Featured paper: Controlling the electronic properties of graphene on silicon carbide.


[Paper: Graphene on the oxidized SiC surface and the impact of the metal intercalation. J.E.Padilha, R.B.Pontes, F. Crasto de Lima, R. Kagimura, R. H. Miwa. Carbon, Volume 145, April 2019, Pages 603-613.]

Controlling the electronic properties of graphene on silicon carbide

A Brazilian scientific team performed a study based on supercomputer simulations that reveals a way to overcome the challenge of controlling the electronic properties of graphene. Solutions to this challenge can make a difference in the development of two-dimensional electronic devices – a dimension in which graphene, the one-atom thick network of carbon atoms, stands out for its properties.

In fact, graphene is an extremely tough, lightweight, flexible and transparent material. It is also an excellent conductor of heat and electricity. However, it is still difficult to control the concentration and flow of electric charges in graphene, which limits its use in electronics.

Solutions have been proposed to overcome this technological limitation of graphene. Some of them are based on the insertion of small amounts of metallic atoms that modulate the electronic properties of the material without impairing the other characteristics. The method is similar to the doping of silicon, practiced routinely in the manufacture of semiconductors for the electronics industry.

Representation of the studied system: graphene sheet on substrate of oxidized silicon carbide with layer of intercalated metallic atoms (in this case, gold).
Representation of the studied system: graphene sheet on substrate of oxidized silicon carbide with layer of intercalated metallic atoms (in this case, gold).

In the study that was recently reported in the scientific journal Carbon (impact factor 7,466), the Brazilian team investigated the structure and electronic properties of a graphene sheet on a silicon carbide (SiC) substrate – material often used to deposit or grow graphene. In this system, graphene remains attached to the substrate without chemical bonds, by means of distance-dependent weak attraction forces, called Van der Waals forces.

Given that in the production of graphene the presence of oxygen usually oxidizes the surface of the silicon carbide, the Brazilian scientists included in the simulations a layer of silicon oxide between the graphene and the substrate. Finally, in order to understand in detail the effect of the insertion of metallic atoms into this type of materials, the scientists added to the simulated system a layer of gold or aluminum atoms embedded in the oxide layer (in this case, Si2O5) in the interface region with graphene.

The researchers verified that the presence of the metallic layer modulates the concentration of the positive (so-called holes) and negative (the electrons) charge carriers in both the graphene sheet and Si2O5. In addition, the gold and aluminum atoms embedded in the Si2O5, which is semiconductor, induce the formation of conducting regions on the surface of this layer, in which the excess of electrons or holes is concentrated, induced by the presence of gold or aluminum, respectively. As a result, conductive channels are formed on the surface of the Si2O5, through which the charges flow.

This two-dimensional map series shows the concentrations of electrons and holes in the graphene sheet in the two graphene systems on the silicon carbide surface finished in Si [(a) and (c)] and terminated in C [(b) and ( d)]; in the presence of an aluminum monolayer [(a) and (b)] and the other containing a gold layer [(c) and (d)].
This two-dimensional map series shows the concentrations of electrons and holes in the graphene sheet in the two graphene systems on the silicon carbide surface finished in Si [(a) and (c)] and terminated in C [(b) and ( d)]; in the presence of an aluminum monolayer [(a) and (b)] and the other containing a gold layer [(c) and (d)].
Finally, the team verified that the “doping” effect (the change in the concentration of electrons and holes) can be enhanced by the application of an external electric field, perpendicular to the interface between the graphene and the substrate.

Based on these evidences, which were obtained mainly through computational simulations based on the Density Functional Theory, the paper suggests a way to control the concentration and flow of electrical charges on graphene sheets on silicon carbide substrates. The study also shows that the system studied (graphene sheet on oxidized silicon carbide with intercalated metal layer) can be a good platform for engineering electronic properties.

“The main contribution of the study is to show an efficient way of controlling the electronic properties of graphene on a solid surface covered with a metallic layer, by applying an external electric field,” says Professor Roberto Hiroki Miwa (Federal University of Uberlândia, UFU ), corresponding author of the paper. “We show that in addition to controlling the doping level of graphene, which is fundamental for the development of electronic devices in two-dimensional (2D) systems, the presence of the metallic monolayer allows the formation of conducting channels on the surface of the silicon carbide,” he adds. According to Miwa, the study may contribute to the development of faster, more accurate sensors, transistors and other electronic devices for charge transport and signal delivery.

At the beginning the work was motivated by the interest of UFU professors Roberto Hiroki Miwa and Ricardo Kagimura in understanding the graphene/oxide interfaces at the atomic level. The focus of the study matured as the authors delved into the scientific literature. As the volume and complexity of calculations increased, the researchers included new collaborators: a physics doctoral student at UFU (Felipe David Crasto de Lima) and professors from other institutions (José Eduardo Padilha de Sousa, from the Federal University of Paraná – Jandaia do Sul campus, and Renato Borges Pontes, Federal University of Goiás).

The authors of the paper. From the left: J. E. Padilha, R. B. Pontes, F. Crasto de Lima, R. Kagimura, R. H. Miwa.
The authors of the paper. From the left: J. E. Padilha, R. B. Pontes, F. Crasto de Lima, R. Kagimura, R. H. Miwa.

In order to perform the calculations that support the simulations, the authors used computational resources from the Brazilian National Center for High Performance Processing (CENAPD) and the SDumont supercomputer of the Brazilian National Laboratory of Scientific Computation (LNCC). The work was funded by federal agencies CNPq and CAPES and the state agency FAPEMIG (Minas Gerais).

B-MRS members are editors of a MRS journal focus issue on nanomaterials for biomedical applications.


Four young B-MRS members are part of the team of invited editors of the latest issue of the Journal of Materials Research, a journal of the Materials Research Society (MRS). They are Bruno Vinícius Manzolli Rodrigues (Brazil University), Jorge Augusto de Moura Delezuk (IFPR), Mariana Amorim Fraga (Unifesp) and Rodrigo Sávio Pessoa (ITA).

The issue, which was published online June 14, is devoted to articles on nanomaterials for medical applications. Entitled “(Nano)materials for Biomedical Applications,” the edition can be accessed at: https://www.cambridge.org/core/journals/journal-of-materials-research/latest-issue.

From the left, Bruno Vinícius Manzolli Rodrigues (Universidade Brasil), Jorge Augusto de Moura Delezuk (IFPR), Mariana Amorim Fraga (Unifesp), and Rodrigo Sávio Pessoa (ITA).
From the left, Bruno Vinícius Manzolli Rodrigues (Universidade Brasil), Jorge Augusto de Moura Delezuk (IFPR), Mariana Amorim Fraga (Unifesp), and Rodrigo Sávio Pessoa (ITA).

Students awards of the B-MRS Meeting: applications by July 14th.


logo médioThe best undergraduate and graduate student contributions presented at the XVIII B-MRS Meeting (Balneário Camboriú, Brazil, September 22-26, 2019) will receive awards from B-MRS and ACS Publications, the scholarly publisher of the American Chemical Society.

To compete for awards, the author (student) must submit, by July 14, an extended abstract additional to the conventional abstract. Prizes will only be awarded for works presented by students at the symposia of the event, and only if the authors (students) are present at the ceremony, which will be held at the closing session of the event, on September 26.

B-MRS will award up to 46 contributions within the Bernhard Gross Award, that annually distinguishes the best student work from each symposium (up to 1 oral and 1 poster per symposium). To elect the winners, the committee will consider the quality of the extended abstract and presentation, as well as the scientific contribution of the work.

Among the winners of the Bernhard Gross Award, the top five oral and five best posters will receive a cash prize (US $ 500.00) and a certificate from ACS Publications.

See more information about the awards, and instructions and template for elaborating the extended abstract: https://www.sbpmat.org.br/18encontro/#authors

International Union of Materials Research Society (IUMRS) endorses UNESCO´s International Year of the Periodic Table.


[IUMRS News Release]

The Periodic Table of Chemical Elements Underlies All of Our Modern Materials

Seminal work of Dmitri Mendeleev one hundred and fifty years ago revealed systematic interrelationships of all the chemical elements known and predicted at the time, and, remarkably, of those subsequently discovered.Those elements are the stuff of which everything and everyone we see is made. The phenomenal natural evolution of our world, including of life itself, assembles the necessary major and often crucial minor elemental ingredients required for Nature’s grand design. Mendeleev’s Periodic Table of the Chemical Elements and its legacy gave us the tools and understanding to invent and design well beyond what Nature has provided.

Whereas empirical uses of materials date to the Bronze and Iron Ages, our electronics, pharmaceuticals, and skyscrapers owe their existence to invention informed by knowledge of the properties of the elements and of the likely properties of myriad compounds and alloys that they form. Such research and invention continue apace in the laboratories of universities and companies with no end in sight. The community of materials researchers depends on, and fully participates in, this exciting progress. The International Union of Materials Research Societies (IUMRS) therefore enthusiastically endorses UNESCO’s declaration of 2019 as the “International Year of the Periodic Table of Chemical Elements (IYPT2019). See https://www.iypt2019.org.

According to IUMRS President Professor Y.F. HAN, “The thousands of researchers affiliated with our membership, who devote their careers to uncovering the next great innovation enabled by advanced materials, all rely on their early training which included Mendeleev’s Table and which emains invaluable in formulating the next new approach to solving problems and making new discoveries in the laboratory. It  is therefore entirely appropriate for IUMRS to recognise this sesquicentennial anniversary on their behalf.”


IUMRS Head Office: Room 2112, No. 62 Zizhuyuan Road, Haidian, Beijing, China.
For more information about this topic, contact Dr. Fenfen Liang at +86 10 6872 2032, fax to 86-10-6872-2033, or email to liangff_cmrs@163.com.
Alternative contact: IUMRS Chief Advocacy Officer at cao@iumrs.net

B-MRS Newsletter. Year 6, issue 5.


 

logo header 400

Newsletter of the
Brazilian Materials
Research Society

Year 6, issue 5. June 7, 2019.

B-MRS News

– With more than 2,450 submitted abstracts, the XVIII B-MRS Meeting (Balneário Camboriú, 22 – 26 September 2019) sets a new record in the history of B-MRS annual meetings. Know more.

Featured Paper

A team of Brazilian researchers developed a method that allows studying the structure of nanomaterials locally and used it to understand the occurrence of disorder in the structure of nanocrystals. The method, which should help develop more efficient materials, is available to the community at LNNano. The study was reported in The Journal of Physical Chemistry Letters. Know more.

nanocristal_news

From Idea to Innovation

Using its own technology based on nanomaterials, Krilltech manufactures products that, without negative impacts on the environment, increase crop productivity and nutritional quality of food. The Brazilian startup plans to disseminate the benefits of its technology on planet Earth… and beyond. Learn more about Krilltech here.

krilltech_news

Featured Scientist

We interviewed Norbert Koch, a professor at the Humboldt-Universität zu Berlin (Germany). Through fundamental research, the scientist made important contributions to the development of more efficient optoelectronic devices (such as LEDs and solar cells). At the B-MRS Meeting, he will talk about combining organic and inorganic materials into these devices. Know more.

koch

News from B-MRS Members

B-MRS founding member Edgar Zanotto (UFSCar) won the American Ceramic Society award for the best contribution to the study of phase equilibrium published in 2018. Know more.

banner evento

XVIII B-MRS Meeting
(Balneário Camboriú, SC, Brazil, September 22 – 26, 2019)

Site do evento: www.sbpmat.org.br/18encontro/

More than 2.450 abstracts were submitted to XVIII B-MRS Meeting!

Upcoming dates for authors of works. Approval, modification, or rejection notifications will be sent by June 10. Abstracts that need modification must be corrected and resubmitted to the system by June 24. The authors of these abstracts will receive the final approval/rejection notices by June 30.

Awards for students. To apply for awards for undergraduate and graduate students (Bernhard Gross Award and ACS Publications Prizes), authors are required to submit an extended abstract by July 14. Learn more here.

Registration is now open. More information, here.

Venue. The meeting will be held in the delightful Balneário Camboriú at the Hotel Sibara Flat & Conventions, located in the center of the city, close to many hotels, restaurants and shops, and only 100 meters from the sea. More information, here.

Opening ceremony venue. The opening ceremony, the memorial lecture and the welcome cocktail will be held on September 22 (Sunday) at the Cristo Luz complex, one of the main tourist attractions in the city. There will be transportation to the venue, leaving the Hotel Sibara from 17:00 on. Know more about this place, here.

Memorial Lecture. The traditional Memorial Lecture Joaquim da Costa Ribeiro will be given by Professor Yvonne Primerano Mascarenhas (IFSC – USP). Know more about the speaker.

Event party. The party will be held in the lounge of the Green Valley, a prominent nightclub. Learn more about Green Valley here, aqui. The party will feature the striking Brothers band. Watch the Brothers, here.

Host city. Balneário Camboriú (SC) is an important tourist destination that offers urban and wild beaches, ecotourism and adventure sports, boat trips, bicycles and cable cars – all within a unique landscape that combines mountains, sea and skyscrapers. The visitor has access to many options of gastronomy, lodging and shopping, as well as the bustling nightlife that stands out in the Brazilian scenario.

Lodging, tickets, transfers etc. Check the hotel options and the official agency of the event, here.

Plenary lectures. Leading scientists from institutions in Germany, Italy, Spain and the United States will deliver plenary talks on cutting-edge issues at the event. There will also be a plenary session by the Brazilian scientist Antônio José Roque da Silva, director of CNPEM and the Sirius project (new Synchrotron Light Lab). Learn more about the plenary sessions, here.

Symposia. 23 symposia proposed by the international scientific community compose this edition of the event. See the symposia list, here.

Organization. The chair of the event is Professor Ivan Helmuth Bechtold (Physics Department of UFSC) and the co-chair is Professor Hugo Gallardo (Department of Chemistry of UFSC). The program committee is formed by professors Iêda dos Santos (UFPB), José Antônio Eiras (UFSCar), Marta Rosso Dotto (UFSC) and Mônica Cotta (Unicamp). Get to know all the organizers, here.

Exhibitors and sponsors. 38 companies have already confirmed their participation in the event. Those interested in sponsoring/support can contact Alexandre at the e-mail comercial@sbpmat.org.br.

Reading Tips

– Scientists are able to deposit inorganic epitaxial thin films (oriented with respect to the substrate) with simple and economic method (spin coating). This advance can massify these materials, required for electronic and optoelectronic applications (Science). Know more here.

New 2D material: Scientists are able to make phosphorene nanoribbons, whose exceptional properties for energy and electronics applications have been predicted in more than 100 articles. The discovery happened accidentally (Nature). Know more here.

Organic semiconductors: Scientists reveal how nanotraps slow down conductivit in organic materials, and they show how to eliminate them (Nature Materials). Know more here.

Opportunities

Postdoctoral position on Perovskite materials and solar cells. Saiba mais.

Events

III Escola de Pesquisadores da USP. São Carlos, SP (Brazil). June 12 – 13, 2019. Site.

10th International Conference on Materials for Advanced Technologies (ICMAT 2019). Singapore. June 23 – 28, 2019. Site.

Webinar: Nanomaterials for Biomedical Applications. June 25, 2019. Site.

X Método Rietveld. Fortaleza, CE (Brazil). July 8 – 12, 2019. Site.

20th International Sol-Gel Conference. Saint Petersburg (Russia). August 25 – 30, 2019. Site.

21st Materials Research Society of Serbia Annual Conference (YUCOMAT 2019) and 11th IISS World Round Table Conference on Sintering (WRTCS 2019). Herceg Novi (Montenegro). September 2 – 6, 2019. Site.

XVIII B-MRS Meeting. Balneário Camboriú, SC (Brazil). September 22 – 26, 2019. Site.

XL CBRAVIC (Brazilian Congress on Vacuum Applications in Industry and Science). October, 7 – 11, 2019. Site.

XII Brazilian Symposium on Glass and Related Materials. Lavras, MG (Brazil). October, 22 – 25, 2019. Site.

19th Brazilian Workshop on Semiconductor Physics. Fortaleza, CE (Brazil). November 18 – 22, 2019. Site.

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You can suggest news, opportunities, events or reading tips in the materials field to be covered by B-MRS Newsletter. Write to comunicacao@sbpmat.org.br.

 

 

Featured paper: Disclosing structural disorder in nanomaterials.


[Paper: Decreasing Nanocrystal Structural Disorder by Ligand Exchange: An Experimental and Theoretical Analysis. Gabriel R. Schleder, Gustavo M. Azevedo, Içamira C. Nogueira, Querem H. F. Rebelo, Jefferson Bettini, Adalberto Fazzio, Edson R. Leite. J. Phys. Chem. Lett. 2019 10 1471-1476. https://doi.org/10.1021/acs.jpclett.9b00439]

Disclosing structural disorder in nanomaterials

It is known that it is very important to know and control the structure of a material (how its atoms are arranged in three-dimensional space) as it is largely responsible for the properties of the material and therefore for its applications. For example: regions of disorder in crystalline materials (whose atoms, ideally, are ordered in regular patterns) change some expected behaviors for these materials. Unfortunately, knowing the structure of some materials in detail can be a difficult task – particularly when it comes to nanomaterials.

Concentrating various skills and experimental and theoretical resources, a Brazilian team developed a method to establish the degree and location of disorder in the structure of crystalline and non-crystalline nanomaterials, interfaces and surfaces. The method, which is based on the combination of an experimental technique (transmission electron microscopy), a data analysis method (pair distribution function) and computational simulations, is already available to the scientific community at the Brazilian National Nanotechnology Laboratory (LNNano), and should help develop better performing materials.

In addition to developing the technique, the team applied it in the study of structural disorder in nanocrystals, which are basic elements of nanotechnology and are used for example, in solar cells and electronic devices. Although by definition they have ordered structures, these crystals of nanometric dimension can exhibit, in practice, regions with structural disorder.

In order to carry out the study, the scientists produced faceted nanocrystals of about 3.2 nm in diameter, formed by a core of zirconium dioxide (ZrO2), inorganic material, and a shell made up of organic substances known as ligands, whose atoms form chemical bonds with atoms that are on the surface of the inorganic nucleus. Ligands have the important role of stabilizing the nanocrystals, thus preventing them from aggregating.

The team produced a first series of nanoparticles with ligands containing an aromatic ring and analyzed it using the developed method. The samples were then subjected to a process known as ligand exchange in which chemical reactions occur in the material in the presence of a solvent at a temperature above its boiling point. In these reactions, some connections break down and new connections occur. As a result of the ligand exchange, the team was able to produce nanoparticles with shells containing oleic acid, which were also analyzed using the developed method.

This figure refers to a nanocrystal of ZrO2 before and after the ligand exchange. The figure includes high-resolution images of transmission electron microscopy, structural models and PDF patterns obtained by the developed method.
This figure refers to a nanocrystal of ZrO2 before and after the ligand exchange. The figure includes high-resolution images of transmission electron microscopy, structural models and PDF patterns obtained by the developed method.

The scientists concluded that, unlike the ideal nanocrystal of zirconium dioxide, the two types of nanocrystals analyzed had a degree of structural disorder located on the surface of the nucleus.  In addition, in the second group of nanoparticles, the disorder was significantly lower. The researchers interpreted this reduction as a result of the high temperature of the ligand exchange process, which altered the tensions of the network of atoms.

“In our work, we were able to directly assess the degree and location of disorder in the nanocrystals, which until then was not technically feasible,” says Gabriel Schleder, PhD candidate in the Graduate Program in Nanosciences and Advanced Materials of the Brazilian Federal University of the ABC (UFABC).

By better understanding structural disorder and its causes, the researchers were able to point out a way to control it. “Any property that significantly depends on surface-located structural disorder could be in principle controlled by this kind of ligand exchange process,” says Schleder. “Mechanical properties, photoluminescence, electronic transport and catalytic properties are some of them,” he adds.

The research was reported in a recently published article in The Journal of Physical Chemistry Letters (impact factor = 8,709).

Overcoming the challenge through collaborations

The initial idea of the study appeared in a meeting held at the end of 2017 at the National Center for Research in Energy and Materials (CNPEM), located in the city of Campinas, São Paulo. At the meeting, a group of reserachers discussed the implementation in Sirius (the next Brazilian synchrotron light source) of a technique that allows locally analyzing structural issues such as disorder and defects, called pair distribution function (PDF). The technique describes the distances between pairs of atoms by means of a mathematical function. To apply it, the specialist generally uses the results of X-ray diffraction measurements – an experimental technique that provides information about the structure of materials. However, in order to implement the analysis by PDF, the X-ray beam focused on the sample must be of very high energy – higher than that provided by the current Brazilian synchrotron light source.

During the meeting at CNPEM, Professor Gustavo de Medeiros Azevedo, researcher at the National Laboratory of Synchrotron Light (LNLS), and Professor Edson Leite, LNNano’s scientific director, decided to begin applying PDF using electron diffraction results, a specialty of LNNano’s researcher Jefferson Bettini. The electron beams would be generated by the transmission electron microscope (TEM) of LNNano. In fact, this instrument allows the control of the electron beam so that it focuses a small area of the sample, allowing the desired local analysis of the structure. Besides that, when switching from the “diffraction mode” to the “image mode”, the microscope would made possible to choose precisely the area of the sample to be analyzed.

Simulation of an ideal ZrO2 nanocrystal.
Simulation of an ideal ZrO2 nanocrystal.

The development team also involved professors Içamira Costa Nogueira, from the Federal University of Amazonas (UFAM) and Querem Hapuque Felix Rebelo, from the Federal University of the West of Pará (UFOPA), who contributed with the synthesis of nanocrystals that would be studied and with the development of the analysis methodology.

During the development of the technique, another challenge had to be faced. To interpret the PDF results, it would be necessary to have a simulation of an ideal nanocrystal – a nanocrystal model without structural disorganization that could be used as a reference.

New skills were then incorporated into the team, which was then joined by Professor Adalberto Fazzio, director general of LNNano and leader of a UFABC research group dedicated to computational techniques applied to materials, and his doctoral student Gabriel Schleder. Based on the Density Functional Theory (DFT), a computational modeling method in the field of Quantum Physics, the researchers were able to simulate the ideal nanocrystal that served as the analysis model.

“Something very positive we perceived is that the main results arose from the process of interaction, discussion and exchange of information mainly between theory/computational simulation and experiments. Without this, we certainly would not have good final conclusions,” says Schleder.

The authors of the paper. From the left: Gabriel R. Schleder, Gustavo M. Azevedo, Içamira C. Nogueira, Querem H. F. Rebelo, Jefferson Bettini, Adalberto Fazzio and Edson R. Leite.
The authors of the paper. From the left: Gabriel R. Schleder, Gustavo M. Azevedo, Içamira C. Nogueira, Querem H. F. Rebelo, Jefferson Bettini, Adalberto Fazzio and Edson R. Leite.

Featured scientist: Prof. Norbert Koch (Humboldt-Universität zu Berlin, Germany).


Prof Norbert Koch
Prof Norbert Koch

While a large part of humanity benefits from the advantages of solar cells, LEDs and other optoelectronic devices, some scientists are striving to find new materials and structures that enable new developments in optoelectronic technologies.

Norbert Koch (Professor at the Humboldt-Universität zu Berlin, and research group leader in that university and at the Helmholtz-Zentrum Berlin) belongs to the latter group of qualified people.

Prof. Koch studied technical physics at the Technische Universität Graz (Austria), where he also did his doctoral studies in solid-state physics. He spent two years as postdoc at Princeton University (USA). In 2003, he started setting up a research group at the Humboldt-Universität zu Berlin, where he was appointed as professor in 2009. His scientific production has more than 16,300 citations and his h-index is 66 (Google Scholar).

This scientist will be in September in Balneário Camboriú (Brazil), giving a plenary lecture at the XVIII B-MRS Meeting. In the talk, he will speak about very promising structures in the field of optoelectronics, which are based on a combination of organic and inorganic materials.

See our mini interview with Professor Norbert Koch.

B-MRS Newsletter: – We´d like to know more about your scientific work. Please choose one or two of your favorite contributions, briefly describe them, and share the references.

All modern optoelectronic devices are complex multilayer structures. To arrive at the desired function, e.g., light emission or energy conversion, with the highest possible efficiency, an optimized alignment of the electronic energy levels is key. For novel and emerging materials, such as organic and 2-dimensional semiconductors, this cannot be achieved readily because the fundamental underlying mechanisms, which govern the level alignment, are not properly understood. Consequently, my research is geared towards unraveling this understanding, and to devise means of optimizing interfacial energy levels. For instance, for a long time it was believed that the level alignment with organic semiconductors is substantially different from what was known for traditional inorganic semiconductors like silicon. The concerted effort of many groups worldwide has finally provided the insight that the established mechanisms do hold, but peculiarities of the organic compounds have to be considered appropriately. It turned out that the energy and density distribution of electronic states of the organic semiconductor critically determines the level alignment, at interfaces towards electrodes [Nat. Commun. 5, 4174 (2014)] and at semiconductor heterostructures [Sci. Adv. 1, e1501127 (2015)]. With this understanding at hand, device engineers can now minimize electrical losses at contacts and precisely tune the energy level offset at heterojunctions.

B-MRS Newsletter: – In your plenary talk at the B-MRS Meeting, you will talk about hybrid (organic / inorganic) structures for optoelectronics. Could you give examples of such structures and their present and/or future applications? Why this type of structure is relevant for developing optoelectronic devices?

The idea to combine inorganic and organic semiconductors is based on the notion to take advantage of the beneficial properties of each component while compensating their respective weaknesses. For instance, inorganic semiconductors typically exhibit high charge carrier mobility and organic ones stand out by very strong light-matter coupling. In a hybrid light emitting diode (LED), one can imagine to electrically pump the inorganic semiconductor at highest levels, and upon energy transfer the desired light is emitted by the organic semiconductor. This could result in LEDs with high brilliance at virtually any color that also feature ultrahigh modulation bandwidth.

For more information on this speaker and the plenary talk he will deliver at the XVIII B-MRS Meeting, click on the speaker’s photo and the title of the lecture here https://www.sbpmat.org.br/18encontro/#lectures.

From idea to innovation: nanotechnology for sustainable and productive agriculture.


krilltechUsing nanotechnology to solve important human problems has for many years been a personal goal of Marcelo Oliveira Rodrigues, a professor at the University of Brasília (UnB) and a partner at Krilltech. One of these problems is undoubtedly the problem of food production. Data from the UN and FAO show that food demand will grow by more than 50% by 2050, while the expansion of areas available for agriculture will not keep pace with this growth.

Krilltech was launched on the market this year as the culmination of seven years of research, development and testing. The startup will soon be able to make its contribution, through nanotechnology, to a more productive and ecologically correct agriculture, which produces foods with better nutritional quality. “Our technology is a revolution in the modes of production and the way in which sustainable agriculture is done,” says Rodrigues.

In addition to some projects under development, the startup already has a portfolio of products, which includes a line adaptable to customer needs. The products can be applied to the soil or leaves of plants, or even in water, in the case of hydroponic crops. Krilltech products increase the photosynthesis rates of cultivated plants, make their water consumption more efficient and accelerate their metabolism (biostimulants). At the same time, they act as fertilizers to provide micro and macro nutrients that are necessary for plant growth (nitrogen, carbon, phosphorus, potassium, and others). “Our nanoproducts are multifunctional,” says Rodrigues. The startup also has a product line to incorporate mineral salts such as zinc and iron into grains and vegetables. “Producing potatoes, corn, lentils and chickpeas enriched with iron and zinc will contribute to resolving public health problems associated with the deficiency of essential minerals,” exemplifies the professor – researcher – entrepreneur.

Because they are based on nanotechnology, these biostimulants–fertilizers overcome the limitations of conventional technologies and are able to deliver much more nutrients to the crops. “Stabilizing in aqueous media all macro and micronutrients in a solution requires a high surface area and extremely hydrophilic material. Without nanotechnology this is an extremely difficult task,” explains Rodrigues.

According to him, Krilltech’s products do not affect the biota of soils and bodies of water, they do not accumulate in plant tissues (they are metabolized), and are not toxic to fungi, bacteria and animals. In order to guarantee the non-toxicity of its products, Krilltech counts on results of tests carried out with larvae, worms, fungi, bacteria, fish, several lineages of healthy and tumor cells and mice.

As for Krilltech’s production processes, they are of relatively low costs, partly due to the lean system adopted by the startup, based on leveling production according to demand and focusing on increasing efficiency and avoiding waste in production processes. “We work with sophisticated products, but production processes are efficient and we do not need imported equipment for our production,” says Rodrigues. In addition, Krilltech does not use toxic reagents in its processes and does not generate waste, says Rodrigues.

With these characteristics of its technology, production processes and products, Krilltech wants to gain a place in the growing biostimulant market, currently dominated by multinational companies headquartered mainly in Europe, North America and India. According to estimates reported by Krilltech, the demand for biostimulants will increase mainly in Asia and South America. It is estimated that this market will move around US$ 3.5 billion in 2022.

Emergence of the startup: a partnership between an university and a state-owned research corporation 

Krilltech partners. Above: Ataílson Oliveira (technology director), Rogério Faria (industrial director) and Carime Vitória (R&D diretor), all doctoral students in Chemistry at UnB. Below: Marcelo Rodrigues and Marcelo Henrique (professors at UnB).
Krilltech partners. Above: Ataílson Oliveira (technology director), Rogério Faria (industrial director) and Carime Vitória (R&D diretor), all doctoral students in Chemistry at UnB. Below: Marcelo Rodrigues and Marcelo Henrique (professors at UnB).

“Transforming scientific research into technologies absorbed by the consumer market has always been a personal desire,” says Professor Rodrigues. So in 2012, shortly after joining UnB as an adjunct professor, he identified projects from his research group that had the potential to become innovations. By 2016, the group had developed a nanoformulation based on a high-cost drug, used in the Brazilian public system to treat fungal infections. “We were able to reduce the toxicity and cost of the drug by about 40 percent, but we were frustrated by the lack of resources to advance pre-clinical studies according to the Brazilian health regulatory agency standards,” says Rodrigues.

Also in 2016, the group began discussions with a unit of the Brazilian Agricultural Research Corporation, Embrapa. Initially, the goal was the development of plastics with special optical properties for use in protected cultivation (greenhouse and similar). “The conversations with Dr. Juscimar Silva (Embrapa) have evolved toward the development of our nanobiostimulants,” says Rodrigues.

The laboratory development of the technology was carried out at UnB, with the participation of undergraduate and graduate students, and with the support of the Brazilian government agencies FAP-DF, CNPq and Capes through scholarships and resources for consumables. “Public funding was essential for the early stages of development,” emphasizes Rodrigues. With support from Embrapa, the technology was tested on tomato, pepper and lettuce. “We are currently evaluating our products in the large monocultures of the country in partnership with national and multinational companies,” says the partner of Krilltech.

In 2018, the startup entered the pre-incubation program of the Technological Development Support Center (CDT) of UnB, which aims to assist in the development of the business model and the formalization of the future company.

Currently, Krilltech, together with UnB and Embrapa, is in the final stage of filing the patent application for the technology used in the products. “Krilltech has the exclusive right to exploit the technologies,” states Rodrigues.

Confident in the high performance of its products and agility in the development of innovations, Krilltech already has new partners and new projects. The startup has a partnership to enable hops culture in the center of Brasil. Also, Krilltech is testing its technology in microgravity conditions to contribute to farming projects outside the planet Earth (space farming). In addition, Rodrigues adds, a second startup will soon be created to explore nanobiopesticides of very low toxicity developed by the group.

See our brief interview with Rodrigues, PhD in Chemistry (2010) from the Brazilian Federal University of Pernambuco.

B-MRS Newsletter: What were the most important factors in enabling the creation and development of the startup?

Marcelo Oliveira Rodrigues:  Undoubtedly, the support offered by UnB, the Brazilian Ministry of Science, Technology, Innovation and Communication and EMBRAPA in terms of technology protections, consulting and training were fundamental to the creation of Krilltech. However, I would like to emphasize that the crisis which Brazilian science has been subjected to and the difficulties of entering into cooperation agreements between the University and the private sector were two factors that contributed greatly to initiate this undertaking.

B-MRS Newsletter: What were the main difficulties the startup has faced thus far?

Marcelo Oliveira Rodrigues:  Leaving the comfort zone implies difficulties that need to be overcome. Learning to undertake this endeavor required a cultural change in the way we planned and developed our projects; I think that was the great difficulty we have overcome.

B-MRS Newsletter: What, in your opinion, is the startup’s main contribution to society?

Marcelo Oliveira Rodrigues: Our technology contributes to reduce the environmental impact caused by the application of conventional fertilizers. For example, when fertilizer phosphorus and nitrogen are improperly leached to rivers, lakes and oceans, they can induce the formation of dead-zones, as the eutrophication process can induce excessive growth of algae that depletes water oxygen.

Unlike conventional nanomaterials (metal nanoparticles and metal oxides, polymer micelles, etc.), our technology enables the use of nanotechnology in agriculture. Krilltech has contributed to reformulating the fertilizer and phytostimulant industry, since our technology represents:

-The development of sustainable agriculture based on ecological agrochemicals;

-Contribute to eliminate and reduce the use of inputs and practices of hazardous agrochemicals (less hazardous chemical inputs);

-Mitigate environmental and human health risks due to non-toxicity of our products (design of safer chemicals);

-Elimination of the adverse impact of trophic transfer of conventional nanoparticles in the food chain;

-A disruptive paradigm needed for innovation in food production based on green nanomaterials.

B-MRS Newsletter: What is your goal/dream for the startup?

Marcelo Oliveira Rodrigues:  We will have Krilltech units scattered around the world, we will see our technology contribute to sustainable development and we will contribute to reduce the impact of nutritional erosion and malnutrition.

B-MRS Newsletter: Leave a message to our newsletter readers and social network followers that assess the possibility of creating a startup.

Marcelo Oliveira Rodrigues:  You should master the technology well, know the market and do not give up in the face of difficulties. The innovation environment in Brazil is unhealthy and standing out in these conditions increases the chances of success.