Tag: ciência de materiais

Featured scientists: interviews with winners of the CAPES Award for Best Doctoral Theses.

Posted on Wednesday 31 de January de 2018

On December 7th in Brasília, the Brazilian Coordination for the Improvement of Higher Education Personnel (CAPES) awarded the prizes to the best doctoral theses defended in 2016 in graduate programs in Brazil. The authors of the theses selected received a diploma, medal and a national postdoctoral fellowship of up to 12 months, in addition to pay the travel expenses of the author and thesis supervisor to participate in the awards ceremony.

B-MRS Newsletter interviewed some of the winners, who were rewarded for their work on materials field. Meet these four young doctors and their works.

Interview with Eliézer Fernando de Oliveira, winner of the award for the best thesis in the Materials area

Eliézer Fernando de Oliveira
Eliézer Fernando de Oliveira

Thesis: Electronic structure of organic materials for applications in the active layers of solar cells.

PhD Course  in Materials Science and Technology – POSMAT, State University of São Paulo Júlio de Mesquita Filho (UNESP).

Author: Eliézer Fernando de Oliveira

Advisor: Francisco Carlos Lavarda (UNESP – campus Bauru)

In his master’s thesis, Eliézer Fernando de Oliveira, who holds a degree in Physics, had already immersed in the topic of conductive polymers for solar cell application. During the PhD, his deep involvement continued, with great results. In fact, he was able to determine that by means of computational methods it is possible to predict certain properties of new polymers in order to choose, before producing them, the most suitable ones for the desired application. Using this method, Eliézer de Oliveira suggested in the thesis a series of new polymers that would be more efficient than the one used so far to convert solar energy to electric energy in solar cells. During his doctorate, Oliveira comprehensively used the computational resources of the Center of Scientific Computing of UNESP and carried out an internship at Instituto Madrileño de Estudios Avanzados en Nanosciencia (Spain). Oliveira is currently a postdoctoral fellow at Unicamp.

B-MRS Newsletter: In your opinion, what is the most relevant contribution of the awarded thesis?

Representation of an organic solar cell.
Representation of an organic solar cell.

Eliézer de Oliveira:  My doctoral work focused on exploring new organic materials, more specifically conductive polymers for application in the active layers (where conversion from solar to electric takes place) of solar cells to obtain these materials in a planned way using calculation methods of the electronic structure of materials. This work contributed to the area, since we suggested several new polymers that display better electronic and transport properties than those already in use. In my opinion, most relevant aspect of the work was the fact that we demonstrated there is a way to predict in advance the electronic and optical properties of new copolymers with similar comonomers. In these types of polymers, the repeating unit (monomer) is formed by two comonomers that are similar to each other (based on the same compound), only differing the functional groups that are in each comonomer. This demonstrated, by means of a linear relation, that we can determine the electronic and optical properties of a copolymer constructed by various compositions of similar comonomers. This allows for an initial analysis to choose the copolymers that actually present a real application so that later they can be synthesized.

B-MRS Newsletter: Cite the main results generated from the award-winning thesis (papers, patents, products, startups, other awards, etc.).

Eliézer de Oliveira:  Eight scientific articles related to the topic of my PhD thesis were published.

  • Oliveira, E. F.; Lavarda, F. C. Effect of the length of alkyl side chains in the electronic structure of conjugated polymers. Mat. Res. 2014, 17, 1369-1374 (DOI: 10.1590/1516- 1439.278814)
  • Oliveira, E. F.; Lavarda, F. C. Molecular design of new P3HT derivatives: Adjusting electronic energy levels for blends with PCBM. Mater. Chem. Phys. 2014, 148, 923-932 (DOI: 10.1016/j.matchemphys.2014.09.002)
  • Oliveira, E. F.; Lavarda, F. C. Copolymers with similar comonomers: tuning frontier orbital energies for application in organic solar cells. Polym. Eng. Sci. 2016, 56, 479-487 (DOI: 10.1002/pen.24275).
  • Oliveira, E. F.; Roldao, J. C.; Milián-Medina, B.; Lavarda, F. C.; Gierschner, J.; Calculation of low bandgap homopolymers: Comparison of TD-DFT methods with experimental oligomer series. Chem. Phys. Lett. 2016, 645, 169-173 (DOI: 10.1016/j.cplett.2015.12.059).
  • Oliveira, E. F.; Lavarda, F. C. Reorganization energy for hole and electron transfer of poly(3-hexylthiophene) Derivatives. Polymer 2016, 99, 105-111 (DOI: 10.1016/j.polymer.2016.07.003).
  • Oliveira, E. F.; Silva, L. C.; Lavarda, F. C. Modifying electronic properties of ICBA through chemical modifications for solar cell applications. Structural Chemistry 2017, 28, 1133–1140 (DOI: 10.1007/s11224-017-0916-0)
  • Oliveira, E. F.; Lavarda, F. C. Design of diblock co-oligomers as low bandgap small molecules for organic solar cells. Molecular Simulation, 2017, 43, 1496-1501 (DOI: 10.1080/08927022.2017.1321759).
  • Oliveira, E. F.; Shi, J.; Lavarda, F. C.; Lüer, L.; Milián-Medina, B.; Gierschner, J. Excited state absorption spectra of dissolved and aggregated distyrylbenzene: a TD-DFT state and vibronic Analysis. Journal of Chemical Physics, 2017, 143, 034903 (DOI: 10.1063/1.4993216)

B-MRS Newsletter: In your opinion, what are the main factors that led to the outstanding research at the national level (your thesis)?

Eliézer de Oliveira:  A major factor was scientific funding. During my PhD I had a Fellowship from the São Paulo Research Foundation (FAPESP). This grant enabled my exclusive dedication to research, to participate in national and international conferences and to carry out an internship abroad. Another important factor regarding the theoretical computational aspect of the research was the resources provided by the Center of Scientific Computation (NCC) of the Sao Paulo State University (UNESP) that allowed the computational simulations indispensable for my research. Last but not least, I received great mentoring from my doctoral supervisor and support from my family and friends, all of which was crucial to the success of my scientific career.

B-MRS Newsletter: Leave a message to our readers who are undergraduate or graduate students.

Eliézer de Oliveira: Be patient and remain firm. Scientific trajectory depends on constant research and dedication; during this trajectory maintain a good relationship with your advisor, look for good partnerships and consider the quality of the work produced. There is much to investigate about the universe of science, as Isaac Newton said “What we know is a drop, what we don’t know is an ocean.”

 

Interview with André Luiz da Silva, winner of the honorable mention of the Materials area

André Luiz da Silva
André Luiz da Silva

Thesis: Anatase-rutile phase stability and photocatalytic activiy of Nb2O5-Doped TiO2. 
PhD Course in Materials Science and Engineering from the Brazilian Federal University of Santa Catarina (UFSC).
Author: Andre Luiz da Silva.
Advisors: Dachamir Hotza (UFSC), Ricardo H. R. Castro (UC Davis, USA) e Michele Dondi (ISTEC, Italy)

When he began his doctorate, André Luiz da Silva, Ceramics technologist with a Master’s in Materials Science and Engineering, proposed a useful contribution to the ceramic coating industry, a segment in which he had worked for 10 years. The chosen theme was the stabilization of one of the phases of titanium dioxide (TiO2) for application in self-cleaning ceramic coatings. Da Silva initially devoted his efforts to understand the scientific foundations that could help him solve the technological problem. Subsequently, the application of this knowledge led him to obtain more efficient self-cleaning ceramics than those available in the market. During his doctorate, André da Silva searched abroad for laboratory infrastructure that did not exist in Brazil and expertise through an internship at the Nanoceramics Thermochemistry Laboratory of UC Davis in the United States and another internship at the Istituto di Scienza e Tecnologia dei Materiali Ceramici (ISTEC-CNR), in Italy. At the end of his doctorate, da Silva gained in-depth knowledge on the topics covered in the thesis, fluency in English and Italian, and the satisfaction of having made contributions to science and industry. Silva is currently a postdoctoral fellow at USP.

B-MRS Newsletter: In your opinion, what is the most relevant contribution of the awarded thesis?

Phase diagram that predicts the anatase-rutile phase transformation as a function of grain size and dopant percentage. Blue region: region of thermodynamic stability of the anatase phase. Red region: region of thermodynamic stability of the rutile phase. The separation line between the two colors corresponds to the phase transformation crossover. Blue and red dots are experimental points, which represent the anatase and rutile phases, respectively. This diagram is published in the journal "Applied Surface Science".
Phase diagram that predicts the anatase-rutile phase transformation as a function of grain size and dopant percentage. Blue region: region of thermodynamic stability of the anatase phase. Red region: region of thermodynamic stability of the rutile phase. The separation line between the two colors corresponds to the phase transformation crossover. Blue and red dots are experimental points, which represent the anatase and rutile phases, respectively. This diagram is published in the journal “Applied Surface Science”.

André da Silva: In my opinion, there were two very relevant contributions of the thesis.

The first concerns the scientific underpinnings of the anatase-rutile phase transformation of titanium dioxide (TiO2). It was proposed to chemically modify titanium dioxide by doping with niobium pentoxide (Nb2O5) and also understand the thermodynamic stability of the anatase-rutile phases. By means of the surface energy measurements and the enthalpy dissolution measurements, in which a non-existent laboratory structure was used in Brazil, a nanoscale phase diagram was created for TiO2 doped with Nb2O5, which predicts phase transformation through the crystallite size as a function of the chemical composition. It was observed that the doping of TiO2 with Nb2O5 thermodynamically stabilizes the anatase phase, delaying the phase transition temperature for rutile. Through the diagram it can be observed that niobium allows a larger growth of the TiO2 nanoparticles before the phase transformation occurs. This thermodynamic stability occurs through the segregation of Nb2O5 on the surface of the TiO2 nanoparticles, resulting in a decrease in the surface energy of the material.

The second contribution of the thesis is from the point of view of industrial application. The TiO2 doped with Nb2O5 in an optimized percentage was applied to the surface of ceramic coatings, which allowed the production of photocatalytic / self-cleaning ceramics with a higher performance than the current market. In addition, the proposed formulation allowed the sintering of the ceramic coatings at temperatures applicable to the industry, which was one of the major difficulties the companies faced in the manufacture of these coatings.

B-MRS Newsletter: Cite the main results generated from the award-winning thesis (papers, patents, products, startups, other awards, etc.).

André da Silva: During the time of the thesis, 9 international papers were produced, related directly or indirectly to the research theme, corresponding to high-impact indexed journals in areas related to Materials. Of these papers, I consider the first four (all in QUALIS A1 periodicals in the materials area) as the main ones related to the thesis.

  • DA SILVA, A. L.; HOTZA, D.; CASTRO, R.H.R. Surface energy effects on the stability of anatase and rutile nanocrystals: A predictive diagram for Nb2O5-doped-TiO2. Applied Surface Science, v. 393, p. 103-109, 2017. https://doi.org/10.1016/j.apsusc.2016.09.126
  • DA SILVA, A. L.; MUCHE, D.N.F. ; DEY, S.; HOTZA, D. ; CASTRO, R.H.R. . Photocatalytic Nb2O5-doped TiO2 nanoparticles for glazed ceramic tiles. Ceramics International, v. 42, p. 5113-5122, 2016. https://doi.org/10.1016/j.ceramint.2015.12.029
  • DA SILVA, A. L.; DONDI, M.; HOTZA, D. Self-cleaning ceramic tiles coated with Nb2O5-doped-TiO2 nanoparticles. Ceramics International, v. 43, p. 11986-11991, 2017. https://doi.org/10.1016/j.ceramint.2017.06.049
  • DA SILVA, A. L.; DONDI, M.; RAIMONDO, M.; HOTZA, D. Photocatalytic Ceramic Tiles: Challenges and Technological Solutions. Journal of the European Ceramic Society. https://doi.org/10.1016/j.jeurceramsoc.2017.11.039
  • GOMEZ, S. Y.; DA SILVA, A.L.; GOUVEIA, D.; CASTRO, R. H. R.; HOTZA, D. Nanocrystalline yttria-doped zirconia sintered by fast firing. Materials Letters (General ed.), v. 166, p. 196-200, 2016. https://doi.org/10.1016/j.matlet.2015.12.042
  • MIAGAVA, J.; DA SILVA, A.L.; NAVROTSKY, A.; CASTRO, R.H.R.; GOUVÊA, D. The Nanocrystalline SnO 2 -TiO 2 System-Part II: Surface Energies and Thermodynamic Stability. Journal of the American Ceramic Society, v. 99, p. 638–644, 2016. doi:10.1111/jace.13954
  • DA SILVA, A.L.; FELTRIN, J.; DAL BÓ, M.; BERNARDIN, A.M. ; HOTZA, D. Effect of reduction of thickness on microstructure and properties of porcelain stoneware tiles. Ceramics International, v. 40, p. 14693-14699, 2014.
  • DA SILVA, A. L.; FELTRIN, J.; BERNARDIN, A.M. Morphology and Fluidity of Spray-Dried Powder Transported by Compressed Air. Materials Science Forum (Online), v. 798-799, p. 334-339, 2014.
  • DA SILVA, A. L.; BERNARDIN, A.M.; HOTZA, D. Forming of thin porcelain tiles: a comparison between tape casting and dry pressing. Ceramics International, v. 40, p. 3761-3767, 2013.

B-MRS Newsletter: In your opinion, what are the main factors that led to the outstanding research at the national level (your thesis)?

André da Silva: There are several factors that allowed the realization/award of the work conducted. I will highlight some factors:

Planning activities in a concise but detailed and organized manner.

The support, help and teachings from the advisors, who were always present, Prof. Dr. Dachamir Hotza (UFSC), Dr. Ricardo Castro (University of California, Davis, USA) and Michele Dondi (ISTEC, Faenza, Italy), as well as the support of the Graduate Program in Materials Engineering at the Federal University of Santa Catarina (PGMAT).

My ability to accept new challenges, in search of the knowledge necessary to carry out the work and the awareness that learning must be a constant habit, certainly were fundamental for the favorable development of the thesis. In addition to technical knowledge, I also emphasize the importance of mastering a new language, especially English, which opened the door to international collaborations, conferences and writing papers.

My family’s support, especially from my wife Caroline, always by my side, providing strength and encouragement.

I also highlight the International collaborations with the University of California, Davis, USA, Dr. Ricardo Castro and the Institute of Science and Technology of Ceramic Materials, Faenza, Italy, through Dr. Michele Dondi. These collaborations were also possible thanks to the CAPES and CNPq internship programs abroad.

B-MRS Newsletter: Leave a message to our readers who are undergraduate or graduate students.

André da Silva: A graduate or postgraduate degree, especially when working with research, is done like the construction of a wall. You should lay a brick a day, that is, do a little every day, but constantly focused and dedicated. Often, because we do not see immediate results, students end up steering away and the results are not as good as expected. Focus your efforts on what will generate the most of your results, take time to study and update yourself in your area and have a well-defined end goal. Do not forget to take care of your health, have friends and family nearby. Believe in yourself and in your potential, your work is very important for our country.

 

Interview with Juliano Avelar Araujo, winner of the award for the best thesis in the area of Engineering II

Juliano Avelar Araujo
Juliano Avelar Araujo

Thesis: Obtaining and microstructural and chemical characterization of multilayer NBN / CRN coatings for tribological applications by the physical vapor deposition process.
PhD Course in Metallurgical Engineering from the Polytechnic School of the University of São Paulo (Poli-USP). 
Author: Juliano Avelar Araujo.
Advisor: Andre Paulo Tschiptschin (Poli-USP).

When Juliano Avelar Araujo, a metallurgical engineer, decided to do his doctorate nine years after completing his master’s degree in Surface Engineering, he was already working as a researcher in the Mahle group, a supplier and development partner of the global automotive industry. The company supported this initiative, and Araujo was able to study in detail a multilayer coating that, when applied to components of internal combustion engines, saves fuel and consequently reduces traffic-related pollution. In the thesis, he also presented a model that allows developing other nanostructured coatings for automotive applications. Currently working on research and development projects at the Mahle Technology Center, he is taking advantage of the knowledge gained through his PhD to develop products that are likely to be marketed in 2019.

B-MRS Newsletter: In your opinion, what is the most relevant contribution of the awarded thesis?

TEM of a NbN/CrN coating with periodicities of about 20 nm. Detail of a macroparticle. Credits: Juliano Araujo and Jefferson Bettini (CNPEM).
TEM of a NbN/CrN coating with periodicities of about 20 nm. Detail of a macroparticle. Credits: Juliano Araujo and Jefferson Bettini (CNPEM).

Juliano Araujo: The regulations of the automobile industry are increasingly oriented towards reducing the emission of polluting gases. Thus, components of the internal combustion engine must innovate characteristics such as mechanical losses by friction and wear reductions to obtain lower fuel consumption and consequently reduced emissions. In this line, the doctoral work explored and developed a coating that meets these characteristics, while also formulating a model that can be employed to accelerate the development of coatings to meet the functionality of the part throughout the engine’s lifespan.

B-MRS Newsletter: Cite the main results generated from the award-winning thesis (papers, patents, products, startups, other awards, etc.).

Juliano Araujo::   There were 3 articles in international publications: 2 journals (WEAR and Surface & Coatings Technology) and 1 journal (SVC), 1 paper published in annals of international conferences, 3 patent applications and the 2016 Environment AEA Award (Automotive Engineering Association )  – Honorable Mention – Academic Category, with the work “Morphology of nanostructured CrN/NbN coatings deposited by PVD,” of the authors Juliano Avelar Araujo, André Paulo Tschiptschin, Nelson Batista de Lima and Roberto Martins de Souza.

Papers:

  • ARAUJO, JULIANO AVELAR; ARAUJO, GISELA MARQUES; SOUZA, ROBERTO MARTINS; TSCHIPTSCHIN, ANDRÉ PAULO. Effect of periodicity on hardness and scratch resistance of CrN/NbN nanoscale multilayer coating deposited by cathodic arc technique. WEAR.  , v.330-331, p.469 – 477, 2015.
  • ARAUJO, JULIANO AVELAR; SOUZA, ROBERTO MARTINS; LIMA, NELSON BATISTA DE; TSCHIPTSCHIN, ANDRÉ PAULO. Thick CrN/NbN Multilayer Coating Deposited by Cathodic Arc Technique. Materials Research-Ibero-american Journal of Materials.  , v.20, p.200 – 209, 2017.
  •  ARAUJO, JULIANO AVELAR; GIORJÃO, RAFAEL ARTHUR REGHINE; BETTINI, JEFFERSON; SOUZA, ROBERTO MARTINS; TSCHIPTSCHIN, ANDRÉ PAULO.    Modeling intrinsic residual stresses built-up during growth of nanostructured multilayer NbN/CrN coatings. SURFACE & COATINGS TECHNOLOGY.  , v.308, p.264 – 272, 2016.
  • ARAUJO, JULIANO AVELAR; MARQUES, G. A. Engineered PVD Coatings for Piston Rings application: Society of Vacuum Coaters. Spring Buletim, p. 46-52, 2012.

Patents:

  • ARAUJO, J.A.; Piston ring for internal combustion engine with a multilayer coating applied by PVD_Niobium nitride   WO2009155677-A1 – PCT/BR2009/000184 (PI0901939-1)    US20110148047-A1   26/06/2009. ANEL DE PISTÃO PARA MOTOR DE COMBUSTÃO INTERNA, 2009. Categoria: Produto. Instituição onde foi depositada: INPI – Instituto Nacional da Propriedade Industrial. País: Brasil. Natureza: Patente de Invenção. Número do registro: PI0901939. Data de depósito: 23/06/2009. Data da concessão: 26/09/2017. Depositante/Titular: Juliano Avelar Araujo.
  • ARAUJO, J. A. Multilayer CrN/Cr2N PVD, 2010. Categoria: Produto. Instituição onde foi depositada: INPI – Instituto Nacional da Propriedade Industrial. País: Brasil. Natureza: Patente de Invenção. Número do registro: PI09023399. Número do depósito PCT: 9023399. Data de depósito: 29/06/2010. Depositante/Titular: Juliano Avelar Araujo. Depositante/Titular: Mahle Metal Leve.
  • ARAUJO, JULIANO AVELAR; MORDENTE, P. J. R. ELEMENTO DESLIZANTE PARA MOTORES DE COMBUSTÃO INTERNA, 2016. Categoria: Produto. Instituição onde foi depositada: INPI – Instituto Nacional da Propriedade Industrial. País: Brasil. Natureza: Patente de Invenção. Número do registro: BR1020160153921. Data de depósito: 30/06/2016. Depositante/Titular: Juliano Avelar Araujo.

B-MRS Newsletter: In your opinion, what are the main factors that led to the outstanding research at the national level (your thesis)?

Juliano Araujo: I start with the teaching institution (University of São Paulo – USP/POLI) where I developed the doctoral work based on its tradition and recognized projection in the academic world, also the experienced guidance of Professors Dr. Andre Tschiptschin and Roberto Martins. Allied to this, the most modern techniques and equipment in the world were used, the exchange of experience with the most important laboratories and researchers in the area of coatings deposited by PVD, and the support and backing from MAHLE Metal Leve where I am a Research Engineer at the Technological Center. And finally, much discipline.

B-MRS Newsletter: Leave a message to our readers who are undergraduate or graduate students.

Juliano Araujo: Once or twice I thought about giving up on my doctorate because I believed I could not finish the thesis, I also thought about not enrolling in the Capes de Thesis Prize, because I felt I would not be competitive enough. We often underestimate ourselves… and sometimes it’s really good to be wrong! Do not give up!

 

Interview with Robson Rosa da Silva, winner of the honorable mention in the Chemistry area

Robson Rosa da Silva
Robson Rosa da Silva

Thesis: New photonic structures: I – Self assembly of 1D Te structures; II – Multifunctional biopolymers and reused plastics.

PhD Course in Chemistry from the Araraquara Institute of Chemistry of the São Paulo State University Júlio de Mesquita Filho (UNESP).

Author: Robson Rosa da Silva.

Advisors: Sidney Jose Lima Ribeiro (UNESP) and Pedro H. C. Camargo (USP)

During Robson da Silva’s doctorate there was no lack of collaborations or scientific discussions, both with Brazilian laboratories and with international groups (the latter, from the internships at the NIMS, Japan, and Georgia Institute of Technology, USA). Robson da Silva’s thesis presents a collection of nanostructures, including one-dimensional structures, produced in order to control the shape (helices, wires and tubes) from tellurium, silver and copper. The work also reports the manufacture of films based on natural and synthetic polymers. All these materials have in common their applications in the Photonics area. Robson da Silva holds a Bachelor’s degree, a Master’s and a PhD in Chemistry. He is currently a postdoctoral fellow at the São Carlos Institute of Physics at the University of São Paulo (IFSC-USP).

 

B-MRS Newsletter: In your opinion, what is the most relevant contribution of the awarded thesis?

A) SEM and MET of ultra-fine silver nanowires and, B) nanohybrid phenolic resin modified with nanoparticles of gold. 1D tellurium nanostructures were used as mold of sacrifice. C) and D) Hybrid Film Photographs of fibroin and cellulose acetate, respectively, modified with fibroin epoxysilane; E) Thin films of recycled expanded polystyrene containing europium under white light illumination (upper part) and black light (lower part); F) Bragg gratings of silk doped fibroin with rhodamine obtained by the replica of the diffraction of a DVD. The introduction of light scattering nanoparticles (such as silver and silica nanoparticles) in the Bragg grids of fibroin has been shown to be efficient for laser distributed feedback.
A) SEM and MET of ultra-fine silver nanowires and, B) nanohybrid
phenolic resin modified with nanoparticles of
gold. 1D tellurium nanostructures were used as
mold of sacrifice. C) and D) Hybrid Film Photographs
of fibroin and cellulose acetate, respectively, modified with
fibroin epoxysilane; E) Thin films of
recycled expanded polystyrene containing
europium under white light illumination (upper part) and black light
(lower part); F) Bragg gratings of silk doped fibroin with
rhodamine obtained by the replica of the
diffraction of a DVD. The introduction of light scattering nanoparticles
(such as silver and silica nanoparticles) in the Bragg grids of
fibroin has been shown to be efficient for laser
distributed feedback.

Robson Rosa da Silva: I believe that the best description of the thesis is that it is the result of multifaceted and interdisciplinary works in the field of photonics and nanomaterials. Due to its anisotropic structure, tellurium (Te) is one of the simplest materials to produce one-dimensional structures on a nanoscale, assuming different forms such as wires and tubes. From the work developed in the master’s, we discovered a scalable synthesis route to produce nanohelices, until then not found in the literature. We used Te nanohelices and functionalized their surface with phenolic resin for developing multifunctional 1D hybrids.  Regarding the preparation of optically active materials, we have demonstrated that Te nanohelices are excellent sacrificial molds for the preparation of one-dimensional hybrid structures containing metallic nanoparticles (Ag and Au) and luminescent ones based on lanthanide ions.  This work includes the collaboration of Professor Katsuhiko Ariga and Dr. Lok Shrestha who supervised me during the two-month internship period at the National Institute for Materials Science (NIMS), Japan.

I worked under Prof. Younan Xia of the Georgia Institute of Technology, USA, for one year, and continued working with one-dimensional nanostructures, however, obtained through metals such as silver and copper. During this period, I adapted the polyol synthesis to obtain ultrafine silver nanowires and collaborated with two other works related to the synthesis of ultrafine copper nanowires and silver nanorods. I also investigated the preparation of photonic crystals and magnetic nanocomposites encapsulated in metallic particles.

The thesis presents a series of studies that evaluate the potential of biopolymers (natural polymers and their derivatives) as host matrix for the incorporation of optically active species. In this case we evaluated luminophores (nanoparticles and complexes) derived from lanthanide ions. Some of the matrices investigated are soluble derivatives of cellulose, fibroin extracted from the cocoon of silkworms and cellulose biosynthesized by bacteria. These matrices can be processed in the form of transparent films, micrometric waits, sponges, etc., and also modified with dielectric, magnetic and metallic nanoparticles to produce functional materials.

Although biodegradable and transparent in the visible region, films derived from these biopolymers have few functional groups and are fragile. One of the contributions of this thesis is the successful modification of these matrices with organic-inorganic hybrids based on epoxysilanes by the sol-gel process and the simultaneous incorporation of lanthanide ion-based luminophores. This allowed producing films with excellent optical quality, rich in functional and non-cytotoxic groups and with superior mechanical properties compared to the pure biopolymer matrix with potential application in biophotonics.

In particular, we have demonstrated that silk fibroin is an extremely interesting matrix for replicating diffraction gratings and for harboring light scattering nanoparticles. Together with physicists from the Federal University of Pernambuco, we combined these materials to evaluate the synergism of a hybrid laser system formed by a distributed feedback laser and a random laser.

Finally, we investigate the recovery of plastics, whose recycling by traditional routes is not attractive, for the manufacture of high-optical quality thin films and with the potential to be used as wave guides. Some of the plastics studied include expanded polystyrene (Isopor®) and polycarbonate. The most important contribution is the fact that we used a dissolution route based on green solvent derived from plants, which allow incorporating emitting luminophores in the visible region.

B-MRS Newsletter: Cite the main results generated from the award-winning thesis (papers, patents, products, startups, other awards, etc.).

Robson Rosa da Silva: The results of the studies investigated during the doctoral period were published in scientific journals, book chapters and patents, besides national and international conferences.

From these publications, I would highlight the following works:

  • ACS Applied Materials and Interface: Fabrication of Biocompatible, Functional, and Transparent Hybrid Films Based on Silk Fibroin and Epoxy Silane for Biophotonics. v.9 (33), 27905-27917.
  • ACS Nano: Facile Synthesis of Sub-20 nm Silver Nanowires Through a Bromide-Mediated Polyol Method. v. 10 (8), 7892-7900, 2016.
  • Journal of Materials Chemistry C: Silk fibroin biopolymer films as efficient hosts for DFB laser operation. v.1 (43), 7181-7190, 2013
  • Journal of Sol-Gel Science and Technology: Multifunctional organic–inorganic hybrids based on cellulose acetate and 3-glycidoxypropyltrimethoxysilane. v.81(1), 114–126, 2017.
  • ACS Nano: Facile synthesis of Ag nanorods with no plasmon resonance peak in the visible region by using Pd decahedra of 16 nm in size as seeds. v.9 (10), 10523-10532, 2015.

B-MRS Newsletter: From your point of view, what are the main factors that led to the outstanding research at the national level (your thesis)?

Robson Rosa da Silva:  I believe that the factors that allowed conceiving the works that comprise the thesis arise from when we identified the balance between opportunity, confidence and pleasure in what is being done.

The main factor I emphasized here was the support, guidence, credibility and friendship of Professor Sidney J. L. Ribeiro. The dynamic mentoring I received has certainly helped to spark a definite variety in the research, sowing opportunities to interact with high-level researchers and research centers of excellence. The Laboratory of Photonic Materials in Araraquara has always advanced an environment of rich scientific discussions and collaborations, as well as provide an excellent infrastructure for the characterization of the materials in this thesis.

I attribute the research success to the co-orientation of Prof. Pedro Camargo from USP in São Paulo, who undoubtedly helped perfect the thesis with very productive and challenging discussions.

The internships abroad were in fact one of the factors that positively allowed to accomplish high quality work. Posture, professionalism, administration and discipline in research are values that have contributed greatly to my evolution as a researcher.

I also think it is very important to supervise and coordinate scientific activities in the post graduate program. The assistance of these researchers was indispensable to carry out the projects. Moreover, assemble an efficient and solid network of collaborators during my post-graduate studies has been an essential point to develop the research carried out. y of Microscopy of the National Laboratory of Nanotechnology and the institutional infrastructure of the National Institute of Photonics (INFO) was fundamental, in addition to the financial support of CAPES and FAPESP (13/12367-6) during the doctorate.

Above all, family support was crucial.

B-MRS Newsletter: Leave a message to our readers who are undergraduate or graduate students.

Robson Rosa da Silva: The message I would like to leave is inspired by a phrase I saw during the internship at NIMS, of unknown authorship: “The fruits of your research are proportional to the number of conversations with others.” So talk, question, but also listen, interpret the criticisms and do not stop trying to seriously solve the daily demands that surround us… and there are many. In research, feel uncomfortable because everything that is very comfortable creates inertia.

B-MRS newsletter. Year 4, issue 12.

Posted on Monday 18 de December de 2017

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Newsletter of the
Brazilian Materials
Research Society

Year 4, issue 12. December 19th, 2017.
New Year´s message

ano novo 2018

With this New Year’s message, I greet the entire B-MRS community in Brazil and abroad.

2017 was especially difficult for the areas of science, technology and innovation in Brazil, and B-MRS has aligned itself with other scientific societies by echoing voices calling for more responsible policies by governments in our sector. It has been a difficult battle to convince leaders regarding the growing importance of research investment, given that society increasingly relies on knowledge to achieve sustainable development. For a country with so much social inequality, such as Brazil, there is no alternative means to create and incorporate technologies to improve the lives of the population. We all need to join in and repeat the slogan advocated by many of our colleagues: “Science is not an expense. It’s an investment!”

Despite the difficulties, the Brazilian scientific community has shown remarkable resilience. For B-MRS, for example, 2017 was marked by an excellent Meeting in Gramado, whose scientific level was equivalent to the best international meetings in materials science and engineering. The Meeting was also an exceptional opportunity to bring together researchers from Latin America, as well as from other continents, as part of B-MRS’s effort to position itself on the international landscape. In this regard, perhaps the greatest highlight of the year was the participation of Brazilian postdoctoral researchers at the Forum for Young Researchers in Strasbourg, France, organized by the European Society for Materials Research (E-MRS) and by the International Union of Materials Research Societies (IUMRS). These postdoctoral fellows were selected in a competitive national contest.

It is always gratifying to follow over the year, in the B-MRS Newsletter, some of the achievements and contributions of Brazilian researchers in various materials areas. In 2017, much was done in Brazil, a demonstration of the strength of our community.

I end by thanking the B-MRS community, with heartfelt wishes for health and success in 2018, hoping to meet many of you in Natal (state of Rio Grande do Norte), from September 16 to 20, in our next Meeting.

Professor Osvaldo Novais de Oliveira Junior
President of B-MRS
XVII B-MRS Meeting
(Natal, Brazil, September 16 – 20, 2018)

natal news

Call for symposium proposals. Researchers from the international scientific community may submit symposium proposals by January 31, 2018. Know more.

Exhibitors and sponsors. Companies interested in participating in the event with booths and other dissemination modes may contact Alexandre at comercial@sbpmat.org.br. Until December 22 there are discounts for the booths and for sponsorship quotas.

Chairman. The meeting chair is Professor Antonio E. Martinelli, from the Brazilian Federal University of Rio Grande do Norte (UFRN).

Venue. The event will be held in the convention center of Hotel Praiamar, located a few meters from the famous beach of Ponta Negra.

natal

B-MRS election process

The Electoral Commission encourages B-MRS members who are interested in participating in the process to register an Executive Board or express interest in joining the Council, by writing to eleicoes2017@sbpmat.org.br until December 22.

More info.

elections

B-MRS news

The president of B-MRS, Professor Osvaldo Novais de Oliveira Jr (IFSC-USP), was against the suggestion in the report from the World Bank to end the tuition-free public higher education institutes in Brazil. His argument, along with that of 43 other representatives of scientific and academic entities, was published in the Jornal da Ciência. See here.

jornal da ccia

News from the community

Four B-MRS members were part of a select international group of young researchers that participated in a forum and a summit on materials research in Strasbourg (France). Topics related to materials innovations for a sustainable society and a global circular economy were discussed in the events. In a short interview, the young B-MRS members shared with us their experience in Strasbourg. See here.

socios estrasburgo

Co-founder of B-MRS awarded the “Global Ambassador” of the American Ceramic Society. Know more.

zanotto

Events

  • Primer Encuentro de Jóvenes Investigadores en Ciencias de Materiales. Montevideo (Uruguay). April, 13 – 14, 2018. Site.
  • 6º Encontro Nacional de Engenharia Biomecânica (ENEBI 2018). Águas de Lindoia, SP (Brazil). May, 8 – 11, 2018. Site.
  • Photonic Colloidal Nanostructures: Synthesis, Properties, and Applications. (PCNSPA 2018). Saint Petersburg (Russia). June 4 – 8, 2018. Site.
  • International Conference on Electronic Materials 2018 (IUMRS-ICEM). Daejeon (South Korea). August, 19 – 24, 2018. Site.
  • XVII B-MRS Meeting. Natal, RN (Brazil). September 16 – 20, 2018. Call for symposium proposals.
  • International Conference of Young Researchers on Advanced Materials (ICYRAM 2018). Adelaide (Australia). November 4 – 8, 2018. Site.

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Participation of B-MRS young members in international events on sustainable materials.

Posted on Friday 15 de December de 2017
The B-MRS group at the headquarters of the Council of Europe. From the left, Gisele Amaral-Labat (B-MRS member), Eduardo Neiva (member), Professor Osvaldo Novais de Oliveira Jr (president of SBPMat), Kassio Zanoni (member) and Parinaz Akhlaghi (member).
The B-MRS group at the headquarters of the Council of Europe. From the left, Gisele Amaral-Labat (B-MRS member), Eduardo Neiva (member), Professor Osvaldo Novais de Oliveira Jr (president of SBPMat), Kassio Zanoni (member) and Parinaz Akhlaghi (member).

Four members of B-MRS were part of the select group of about 30 young researchers from several countries who participated in two events held in the city of Strasbourg, France, along with 60 other participants. The main subject of both events was material innovation for a sustainable society and a global circular economy (i.e., based on reduction, reuse, recovery and recycling of materials and/or energy). The events were organized by several research societies in materials research, the International Union of Materials Research Societies (IUMRS) and other entities, with the support of UNESCO.

Post-doctoral fellows Eduardo Guilherme Cividini Neiva (currently full-time professor at FURB, after completing a post-doc at UFPR), Gisele Amaral-Labat (USP), Kassio Papi Silva Zanoni (IFSC-USP) and Sedeyeh Parinaz Akhlaghi (UNICAMP) were the young B-MRS members who participated in the events. The four postdocs were selected from 20 candidates in the context of the B-MRS Young Researcher Award. They have earned the right to attend the events (which are not open to the public), as well as travel costs. The award was made in partnership with the European Materials Research Society (E-MRS).

The first of the events was the “Forum for the Next Generation of Researchers 2017,” held on 18 and 19 November of this year at the headquarters of the European Youth Center. The forum brought together different generations of researchers around science and technology for a sustainable world. The event included lectures by senior scientists, poster presentations of young researchers and discussions among all participants. In addition, all young scientists participated in the preparation of a report that was presented at the end of the event.

Then, on the 20th and 21st, the “6th World Materials Summit” was held at the headquarters of the Council of Europe. The subject of innovation in sustainable materials and the circular economy was discussed through lectures by scientists from various countries and round tables.

According to Kassio Zanoni, the discussions of the two events showed an academic, political, social and environmental view about themes related to sustainability, as well as the perspectives of Materials research in this context. According to the B-MRS participants, some of the topics addressed were the conversion, storage and distribution of energy (solar, for example); production of more efficient and less polluting batteries; capture and reuse of carbon dioxide; materials recycling; and many other topics.

The president of SBPMat, Osvaldo Novais de Oliveira Jr, professor at IFSC-USP, represented SBMat in the international committee of the summit and gave a lecture in the forum about nanomaterials and their applications.

Read our interview with the B-MRS young members who attended the events.

box parinaz ENB-MRS Newsletter:  Briefly tell us about the work you presented in the “Forum for the New Generation of Researchers 2017”.

Eduardo Neiva:  I presented a poster about my postdoctoral work, whose theme involved the application of graphene nanocomposites in the construction of energy storage devices.

Gisele Amaral-Labat: My panel discussion consisted of activities that are currently being developed in my postdoctoral fellowship. The work is based on the use of pulp and paper industry waste, crude black liquor, in the synthesis of porous carbon foams in the presence of nickel, for direct ethanol fuel cell applications. The synthesis form used generates a product with a greater amount of residues, besides the low cost when compared to the electrocatalysts used in the current market.

Kassio Zanoni: I presented a poster of the work I am developing in the postdocs, on ways and concepts for energy conversion and sustainability.

Parinaz Akhlaghi: I presented my postdoctoral work (referring to the years 2015-2017) at UNICAMP (Institute of Chemistry), still in progress, as well as part of the work developed during my doctorate (2010-2014) at the University of Waterloo (Dept. of Chemical Engineering) in the form of a poster titled “Preparation and Characterization of Novel Nanomaterials for Biomedical Applications.”

B-MRS Newsletter: How did your participation in these events contribute to your development?

Eduardo Neiva: Unlike other events, I had the opportunity to participate in discussions involving topics of global importance. My participation in this event will also result in future international and national partnerships, where in the event, I and the participant Gisele conceived projects to be developed in the near future.

Gisele Amaral-Labat: Undoubtedly, participating in these events was extremely important for my academic background, first due to the type of event, in which a common theme is discussed by two different communities, academic and business, enabling me to know different global views of the subject. Secondly, it created the possibility for collaboration with other research centers, including young and senior researchers, national and international. Furthermore, the event allowed getting to know the work of the other young Brazilian researchers, and a possible collaboration with Eduardo Guilherme Cividini Neiva is in progress. The objective is to synthesize sustainable carbon materials for application in the area of energy storage, taking advantage of the expertise of both of us.

Kassio Zanoni: The event provided the opportunity for meetings with several researchers, increasing our networks of collaborations. It was very interesting to hear the different views and this brought a great deal of professional growth. It really was very productive, perhaps the most productive meeting I’ve ever attended.

Parinaz Akhlaghi: I believe that my participation in these events was one of the most rewarding and most influential experiences in my career as a researcher and as a human being. I was affected in an extremely positive way by being in the presence of young researchers like myself, as well as experienced scientists, shaping my worldview (and my future), my ambitions and desires in the academic career. Being in the presence of scientists that I have admired for so long and being able to exchange ideas with them was very rewarding in several aspects. All the discussions were profound, passionate and motivating. It was certainly an experience shared by the other young scientists.

B-MRS Newsletter: What most attracted your attention in the events?

Eduardo Neiva: The direct and prolonged contact with renowned researchers.

Gisele Amaral-Labat: I was delighted with how receptive the senior researchers were with the young researchers. Moreover, the event showed a relevant multidisciplinarity of the professionals and the works presented.

Kassio Zanoni: The different views on the same theme, which vary widely between different countries.

Parinaz Akhlaghi: What at first could have been a barrier, soon proved to be extremely pleasurable. Despite the age difference between the main scientists (some older than 70) and the young researchers (some 25 years old), the exchange of information flowed naturally. On both sides there was passion when talking about science (as a whole), as well as new paths and alternatives for a more hopeful and better future.

Kassio Zanoni (foreground) and other young researchers during the 6th World Materials Summit.
Kassio Zanoni (foreground) and other young researchers during the 6th World Materials Summit.
Parinaz Akhlaghi presenting her work on nanomaterials for biomedical applications during the forum.
Parinaz Akhlaghi presenting her work on nanomaterials for biomedical applications during the forum.
Eduardo Neiva (left) and Gisele Amaral-Labat (right) receiving the participation certificate in the events.
Eduardo Neiva (left) and Gisele Amaral-Labat (right) receiving the participation certificate.

New Year’s Message from B-MRS President.

Posted on Friday 15 de December de 2017

With this New Year’s message, I greet the entire B-MRS community in Brazil and abroad.

2017 was especially difficult for the areas of science, technology and innovation in Brazil, and B-MRS has aligned itself with other scientific societies by echoing voices calling for more responsible policies by governments in our sector. It has been a difficult battle to convince leaders regarding the growing importance of research investment, given that society increasingly relies on knowledge to achieve sustainable development. For a country with so much social inequality, such as Brazil, there is no alternative means to create and incorporate technologies to improve the lives of the population. We all need to join in and repeat the slogan advocated by many of our colleagues: “Science is not an expense. It’s an investment!”

Despite the difficulties, the Brazilian scientific community has shown remarkable resilience. For B-MRS, for example, 2017 was marked by an excellent Meeting in Gramado, whose scientific level was equivalent to the best international meetings in materials science and engineering. The Meeting was also an exceptional opportunity to bring together researchers from Latin America, as well as from other continents, as part of B-MRS’s effort to position itself on the international landscape. In this regard, perhaps the greatest highlight of the year was the participation of Brazilian postdoctoral researchers at the Forum for Young Researchers in Strasbourg, France, organized by the European Society for Materials Research (E-MRS) and by the International Union of Materials Research Societies (IUMRS).  These postdoctoral fellows were selected in a competitive national contest.

It is always gratifying to follow over the year, in the B-MRS Newsletter, some of the achievements and contributions of Brazilian researchers in various materials areas. In 2017, much was done in Brazil, a demonstration of the strength of our community.

I end by thanking the B-MRS community, with heartfelt wishes for health and success in 2018, hoping to meet many of you in Natal (state of Rio Grande do Norte), from September 16 to 20, in our next Meeting.

Professor Osvaldo Novais de Oliveira Junior

President of B-MRS

B-MRS newsletter. Year 4, issue 11.

Posted on Thursday 30 de November de 2017

 

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Newsletter of the
Brazilian Materials
Research Society

Year 4, issue 11. December 6th, 2017.
B-MRS election process

The election of the Executive Board (president and directors) for the next two years and members of the Deliberative Council for the next 4 years will be held at the end of January. The process has already begun.

Who participates? All members in good standing can vote, can form boards for the Executive Board or express interest in being Council members. Good standing = registered membership and paid 2017 annuity.

How to regularize the membership situation? December 11 is the deadline to become a first-time member (registration + annuity 2017) or to regularize membership situation (annuity 2017) in order to participate in this important process of our society.

How to apply? To register an Executive Board or express interest in joining the Council, you must write to eleicoes2017@sbpmat.org.br.

Know more.

elections

XVII B-MRS Meeting
(Natal, Brazil, September 16 – 20, 2018)

Call for symposium proposals. Researchers from the international scientific community may submit symposium proposals by January 31, 2018. Know more.

Exhibitors and sponsors. Companies interested in participating in the event with booths and other dissemination modes may contact Alexandre at comercial@sbpmat.org.br. Until December 22 there are discounts for the booths and for sponsorship quotas.

Chairman. The meeting chair is Professor Antonio E. Martinelli, from the Brazilian Federal University of Rio Grande do Norte (UFRN).

Venue. The event will be held in the convention center of Hotel Praiamar, located a few meters from the famous beach of Ponta Negra.

natal

Featured paper

A study carried out mainly in Brazilian institutions developed a method, based on XMCD, which allowed a unique experimental investigation of the distribution of electrons and magnetism of uranium-based compounds, which due to their toxicity have relatively little experimental data. In addition to the scientific results published in Nature Communications, this work leaves to the scientific community a research system for magnetic materials installed at the Brazilian Synchrotron Light Laboratory (LNLS). Know more.

artigo destaque

Featured scientist

We interviewed Oscar Malta, a professor at UFPE, who recently received an honorary doctorate degree from the prestigious University of Wroclaw (Poland). In 4 decades of fundamental and applied research on lanthanide elements and their compounds, Malta has made a number of high impact contributions. His articles have about 7,000 citations. In the interview, the scientist spoke about his trajectory, the area of lanthanides and the importance of science and technology for humanity. He also left a message for the young audience, urging them to give importance to the study of the theoretical and historical foundations of their research topics. See interview.

malta 2

News from the community

  • Antonio Carlos Hernandes (IFSC-USP), founding member and former director of SBPMat, is the new Vice-Rector of the University of São Paulo (USP). Know more.

Reading tips

  • By combining materials with different reactions to infrared radiation, scientists have created a tissue that heats on one side and cools on the other (Science Advances). Know more.
  • Research conducted by Brazilian scientists shows that NbB, cited as an example of superconductivity for 65 years, is not a superconductor (Physical Review Materials). Know more.

Opportunities

  • Fellowships in sustainable energy. See here.
  • Postdoc at the Brazilian Federal University of Santa Catarina. See here.
  • Call for applications of foreign visiting professors/researchers for the Federal University of Mato Grosso do Sul. See here.

Events

  • Primer Encuentro de Jóvenes Investigadores en Ciencias de Materiales. Montevideo (Uruguay). April, 13 – 14, 2018. Site.
  • Photonic Colloidal Nanostructures: Synthesis, Properties, and Applications. (PCNSPA 2018). Saint Petersburg (Russia). June 4 – 8, 2018. Site.
  • International Conference on Electronic Materials 2018 (IUMRS-ICEM). Daejeon (South Korea). August, 19 – 24, 2018. Site.
  • XVII Encontro da SBPMat/ B-MRS Meeting. Natal (Brazil). September, 16 – 20, 2018. Call for symposium proposals.
  • International Conference of Young Researchers on Advanced Materials (ICYRAM 2018). Adelaide (Australia). November 4 – 8, 2018. Site.

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You can suggest news, opportunities, events or reading tips in the Materials field to be published in this newsletter. Write to comunicacao@sbpmat.org.br.
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Featured paper: Towards two-dimensional diamond.

Posted on Tuesday 31 de October de 2017

Two-dimensional materials, those whose thickness goes from an atom to a few nanometers, have unique properties related to their dimensionality and are protagonists in the development of nanotechnology and nanoengineering.

A team of scientists from five Brazilian institutions and one American institution took an important step in the development of the two-dimensional diamond version. This work on 2D diamond was reported in a paper published in Nature Communications (impact factor 12,124) with open access.

“Our work presented spectroscopic evidence of the formation of a two-dimensional diamond, which we named diamondene”, says Luiz Gustavo de Oliveira Lopes Cançado, professor at the Brazilian Federal University of Minas Gerais (UFMG) and corresponding author of the paper. In choosing the name of the new material, the scientists followed the tradition of using the suffix “ene” for two-dimensional materials, as with graphene, 2D version of the graphite.

box_enIn fact, it was from the compression of graphene sheets that the diamondene was obtained by the team led by Professor Cançado. Initially, the team deposited two layers of graphene one on top of the other and transferred the graphene bilayer to a Teflon substrate, chosen for being chemically inert, preventing the formation of bonds with the graphene.

The sample of bi-layered graphene on Teflon was then subjected to high pressures and simultaneously analyzed by Raman spectroscopy at the Laboratory of Vibrational Spectroscopy and High Pressure of the Department of Physics of the Brazilian Federal University of Ceará (UFC). The experimental system used was a diamond anvil cell with a coupled Raman spectrometer. This equipment allows high pressure to be applied to small samples that are immersed in a pressure transmitting medium (in this case, water). The pressure is applied through two pieces of diamond (material chosen for being one of the hardest and resistant to compression), which compress the transmitting medium, which passes the pressure to the sample. At the same time, the spectrometer allows to monitor the changes that occur in the structure of the sample material against the different pressures applied. “In Raman spectroscopy, light behaves like a probe that measures vibrational states of the material,” explains Cançado. As a result of the probing, the spectrometer generates graphs (spectra), through which it is possible to identify the structure of the material being studied.

By analyzing the spectra, the team of scientists observed changes in the two-dimensional material that indicated the transition from a graphene structure to a diamond structure. The researchers were able to conclude that the diamondene was obtained at a pressure of 7 gigapascals (GPa), tens of thousands of times higher than the atmospheric pressure. “The evidence we present in this work is a signature in the vibrational spectrum obtained from a two-dimensional carbon material that indicates the presence of sp3 bonds, typical of the structure of the diamond,” says Professor Cançado.

To explain the formation of diamondene, the team used first principles calculations following the Density Functional Theory and Molecular Dynamics simulations. “These theoretical results guided the experiments and allowed us understanding the experimental results,” says Cançado.

Scheme of the diamondene formation mechanism from two layers of graphene submitted to high pressures (blue arrows) in water as pressure transmitting medium. The gray colored balls represent the carbon atoms; the red ones, the oxygen atoms, and the blue ones, the hydrogen atoms.
Scheme of the diamondene formation mechanism from two layers of graphene submitted to high pressures (blue arrows) in water as pressure transmitting medium. The gray colored balls represent the carbon atoms; the red ones, the oxygen atoms, and the blue ones, the hydrogen atoms.

According to the theoretical results, when the bilayer graphene system on inert substrate with water as pressure transmitting medium is subjected to high pressures, the distances between the elements of the system decrease and new connections occur among them. “When applying this level of pressure on graphene, connections can change, going from the sp2 configuration to the sp3 configuration,” explains Professor Cançado. The carbon atoms in the upper graphene layer then establish covalent bonds with four neighboring atoms: the atoms of the lower layer and the chemical groups offered by water (OH- and H). The latter are fundamental to stabilize the structure. In the lower layer, in contact with the inert substrate, half of the carbon atoms are bound to only three neighboring atoms. “The pending connections give rise to a gap opening in the electronic structure, as well as polarized spin bands,” adds Cançado.

This feature makes diamondene a promising material for the development of spintronics (the emerging strain of electronics at the nanoscale in spin-bases electronics). According to Cançado, diamondene could also be used in quantum computing, microelectromechanical systems (MEMS), superconductivity, electrodes for electrochemistry-related technologies, DNA engineering substrates and biosensors – applications in which thin diamond films have already proven to have good performance.

However, there is still a long way to go before demonstrating the diamondene applications. Firstly, because the diamondene shown in the article dismantles under normal pressure conditions. To overcome this limitation, the group of Professor Cançado at UFMG is setting up an experimental system that will allow the application of much higher pressures to the samples in the order of 50 GPa and analyze them using Raman spectroscopy. “With this we intend to produce stable diamondene samples, which remain in this form even after having the pressure reduced to the level of ambient pressure,” says Cançado.

In addition, since Raman spectroscopy provides indirect evidence of the structure of the material, it will be necessary to perform direct measurements of the diamondene to know its structure in detail. “The most promising techniques in this case would be X-ray diffraction in synchrotron light sources or electron diffraction,” suggests Cançado. “The complicating factor in this experiment is the need to have the sample subjected to high pressures,” he adds.

The Brazilian history of diamondene

The idea of the 2D diamond formation originated in the doctoral research of Ana Paula Barboza, conducted under the guidance of Professor Bernardo Ruegger Almeida Neves and defended in 2012 in the Department of Physics of UFMG. In this work, Cançado says, atomic force microscopy (AFM) tips were used to apply high pressures on one, two and several layers of graphene. Indirect evidence of the formation of a two-dimensional diamond was obtained by means of electric force microscopy (EFM). The work showed the importance of the presence of two layers of graphene and water for the formation of the sp3 two-dimensional structure. The main results of the research were reported in the article Room-temperature compression induced diamondization of a few-layer graphene [Advanced Materials 23, 3014-3017 (2011)].

Main article authors. On the left, Luiz Gustavo Pimenta Martins (MSc from UFMG and doctoral student at MIT). On the right, Professor Luiz Gustavo Cançado (UFMG).
Main article authors. On the left, Luiz Gustavo Pimenta Martins (MSc from UFMG and doctoral student at MIT). On the right, Professor Luiz Gustavo Cançado (UFMG).

“The idea of measuring the Raman spectrum of graphene under high pressure conditions (using anvil diamond cells) came after Luiz Gustavo Pimenta Martins, an undergraduate student at the time, developed a very efficient method of transferring graphene to different substrates,” says Professor Cançado. This development was carried out during a visit to the laboratory of Professor Jing Kong at the Massachusetts Institute of Technology (MIT), after having won a grant for international mobility of the Formula Santander Award. During his master’s degree at the Physics Department of UFMG, carried out under the guidance of Professor Cançado and defended in 2015, Pimenta Martins carried out an extensive and systematic work to obtain Raman spectra of graphene samples subjected to high pressures. “There were many visits to UFC and much study until understanding the diamondene formation mechanisms,” explains Cançado.

The research reported in the Nature Communications paper was made possible by the collaborative work of several Brazilian research groups with recognized expertise in various subjects, as well as the participation of the MIT researcher in the sample preparations. Scientists from the physics departments of UFMG and UFC have contributed their recognized expertise in Raman spectroscopy applied to carbon nanomaterials and, in the case of UFC, in experiments under high pressure. Also participating in these experiments were researchers from the Brazilian Federal Institute of Education, Science and Technology of Ceará and the Brazilian Federal University of Piauí (UFPI). In addition, theoretical physicists from the Brazilian Federal University of Ouro Preto (UFOP) and UFMG performed calculations and computational simulations.

The research was funded by Brazilian federal agency CNPq, state agencies FAPEMIG and FUNCAP, Formula Santander Program and UFOP.

[Paper: Raman evidence for pressure-induced formation of diamondene. Luiz Gustavo Pimenta Martins, Matheus J. S. Matos, Alexandre R. Paschoal, Paulo T. C. Freire, Nadia F. Andrade, Acrísio L. Aguiar, Jing Kong, Bernardo R. A. Neves, Alan B. de Oliveira, Mário S.C. Mazzoni, Antonio G. Souza Filho, Luiz Gustavo Cançado. Nature Communications 8, Article number: 96 (2017). DOI:10.1038/s41467-017-00149-8. Disponível em: https://www.nature.com/articles/s41467-017-00149-8]