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GrollTex Tackles Sensor Markets With High Quality Graphene

Posted By Dexter Johnson, IEEE Spectrum, Thursday, March 1, 2018

  Jeffrey Draa, CEO, GROLLTEX

 

Last month, The Graphene Council's Executive Director, Terrance Barkan, and its Editor-in-Chief, Dexter Johnson, had the opportunity to have a talk with the CEO of California-based Grolltex Inc., Jeffrey Draa, about the company's business strategies in bringing graphene products to market and his views on graphene's future. Here is that conversation.

Could you tell us a little bit about the background of GrollTex. How did the company get started and how did you get involved with graphene? In particular, could you provide the history of Grolltex as a company?

Sure, so the name Grolltex is short for graphene rolling technologies and the brief history of the company is that my partner and co-founder and really the inventor, Dr. Alexander Zaretski, was a researcher at University of California San Diego.

He was involved with graphene growth and really got deep into graphene manufacturing techniques while he was at the University of California San Diego. One of the issues with this specific kind of graphene, as generated by chemical vapor deposition (CVD), of course, is the ‘transfer’ issue: How does one get single-layer graphene synthesized from copper off of the copper growth substrate and onto a substrate of interest without destroying the copper growth substrate? Of course, the current state-of-the art is to either acid etch the copper off of CVD graphene, or to use an electrolytic solution to sort of bubble the graphene off of the copper and have it rise to the top after a long period of time.

So both of these two processes, which had been state-of-the art, impact the copper in a very negative way so it's very expensive and not manufacturable. And my partner, Alexander, decided if graphene is going to go forward, there has to be a way to manufacture graphene and not destroy or impact that copper.  So he came up with a process to do that, a process that has a rolling schema where we reuse that growth copper over and over again. So that's kind of the background of the company. Alex had decided that he wanted, and felt so passionately about, this transfer technology and bringing it to graphene manufacturing that after completing his work as a researcher at UCSD, he broke out on his own and he asked me if I would be the business side of the company and he had the technical side. So that's kind of a brief background of Grolltex and how we came to be.

I understand you’re privately held company, correct?

We are, yes. We were funded roughly a year and a half ago with our seed funding and we've since about six months ago taken another round.

In terms of your graphene manufacturing that you just laid out, as you said you focused on producing single-layer graphene of the highest quality, so what are the markets that this product offering opens up to you? And what do you see as your strongest market now and do you see that market changing five years from now?

Well, as anybody that has knowledge of the graphene markets knows, single-layer high purity graphene like that synthesized via CVD has many theoretical use cases. We see on the short-term horizon three particular applications that are really kind of starting to command our attention. Those three are number one: sensing. So graphene given its electrical and mass properties makes an excellent sensor at a very, very small level. So sensing is number one.

We also are doing some work in the advanced solar cell arena and we have a grant from the California Energy Commission where we're working on a two-sided solar cell where graphene not only plays the part of barrier material but it's also the electrode material. So that's really exciting.

And for number three we’re also starting to get some inquiries for an application that actually Dr. Andre Geim at the University of Manchester, who, of course, was the discoverer of graphene was very passionate about. This is one of the very first applications that he thought futuristically would really make the world a better place, and that third application that we're starting to see on the horizon is graphene as a proton exchange membrane in a hydrogen fuel cell.

So those are kind of the three leading candidates we see right now. We’re judging that by some initial business that we’re getting in those areas.

You were discussing a number of applications you are pursing, including sensors. On your website you talk about enabling sensors that could be used for the Internet of Things. Can you explain why you see graphene playing such an important role in the development Internet of Things?

I’ll speak a little about graphene as a sensor material. When you combine the electrical conductivity properties along with the fact that graphene is one atom thick, you've got the potential for a sensor that could take us into the future for the next hundred years. We have patents around some designs of graphene-based sensing materials that are so sensitive that, for example, in the biotech world we had some bioengineering folks at Stanford use our sensor to sense the ability of individual heart cells to contract. Currently there only exists a different kind of test that can only count the number of contractions, but our sensor is so sensitive that it picks up the strength of contraction of the individual heart cell when it beats and it's a very robust signal; there's no mistaking it. So that's just one example of the potential of graphene as a sensor and we're seeing good activity there.

What is consistently your biggest challenge when you're talking to potential customers and convincing them how to use your product? Are they worried about pricing of graphene, the quality of product, a consistent supply chain? What stands out as one of the key issues that keeps coming up when you're speaking to these people?

So, I think the first consistent theme would surprise no one, and it's price. Almost any inquiry goes down along the lines of price, especially for a field like solar. If solar is implemented it’s going to need miles and miles of cheap graphene. Now the case of a sensor is not quite as price sensitive, but with regards to the big kind of large applications people think about like flexible displays and some of the other big idea changes for graphene those are really price sensitive. So price is the first one.

We don't get too many concerns with regards to the supply chain. Quality of product is sometimes discussed and that's partly because graphene is such a new field. But a lot of folks have what they are calling graphene and maybe debatably it is not. We don't necessarily have that problem because no one argues that single-layer graphene made by CVD is not graphene, so we don't have any discussion of the quality, but that sometimes can be an issue. So to kind of summarize, and get back to your main question, really price is the first thing that people want and that's the first hurdle you have to get over with almost everyone.

In addition to your graphene product, you're also producing hexagonal boron nitride (sometimes called white graphene). How do you see this material filling out your portfolio and what are the applications for this material that you're currently targeting and do you expect to develop other two-dimensional materials?

Hexagonal boron nitride is something we’re very excited about for several reasons. For the folks that aren't familiar with hexagonal boron nitride, you need to understand how it works with graphene. Graphene is, of course, the most conductive substance known at room temperature; it's on the order of seven times more conductive than copper depending on who you talk to. So as a conductor, graphene is really unparalleled. Now if you're going to design an electronic device of any type, of course, you worry about a conducting material because you can make the wire, the battery, and the switch with the conductive material. But the other thing you have to worry about is the insulating material. What are you going to use for the insulation for graphene? You have to separate the layers of the devices and hexagonal boron nitride is as good an electrical insulator as graphene is a conductor. And hexagonal boron nitride has a hexagonal pattern when it is synthesized in the proper way and that pattern lines up perfectly with the hexagonal lattice pattern of graphene so it also provides the strength benefit too. So it is really the ideal cousin of graphene. If you're an electronic designer, you're going to want both a conductor and an insulator and now we're going to be delivering both.

So that answers your first question and your second question, which was “are we going to develop other two dimensional materials?” As far as basic building blocks, we are going to rest on graphene and hexagonal boron nitride for a time because again those are your two basic building blocks: you need the insulation and the conducting but we also are developing other materials that go into specific devices. So, an example of this is the sensors I talked about that require some precious metal in small quantity—atomic quantity.  There are other materials involved when you go to make a specific device, but as far as the basic building blocks we're going to stand pat on graphene and hBN probably for a while.

What is your perspective on hybrid graphene materials? I am referring to this combination of a conductor and an insulator, or even a conductor with a semiconductor, and based on that will you look to develop those hybrids yourself or have your client make the next step in the value chain?

At the moment our clients are doing that work. Now I'm not going to say that we won't get into it, but we're going to be opportunistic with regard to that. With regard to opportunistic roads that we can go down today, our plate is pretty full, but there are several routes we can take. We are seeing folks in the semiconductor world, which is my background, starting to use other materials and creating devices out of some of those second and third level hybrids as you described and that's really exciting work. So we may get into some of that, but again we have a lot on our plate right now just based on what I described already.

I’d like to get your view of the overall industry over the short, middle and long term—five, ten, fifteen years expectations of graphene and the industry. And what is your strategy for best placing your company in the environment that you see developing?

With regard to our company, just saying the word “graphene” to a lot of people opens up so many thought patterns, channels and ideas that one of the things that's going to have to happen is the standards are going to need to be put in place fairly soon so that people can know what they're saying when they say “graphene”.

There's a lot of graphitic solutions out there and hybrids and powders and all kinds of things that debatably aren't graphene (of course, I would say that because of my company is involved in the area that there is no argument that it is pure graphene). But the point of that is we will need some standards and some nomenclature put in place to help take this whole field to the next level.

There's all kinds of great use cases for graphitic solutions that aren't graphene—great use cases, don't get me wrong—but let's make sure that we can assign proper nomenclature so people know what they are talking about and looking at. With regard to my company specifically, one of our challenges is picking our targets because again there are so many kinds of different opportunities. And when we first started out we decided we were going to have a two-phased approach to our business and we're doing the phase one part of that now.

Phase one for us is to make and sell graphene material as research material. So our core customer for our phase one is the university lab and commercial lab. So we sell graphene on copper substrates, on wafers, we sell graphene on customer specific substrates. You send us your substrate of interest and we’ll put our graphene on it and send it back to you. That phase one of our business that I just described to you is allowing us to pursue all kinds of exciting applications and some of them are helping us go in new directions. So, our challenge in the first five years I think is; number one stay on that phase-one path, get to profitability just as a business and number two really pick our paths carefully with regard to what are going to be the first real big market businesses out there in graphene—the ones that have paying customers.

So from a commercialization perspective, I think what you mention is that the majority, or is it basically all, of your customers are they in the testing or R&D category right now?

Yes, that’s fair to say. There's a population of big players in the industry that have their own graphene “skunkworks” that they're just not talking about. For example, I'm just going to throw some names around freely about big companies that we happen to know that do have graphene labs internally that it's just really very hush-hush. The reason we know this is because we know some of the people that have been hired out of other graphene places into these big companies. For example, Apple is one of them. They don't talk about it but they have a big graphene effort. Hewlett Packard is of one of those. Samsung is not bashful about their graphene efforts. So there are a lot of big companies where there is a lot of activity going on but nobody is talking about it so I think there's a lot more happening in graphene than people are even aware of because it’s not being leaked.

One of the things we’re very interested in doing as the Graphene Council is helping to act as a catalyst and accelerate commercialization.

One of the biggest obstacles to commercialization we’ve seen is simply the education of potential end users and consumers.  Can you talk a little bit about that? I mean as a company trying to educate potential clients one by one is a time consuming and expensive proposition.

What are the some of the other vertical markets or specific application areas—you mentioned sensors, of course? Are there some other specific areas where you think there's good commercial opportunity where we can help educate those populations?

The first one that comes to mind is the display market. So the display folks, of course, have been using indium tin oxide (ITO) as their core material for decades. ITO is really not a great material for them; it's expensive, it involves dirty mining and it is very prone to pollution when getting it out of the earth. It's also brittle which is why everyone’s display on their phone, their laptop, their television, all displays are brittle; they're like glass.

Graphene is actually a plug and play replacement for ITO and graphene enables flexible displays. So, the first big use case I can think of and that would be the most exciting and the most impactful for the most people is ITO replacement for making flexible displays.

But also I think it’s a use case that's pretty far down the road. It’s very price sensitive for one reason and number two there is a huge infrastructure with multiple large multinational corporations already in place and has been in place for decades with a big manufacturing schema, billions of dollars all lined up to process ITO, etc.. That's not going to shut off overnight and just accept a graphene replacement, right? So, from a price perspective and from an implementation perspective there are some challenges with ITO replacement, but I think that it strikes me as the kind of area where we can start hammering away at some of the existing thinking.

_

The Graphene Council thanks Jeffrey Draa, CEO of GROLLTEX for his time and unique insights into the developing market for graphene. 

 

Tags:  chemical vapor deposition  Hexagonal boron nitride  ITO  photovoltaics  sensors 

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How Quantum Dots and Graphene Combined to Change the Landscape for Optoelectronics

Posted By Dexter Johnson, IEEE Spectrum, Wednesday, November 1, 2017

Last June, we covered research that brought graphene, quantum dots and CMOS all together into one to change the future of both optoelectronics and electronics. 

That research was conducted at the Institute of Photonics (ICFO) located just outside of Barcelona, Spain. The Graphene Council has been speaking to Frank Koppens at ICFO since 2015 about how graphene was impacting photonics and optoelectronics.

Now, in a series of in-person interviews with several researchers at ICFO (the first of which you can find here),  we are gaining better insight into how these technologies came to be and where they ultimately may lead.

Gerasimos Konstantatos - group leader at ICFO

The combination of graphene with quantum dots for use in optoelectronics stems in large part from the contributions of Gerasimos Konstantatos, a group leader at ICFO, who worked with Ted Sargent at the University of Toronto, whose research group has been at the forefront of exploiting colloidal quantum dots for use in a range of applications, most notably high-efficiency photovoltaics.

“Our initial expertise and focus was on actually exploiting the properties of solution-process materials particularly colloidal quantum dots as optoelectronic materials for solar cells and photodetectors,” explained Konstantatos. “The uniqueness of these materials is that they give us access to a spectrum that is very rarely reached in the shortwave and infrared and they can do it at a much lower cost than any other technology.”

Konstantatos and his group were able to bring their work with quantum dots to the point of the near-infrared wavelength spectrum, which falls in the wavelength size range of one to five microns. Konstantos is now developing these solution-based quantum dot materials to produce even more sensitive materials capable of getting to 10 microns, putting them squarely in the mid-infrared range.

“My group is now working with Frank Koppens to sensitize graphene and other 2D materials in order to make very sensitive photodetectors at a very low cost that are capable of accessing the entire spectrum, and this cannot be done with any other technology,” said Konstantatos.

What Konstantatos and Koppens have been able to do is to basically eliminate the junction between graphene and the quantum dots and in so doing have developed a way to control the charge transfer in a very efficient way so that they can exploit the very high mobility and transport conductance of graphene.

“We can re-circulate the charges through the materials so that with a single photon we have several billion charges re-circulating through the material and this constitutes the baseline of this material combination,” adds Konstantatos.

With that as their baseline technology, Konstantatos and his colleagues have engineered the quantum dot layer so instead of just having a passive quantum dot layer they have converted it into an electro-diode. In this way they can make much more complex detectors. In the combination of the graphene-based transistor with the quantum dots, it’s not just a collection of quantum dots but is a photodiode made from quantum dots.

“In this way, we kind of get the benefit of both kinds of detectors,” explains Konstantatos. “You have a phototransistor that has a very high sensitivity and a very high gain, but you also get the high quantum efficiency you get in photodiodes. It’s basically a quantum photodiode that activates a transistor.”

In addition to the use of graphene, the ICFO researchers are looking at other 2D materials in this combination, specifically the semiconductor molybdenum disulfide. While this material is a semiconductor and sacrifices somewhat on the electron mobility of graphene, it does make it possible to switch off the material to control the current. As a result, Konstantatos notes that you can have much lower noise in the detector with much lower power consumption.

In continuing research, Konstantatos hinted at yet to be published work on how all of this combination of quantum dots and graphene could be used in solar cell applications.

In the meantime, the work they have been doing with graphene and quantum dots is much further advanced than what they have yet been able to achieve with molybdenum disulfide, mainly because work has advanced much further in making large scale amounts of graphene. But as the processes for producing other 2D materials improves, there will be a real competition between all of the 2D materials to see which provides the best possible performance as well as manufacturability properties.

In any event, Konstantatos sees that the way forward with both quantum dots and 2D materials is using them together.

He adds: “I think we can explore the synergies in between different material platforms. There's no such thing as a perfect material that can do everything right. But there is definitely a group of materials with some unique properties. And if you can actually combine them in a smart way and make hybrid structures, then I think you can have significant added value.”

Tags:  2D materials  graphene  optoelectronics  photodetectors  photonics  photovoltaics  quantum dots 

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NanoXplore Brings Unique Perspective to Graphene Production

Posted By Dexter Johnson, IEEE Spectrum, Thursday, January 26, 2017

 

After Montreal-based NanoXplore launched in 2011, its initial business was contract research in the field of carbon-based technologies. But its identity as a contract R&D company changed in 2014 when it filed a series of patents focused on graphene production.

As the company further developed its technology since then, the main focus of the company has become providing graphene-enhanced polymers for plastics that have enhanced electrical, thermal and mechanical properties.

The company website suggests that these graphene-based polymers have a variety of applications, ranging from photovoltaics to supercapacitors

We wanted to get to know how a relatively new company that started out as an R&D contractor evolved into a graphene-enhanced polymer manufacturer and how they now see the downstream market for their product. To do that, we took the opportunity of NanoXplore becoming a corporate member of The Graphene Council to talk to the company’s chief operating officer, Paul Higgins, and here is that interview.

Q: NanoXplore started out as an R&D contractor in carbon-based technologies. How is it that the company was able to file a patent in graphene production patent just two years after being formed? Were you always doing research in this area, or did you make a concerted effort to find a place in the graphene market?

Working with other carbon-based materials, especially CNTs, it became evident that many commercialization challenges were due to the production processes. The processes had been developed in research environments and were not designed from the ground up with an industrial mindset. We focused from the beginning on low cost, high-yield processes, using existing capital equipment, and with no pre- and post-processing. For example, our graphene production process functionalizes the graphene in-situ, avoiding costly functionalization post-processing for most applications. We were also very cognizant of the need for sustainable, “green” processes; our patented process is water-based, uses no strong acids, and no organic solvents.

A key insight underpinning our patents is that high energy and strong chemical processes create many downstream problems in graphene production. High-energy processes are inefficient and create defected planar structures, resulting in graphene with poor electrical and thermal benefits, in turn requiring high, non-economic loadings of graphene in nanocomposites.  Strong chemical processes require complicated post-processing and recycling processes to be cost effective and require very tightly controlled production environments, adding costs.

Once we had established the frame of potential solutions based upon the above, developing our new technology platform was relatively straightforward.

Q: Were you looking to enter a particular niche of the graphene supply chain or did the process you came up with dictate somewhat the point in the supply chain that you now occupy?

Our process is high yield, large volume, low cost, and produces graphene powder with very high quality. This allows us to target mass industrial material markets such as polymers, markets requiring large volumes of material. And due to the quality of our graphene, we can provide significant benefit to industrial materials at low loadings and viable price points.

Of course, the graphene must be effectively mixed into the polymer matrix. To do this we have developed production processes for the manufacture of graphene-enhanced plastic masterbatches. These masterbatches, which we have been manufacturing and selling since early 2016, are the perfect form factor for the plastic industry. Plastic formers, such as injection and blow molders, and compounders are very comfortable with masterbatches and easily incorporate them into their existing processes.

Q: Do you see the company evolving to develop products further up the supply chain? For instance, it appears you’re involved in energy storage technologies enabled by graphene. Is this where you see your business moving or do you see this is just diversification of your portfolio?

NanoXplore is focusing our current commercial efforts on graphene-enhanced polymers. We see this as a large market, hungry for innovative materials, where our graphene has a strong competitive advantage.

We also have a patent on a unique graphene-graphite composite material that is useful for energy storage applications. This material was the impetus for our original research in the energy field. This initial research showed great promise and leads us into development of a range of materials for Si-graphene anodes and S-graphene cathodes.

From our current polymer efforts and the emerging energy storage materials, we see a sustainable growth model for the company. Our core research efforts develop graphene-based technologies for a target market, and then transition to product development. During the transition, we will develop technologies for the next target industry. And repeat. Graphene is so broadly applicable that we foresee being able to continue in this vein for some time.

Q: How does your company envision the landscape for the graphene market evolving over the next five years, i.e. are there particular markets that will be winners and losers, what applications are not being sufficiently targeted, etc.?

The graphene market has changed significantly over the last three years. Three years ago the challenge for end users was to obtain decent material, in volume, at a reasonable price. Today there are several producers, including NanoXplore, producing large volumes of good quality graphene. Prices per kg for high quality graphene have fallen during this period from $30,000 kg to $100 Kg and are set to fall to $30 kg over the next five years.

[NB: Above and subsequent comments pertain to high quality - low defect, functionalized few layer graphene and graphene nanoplatelets. Graphene from CVD is excluded as is reduced Graphene Oxide (rGO)].

The current challenge for the graphene industry is to incorporate graphene into real-world products and industrial processes. One of the major hurdles is that graphene is sold into a supply chain, with many players between the graphene producer and the final product. And each of these players has their own calculus of risk versus benefit. To be successful the graphene producer must demonstrate benefits to each player at every step along the supply chain, while meeting standards, helping to modify processes, overcoming regulatory hurdles and minimising supply chain disruptions. The successful companies will expand to cover several steps in the supply chain – for example graphene material, polymer compounds, plastic forming – and develop partnerships with other key supply chain players.

Over the next 3-5 years, one can imagine the commercial introduction of novel graphene enabled subsystems and systems. This category of products will include strong, light weight and highly functional nanocomposites for electric transportation vehicles, greatly improved energy systems (e.g., next generation batteries), high barrier packaging, smart textiles, and others. Solutions for highly regulated industries (e.g., medical, aerospace), some being demonstrated today, will start to exit their testing regimes and enter the marketplace.

Ultimately graphene will be part of building a sustainable future, playing a significant role in the replacement of costly, single function, or scarce materials with abundant, cheaper, and higher-performing ones. It will replace multiple and occasionally toxic additives with a single multi-functional material. It will reduce weight while increasing strength for a wide range of structural polymers and composites often leading to significant fuel savings in vehicles. It will extend the useful lifetime of paints, coatings and lubricants. And it will improve thermal management and energy storage in a wide range of applications, again improving efficiency while husbanding scarce resources.

NanoXplore is very well positioned to help customers participate in this emerging new world. With the combination of high quality graphene material, expertise in mixing graphene with a wide array of industrial materials, and a team of seasoned business leaders and material scientists with broad industrial experience, NanoXplore enables customers to achieve significant and affordable product improvements with very little added graphene.

Tags:  masterbatches  photovoltaics  polymers  supercapacitors 

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