Category Archives: Packaging Materials

If scientists are ever going to deliver on the promise of implantable artificial organs or clothing that dries itself, they’ll first need to solve the problem of inflexible batteries that run out of juice too quickly. They’re getting closer, and today researchers report that they’ve developed a new material by weaving two polymers together in a way that vastly increases charge storage capacity.

The researchers will present their work today at the 255th National Meeting & Exposition of the American Chemical Society (ACS). ACS, the world’s largest scientific society, is holding the meeting here through Thursday. It features more than 13,000 presentations on a wide range of science topics.

Supercapacitors woven like the red and white of a candy cane could have increased charge storage capacity compared to current technology. Credit: Tiesheng Wang

Supercapacitors woven like the red and white of a candy cane could have increased charge storage capacity compared to current technology. Credit: Tiesheng Wang

“We had been developing polymer networks for a different application involving actuation and tactile sensing,” Tiesheng Wang says. “After the project, we realized that the stretchable, bendable material we’d made could potentially be used for energy storage.”

Batteries, specifically lithium-ion batteries, dominate the energy storage landscape. However, the chemical reactions underlying the charging and discharging process in batteries are slow, limiting how much power they can deliver. Plus, batteries tend to degrade over time, requiring replacement. An alternate energy storage device, the supercapacitor, charges rapidly and generates serious power, which could potentially allow electric cars to accelerate more quickly, among other applications. Plus, supercapacitors store energy electrostatically, not chemically, which makes them more stable and long-lasting than many batteries. But today’s commercially available supercapacitors require binders and have low energy density, limiting their application in emerging go-anywhere electronics.

Wang, a graduate student in the lab of Stoyan Smoukov, Ph.D., at the University of Cambridge (U.K.) suspected that a flexible conducting polymer-based material from another project they were working on could be a better alternative. Conducting polymers, such as poly(3,4-ethylenedioxythiophene) (PEDOT), are candidate supercapacitors that have advantages over traditional carbon-based supercapacitors as charge storage materials. They are pseudocapacitive, meaning they allow reversible electrochemical reactions, and they also are chemically stable and inexpensive. However, ions can only penetrate the polymers a couple of nanometers deep, leaving much of the material as dead weight. Scientists working to improve ion mobility had previously developed nanostructures that deposit thin layers of conducting polymers on top of support materials, which improves supercapacitor performance by making more of the polymer accessible to the ions. The drawback, according to Wang, is that these nanostructures can be fragile, difficult to make reproducibly when scaled-up and poor in electrochemical stability, limiting their applicability.

So, Smoukov and Wang developed a more robust material by weaving together a conducting polymer with an ion-storage polymer. The two polymers were stitched together to form a candy cane-like geometry, with one polymer playing the role of the white stripe and the other, red. While PEDOT conducts electricity, the other polymer, poly(ethylene oxide) (PEO), can store ions. The interwoven geometry is instrumental to the energy storage benefits, Wang says, because it allows the ions to access more of the material overall, approaching the “theoretical limit.”

When tested, the candy cane supercapacitor demonstrated improvements over PEDOT alone with regard to flexibility and cycling stability. It also had nearly double the specific capacitance compared to conventional PEDOT-based supercapacitors.

Still, there’s room for improvement, Smoukov says. “In future experiments, we will be substituting polyaniline for PEDOT to increase the capacitance,” he says. “Polyaniline, because it can store more charge per unit of mass, could potentially store three times as much electricity as PEDOT for a given weight.” That means lighter batteries with the same energy storage can be charged faster, which is an important consideration in the development of novel wearables, robots and other devices.

Some novel materials that sound too good to be true turn out to be true and good. An emergent class of semiconductors, which could affordably light up our future with nuanced colors emanating from lasers, lamps, and even window glass, could be the latest example.

These materials are very radiant, easy to process from solution, and energy-efficient. The nagging question of whether hybrid organic-inorganic perovskites (HOIPs) could really work just received a very affirmative answer in a new international study led by physical chemists at the Georgia Institute of Technology.

Laser light in the visible range is processed for use in the testing of quantum properties in materials in Carlos Silva's lab at Georgia Tech. Credit: Georgia Tech/Allison Carter

Laser light in the visible range is processed for use in the testing of quantum properties in materials in Carlos Silva’s lab at Georgia Tech. Credit: Georgia Tech/Allison Carter

The researchers observed in an HOIP a “richness” of semiconducting physics created by what could be described as electrons dancing on chemical underpinnings that wobble like a funhouse floor in an earthquake. That bucks conventional wisdom because established semiconductors rely upon rigidly stable chemical foundations, that is to say, quieter molecular frameworks, to produce the desired quantum properties.

“We don’t know yet how it works to have these stable quantum properties in this intense molecular motion,” said first author Felix Thouin, a graduate research assistant at Georgia Tech. “It defies physics models we have to try to explain it. It’s like we need some new physics.”

Quantum properties surprise

Their gyrating jumbles have made HOIPs challenging to examine, but the team of researchers from a total of five research institutes in four countries succeeded in measuring a prototypical HOIP and found its quantum properties on par with those of established, molecularly rigid semiconductors, many of which are graphene-based.

“The properties were at least as good as in those materials and may be even better,” said Carlos Silva, a professor in Georgia Tech’s School of Chemistry and Biochemistry. Not all semiconductors also absorb and emit light well, but HOIPs do, making them optoelectronic and thus potentially useful in lasers, LEDs, other lighting applications, and also in photovoltaics.

The lack of molecular-level rigidity in HOIPs also plays into them being more flexibly produced and applied.

Silva co-led the study with physicist Ajay Ram Srimath Kandada. Their team published the results of their study on two-dimensional HOIPs on March 8, 2018, in the journal Physical Review Materials. Their research was funded by EU Horizon 2020, the Natural Sciences and Engineering Research Council of Canada, the Fond Québécois pour la Recherche, the Research Council of Canada, and the National Research Foundation of Singapore.

The ‘solution solution’

Commonly, semiconducting properties arise from static crystalline lattices of neatly interconnected atoms. In silicon, for example, which is used in most commercial solar cells, they are interconnected silicon atoms. The same principle applies to graphene-like semiconductors.

“These lattices are structurally not very complex,” Silva said. “They’re only one atom thin, and they have strict two-dimensional properties, so they’re much more rigid.”

“You forcefully limit these systems to two dimensions,” said Srimath Kandada, who is a Marie Curie International Fellow at Georgia Tech and the Italian Institute of Technology. “The atoms are arranged in infinitely expansive, flat sheets, and then these very interesting and desirable optoelectronic properties emerge.”

These proven materials impress. So, why pursue HOIPs, except to explore their baffling physics? Because they may be more practical in important ways.

“One of the compelling advantages is that they’re all made using low-temperature processing from solutions,” Silva said. “It takes much less energy to make them.”

By contrast, graphene-based materials are produced at high temperatures in small amounts that can be tedious to work with. “With this stuff (HOIPs), you can make big batches in solution and coat a whole window with it if you want to,” Silva said.

Funhouse in an earthquake

For all an HOIP’s wobbling, it’s also a very ordered lattice with its own kind of rigidity, though less limiting than in the customary two-dimensional materials.

“It’s not just a single layer,” Srimath Kandada said. “There is a very specific perovskite-like geometry.” Perovskite refers to the shape of an HOIPs crystal lattice, which is a layered scaffolding.

“The lattice self-assembles,” Srimath Kandada said, “and it does so in a three-dimensional stack made of layers of two-dimensional sheets. But HOIPs still preserve those desirable 2D quantum properties.”

Those sheets are held together by interspersed layers of another molecular structure that is a bit like a sheet of rubber bands. That makes the scaffolding wiggle like a funhouse floor.

“At room temperature, the molecules wiggle all over the place. That disrupts the lattice, which is where the electrons live. It’s really intense,” Silva said. “But surprisingly, the quantum properties are still really stable.”

Having quantum properties work at room temperature without requiring ultra-cooling is important for practical use as a semiconductor.

Going back to what HOIP stands for — hybrid organic-inorganic perovskites – this is how the experimental material fit into the HOIP chemical class: It was a hybrid of inorganic layers of a lead iodide (the rigid part) separated by organic layers (the rubber band-like parts) of phenylethylammonium (chemical formula (PEA)2PbI4).

The lead in this prototypical material could be swapped out for a metal safer for humans to handle before the development of an applicable material.

Electron choreography

HOIPs are great semiconductors because their electrons do an acrobatic square dance.

Usually, electrons live in an orbit around the nucleus of an atom or are shared by atoms in a chemical bond. But HOIP chemical lattices, like all semiconductors, are configured to share electrons more broadly.

Energy levels in a system can free the electrons to run around and participate in things like the flow of electricity and heat. The orbits, which are then empty, are called electron holes, and they want the electrons back.

“The hole is thought of as a positive charge, and of course, the electron has a negative charge,” Silva said. “So, hole and electron attract each other.”

The electrons and holes race around each other like dance partners pairing up to what physicists call an “exciton.” Excitons act and look a lot like particles themselves, though they’re not really particles.

Hopping biexciton light

In semiconductors, millions of excitons are correlated, or choreographed, with each other, which makes for desirable properties, when an energy source like electricity or laser light is applied. Additionally, excitons can pair up to form biexcitons, boosting the semiconductor’s energetic properties.

“In this material, we found that the biexciton binding energies were high,” Silva said. “That’s why we want to put this into lasers because the energy you input ends up to 80 or 90 percent as biexcitons.”

Biexcitons bump up energetically to absorb input energy. Then they contract energetically and pump out light. That would work not only in lasers but also in LEDs or other surfaces using the optoelectronic material.

“You can adjust the chemistry (of HOIPs) to control the width between biexciton states, and that controls the wavelength of the light given off,” Silva said. “And the adjustment can be very fine to give you any wavelength of light.”

That translates into any color of light the heart desires.

The ConFab — an executive invitation-only conference now in its 14th year — brings together influential decision-makers from all parts of the semiconductor supply chain for three days of thought-provoking talks and panel discussions, networking events and select, pre-arranged breakout business meetings.

In the 2018 program, we will take a close look at the new applications driving the semiconductor industry, the technology that will be required at the device and process level to meet new demands, and the kind of strategic collaboration that will be required. It is this combination of business, technology and social interactions that make the conference so unique and so valuable. Browse this slideshow for a look at this year’s speakers, keynotes, panel discussions, and special guests.

Visit The ConFab’s website for a look at the full, three-day agenda for this year’s event.

KEYNOTE: How AI is Driving the New Semiconductor Era

Rama Divakaruni_June_2014presented by Rama Divakaruni, Advanced Process Technology Research Lead, IBM

The exciting results of AI have been fueled by the exponential growth in data, the widespread availability of increased compute power, and advances in algorithms. Continued progress in AI – now in its infancy – will require major innovation across the computing stack, dramatically affecting logic, memory, storage, and communication. Already the influence of AI is apparent at the system-level by trends such as heterogeneous processing with GPUs and accelerators, and memories with very high bandwidth connectivity to the processor. The next stages will involve elements which exploit characteristics that benefit AI workloads, such as reduced precision and in-memory computation. Further in time, analog devices that can combine memory and computation, and thus minimize the latency and energy expenditure of data movement, offer the promise of orders of magnitude power-performance improvements for AI workloads. Thus, the future of AI will depend instrumentally on advances in devices and packaging, which in turn will rely fundamentally on materials innovations.

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One of the problems for Javier Vela and the chemists in his Iowa State University research group was that a toxic material worked so well in solar cells.

And so any substitute for the lead-containing perovskites used in some solar cells would have to really perform. But what could they find to replace the perovskite semiconductors that have been so promising and so efficient at converting sunlight into electricity?

What materials could produce semiconductors that worked just as well, but were safe and abundant and inexpensive to manufacture?

“Semiconductors are everywhere, right?” Vela said. “They’re in our computers and our cell phones. They’re usually in high-end, high-value products. While semiconductors may not contain rare materials, many are toxic or very expensive.”

Vela, an Iowa State associate professor of chemistry and an associate of the U.S. Department of Energy’s Ames Laboratory, directs a lab that specializes in developing new, nanostructured materials. While thinking about the problem of lead in solar cells, he found a conference presentation by Massachusetts Institute of Technology researchers that suggested possible substitutes for perovskites in semiconductors.

Vela and Iowa State graduate students Bryan Rosales and Miles White decided to focus on sodium-based alternatives and started an 18-month search for a new kind of semiconductor. The work was supported by Vela’s five-year, $786,017 CAREER grant from the National Science Foundation. CAREER grants are the foundation’s most prestigious awards for early career faculty.

They came up with a compound that features sodium, which is cheap and abundant; bismuth, which is relatively scarce but is overproduced during the mining of other metals and is cheap; and sulfur, the fifth most common element on Earth. The researchers report their discovery in a paper recently published online by the Journal of the American Chemical Society.

The paper’s subtitle is a good summary of their work: “Toward Earth-Abundant, Biocompatible Semiconductors.”

“Our synthesis unlocks a new class of low-cost and environmentally friendly ternary (three-part) semiconductors that show properties of interest for applications in energy conversion,” the chemists wrote in their paper.

In fact, Rosales is working to create solar cells that use the new semiconducting material.

Vela said variations in synthesis – changing reaction temperature and time, choice of metal ion precursors, adding certain ligands – allows the chemists to control the material’s structure and the size of its nanocrystals. And that allows researchers to change and fine tune the material’s properties.

Several of the material’s properties are already ideal for solar cells: The material’s band gap – the amount of energy required for a light particle to knock an electron loose – is ideal for solar cells. The material, unlike other materials used in solar cells, is also stable when exposed to air and water.

So, the chemists think they have a material that will work well in solar cells, but without the toxicity, scarcity or costs.

“We believe the experimental and computational results reported here,” they wrote in their paper, “will help advance the fundamental study and exploration of these and similar materials for energy conversion devices.”

The Silicon Integration Initiative’s (Si2) Compact Model Coalition (CMC) has approved two integrated circuit design simulation standards that target the fast-growing global market for gallium nitride semiconductors.

The approved standards are the 12th and 13th models currently funded and supported by the CMC, a collaborative group that develops and maintains cost-saving SPICE (Simulation Program with Integrated Circuit Emphasis) models for IC design.

John Ellis, president and CEO, said gallium nitride devices are used in many high-power and high-frequency applications, including satellite communications, radar, cellular, broadband wireless systems, and automotive. “Although it’s currently a small market, gallium nitride devices are expected to show remarkable growth over the coming years.”

To reduce research and developments costs and increase simulation accuracy, the semiconductor industry relies on the CMC to share resources for funding standard SPICE models. Si2 is a research and development joint venture focused on IC design and tool operability standards. “Once the standard models are proven and accepted by CMC, they are incorporated into design tools widely used by the semiconductor industry. The equations at work in the standard model-setting process are developed, refined and maintained by leading universities and national laboratories. The CMC directs and funds the universities to standardize and improve the models,” Ellis explained.

Dr. Ana Villamor, technology and market analyst at Yole Développement (Yole), Lyon, France, said that “2015 and 2016 were exciting years for the gallium nitride power business. We project an explosion of this market with 79% CAGR between 2017 and 2022. Market value will reach US $460 million at the end of the period1. It’s still a small market compared to the impressive US $30 billion silicon power semiconductor market,” Villamor said. “However, its expected growth in the short term is showing the enormous potential of the power gallium nitride technology based on its suitability for high performance and high frequency solutions.”

Yole_GaN_power_device_market_size_split_by_application_M_

Peter Lee, manager at Micron Memory Japan and CMC chair, said that “Gallium nitride devices are playing an increasingly important part in the field of RF and power electronics. With these two advanced models established as the first, worldwide gallium nitride model standards, efficiencies in design will greatly increase by making it possible to take into account accurate device physical behavior in design, and enabling the use of the various simulation tools in the industry with consistent results.”

Click here to download standard models.

 

Scientists at Rice University and the Indian Institute of Science, Bangalore, have discovered a method to make atomically flat gallium that shows promise for nanoscale electronics.

The Rice lab of materials scientist Pulickel Ajayan and colleagues in India created two-dimensional gallenene, a thin film of conductive material that is to gallium what graphene is to carbon.

Extracted into a two-dimensional form, the novel material appears to have an affinity for binding with semiconductors like silicon and could make an efficient metal contact in two-dimensional electronic devices, the researchers said.

The new material was introduced in Science Advances.

Gallium is a metal with a low melting point; unlike graphene and many other 2-D structures, it cannot yet be grown with vapor phase deposition methods. Moreover, gallium also has a tendency to oxidize quickly. And while early samples of graphene were removed from graphite with adhesive tape, the bonds between gallium layers are too strong for such a simple approach.

So the Rice team led by co-authors Vidya Kochat, a former postdoctoral researcher at Rice, and Atanu Samanta, a student at the Indian Institute of Science, used heat instead of force.

Rather than a bottom-up approach, the researchers worked their way down from bulk gallium by heating it to 29.7 degrees Celsius (about 85 degrees Fahrenheit), just below the element’s melting point. That was enough to drip gallium onto a glass slide. As a drop cooled just a bit, the researchers pressed a flat piece of silicon dioxide on top to lift just a few flat layers of gallenene.

They successfully exfoliated gallenene onto other substrates, including gallium nitride, gallium arsenide, silicone and nickel. That allowed them to confirm that particular gallenene-substrate combinations have different electronic properties and to suggest that these properties can be tuned for applications.

“The current work utilizes the weak interfaces of solids and liquids to separate thin 2-D sheets of gallium,” said Chandra Sekhar Tiwary, principal investigator on the project he completed at Rice before becoming an assistant professor at the Indian Institute of Technology in Gandhinagar, India. “The same method can be explored for other metals and compounds with low melting points.”

Gallenene’s plasmonic and other properties are being investigated, according to Ajayan. “Near 2-D metals are difficult to extract, since these are mostly high-strength, nonlayered structures, so gallenene is an exception that could bridge the need for metals in the 2-D world,” he said.

Semiconductors–a class of materials that can function as both electrical conductor and insulator, depending on the circumstances–are an essential technology for all modern electronic innovations.

Silicon has long been the most famous semiconductor, but in recent years researchers have studied a wider range of materials, including molecules that can be tailored to serve specific electronic needs.

Perhaps appropriately, one of the most cutting-edge electronics–supercomputers–are indispensable research tools for studying complex semiconducting materials at a fundamental level.

Recently, a team of scientists at TU Dresden used the SuperMUC supercomputer at the Leibniz Supercomputing Centre to refine its method for studying organic semiconductors.

Illustration of a doped organic semiconductor based on fullerene C60 molecules (green). The benzimidazoline dopant (purple) donates an electron to the C60 molecules in its surrounding (dark green). These electrons can then propagate through the semiconductor material (light green). Credit: S. Hutsch/F. Ortmann, TU Dresden

Illustration of a doped organic semiconductor based on fullerene C60 molecules (green). The benzimidazoline dopant (purple) donates an electron to the C60 molecules in its surrounding (dark green). These electrons can then propagate through the semiconductor material (light green). Credit: S. Hutsch/F. Ortmann, TU Dresden

Specifically, the team uses an approach called semiconductor doping, a process in which impurities are intentionally introduced into a material to give it specific semiconducting properties. It recently published its results in Nature Materials.

“New kinds of semiconductors, organic semiconductors, are starting to get used in new device concepts,” said team leader Dr. Frank Ortmann. “Some of these are already on the market, but some are still limited by their inefficiency. We are researching doping mechanisms–a key technology for tuning semiconductors’ properties–to understand these semiconductors’ limitations and respective efficiencies.”

Quantum impurities

When someone changes a material’s physical properties, he or she also changes its electronic properties and, therefore, the role it can play in electronic devices. Small changes in material makeup can lead to big changes in a material’s characteristics–in certain cases one slight atomic alteration can lead to a 1000-fold change in electrical conductivity.

While changes in material properties may be big, the underlying forces–exerting themselves on atoms and molecules and governing their interactions–are generally weak and short-range (meaning the molecules and the atoms of which they are composed must be close together). To understand changes in properties, therefore, researchers have to accurately compute atomic and molecular interactions as well as the densities of electrons and how they are transferred among molecules.

Introducing specific atoms or molecules to a material can change its conducting properties on a hyperlocal level. This allows a transistor made from doped material to serve a variety of roles in electronics, including routing currents to perform operations based on complex circuits or amplifying current to help produce sound in a guitar amplifier or radio.

Quantum laws govern interatomic and intermolecular interactions, in essence holding material together, and, in turn, structuring the world as we know it. In the team’s work, these complex interactions need to be calculated for individual atomic interactions, including interactions among semiconductor “host” molecules and dopant molecules on a larger scale.

The team uses density functional theory (DFT)–a computational method that can model electronic densities and properties during a chemical interaction–to efficiently predict the variety of complex interactions. It then collaborates with experimentalists from TU Dresden and the Institute for Molecular Science in Okazaki, Japan to compare its simulations to spectroscopy experiments.

“Electrical conductivity can come from many dopants and is a property that emerges on a much larger length scale than just interatomic forces,” Ortmann said. “Simulating this process needs more sophisticated transport models, which can only be implemented on high-performance computing (HPC) architectures.”

Goal!

To test its computational approach, the team simulated materials that already had good experimental datasets as well as industrial applications. The researchers first focused on C60, also known as Buckminsterfullerene.

Buckminsterfullerene is used in several applications, including solar cells. The molecule’s structure is very similar to that of a soccer ball–a spherical arrangement of carbon atoms arranged in pentagonal and hexagonal patterns the size of less than one nanometer. In addition, the researches simulated zinc phthalocyanine (ZnPc), another molecule that is used in photovoltaics, but unlike C60, has a flat shape and contains a metallic atom (zinc).

As its dopant the team first used a well-studied molecule called 2-Cyc-DMBI (2-cyclohexyl-dimethylbenzimidazoline). 2-Cyc-DMBI is considered an n-dopant, meaning that it can provide its surplus electrons to the semiconductor to increase its conductivity. N-dopants are relatively rare, as few molecules are “willing” to give away an electron. In most cases, molecules that do so become unstable and degrade during chemical reactions, which in this context can lead to an electronic device failure. 2-Cyc-DMBI dopants are the exception, because they can be sufficiently weakly attractive for electrons–allowing them to move over long distances–while also remaining stable after donating them.

The team got good agreement between its simulations and experimental observations of the same molecule-dopant interactions. This indicates that they can rely on simulation to guide predictions as they relate to the doping process of semiconductors. They are now working on more complex molecules and dopants using the same methods.

Despite these advances, the team recognizes that next-generation supercomputers such as SuperMUC-NG–announced in December 2017 and set to be installed in 2018–will help the researchers expand the scope of their simulations, leading to ever bigger efficiency gains in a variety of electronic applications.

“We need to push the accuracy of our simulations to the maximum,” Ortmann said. “This would help us extend the range of applicability and allow us to more precisely simulate a broader set of materials or larger systems of more atoms.”

Ortmann also noted that while current-generation systems allowed the team to gain insights in specific situations and prove its concept, there is still room to get better. “We are often limited by system memory or CPU power,” he said. “The system size and simulation’s accuracy are essentially competing for computing power, which is why it is important to have access to better supercomputers. Supercomputers are perfectly suited to deliver answers to these problems in a realistic amount of time.”

Linde LienHwa, a key supplier of gases and chemicals to the electronics industry, continues to invest with its customers in Mainland China and Taiwan. On-site nitrogen generator plants are an early, tangible and significant demonstration of commitment to individual customers as they plan and execute new semiconductor and display panel plants.

The company is also expanding its production of electronic special gases (ESGs). This enhances its portfolio to meet the growing demand of local customers in the semiconductor and display industries. Linde LienHwa is leveraging access to global expertise to build first-in-kind capabilities in Taiwan to innovate locally for customers.

In March, Linde LienHwa will highlight its position in the electronics material sector with presentations by its executives at two industry forums held in Shanghai. The company invites customers and others in the electronics industry to visit its booth at the SEMICON China trade show for one-on-one discussions about their requirements and how Linde LienHwa is their local partner with global expertise.

Investing and growing with customers in Mainland China with on-site nitrogen production

Mainland China has made a large commitment to the electronics industry through the Sino IC Industry Investment Fund, more commonly known as The Big Fund. This has spurred an unprecedented number of new semiconductor and display projects launch in 2017, on top of very active preceding years in 2015 and 2016.

Nitrogen gas is used in high volumes at these facilities in almost all manufacturing steps to purge and inert chemically sensitive processes. For most facilities, it is much more economical to produce the required volume of nitrogen on-site, rather than to supply the gas by truck delivery. On-site nitrogen generators are built at an early phase of each project because nitrogen is required to be ready before the facility equipment arrives.

SPECTRA-N® nitrogen generators from the Linde Engineering division of the Linde Group support customers with their high quality products, flexible capacity and production and energy efficiency. These plants are designed, fabricated and executed by teams located in Hangzhou and Dalian, China.

Linde LienHwa has been successful in addressing the market needs with a number of new project signings. “These wins were punctuated in 2017 by a Linde LienHwa commitment of over RMB 1.5 billion investment in on-site gas production and bulk gas installations for electronics customers in Mainland China, which will fuel electronics revenue growth for us over the next five years,” said Stan Tang, President of LLH China. “This is only possible with a strong network of bulk gas production plants and fleet delivery throughout Mainland China, which back-up the on-site nitrogen plants as well as offer competitive supplies of oxygen, argon, hydrogen and other products.”

GeH4 precision blending and filling at Taichung Harbor

Linde LienHwa’s capability for blending and filling of germane in Taichung Harbor is the first and only of its kind in Taiwan. The facility produces mixtures between 1 to 20% germane in ultra-high purity hydrogen with extreme precision and state-of-the-art analysis. Germane-hydrogen mixtures are used by leading-edge semiconductor companies to make the most critical elements of computer chips, and precision of the blend is essential to making a working device.

Fluorine production at Guanyin

Another first in Taiwan is Linde LienHwa’s production of electronics-grade fluorine in Guanyin, a district of Taoyuan City. This special high-purity grade of fluorine is produced using generators from Linde developed for the electronics industry. The fluorine is typically blended with nitrogen or other inert gases, packaged in cylinders and used by electronics customers to remove particles and unwanted deposits from the interior surfaces of manufacturing tools.

Local partner. Global expertise.

“By investing locally in material processing, we are significantly reducing the supply chain risk and increasing material availability for our customers,” notes Alex Tong, President of Linde LienHwa. “These new facilities represent the latest phases in our commitment to expand ESG production in both Taiwan and China.”

Linde LienHwa maintains an extensive network of on-site gas production, bulk gases for electronics customers, ESGs, ultra-pure wet chemicals, chemical production and stocking facilities. Linde LienHwa offers a widest number of electronics materials. Its products enable leading-edge manufacturing in the semiconductor, solar, display and solid state lighting/LED industries.

Linde Electronics, its global partner, is the electronics materials and service business of The Linde Group, an industry leader in the industrial gas sector. Linde Gas operates in more than 100 countries, with world-class R&D centers, including its newest Electronics R&D Center in Taichung Harbor, Taiwan.

SEMICON China and the Global Semiconductor Forum

Linde LienHwa will be exhibiting at the SEMICON China tradeshow in Shanghai 14-16 March 2018. Its focus will be on the quality, expertise, service and technical leadership that Linde LienHwa and its global partner Linde Electronics bring to the semiconductor industry through such offerings as electronic specialty gases, bulk gases for electronics customers and on-site solutions like SPECTRA-N nitrogen plants.

Anshul Sarda, Vice President of Electronics Special Gases for the Linde Group, will be speaking at the SEMICON China Win-Win: Build China’s IC Ecosystem forum, for which LLH is a sponsor, on 15 March in the Pudong Ballroom of the Kerry Hotel. His talk entitled “Integrating domestic and international electronic material solutions” given at 16:00 will explain the challenges of materials supply in a dynamic landscape of established and newly-launched customers and material producers.

Dr. Anish Tolia, Vice President of Global Marketing for Linde Electronics, will be speaking at the Global Semiconductor Forum on 9 March at the Grand Kempinski Hotel in Shanghai. His workshop entitled “Supplying China: Combining local partnerships with global expertise by electronic material providers” will instruct on how material providers can adapt global experience in supply chains to the burgeoning opportunities and requirements of the China electronics market.

Phonons, which are packets of vibrational waves that propagate in solids, play a key role in condensed matter and are involved in various physical properties of materials. In nanotechnology, for example, they affect light emission and charge transport of nanodevices. As the main source of energy dissipation in solid-state systems, phonons are the ultimate bottleneck that limits the operation of functional nanomaterials.In an article recently published in Nature Communications, an INRS team of researchers led by Professor Luca Razzari and their European collaborators show that it is possible to modify the phonon response of a nanomaterial by exploiting the zero-point energy (i.e., the lowest possible – “vacuum” – energy in a quantum system) of a terahertz nano-cavity. The researchers were able to reshape the nanomaterial phonon response by generating new light-matter hybrid states. They did this by inserting some tens of semiconducting (specifically, cadmium sulfide) nanocrystals inside plasmonic nanocavities specifically designed to resonate at terahertz frequencies, i.e., in correspondence of the phonon modes of the nanocrystals.

“We have thus provided clear evidence of the creation of a new hybrid nanosystem with phonon properties that no longer belong to the original nanomaterial,” the authors said.

This discovery holds promise for applications in nanophotonics and nanoelectronics, opening up new possibilities for engineering the optical phonon response of functional nanomaterials. It also offers an innovative platform for the realization of a new generation of quantum transducers and terahertz light sources.

Solar cells have great potential as a source of clean electrical energy, but so far they have not been cheap, light, and flexible enough for widespread use. Now a team of researchers led by Tandon Associate Professor André D. Taylor of the Chemical and Biomolecular Engineering Department has found an innovative and promising way to improve solar cells and make their use in many applications more likely.

Most organic solar cells use fullerenes, spherical molecules of carbon. The problem, explains Taylor, is that fullerenes are expensive and don’t absorb enough light. Over the last 10 years he has made significant progress in improving organic solar cells, and he has recently focused on using non-fullerenes, which until now have been inefficient. However, he says, “the non-fullerenes are improving enough to give fullerenes a run for their money.”

Think of a solar cell as a sandwich, Taylor says. The “meat” or active layer – made of electron donors and acceptors – is in the middle, absorbing sunlight and transforming it into electricity (electrons and holes), while the “bread,” or outside layers, consist of electrodes that transport that electricity. His team’s goal was to have the cell absorb light across as large a spectrum as possible using a variety of materials, yet at the same time allow these materials to work together well. “My group works on key parts of the ‘sandwich,’ such as the electron and hole transporting layers of the ‘bread,’ while other groups may work only on the ‘meat’ or interlayer materials. The question is: How do you get them to play together? The right blend of these disparate materials is extremely difficult to achieve.”

Using a squaraine molecule in a new way – as a crystallizing agent – did the trick. “We added a small molecule that functions as an electron donor by itself and enhances the absorption of the active layer,” Taylor explains. “By adding this small molecule, it facilitates the orientation of the donor-acceptor polymer (called PBDB-T) with the non-fullerene acceptor, ITIC, in a favorable arrangement.”

This solar architecture also uses another design mechanism that the Taylor group pioneered known as a FRET-based solar cell. FRET, or Förster resonance energy transfer, is an energy transfer mechanism first observed in photosynthesis, by which plants use sunlight. Using a new polymer and non-fullerene blend with squaraine, the team converted more than 10 percent of solar energy into power. Just a few years ago this was considered too lofty a goal for single-junction polymer solar cells. “There are now newer polymer non-fullerene systems that can perform above 13 percent, so we view our contribution as a viable strategy for improving these systems,” Taylor says.

The organic solar cells developed by his team are flexible and could one day be used in applications supporting electric vehicles, wearable electronics, or backpacks to charge cell phones. Eventually, they could contribute significantly to the supply of electric power. “We expect that this crystallizing-agent method will attract attention from chemists and materials scientists affiliated with organic electronics,” says Yifan Zheng, Taylor’s former research student and lead author of the article about the work in the journal Materials Today.

Next for the research team? They are working on a type of solar cell called a perovskite as well as continuing to improve non-fullerene organic solar cells.