Credit: John-Charles Dupin

A pioneering graphene work and a first for the Arab World

A December 11, 2022 news item on Alarabiya news (and on CNN) describes the ‘graphene’ launch which was also marked the Arab World’s first mission to the moon,

The United Arab Emirates’ Rashid Rover – the Arab world’s first mission to the Moon – was launched on Sunday [December 11, 2022], the Mohammed bin Rashid Space Center (MBRSC) announced on its official Twitter account.

The launch came after it was previously postponed for “pre-flight checkouts.”

The launch of a SpaceX Falcon 9 rocket carrying the UAE’s Rashid rover successfully took off from Cape Canaveral, Florida.

The Rashid rover – built by Emirati engineers from the UAE’s Mohammed bin Rashid Space Center (MBRSC) – is to be sent to regions of the Moon unexplored by humans.

What is the Graphene Flagship?

In 2013, the Graphene Flagship was chosen as one of two FET (Future and Emerging Technologies) funding projects (the other being the Human Brain Project) each receiving €1 billion to be paid out over 10 years. In effect, it’s a science funding programme specifically focused on research, development, and commercialization of graphene (a two-dimensional [it has length and width but no depth] material made of carbon atoms).

You can find out more about the flagship and about graphene here.

Turning asphaltene into graphene

Asphaltene (or asphaltenes are) is waste material that can be turned into graphene according to scientists at Rice University (Texas, US), from a November 18, 2022 news item on ScienceDaily,

Asphaltenes, a byproduct of crude oil production, are a waste material with potential. Rice University scientists are determined to find it by converting the carbon-rich resource into useful graphene.

Muhammad Rahman, an assistant research professor of materials science and nanoengineering, is employing Rice’s unique flash Joule heating process to convert asphaltenes instantly into turbostratic (loosely aligned) graphene and mix it into composites for thermal, anti-corrosion and 3D-printing applications.

The process makes good use of material otherwise burned for reuse as fuel or discarded into tailing ponds and landfills. Using at least some of the world’s reserve of more than 1 trillion barrels of asphaltene as a feedstock for graphene would be good for the environment as well.

A November 17, 2022 Rice University news release (also on EurekAlert), which originated the news item, expands on this exciting news, Note: Links have been removed,

“Asphaltene is a big headache for the oil industry, and I think there will be a lot of interest in this,” said Rahman, who characterized the process as both a scalable and sustainable way to reduce carbon emissions from burning asphaltene.

Rahman is a lead corresponding author of the paper in Science Advances co-led by Rice chemist James Tour, whose lab developed flash Joule heating, materials scientist Pulickel Ajayan and Md Golam Kibria, an assistant professor of chemical and petroleum engineering at the University of Calgary, Canada.

Asphaltenes are 70% to 80% carbon already. The Rice lab combines it with about 20% of carbon black to add conductivity and flashes it with a jolt of electricity, turning it into graphene in less than a second. Other elements in the feedstock, including hydrogen, nitrogen, oxygen and sulfur, are vented away as gases.

“We try to keep the carbon black content as low as possible because we want to maximize the utilization of asphaltene,” Rahman said.

“The government has been putting pressure on the petroleum industries to take care of this,” said Rice graduate student and co-lead author M.A.S.R. Saadi. “There are billions of barrels of asphaltene available, so we began working on this project primarily to see if we could make carbon fiber. That led us to think maybe we should try making graphene with flash Joule heating.”

Assured that Tour’s process worked as well on asphaltene as it did on various other feedstocks, including plastic, electronic waste, tires, coal fly ash and even car parts, the researchers set about making things with their graphene. 

Saadi, who works with Rahman and Ajayan, mixed the graphene into composites, and then into polymer inks bound for 3D printers. “We’ve optimized the ink rheology to show that it is printable,” he said, noting the inks have no more than 10% of graphene mixed in. Mechanical testing of printed objects is forthcoming, he said.

Rice graduate student Paul Advincula, a member of the Tour lab, is co-lead author of the paper. Co-authors are Rice graduate students Md Shajedul Hoque Thakur, Ali Khater, Jacob Beckham and Minghe Lou, undergraduate Aasha Zinke and postdoctoral researcher Soumyabrata Roy; research fellow Shabab Saad, alumnus Ali Shayesteh Zeraati, graduate student Shariful Kibria Nabil and postdoctoral associate Md Abdullah Al Bari of the University of Calgary; graduate student Sravani Bheemasetti and Venkataramana Gadhamshetty, an associate professor, at the South Dakota School of Mines and Technology and its 2D Materials of Biofilm Engineering Science and Technology Center; and research assistant Yiwen Zheng and Aniruddh Vashisth, an assistant professor of mechanical engineering, of the University of Washington.

The research was funded by the Alberta Innovates for Carbon Fiber Grand Challenge programs, the Air Force Office of Scientific Research (FA9550-19-1-0296), the U.S. Army Corps of Engineers (W912HZ-21-2-0050) and the National Science Foundation (1849206, 1920954).  

Here’s a link to and a citation for the paper,

Sustainable valorization of asphaltenes via flash joule heating by M.A.S.R. Saadi, Paul A. Advincula, Md Shajedul Hoque Thakur, Ali Zein Khater, Shabab Saad, Ali Shayesteh Zeraati, Shariful Kibria Nabil, Aasha Zinke, Soumyabrata Roy, Minghe Lou, Sravani N. Bheemasetti, Md Abdullah Al Bari, Yiwen Zheng, Jacob L. Beckham, Venkataramana Gadhamshetty, Aniruddh Vashisth, Md Golam Kibria, James M. Tour, Pulickel M. Ajayan, and Muhammad M. Rahman. Science Advances 18 Nov 2022 Vol 8, Issue 46 DOI: 10.1126/sciadv.add3555

This paper is open access.

Graphene can be used in quantum components

A November 3, 2022 news item on phys.org provides a brief history of graphene before announcing the latest work from ETH Zurich,

Less than 20 years ago, Konstantin Novoselov and Andre Geim first created two-dimensional crystals consisting of just one layer of carbon atoms. Known as graphene, this material has had quite a career since then.

Due to its exceptional strength, graphene is used today to reinforce products such as tennis rackets, car tires or aircraft wings. But it is also an interesting subject for fundamental research, as physicists keep discovering new, astonishing phenomena that have not been observed in other materials.

The right twist

Bilayer graphene crystals, in which the two atomic layers are slightly rotated relative to each other, are particularly interesting for researchers. About one year ago, a team of researchers led by Klaus Ensslin and Thomas Ihn at ETH Zurich’s Laboratory for Solid State Physics was able to demonstrate that twisted graphene could be used to create Josephson junctions, the fundamental building blocks of superconducting devices.

Based on this work, researchers were now able to produce the first superconducting quantum interference device, or SQUID, from twisted graphene for the purpose of demonstrating the interference of superconducting quasiparticles. Conventional SQUIDs are already being used, for instance in medicine, geology and archaeology. Their sensitive sensors are capable of measuring even the smallest changes in magnetic fields. However, SQUIDs work only in conjunction with superconducting materials, so they require cooling with liquid helium or nitrogen when in operation.

In quantum technology, SQUIDs can host quantum bits (qubits); that is, as elements for carrying out quantum operations. “SQUIDs are to superconductivity what transistors are to semiconductor technology—the fundamental building blocks for more complex circuits,” Ensslin explains.

A November 3, 2022 ETH Zurich news release by Felix Würsten, which originated the news item, delves further into the work,

The spectrum is widening

The graphene SQUIDs created by doctoral student Elías Portolés are not more sensitive than their conventional counterparts made from aluminium and also have to be cooled down to temperatures lower than 2 degrees above absolute zero. “So it’s not a breakthrough for SQUID technology as such,” Ensslin says. However, it does broaden graphene’s application spectrum significantly. “Five years ago, we were already able to show that graphene could be used to build single-electron transistors. Now we’ve added superconductivity,” Ensslin says.

What is remarkable is that the graphene’s behaviour can be controlled in a targeted manner by biasing an electrode. Depending on the voltage applied, the material can be insulating, conducting or superconducting. “The rich spectrum of opportunities offered by solid-state physics is at our disposal,” Ensslin says.

Also interesting is that the two fundamental building blocks of a semiconductor (transistor) and a superconductor (SQUID) can now be combined in a single material. This makes it possible to build novel control operations. “Normally, the transistor is made from silicon and the SQUID from aluminium,” Ensslin says. “These are different materials requiring different processing technologies.”

An extremely challenging production process

Superconductivity in graphene was discovered by an MIT [Massachusetts Institute of Technology] research group five years ago, yet there are only a dozen or so experimental groups worldwide that look at this phenomenon. Even fewer are capable of converting superconducting graphene into a functioning component.

The challenge is that scientists have to carry out several delicate work steps one after the other: First, they have to align the graphene sheets at the exact right angle relative to each other. The next steps then include connecting electrodes and etching holes. If the graphene were to be heated up, as happens often during cleanroom processing, the two layers re-align the twist angle vanishes. “The entire standard semiconductor technology has to be readjusted, making this an extremely challenging job,” Portolés says.

The vision of hybrid systems

Ensslin is thinking one step ahead. Quite a variety of different qubit technologies are currently being assessed, each with its own advantages and disadvantages. For the most part, this is being done by various research groups within the National Center of Competence in Quantum Science and Technology (QSIT). If scientists succeed in coupling two of these systems using graphene, it might be possible to combine their benefits as well. “The result would be two different quantum systems on the same crystal,” Ensslin says.

This would also generate new possibilities for research on superconductivity. “With these components, we might be better able to understand how superconductivity in graphene comes about in the first place,” he adds. “All we know today is that there are different phases of superconductivity in this material, but we do not yet have a theoretical model to explain them.”

Here’s a link to and a citation for the paper,

A tunable monolithic SQUID in twisted bilayer graphene by Elías Portolés, Shuichi Iwakiri, Giulia Zheng, Peter Rickhaus, Takashi Taniguchi, Kenji Watanabe, Thomas Ihn, Klaus Ensslin & Folkert K. de Vries. Nature Nanotechnology volume 17, pages 1159–1164 (2022) Issue Date: November 2022 DOI: https://doi.org/10.1038/s41565-022-01222-0 Published online: 24 October 2022

This paper is behind a paywall.

Neuromorphic (brainlike) computing and your car (a Mercedes Benz Vision AVTR concept car)

If you’ve ever fantasized about a batmobile of your own, the dream could come true soon,

Mercedes Berz VISION AVTR [downloaded from https://www.mercedes-benz.com/en/innovation/concept-cars/vision-avtr/]

It was the mention of neuromorphic computing in a television ad sometime in September 2022 that sent me on a mission to find out what Mercedes Benz means when they use neuromorphic computing to describe a feature found in their Vision AVTR concept car. First, a little bit about the car (from the Vision AVTR webpage accessed in October 2022),

VISION AVTR – inspired by AVATAR.

The name of the groundbreaking concept vehicle stands not only for the close collaboration in developing the show car together with the AVATAR team but also for ADVANCED VEHICLE TRANSFORMATION. This concept vehicle embodies the vision of Mercedes-Benz designers, engineers and trend researchers for mobility in the distant future.

,,,

Organic battery technology.

The VISION AVTR was designed in line with its innovative electric drive. This is based on a particularly powerful and compact high-voltage battery. For the first time, the revolutionary battery technology is based on graphene-based [emphasis mine] organic cell chemistry and thus completely eliminates rare, toxic and expensive earths such as metals. Electromobility thus becomes independent of fossil resources. An absolute revolution is also the recyclability by composting, which is 100% recyclable due to the materiality. As a result, Mercedes-Benz underlines the high relevance of a future circular economy in the raw materials sector.

Masterpiece of efficiency.

At Mercedes-Benz, the consideration of efficiency goes far beyond the drive concept, because with increasing digitalisation, the performance of the large number of so-called secondary consumers also comes into focus – along with their efficient energy supply, without negatively affecting the drive power of the vehicle itself. Energy consumption per computing operation is already a key target in the development of new computer chips. This trend will continue in the coming years with the growth of sensors and artificial intelligence in the automotive industry. The neuro-inspired approach of the VISION AVTR, including so-called neuromorphic hardware, promises to minimise the energy requirements of sensors, chips and other components to a few watts. [emphasis mine] Their energy supply is provided by the cached current of the integrated solar plates on the back of the VISION AVTR. The 33 multi-directionally movable surface elements act as “bionic flaps”.

Interior and exterior merge.

For the first time, Mercedes-Benz has worked with a completely new design approach in the design of the VISION AVTR. The holistic concept combines the design disciplines interior, exterior and UX [user experience] from the first sketch. Man and human perception are the starting point of a design process from the inside out. The design process begins with the experience of the passengers and consciously focuses on the perception and needs of the passengers. The goal was to create a car that prolongs the perception of its passengers. It was also a matter of creating an immersive experience space in which passengers connect with each other, with the vehicle and the surrounding area [emphasis mine ] in a unique way.

Intuitive control.

The VISION AVTR already responds to the approach of the passengers by visualising the energy and information flow of the environment with digital neurons that flow through the grille through the wheels to the rear area. The first interaction in the interior between man and vehicle happens completely intuitively via the control unit: by placing the hand on the centre console, the interior comes to life and the vehicle recognises the driver by his breathing. This is made visible on the instrument panel and on the user’s hand. The VISION AVTR thus establishes a biometric connection with the driver [emphasis mine] and increases his awareness of the environment. The digital neurons flow from the interior into the exterior and visualise the flow of energy and information. For example, when driving, the neurons flow over the outside of the vehicle. [emphasis mine] When changing direction, the energy flows to the corresponding side of the vehicle.

The vehicle as an immersive experience space.

The visual connection between passengers and the outside world is created by the curved display module, which replaces a conventional dashboard. The outside world around the vehicle and the surrounding area is shown in real-time 3D graphics and at the same time shows what is happening on the road in front of the vehicle. Combined with energy lines, these detailed real-time images bring the interior to life and allow passengers to discover and interact with the environment in a natural way with different views of the outside world. Three wonders of nature – the Huangshan Mountains of China, the 115-metre-high Hyperion Tree found in the United States and the pink salt Lake Hillier from Australia – can be explored in detail. Passengers become aware of various forces of nature that are not normally visible to the human eye, such as magnetic fields, bioenergy or ultraviolet light.

The curved display module in the Mercedes-Benz VISION AVTR – inspired by AVATAR
[downloaded from https://www.mercedes-benz.com/en/innovation/concept-cars/vision-avtr/]

Bionic formal language.

When the boundaries between vehicle and living beings are lifted, Mercedes-Benz combines luxury and sustainability and works to make the vehicles as resource-saving as possible. With the VISION AVTR, the brand is now showing how a vehicle can blend harmoniously into its environment and communicate with it. In the ecosystem of the future, the ultimate luxury is the fusion of human and nature with the help of technology. The VISION AVTR is thus an example of sustainable luxury in the field of design. As soon as you get in, the car becomes an extension of your own body and a tool to discover the environment much as in the film humans can use avatars to extend and expand their abilities.

A few thoughts

The movie, Avatar, was released in 2009 and recently rereleased in movie houses in anticipation of the sequel, Avatar: The Way of Water to be released in December 2022 (Avatar [2009 film] Wikipedia entry). The timing, Avatar and AVTR, is interesting, oui?

Moving onto ‘organic’, which means carbon-based in this instance and, specifically, graphene. Commercialization of graphene is likely top-of-mind for the folks (European Commission) who bet 1B Euros in 2013 with European Union money to fund the Graphene Flagship project. This battery from German company Mercedes Benz must be exciting news for the funders and for people who want to lessen dependency on rare earths. Your battery can be composted safely (according to the advertising).

The other piece of good news, is the neuromorphic computing,

“The neuro-inspired approach of the VISION AVTR, including so-called neuromorphic hardware, promises to minimise the energy requirements of sensors, chips and other components to a few watts.”

On the other hand and keeping in mind the image above (a hand with what looks like an embedded object), it seems a little disconcerting to merge with one’s car, “… passengers connect with each other, with the vehicle and the surrounding area …” which becomes even more disconcerting when this appears in the advertising,

… VISION AVTR thus establishes a biometric connection with the driver … The digital neurons flow from the interior into the exterior and visualise the flow of energy and information. For example, when driving, the neurons flow over the outside of the vehicle.

Are these ‘digital neurons’ flowing around the car like a water current? Also, the car is visualizing? Hmm …

I did manage to find a bit more information about neuromorphic computing although it’s for a different Mercedes Benz concept car (there’s no mention of flowing digital neurons) in a January 18, 2022 article by Sally Ward-Foxton for EE Times (Note: A link has been removed),

The Mercedes Vision EQXX concept car, promoted as “the most efficient Mercedes-Benz ever built,” incorporates neuromorphic computing to help reduce power consumption and extend vehicle range. To that end, BrainChip’s Akida neuromorphic chip enables in-cabin keyword spotting as a more power-efficient way than existing AI-based keyword detection systems.

“Working with California-based artificial intelligence experts BrainChip, Mercedes-Benz engineers developed systems based on BrainChip’s Akida hardware and software,” Mercedes noted in a statement describing the Vision EQXX. “The example in the Vision EQXX is the “Hey Mercedes” hot-word detection. Structured along neuromorphic principles, it is five to ten times more efficient than conventional voice control,” the carmaker claimed.

That represents validation of BrainChip’s technology by one of its early-access customers. BrainChip’s Akida chip accelerates spiking neural networks (SNNs) and convolutional neural networks (via conversion to SNNs). It is not limited to a particular application, and also run [sic] person detection, voice or face recognition SNNs, for example, that Mercedes could also explore.

This January 6, 2022 article by Nitin Dahad for embedded.com describes what were then the latest software innovations in the automotive industry and segues into a description of spiking neural networks (Note: A link has been removed),

The electric vehicle (EV) has clearly become a key topic of discussion, with EV range probably the thing most consumers are probably worried about. To address the range concern, two stories emerged this week – one was Mercedes-Benz’ achieving a 1,000 km range with its VISION EQXX prototype, albeit as a concept car, and General Motors announcing during a CES [Consumer Electronics Show] 2022 keynote its new Chevrolet Silverado EV with 400-mile (640 km) range.

In briefings with companies, I often hear them talk about the software-defined car and the extensive use of software simulation (or we could also call it a digital twin). In the case of both the VISION EQXX and the Silverado EV, software plays a key part. I also spoke to BlackBerry about its IVY platform and how it is laying the groundwork for software-defined vehicles.

Neuromorphic computing for infotainment

This efficiency is not just being applied to enhancing range though. Mercedes-Benz also points out that its infotainment system uses neuromorphic computing to enable the car to take to “take its cue from the way nature thinks”.

Mercedes-Benz VISION EQXXMercedes-Benz VISION EQXX

The hardware runs spiking neural networks, in which data is coded in discrete spikes and energy only consumed when a spike occurs, reducing energy consumption by orders of magnitude. In order to deliver this, the carmaker worked with BrainChip, developing the systems based on its Akida processor. In the VISION EQXX, this technology enables the “Hey Mercedes” hot-word detection five to ten times more efficiently than conventional voice control. Mercedes-Benz said although neuromorphic computing is still in its infancy, systems like these will be available on the market in just a few years. When applied on scale throughout a vehicle, they have the potential to radically reduce the energy needed to run the latest AI technologies.

For anyone curious about BrainChip, you can find out more here.

It took a little longer than I hoped but I’m glad that I found out a little more about neuromorphic computing and one application in the automotive industry.

Synaptic transistors for brainlike computers based on (more environmentally friendly) graphene

An August 9, 2022 news item on ScienceDaily describes research investigating materials other than silicon for neuromorphic (brainlike) computing purposes,

Computers that think more like human brains are inching closer to mainstream adoption. But many unanswered questions remain. Among the most pressing, what types of materials can serve as the best building blocks to unlock the potential of this new style of computing.

For most traditional computing devices, silicon remains the gold standard. However, there is a movement to use more flexible, efficient and environmentally friendly materials for these brain-like devices.

In a new paper, researchers from The University of Texas at Austin developed synaptic transistors for brain-like computers using the thin, flexible material graphene. These transistors are similar to synapses in the brain, that connect neurons to each other.

An August 8, 2022 University of Texas at Austin news release (also on EurekAlert but published August 9, 2022), which originated the news item, provides more detail about the research,

“Computers that think like brains can do so much more than today’s devices,” said Jean Anne Incorvia, an assistant professor in the Cockrell School of Engineering’s Department of Electrical and Computer Engineer and the lead author on the paper published today in Nature Communications. “And by mimicking synapses, we can teach these devices to learn on the fly, without requiring huge training methods that take up so much power.”

The Research: A combination of graphene and nafion, a polymer membrane material, make up the backbone of the synaptic transistor. Together, these materials demonstrate key synaptic-like behaviors — most importantly, the ability for the pathways to strengthen over time as they are used more often, a type of neural muscle memory. In computing, this means that devices will be able to get better at tasks like recognizing and interpreting images over time and do it faster.

Another important finding is that these transistors are biocompatible, which means they can interact with living cells and tissue. That is key for potential applications in medical devices that come into contact with the human body. Most materials used for these early brain-like devices are toxic, so they would not be able to contact living cells in any way.

Why It Matters: With new high-tech concepts like self-driving cars, drones and robots, we are reaching the limits of what silicon chips can efficiently do in terms of data processing and storage. For these next-generation technologies, a new computing paradigm is needed. Neuromorphic devices mimic processing capabilities of the brain, a powerful computer for immersive tasks.

“Biocompatibility, flexibility, and softness of our artificial synapses is essential,” said Dmitry Kireev, a post-doctoral researcher who co-led the project. “In the future, we envision their direct integration with the human brain, paving the way for futuristic brain prosthesis.”

Will It Really Happen: Neuromorphic platforms are starting to become more common. Leading chipmakers such as Intel and Samsung have either produced neuromorphic chips already or are in the process of developing them. However, current chip materials place limitations on what neuromorphic devices can do, so academic researchers are working hard to find the perfect materials for soft brain-like computers.

“It’s still a big open space when it comes to materials; it hasn’t been narrowed down to the next big solution to try,” Incorvia said. “And it might not be narrowed down to just one solution, with different materials making more sense for different applications.”

The Team: The research was led by Incorvia and Deji Akinwande, professor in the Department of Electrical and Computer Engineering. The two have collaborated many times together in the past, and Akinwande is a leading expert in graphene, using it in multiple research breakthroughs, most recently as part of a wearable electronic tattoo for blood pressure monitoring.

The idea for the project was conceived by Samuel Liu, a Ph.D. student and first author on the paper, in a class taught by Akinwande. Kireev then suggested the specific project. Harrison Jin, an undergraduate electrical and computer engineering student, measured the devices and analyzed data.

The team collaborated with T. Patrick Xiao and Christopher Bennett of Sandia National Laboratories, who ran neural network simulations and analyzed the resulting data.

Here’s a link to and a citation for the ‘graphene transistor’ paper,

Metaplastic and energy-efficient biocompatible graphene artificial synaptic transistors for enhanced accuracy neuromorphic computing by Dmitry Kireev, Samuel Liu, Harrison Jin, T. Patrick Xiao, Christopher H. Bennett, Deji Akinwande & Jean Anne C. Incorvia. Nature Communications volume 13, Article number: 4386 (2022) DOI: https://doi.org/10.1038/s41467-022-32078-6 Published: 28 July 2022

This paper is open access.