Stanford Medicine researchers created an algorithm to notify smartwatch wearers of stress, capturing events such as air travel, extended exercise, and illness. Using data from smartwatches, a new algorithm reads heart rate as a proxy for physiological or mental stress, potentially alerting wearers they’re falling ill before they have symptoms. Researchers led by Michael Snyder, Ph.D., professor and chair of genetics, have enrolled thousands of participants in a study that employs the algorithm to look for extended periods during which heart rate is higher than normal — a telltale sign that something may be amiss. But figuring out what may be wrong takes a little sleuthing. During the study, many stressors triggered an alert. Some folks received them while traveling; some while running a marathon; others after over-indulging at the bar. The most exciting finding, Snyder said, was that the algorithm was able to detect 80% of confirmed COVID-19 cases before or when participants were symptomatic. “The idea is for people to eventually use this information to decide whether they need to get a COVID-19 test or self-isolate,” Snyder said. “We’re not there yet — we still need to test this in clinical trials — but that’s the ultimate goal.” The algorithm can’t differentiate between someone who’s knocked back a few too many, someone’s who’s stressed because of work, and someone who’s ill with a virus. Although it pinged users who had COVID-19, more refining is needed before people can depend on their smartwatches to warn them of an impending infection with SARS-CoV-2 or other viruses. A paper "Real-time alerting system for COVID-19 and other stress events using wearable data" detailing the study was published online in Nature Medicine on Nov. 29. The alert system was built using MyPHD, a scalable, secure platform for health data. Stress detection During the study, which ran for about eight months in 2020 and 2021, 2,155 participants donned a smartwatch, which tracked mental and physical “stress events” via heart rate. When notified of a stress event, through an alert paired with an app on their phone, participants recorded what they were doing. To trigger an alert, their heart rate needed to be elevated for more than a few hours, so a quick jog around the block or a sudden loud noise didn’t set it off. “What’s great about this is people can contextualize their alerts,” Snyder said. “If you’re traveling via airline and you receive an alert, you know that air travel is likely the culprit.” If, however, you’re sitting on the couch with a cup of chamomile tea and you receive an alert, that may be a sign that something else — an infection, perhaps — is brewing. Snyder hopes wearers will be able to discern when an alert means they should consider getting tested. Of 84 people who were diagnosed with COVID-19 during the study, the algorithm flagged 67. Most alerts fell into other categories, such as travel, eating a large meal, menstruation, mental stress, intoxication, or non-COVID-19 infections. The algorithm also flagged a period of stress after many participants received a COVID-19 vaccine, reflecting the uptick in immune response prompted by the shot. Refining the algorithm. As Snyder and the team recruit more participants into the study, they’re planning to hone the specificity of the alerts by adding data — including step count, sleep patterns, and body temperature — in the hope that data patterns can correspond to and flag distinct stress events. In addition, the researchers plan to run a clinical trial to determine if the alerts can reliably detect a COVID-19 infection and be used to guide medical choices. For more information, visit: https://med.stanford.edu/news/all-news/2021/11/smartwatch-stress-alert-covid-19.html

In the development and manufacturing of microfluidic consumables bonding is often a challenge as well as an essential process that must be scalable and cost-efficient. Other parameters that are critical for this process are that the bond is stable and does not leak. Imaging often plays an important role especially in diagnostic testing, so the optical properties of a bonded part are also often of importance. As the consumable will likely be in contact with biological materials it is often required to eliminate the contact to glues or keep it to a minimum. At Axxicon we developed a bonding process that addresses these challenges and is based on a precision printing process using modified UV glues. The glue will be printed in a defined pattern around the microfluidic structures. The process is defined in three steps: 1. Designing The print design is custom-made per product and is completely adaptable. Creating a design can be done as early as in the design for manufacturing phase (DFM) of the product. There are only a few limitations that need to be kept in mind. Because of the printing technique used there is minimal space required between microfluidic features. And adding alignment features increases the level of accuracy to 3-5µm on x- and y-axis. Printing Using alignment features makes it possible to print on complex structures and non-conform outer shapes of products with very high precision. The printing process is optimized per product. By tweaking the design and parameters it is possible to control the flow of the adhesive after printing to prevent flowing into the channel. The type of composition of the adhesive can be changed to match the application’s requirements. 2. Printing Using alignment features makes it possible to print on complex structures and non-conform outer shapes of products with very high precision. The printing process is optimized per product. By tweaking the design and parameters it is possible to control the flow of the adhesive after printing to prevent flowing into the channel. The type or composition of the adhesive can be changed to match the application’s requirements. 3. Curing Bonding is done in a press that is custom-made. With the help of guiding plates, it is possible to bond the parts very accurately on the outer dimensions of the product. The microfluidic slides will be pressed together with controlled force and alignment. After this, they will be exposed to UV light. The press is controlled with a Programmable logic controller (PLC), which takes away the human error. An array of parameters can be modified to achieve the wanted bond and consider the duration or intensity of the UV light. Commercial properties Axxicon’s UV-adhesive-based bonding technique has strong advantages when it comes to scalability. The printing technology can easily be upscaled to a situation where it could be integrated into an automated production line and can be done in one movement. For low production volumes, it can be done manually, the cycle time of this is around 60 seconds, depending on the design and size of the product. • At medium production volumes (10k and up batches) it can be upscaled to a semi-automatic process where the cycle time lowers to ~30-40 seconds. • At high production volumes, an in-line process can be set up. The cycle time per product then reaches the speed of injection moulding products from 10-15 seconds. The cost of the adhesive itself has very little impact on the cost of the consumable as it is below 0.1 cents per bonded sample. The shelf-life after bonding is 12+ months. For more information, visit: https://info.axxicon.com/whitepaper-uv-bonding?utm_campaign=A%20%7C%20UV%20Bonding%20whitepaper&utm_content=188853764&utm_medium=social&utm_source=linkedin&hss_channel=lcp-72596

FOM Technologies is now a subcontractor of advanced equipment for the Power-to-X technology. This is done through the delivery of slot-die equipment to Danish Haldor Topsøe, which is one of the leading international players in the areas of energy storage and green fuels. FOM sees a great future commercial potential in the Power-to-X technology and its application, in connection with the global transition to a fossil-free world. FOM Technologies is proud to announce the company’s first Danish commercial customer. This is achieved by Haldor Topsøe awarding FOM an order for the company’s flagship slot-die coater. The equipment will be used in the development of Power-to-X technology, which includes energy storage of electricity from wind turbines, which is then converted to hydrogen or other future fuels. CEO of FOM Technologies Michael Stadi says: “It is a great honor to supply equipment for a Danish technological pioneer throughout decades. Haldor Topsøe is a world leader in their field, and we see an exciting future global potential in the Power-to-X technology, which is still in its infancy. With December just ahead of us, we will do our utmost to ensure that our equipment is delivered before Christmas. For more information, visit: https://www.fomtechnologies.com/news/fom-technologies-signs-first-power-to-x-equipment-contract?utm_campaign=Investor%20related%20content&utm_content=189621125&utm_medium=social&utm_source=linkedin&hss_channel=lcp-2756722

New EverVolt 2.0 Home Battery delivers enhanced customization, flexible design, and outdoor-rated performance for energy-conscious consumers Panasonic announced the latest innovation in its robust solar energy portfolio of Total Home Energy Solution offerings, the EverVolt™ 2.0. A result of Panasonic’s ongoing commitment to developing advanced solar and energy storage technologies, EverVolt 2.0 offers enhancements for greater customization and features a convenient modular footprint and weatherproof design. The new EverVolt 2.0 provides continuous power output of 7.6 kW off-grid a and 9.6 kW with grid, enough to power an average household load, and boasts two energy storage capacity 17.1 kWh or 25.65 kWh (usable capacity) per system. The system can be AC- and DC-coupled, allowing it to work with both new and existing solar energy systems. EverVolt 2.0 is comprised of two primary components: the floor-standing battery cabinet and a hybrid smart inverter with 4 MPPTs, and offers simple installation and flexible placement either inside or outside, thanks to its weatherproof design with an outdoor protection rating of IP55 (NEMA 3R). Other features of the Panasonic EverVolt 2.0 Home Battery include: A modular design that allows homeowners to tailor their energy storage solution to their needs; up to three systems can be stacked together to obtain more power output and energy storage capacity Multiple operating modes, including back-up mode, residential mode, time-of-use mode, and custom modes which can be set by the system owner Up to 12kW of solar can be tied to the EverVolt inverter – for both supplying to the loads and charging the batteries Field serviceability A new user-friendly mobile app that allows homeowners to monitor the system data and set the operating mode An optional wireless color LCD display, which provides visibility into battery monitoring data and control over system settings “Innovations in energy storage have never been more exciting—and necessary--than they are today,” said Mukesh Sethi, Director of Solar and Energy Storage at Panasonic. “As part of our ongoing commitment to providing top-notch solar and storage solutions for homeowners, the Panasonic EverVolt 2.0boasts new features that not only meet the needs of energy-conscious homeowners but support broader sustainability goals. The recently announced federal goals for nationwide solar adoption, paired with consumers’ increasing desire for resiliency, only underscore the necessity for solar and storage solutions like this.” Backed by more than a century of Panasonic innovation, EverVolt 2.0 is protected by Panasonic’s 10-year product and performance warranty when installed by a Certified EverVolt Installer. The EverVolt 10-year warranty is one of the best in its class for homeowners. For more information, visit: https://na.panasonic.com/us/news/panasonic-launches-next-generation-solar-energy-battery-storage-system-evervolttm-20 https://na.panasonic.com/us/evervolt

First Graphene Limited (ASX: FGR; “First Graphene” or “the Company”) is pleased to announce the achievement of a critical milestone on its program to develop high-performing supercapacitor materials. Previously, the Company reported that high capacitance “hybrid active materials” could be successfully scaled using its unique electrochemical process technology. These novel materials demonstrated high capacitance per unit area when tested in a simple cell prototype. Recent work has focused on the development of an optimized bill of materials for a supercapacitor device to deliver a high energy and power densities. First Graphene is now pleased to announce that following multiple laboratory trials, the Company has demonstrated that in a standard test cell, PureGRAPH® hybrid active materials outperform leading activated carbon materials over 100 cycles. Figure 1 shows the PureGRAPH® hybrid active materials have a specific capacitance of 140 farads per gram (F/g) while activated carbon cells typically have a specific capacitance of 35 F/g. This clearly demonstrates that PureGRAPH® hybrid active materials can be successfully formulated into an electrode slurry for use in device manufacture, retaining their high specific capacitance and operating at high charge/discharge rates. A detailed literature review indicates that further progress to higher power density and energy density devices requires the development of improved supercapacitor devices. The research focus switched to an improved bill of materials for the device, which includes enhanced electrolytes and separators. Published research indicates that an optimized cell with high capacitance operating at high voltage can achieve the “10 plus 10” target of power density above 10kW/L and energy density above 10Wh/L. Alternative electrolytes have been tested by the Company to deliver high power and energy densities. In an initial test with a dense, protic, aqueous electrolyte to enable a higher voltage window, First Graphene demonstrated an increase in energy density of 85 percent. Further electrolyte modifications are currently under development and the Company has established relationships with leading experts in cell design and electrolyte materials. By identifying ideal PureGRAPH® hybrid active materials and electrolyte combinations, First Graphene anticipates world-leading performance with power density greater than 10kW/L and energy density greater than 10Wh/L. Commercialization Having demonstrated a significant improvement in performance over activated carbon, First Graphene is now in a strong position to develop commercial partnerships with large supercapacitor manufacturing companies globally looking to develop the next generation of supercapacitors. There are currently no agreements in place or an assessment of economic impact available yet. This is a key technological breakthrough for the Company, which allows improved access to a completely new market segment globally. The market and applications The supercapacitor device market is projected to grow from US$409 million in 2020 to US$720 million by 2025 at an expected CAGR of 12.0 percent. The growth of the market is driven by increasing demand in energy harvesting applications and the rising use of supercapacitors in trains and aircraft. Moreover, the increasing global demand for electric vehicles is likely to fuel the growth of the market. Potential large volume applications include twinned supercapacitor-battery power supplies in which the supercapacitor provides peak power smoothing during acceleration or regenerative braking, reducing the load on the batteries and extending battery life. The Company has completed a thorough review of supercapacitor devices, including desktop analysis and device testing of available high-performing devices. Current best-in-class devices have power density above 10 kW/L and energy density above 5 Wh/L. To achieve this, the cell must have high specific capacitance and the ability to operate in a high voltage window. Energy storage technologies Supercapacitors, which are based on electrical double layer capacitance (EDLC), offer rapid charging and discharging giving a high-power density. These supercapacitors usually use activated carbon as a high surface area charge storage medium. They do not depend on a chemical reaction as they work on charge separation within the device. This means EDLC supercapacitors are stable and can typically withstand many charge/discharge cycles. For electric vehicles (EVs), an ideal energy storage device combines a chemical battery with high energy density (to enable long-range driving) coupled with a supercapacitor that can rapidly charge and discharge to effectively manage periods where high power is needed for relatively short times, such as when starting and stopping. This will extend the battery life and ultimately extend the range of the vehicle. An ideal route to this combined system is via pseudocapacitor technology, where charge storage occurs through the electrical double layer capacitance mechanism and rapid redox reactions between the ions in the electrolyte and the active materials on the electrode surface. Pseudocapacitance can significantly increase the performance of a supercapacitor. First Graphene’s PureGRAPH® hybrid active materials have been shown to be an enabler to achieving pseudocapacitance. First Graphene Managing Director and CEO Michael Bell said: “We continue to make good progress in the rapidly emerging market for energy storage materials. We have proven that we can manufacture robust, high capacitance materials based on our PureGRAPH® products. Our next challenge is to optimize performance with other device components, with a particular focus on a suitable electrolyte. We have established important strategic relationships to do this.” For more information, visit: https://firstgraphene.net/graphene-based-supercapacitor-materials-deliver-85-improvement-in-energy-density-levels/#_ftnref1

A microfluidic chip takes up a water sample, adds the necessary chemicals, and transports it to the detection site. What's the point? In this way, the water is to be analyzed fully automatically and with various parameters and at the lowest possible cost. A further developed chip prototype for water analysis devices has emerged from the MICROCHIP project at Fraunhofer Institute for Microengineering and Microsystems IMM. Whether in the waterworks, laboratory, in a swimming pool or from the tap - who would not like to have a quick and easy water analysis at hand. With the microfluidic lab-on-a-chip developed in the MICROCHIP project, samples can be analyzed fully automatically from just a few drops in a short time. Thus enabling personnel without training to detect six parameters relevant to water analysis in parallel with a low-cost measuring device additionally saves time and costs. Furthermore, user errors are eliminated with this methodology. Reagents cannot be mixed up and the amount of water suitable for the method is set by the chip. Mirror instead of transparency The chip achieves high measurement accuracy. Among other things, this is possible due to an extended path length and an adapted design that keeps the chip compact. Instead of an originally planned transmission solution, the project partners opted for a so-called mirror solution. The re-design of the hardware with different colored LEDs ultimately enables analytics for the photometry-based measurement method, in which colored water samples are evaluated. Credit card format packed with technology The chip ultimately reaches about the size of a credit card, combined with a lot of technology such as an electronic board with photometric sensors, ultrasonic mixers, pressure reservoirs as well as a peristaltic pump insertion for the chip along with a pressure mechanism that had to be accommodated in the small housing. Compared to previous solutions, this one is much more cost-effective. The project partners show that it is possible to perform multi-parameter water analyses in a polymer chip. They do not use complex and expensive technologies such as blister and freeze-drying. Instead, they dry the reagents directly in chambers in the chip. A simple peristaltic pump is used to direct the measuring liquid through the chip. As a result, the sensors measure the liquid colored by the reagents in the same measuring chamber as the previously colorless reference sample. The chip is manufactured by injection molding. To ensure that the chip is also pressure-tight to the outside, the channels in a black top shell and a transparent bottom shell are welded together using a laser beam process. Previous comparable systems for automated water analysis after adding the water sample in polymer chips are either too bulky or analyze fewer parameters in parallel. The demonstrator developed and implemented in the consortium is not yet ready for mass production. However, the results of the development and tests are already being used by one of the project partners, Water-i.d. GmbH, in the production of further water analysis devices and reagents. For more information, visit: https://www.imm.fraunhofer.de/en/press-publications/project-microchip.html

Like solar panels and wind turbines, the price of lithium-ion batteries has plummeted over this century, with a study from March estimating that cost has dropped by 97% worldwide since their introduction in 1991. Now, the same team of researchers has sought to explain why the price has fallen so much. Publishing their results in Energy and Environmental Science " Determinants of lithium-ion battery technology cost decline", they say that research and development (R&D), particularly in chemistry and materials science, has been the major factor in dropping the price of the batteries. The researchers, who are based at the Massachusetts Institute of Technology, US, examined a range of different financial and scientific documents from the past 30 years.“The data collection effort was extensive,” says co-author Dr Micah Ziegler. “We looked at academic articles, industry and government reports, press releases, and specification sheets. We even looked at some legal filings that came out. We had to piece together data from many different sources to get a sense of what was happening.” In total, according to Ziegler, the researchers collected “about 15,000 qualitative and quantitative data points, across 1000 individual records from approximately 280 references”. The researchers have previously used this method to examine the dropping price of solar cells and rising costs of nuclear energy. "We estimate that the majority of the cost decline, more than 50 percent, came from research-and-development-related activities,” says co-author Professor Jessika Trancik. Private-sector and government-funded research both contributed to this decline.The research helped improve a range of different parts of the lithium-ion landscape, including manufacturing systems, supply chains, and the designs of the batteries themselves. “The cost improvement emerged from a diverse set of efforts and many people, and not from the work of only a few individuals,” says Trancik. “The R&D contribution didn’t end when commercialisation began. In fact, it was still the biggest contributor to cost reduction,” adds Ziegler. The researchers say that there’s still much to be improved in lithium-ion batteries; this paper could help to provide direction for the next places to invest.“What are all the things that different decision makers could do?” asks Trancik. “What decisions do they have agency over so that they could improve the technology? [This is] important in the case of low-carbon technologies, where we’re looking for solutions to climate change and we have limited time and limited resources. “The new approach allows us to potentially be a bit more intentional about where we make those investments of time and money.” For more information, visit: https://cosmosmagazine.com/technology/energy/lithium-ion-batteries-cheaper-investment/

Speaker: Pål Morten Lindberget | Company: CondAlign AS | Date: 11-12 May 2021 | Full Presentation CondAlign’s technology represents a novel process for production of anisotropic, conductive films. Using an electric field to structure and align particles, the results in a z-axis conductive film structure. One product type we can produce is anisotropic conductive adhesive (ACA) films with thicknesses from a few µm to some hundreds µm and resistance below 0,01 Ohm/cm^2. With very high chain densities (pitch below 10µm), these films are currently being tested in several bonding processes, like FOB, FOF, COB, COF, as an alternative to traditional ACF. The process is demonstrated in roll-to-roll production, proofing it is scalable and cost effective. Morten Lindberget VP Business Development @ CondAlign Bio An enabler with 25 years international experience from leadership, sales and business development roles in technology consulting, contract manufacturing, medical device technology and scale up. Morten holds a MSc in Mech. Engineering from TU Delft, the Netherlands, and an Executive Master of Management from BI, Norway. Join TechBlick on an annual pass to join all live online conference or online version of onsite conference access library of on-demand talks (600 talks + PDFs) portfolio of expert led masterclass year-round platform https://www.techblick.com/ And do NOT miss our flagship event in Berlin on 17-18 OCT 2023 focused on Reshaping the Future of Electronics. This event attracts 550-600 participants from all the world and offers a superb ambience and dynamic exhibition floor. To learn more visit https://www.techblick.com/electronicsreshaped To see feedback about previous event see https://www.techblick.com/events-agenda

A new organic (carbon-based) semiconducting material has been developed that outperforms existing options for building the next generation of biosensors. An international research team led by KAUST is the first to overcome some critical challenges in developing this polymer. The work "Regiochemistry-Driven Organic Electrochemical Transistor Performance Enhancement in Ethylene Glycol-Functionalized Polythiophenes" was published in the Journal of the American Chemical Society Much research effort is currently expended into novel types of biosensors that interact directly with the body to detect key biochemicals and serve as indicators of health and disease. “For a sensor to be compatible with the body, we need to use soft organic materials with mechanical properties that match those of biological tissues,” says Rawad Hallani, a former research scientist in the KAUST team, who developed the polymer along with researchers at several universities in the U.S. and the U.K. Hallani explains that the polymer is designed for use in devices called organic electrochemical transistors (OECTs). For these types of devices, the polymer should allow specific ions and biochemical compounds to permeate into the polymer and dope it, which in turn can modulate its electrochemical semiconducting properties. “The fluctuation in the electrochemical properties is what we are actually measuring as an output signal of the OECT,” he says. The team had to confront several chemical challenges because even minor changes in the polymer’s structure can have a significant impact on performance. Many other research groups have tried to make this particular polymer, but the KAUST team is the first to succeed. Their innovation is based on polymers called polythiophenes with chemical groups called glycols attached in precisely controlled positions. Learning how to control the locations of the glycol groups in ways not previously achieved was a key aspect of the breakthrough. “Identifying the right polymer design to fit all the criteria that you are looking for is the tough part,” says Hallani. “Sometimes what can optimize the performance of the material can negatively affect its stability, so we need to keep in mind the energetic as well as the electronic properties of the polymer.” Sophisticated computational chemistry modeling was used to help achieve the right design. The team was also aided by specialized x-ray scattering analysis and scanning tunneling electron microscopy to monitor the structure of their polymers. These techniques revealed how the location of the glycol groups affected the material’s microstructure and electronic properties. “We are excited by the progress Rawad made on the polymer synthesis, and we are now looking forward to testing our new polymer in specific biosensor devices,” says Iain McCulloch of the KAUST team, who is also attached to the University of Oxford in the U.K. McCulloch says that the research group is now trying to improve the stability of their polymers and the sensors built from them, as they move from laboratory demonstrations toward real-world applications. For more information, visit: https://discovery.kaust.edu.sa/en/article/1148/building-a-better-biosensor-polymer

Human body communication (HBC) that takes advantage of the most conductive features of body tissues can provide highly secure and power-efficient data transmission among wearable, implanted and ingested medical devices, KAUST researchers have published this work "The Internet of Bodies: A Systematic Survey on Propagation Characterization and Channel Modeling" in IEEE Internet of Things Journal. The findings open the way for the interconnection of long-lasting wireless devices as the foundation for the internet of bodies (IoB). The internet of things (IoT) is a technology framework in which a myriad of devices can be interconnected to provide seamless functionality and unprecedented depth of data on the world around us. Autonomous vehicles and smart homes, for example, rely on IoT technologies for monitoring and control. But what if the same idea could be applied to monitoring our own bodies and alerting us to health signals? That is the concept behind the IoB. “The IoB is a network of wearable, implantable, ingestible and injectable smart objects that allows for in-, on- and off-body communications,” says Ahmed Eltawil. “For example, smartwatches, smart shoes, pacemakers, and cochlear implants could be interconnected to monitor our biomarkers.” However, interconnecting these devices using radio waves like those used in Wifi networks — the conventional go-to technology for such applications — can produce stray outward signals that could allow eavesdropping or biohacking, as well as using excess energy. Through a systematic investigation of potential IoB interconnection technologies, Eltawil and colleagues Abdulkadir Celik, Abeer Alamoodi and Khaled Salama revealed HBC to be the most promising. “HBC uses harmless tiny electrical signals to transmit data through conductive body tissue,” says Celik. “Not only does HBC use a thousand times less energy per bit than radio, it also benefits from much better channel quality.” The potential of HBC is not just limited to interdevice networking, however; due to the unique conductance characteristics of each person, the technology could also be used for bioauthentication, just like a fingerprint. “Imagine a scenario where simply touching a car steering wheel or the keys on your laptop can continuously authenticate that you are the owner,” says Celik. The researchers suggest that IoB using human body channels could be a disruptive technology in many sectors, such as personalized healthcare, remote patient monitoring, smart homes, assisted independent living, occupational health, and safety, fitness, sport, and entertainment. “While numerous technical challenges still need to be addressed, such as developing robust, seamless interfaces between the sensor and the human body, HBC certainly opens the possibility of realizing extremely compact, cheap, low-power body sensors,” Eltawil says. For more information, visit: https://discovery.kaust.edu.sa/en/article/1190/connect-the-internet-of-bodies

KAUST scientists have created micrometer-scale light-emitting diodes of unprecedented small size that could be used in mobile phone screens or televisions. They published their work "630-nm red InGaN micro-light-emitting diodes (<20 μm × 20 μm) exceeding 1 mW/mm2 for full-color micro-displays" in Photonics Research journal. Micrometer-scale light-emitting diodes (μLEDs) are the ideal building block for next-generation microLED displays used in head-mounted monitors, mobile phones, and televisions because they are bright, respond quickly, offer longevity, and consume little energy. KAUST researchers have shown that these scaled-down devices can efficiently emit light across the entire visible light spectrum. Just as with conventional LED displays, full-color μLEDs products will require arrays of blue, green, and red light sources. Nitride-based alloys are a group of semiconducting materials that offer one route to achieving this because, with the right chemical mix, they can emit all three colors. However, when nitride devices are reduced in size to micrometer scales, they become very poor emitters of light. “The main obstacle to reducing the size of the devices is the damage to the sidewalls of the LED structure generated during the fabrication process,” explains Ph.D. student Martin Velazquez-Rizo. “Defects provide an electrical path for a leakage current that does not contribute to the light emission.” This effect gets worse as the size of the LED shrinks, which has limited the LED size to approximately 400 by 400 micrometers. Velazquez-Rizo, along with his colleagues Zhe Zhuang, Daisuke Iida, and Kazuhiro Ohkawa, have developed bright red indium gallium nitride micro light-emitting diodes (µLEDs) of just 17 × 17 micrometers. The team used a thoroughly calibrated atom deposition technique to create a 10 by 10 array of red μLEDs. The damage to the μLED sidewalls was then eliminated using a chemical treatment. “We confirmed with atomic-scale observations that the sidewalls had high crystallinity after the treatment,” says Velazquez-Rizo. “Performing this type of observation requires specialized tools and sample preparation.” And the leader of the research Ohkawa agrees. “Without this microscope technology, we could not realize and confirm this achievement.” They observed very high output power of 1.76 milliwatts from each square millimeter on the device’s surface — a notable improvement on previous devices that reported an output power of less than 1 milliwatt per millimeter square. The team then demonstrated their red μLEDs with green and blue indium gallium nitride μLEDs to create a wide color-range device. “The next step in our research is to further improve the efficiency of our μLEDs and decrease their lateral dimensions below 10 micrometers,” says Velazquez-Rizo. For more information, visit: https://discovery.kaust.edu.sa/en/article/1179/full-color-leds-cut-down-to-size

An electrode coating just one molecule thick can significantly enhance the performance of an organic photovoltaic cell, KAUST researchers have found. The coating outperforms the leading material currently used for this task and may pave the way for improvements in other devices that rely on organic molecules, such as light-emitting diodes and photodetectors. The work "18.4 % Organic Solar Cells Using a High Ionization Energy Self-Assembled Monolayer as Hole-Extraction Interlayer" was published in Chemistry–Sustainability–Energy–Materials Journal. Unlike the most common photovoltaic cells that use crystalline silicon to harvest light, organic photovoltaic cells (OPVs) rely on a light-absorbing layer of carbon-based molecules. Although OPVs cannot yet rival the performance of silicon cells, they could be easier and cheaper to manufacture at a very large scale using printing techniques. When light enters a photovoltaic cell, its energy frees a negative electron and leaves behind a positive gap, known as a hole. Different materials then gather the electrons and holes and guide them to different electrodes to generate an electrical current. In OPVs, a material called PEDOT: PSS is widely used to ease the transfer of generated holes into an electrode; however, PEDOT: PSS is expensive, acidic, and can degrade the cell’s performance over time. The KAUST team has now developed a better alternative to PEDOT: PSS. They use a much thinner coating of a hole-transporting molecule called Br-2PACz, which binds to an indium tin oxide (ITO) electrode to form a single-molecule layer. The organic cell using Br-2PACz achieved a power conversion efficiency of 18.4 percent, whereas an equivalent cell using PEDOT: PSS reached only 17.5 percent. “We were very surprised indeed by the performance enhancement,” says Yuanbao Lin, Ph.D. student and member of the team. “We believe Br-2PACz has the potential to replace PEDOT: PSS due to its low cost and high performance.” Br-2PACz increased the cell’s efficiency in several ways. Compared with its rival, it caused less electrical resistance, improved hole transport, and allowed more light to shine through to the absorbing layer. Br-2PACz also improved the structure of the light-absorbing layer itself, an effect that may be related to the coating process. The coating could even improve the recyclability of the solar cell. The researchers found that the ITO electrode could be removed from the cell, stripped of its coating, and then reused as if it was new. In contrast, PEDOT: PSS roughens the surface of the ITO so that it performs poorly if reused in another cell. “We anticipate this will have a dramatic impact on both the economics of OPVs and the environment,” says Thomas Anthopoulos, who led the research. For more information, visit: https://discovery.kaust.edu.sa/en/article/1138/molecular-coating-enhances-organic-solar-cells