Featured paper: Optimizing nanotubes for green hydrogen production.


Hydrogen generation in a photoelectrochemical cell with the photoanode developed by the Pernambuco team.
Hydrogen generation in a photoelectrochemical cell with the photoanode developed by the Pernambuco team.

A work carried out in institutions from the state of Pernambuco (Brazil) contributes to the development of nanomaterials with the potential to overcome an important energy challenge: the generation of hydrogen through sustainable processes. In fact, the hydrogen molecule is considered a clean fuel because its use, or “burning”, does not emit greenhouse gases. However, the production of this molecule is responsible for emitting hundreds of tons of carbon dioxide per year.

Fortunately, more sustainable ways to produce molecular hydrogen are being explored by scientists around the world. The “greenest” of all are the photoelectrochemical processes, which consist of breaking down the water molecule (H2O) using electricity from photovoltaic conversion (the transformation of photons into electrons). These processes are carried out in photoelectrochemical cells – simple and low-cost systems basically composed of a photoanode, where sunlight is absorbed, thus generating a current of electrons, and a cathode, on whose surface the hydrogen detaches from the water molecule by the action of the electricity generated in the photoanode. In this context, it is essential to develop materials for the photoanode that are efficient and durable, and which can be produced using low-cost and environmentally friendly processes.

In an article recently published in the Journal of Power Sources (impact factor 9.1270), scientists from the Center for Strategic Technologies of the Northeast (CETENE) and the Federal University of Pernambuco (UFPE) report a simple and clean method to produce nanocomposites capable of generating an electrical current from sunlight. The work also presents good results in the application of the material as a photoanode for hydrogen production.

Challenge: increase photoanode sensitivity

Titanium dioxide (TiO2) is the most used material in photoanodes. Unlike other semiconductors, it is non-toxic and does not degrade easily in contact with light and water. However, this material has a limitation that affects its efficiency: it can only absorb ultraviolet light, not taking advantage of other radiations present in sunlight. For this reason, scientific efforts have been made to expand the sensitivity of TiO2. This was exactly the objective of the CETENE and UFPE team at the beginning of the collaborative work. The strategy they adopted was to integrate semiconductor nanocrystals (quantum dots) to TiO2 nanotubes and, in this way, obtain a material that is more sensitive to sunlight thanks to the synergistic action of both semiconductors.

The researchers started by sensitizing the nanotubes with bismuth sulfide (Bi2S3) nanocrystals, says Denilson V. Freitas, who now works as a researcher at CETENE and has participated in this research line since the beginning, when he was doing his doctorate in Chemistry at UFPE. In the experiments, the scientists noticed that the method of preparing the nanocomposite significantly impacted its photoelectrochemical performance, and reported these results in an article published in 2018 in ACS Applied Energy Materials (impact factor 6.024). “We found that the best photoelectrochemical results were for the linker-assisted method when compared to the hydrothermal method,” says Denilson. Thus, the first method was chosen. In

linker-assisted sensitization, TiO2 nanotubes, supported on titanium sheets, are submerged in a solution containing the chosen nanocrystals. Both materials interact and, at the end of the process, the quantum dots are adsorbed on the surface of the nanotubes.

The second phase of the research was carried out within the Master’s Degree project in Materials Science by Danilo A.P. Velásquez, carried out at UFPE. This time, the scientific team used silver, indium and selenium nanocrystals (AgIn5Se8) with the main objective of determining what would be the optimal submersion time of the nanotubes in the solution, as the researchers had noticed that high concentrations of nanocrystals on the surface of the nanotubes affected in a negative way the performance of the nanocomposite. For this, they performed a series of experiments varying the submersion time between 1 hour and 48 hours.

Titanium dioxide nanotubes without quantum dots (left), sensitized with quantum dots for 2 hours (center) and for 72 hours (right).
Titanium dioxide nanotubes without quantum dots (left), sensitized with quantum dots for 2 hours (center) and for 72 hours (right).

In addition to observing through electron microscopy techniques the concentration of nanocrystals obtained in each case, the researchers checked the performance of each sample. The results showed that the photoletrochemical performance of nanotubes improved with increasing sensitization time up to 24 hours of immersion, when the obtained nanocomposite generated a photocurrent 2.4 times greater than that of pure nanotubes. Furthermore, the optimized nanotubes also improved their performance in hydrogen production, which was 3.1 times greater than that of the material without quantum dots. The experiments also demonstrated that, after 24 hours of immersion, the concentration of nanocrystals became excessive and impaired the functionality of the nanocomposite. “The work showed that the temporal optimization of the sensitization of nanotubes is an important step in the production of more efficient systems,” summarizes Denilson.

The research was carried out by researchers and students linked to postgraduate programs in Chemistry and Materials Science at UFPE, coordinated by professor Marcelo Navarro, and to CETENE, led by researcher and director of the center Giovanna Machado. The acquisition of images of nanotubes sensitized by high resolution transmission electron microscopy were performed at SENAI-MG. The works were funded by Brazilian research funding agencies CNPq, FACEPE, CAPES and Finep.

Os autores do paper. A partir da esquerda: Danilo A. P. Velásquez, Felipe L. N. Sousa, Thiago A. S. Soares, Anderson J. Caires, Denilson V. Freitas, Marcelo Navarro e Giovanna Machado.
The authors of the paper. From the left: Danilo A. P. Velásquez, Felipe L. N. Sousa, Thiago A. S. Soares, Anderson J. Caires, Denilson V. Freitas, Marcelo Navarro e Giovanna Machado.

 


Scientific article reference: Boosting the performance of TiO2 nanotubes with ecofriendly AgIn5Se8 quantum dots for photoelectrochemical hydrogen generation. Danilo A. P.Velásquez, Felipe L. N.Sousa, Thiago A. S. Soares, Anderson J. Caires, Denilson V. Freitas, Marcelo Navarro, Giovanna Machado. Journal of Power Sources. Volume 506, 15 September 2021, 230165. https://doi.org/10.1016/j.jpowsour.2021.230165.

Contact of the corresponding author: Giovanna Machado – giovanna.machado@cetene.gov.br.


 

XIX B-MRS Meeting + IUMRS ICEM: Students Awards and Prizes.


Bernhard Gross Award

(Established by B-MRS in honor of Bernhard Gross, a pioneer of Brazilian materials research. It distinguishes the best oral and poster contributions presented by students in each symposium)

Symposium A – Poster. Ezequiel Lorenzett. Natural latex and graphite nanocomposites for low-cost flexoelectric sensor and energy harvesting devices.

Symposium A – Oral. Lucas Leão Nascimento. Development of Bi2WO6 photoanodes for selective glycerol photoelectroconversion to formic acid.

Symposium D – Poster. Raul Back Campanelli. Superconductivity in Bulk Silicon Crystals.

Symposium D – Oral. Davi Araujo Dalbuquerque Chaves. Influence of heat treatments on microstructural and superconducting properties of YBCO nanowires prepared by Solution Blow Spinning.

Symposium E – Poster. Leonardo Henrique Comini Francisco. Near-infrared emitting Cr3+-doped mixed oxide luminescent materials for optical imaging.

Symposium E – Oral. Antonio Valerio Longo. ZnS:Mn QD-based electroemissive layer for QD-ACTFEL light display.

Symposium F – Poster. Ruan Lucas Sousa Lima. Development of the Stokes spectropolarimetry to investigate emission of conjugated molecules.

Symposium F – Oral. Lucas Scalon. Assessing the donor-acceptor nature and the electrochemical stability of a fluorene-diketopyrrolopyrrole-thiophene based copolymer.

Symposium G – Poster. Victor Buratto Tinti. Giant electrostriction in ceria and the effects of alkaline earth dopants.

Symposium G – Oral. Camila Alves Ribeiro. Cold sintering towards the sustainable manufacturing of barium strontium titanate ceramics.

Symposium H – Oral. Sthefany Zaida Silva do Amparo. Microwave-assisted synthesis of reinforced polyacrylamide preformed particle gels for enhanced oil recovery.

Symposium I – Poster. Camila Raiane Ferreira. PMMA/Fe-Laponite nanocomposites thermal stability: experimental evidence of the diffusion barrier and radical trapping effect.

Symposium I – Oral. Marylyn Setsuko Arai. Development of “turn-on” luminescent sensors based on upconversion nanoparticles.

Symposium K – Oral. Nataly Herrera Reinoza. Atomically precise bottom-up synthesis of h-BNC: graphene doped with h-BN nanoclusters.

Symposium L – Oral. Julia Delatorre Bronzato. Virus Inactivation and Degradation of an Emergent Pollutant by Chiromagnetic Cobalt Oxide Quantum Dots.

Symposium M – Oral. Rapahel F. Moral. Influence of the Vibrational Modes from the Organic Moieties in 2D Lead Halides on Excitonic Recombination and Phase Transition.

Symposium N – Poster. Guilherme B. Strapasson. Microwave assisted green synthesis of silver nanoparticles and its application in photocatalytic hydrogen generation.

Symposium N – Oral. Mariana Monteiro de Lima Forini. Development of lipid nanocarriers labeled with gold nanoparticles and their fate in aquatic plants.

Symposium O – Poster. Bruno Ferrari. Microstructure of Inconel 718 parts produced by casting and additive manufacturing: a comparison.

Symposium O – Oral. Eloisa Pereira Cardozo. Impact of multiple thermal cycles on Nb-Si multilayers.

Symposium P – Poster. Pedro Henrique Fernandes Oliveira. In-situ synchrotron X-ray evaluation on the evolution of dislocation and stacking-fault densities for a Cu-0.7Cr-0.07Zr alloy during cryogenic tensile test.

Symposium P – Oral. Daniel da Silva Costa. In situ study of the formation of NiSi2 nanoplates embedded in a Si(001) wafer.

Symposium Q – Poster. Jailton Romão Viana. A DFT study of the coordination complex of Cu(II) with L-threonine ligand.

Symposium Q – Oral. Julia Aznar. Twist-to-writhe conversion in diamond nanowires: a computational study.

Symposium R – Poster. Giovana Collombaro Cardoso. Development and Microstructural Analysis of novel As-Cast Ti-Mo-Nb Alloys for Biomedical Applications.

Symposium R – Oral. Igor Lebedenco Kitagawa. Titanium-Based Alloy Surface Modification with TiO2 and Poly(Sodium 4-Styrenesulfonate) Multilayers for Dental Implant.

Symposium T – Poster. Lais Pereira Buranello. Characterization of the corona protein formation inthree different manganese ferrite nanoparticles coatings in vitro and its impacts on the circulation time evaluated by AC Biosusceptometry in vivo.

Symposium T – Oral. André Luís Lira. Effects of ultrasmall nanoparticles on blood clotting enzymes.

Symposium U – Poster. Gabriel Yuji Hata. Biosilica from diatom microalgae: structural, morphological and photoelectrochemical characterization.

Symposium U – Oral. Oceane Senepart. Axonal growth stimulated by surface modification using physical and chemical processes.

Symposium UC – Oral. Rafael Taveira Andrade. Development and fabrication of non-disposable Personal Protective Equipment and a decontamination device based on UV-C radiation by Additive Manufacturing.

Symposium V – Poster. Anna Fortunato. Synthesis of metal-triggered hydrogels and their applications in water treatment and food spoilage detection.

Symposium V – Oral. Roger Borges. Colloidal hydrogel-based drug delivery systems overcome the limitation of combining bisphosphonates with bioactive glasses in bone cancer treatment.

Symposium X – Poster. Fabio Caixeta Nunes. Effect of strontium ions on the formation of calcium phosphates on the surface of Al2O3/ZrO2 nanocomposite.

Symposium X – Oral. Marcos Antonio Eufrásio Cruz. The role played by matrix vesicles during bone biomineralization: a materials science vision.

ACS Publications Prizes

(Sponsored by journals of ACS Publications, a division of the American Chemical Society. Prizes for the best student contributions of all the event)

ACS Applied Materials & Interfaces family Prize: Symposium A – Poster. Ezequiel Lorenzett. Natural latex and graphite nanocomposites for low-cost flexoelectric sensor and energy harvesting devices.

Accounts of Materials Research Prize: Symposium F – Poster. Ruan Lucas Sousa Lima. Development of the Stokes spectropolarimetry to investigate emission of conjugated molecules.

ACS Omega, ACS Central Science and JACS Au Prize: Symposium O – Poster. Bruno Ferrari. Microstructure of Inconel 718 parts produced by casting and additive manufacturing: a comparison.

Chemistry of Materials and ACS Materials Letters Prize: Symposium R – Poster. Giovana Collombaro Cardoso. Development and Microstructural Analysis of novel As-Cast Ti-Mo-Nb Alloys for Biomedical Applications.

Langmuir Prize: Symposium T – Poster. Lais Pereira Buranello. Characterization of the corona protein formation inthree different manganese ferrite nanoparticles coatings in vitro and its impacts on the circulation time evaluated by AC Biosusceptometry in vivo

ACS Energy Letters and Energy & Fuels Prize: Symposium A – Oral. Lucas Leão Nascimento. Development of Bi2WO6 photoanodes for selective glycerol photoelectroconversion to formic acid.

ACS Materials Au and ACS Nanoscience Au Prize: Symposium F – Oral. Lucas Scalon. Assessing the donor-acceptor nature and the electrochemical stability of a fluorene-diketopyrrolopyrrole-thiophene based copolymer.

ACS Photonics Prize: Symposium N – Oral. Mariana Monteiro de Lima Forini. Development of lipid nanocarriers labeled with gold nanoparticles and their fate in aquatic plants.

ACS Nano and Nano Letters Prize: Symposium O – Oral. Eloisa Pereira Cardozo. Impact of multiple thermal cycles on Nb-Si multilayers.

JACS Prize: Symposium P – Oral. Daniel da Silva Costa. In situ study of the formation of NiSi2 nanoplates embedded in a Si(001) wafer.

RSC Prizes 

(Sponsored by journals of the Royal Society of Chemistry. Prizes for the best student contributions of all the event)

Symposium D – Poster. Raul Back Campanelli. Superconductivity in Bulk Silicon Crystals.

Symposium P – Poster. Pedro Henrique Fernandes Oliveira. In-situ synchrotron X-ray evaluation on the evolution of dislocation and stacking-fault densities for a Cu-0.7Cr-0.07Zr alloy during cryogenic tensile test.

Symposium V – Poster. Anna Fortunato. Synthesis of metal-triggered hydrogels and their applications in water treatment and food spoilage detection.

Symposium D – Oral. Davi Araujo Dalbuquerque Chaves. Influence of heat treatments on microstructural and superconducting properties of YBCO nanowires prepared by Solution Blow Spinning.

Symposium R – Oral. Igor Lebedenco Kitagawa. Titanium-Based Alloy Surface Modification with TiO2 and Poly(Sodium 4-Styrenesulfonate) Multilayers for Dental Implant.

Symposium T – Oral. André Luís Lira. Effects of ultrasmall nanoparticles on blood clotting enzymes.

B-MRS Newsletter. Year 8, issue 6.


 

B-MRS Newsletter. Year 8, issue 5.

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20Anos_260px

Newsletter of the
Brazilian Materials
Research Society

Year 8, issue 6. July 7, 2021.

20 years of the Brazilian Materials Research Society

On June 26, 2001, B-MRS was created by a group of physicists, chemists and engineers who pursued the interaction among knowledge areas; among basic, applied and technological research; between national and international community. It was in this spirit that the B-MRS and its annual meetings were born. Know more about the creation of B-MRS, here.

Featured paper

A group from UNESP and collaborators from Portugal developed a coating capable of providing corrosion protection to alloys used in aerospace applications. Consisting of a biobased polymer and zinc microparticles, the coating recovers spontaneously after being scratched. The article was published in Chemical Engineering Journal. Know more.

artigo_news

Papers suggested by the community

Lithium disilicate glass produced at high pressure: Characterization of structural, thermal and mechanical properties. Leonardo Resende, Naira M. Balzaretti, Altair S. Pereira, Marcos A. Z. Vasconcellos, Silvio Buchner. Journal of the American Ceramic Society. https://doi.org/10.1111/jace.1770

Using high pressure, researchers from UFRGS and UFR propose an alternative route for the production of high-density vitreous systems.

Would you like to suggest for dissemination articles of your authorship, of high impact and made in Brazil? Send the reference and a sentence about the paper to comunicacao@sbpmat.org.br.

News from B-MRS members

At the invitation of Materials Horizons, Prof Aldo Zarbin (UFPR) wrote a review article on the liquid/liquid interfacial route – a simple and low-cost technique developed in his research group that allows to synthesize, process and modify thin films of all materials. The researcher spoke about the possibilities of this technique “made in Brazil” and the history of its development. See the interview.

socio_news

Prof Mônica Cotta (UNICAMP), president of B-MRS, was named committee member for the VinFuture Prize, an international award dedicated to research and innovations with major impact on the quality of human life and sustainable development. Know more.

monica_news

XIX B-MRS Meeting + IUMRS ICEM 2021 (virtual)

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– Program. The event’s general program is already on the website! Go to program.

– Guidelines for presenters. Instructions for oral and poster presentations, as well as general guidelines for the virtual event, are available. See here.

Awards for undergraduate and graduate students. The Bernhard Gross Awards, from B-MRS, will distinguish the best poster and best oral presentation of each symposium. The American Chemical Society’s ACS Publications Prizes will award cash prizes to the best works from the event. The RSC Award, from the Royal Society of Chemistry, will award the top 6 posters with vouchers to purchase books. Submission of extended abstracts to participate in the awards can be made after abstract approval, until July 19th. Know more.

Plenary and memorial lectures. Paula Vilarinho (University of Aveiro) and Sergio Rezende (UFPE) join the event plenary speakers. Ten world-renowned scientists will speak on bioinspired materials, characterization of materials with high degree of structural disorder, superconductors, microfluidic technologies, bioelectronics, inverse design, organic semiconductors, plasmonic nanocomposites and spintronics. See names and bios, titles and abstracts on the website home page.

Other activities. In addition to the symposium and plenary sessions, the event will feature workshops and discussion panels on writing and presenting scientific papers; under-representation of gender, race and geographic distribution in science; perovskites and photovoltaic industry. Know more.

– Registration. Early registration discount is available until July 30th. Check the fees, here.

– Support and sponsorship. This virtual edition of the event offers several possibilities for companies and entities interested in connecting with the community and exhibiting their products and services. Interested parties can contact Alexandre Alves at comercial@sbpmat.org.br.

Event website: https://www.sbpmat.org.br/19encontro/

Opportunities

– The Brazilian Nanotechnology National Laboratory (LNNano) offers one position as Researcher for highly-motivated and experienced candidates to lead cutting-edge experimental research on Nanoelectronics. Know more.

Reading tips from Brazil

– UNESP researchers propose a method to magnetize paramagnetic material without applying an external magnetic field (Scientific Reports). Know more.

– A team with the participation of researchers from UFABC develops suture threads capable of releasing anti-inflammatory drugs in a controlled manner over time. The work was awarded the best paper of the year by the Journal of Drug Delivery Science and Technology. Know more.

– UFG researchers develop a magnetic nanoparticle capable of generating and monitoring heat in thermal therapies for localized cancer treatment (ACS Applied Nano Materials). Know more.

– Researchers at IQSC-USP develop a computational method to select promising two-dimensional materials for high-performance solar cells and screen 72 transition metal dichalcogenides (ACS Applied Energy Materials).  Know more.

Events

– VIRTUAL. International Conference on Materials for Humanity (MH 21). July 6 – 9, 2021. Site.

WEBINAR: Electrochemistry at the Nanoscale: Application to Materials for Energy Storage. Speaker: Patrice Simon (Université Paul Sabatier). Organization: CINE. July 9, 2021. Site.

– VIRTUAL. XIX B-MRS Meeting (Encontro da SBPMat) + IUMRS ICEM (International Conference on Electronic Materials). August 30 – September 3, 2021. Site.

– 7th International Polysaccharide Conference (EPNOE 2021). Nantes (France). October 11 – 15, 2021. Site.

– VIRTUAL. II Workshop Internacional da Pós Graduação em Engenharia Física da UFRPE. October 19 – 20, 2021. Site.

– 7th Meeting on Self Assembly Structures in Solution and at Interfaces. Bento Gonçalves, RS (Brazil). November 3 – 5, 2021. Site.

– 4th Workshop on Coated Tools & Multifunctional Thin Films. Campinas, SP (Brazil). March 29 – April 1, 2022. Site.

– XVIII International Small Angle Scattering Conference.Campinas, SP (Brazil). September 11 – 16, 2022. Site.

– 11th International Conference of the African Materials Research Society (AMRS2022 ). Dakar (Senegal). December 12 – 15, 2022. Site.

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B-MRS Newsletter. Year 8, issue 5.


 

logo header 400

Newsletter of the
Brazilian Materials
Research Society

Year 8, issue 4. June 10, 2021.

Featured Paper

A team of Brazilian researchers produced nanocomposites of graphene oxide and ultra-small quantum dots whose electrical response can be easily adjusted. This discovery opens possibilities for the development of more sensitive devices in the energy and health field. The study was reported in The Journal of Physical Chemistry C. Saiba mais.

imagem news

XIX B-MRS Meeting + IUMRS ICEM 2021 (virtual)

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– Submissions. The XIX B-MRS Meeting received more than 1,100 abstracts from 31 countries in the Americas, Europe, Asia and Africa, as well as from all regions of Brazil!

– Important dates. Revised abstracts may be resubmitted until June 21st. Final notification to these authors will be sent by June 28th.

– Symposia. See list, here.

– Guidelines for presenters. Instructions for oral and poster presentations, as well as general guidelines for the virtual event, are now available. See here.

Awards for undergraduate and graduate students. The Bernhard Gross Awards, from B-MRS, will distinguish the best poster and best oral presentation of each symposium. The American Chemical Society’s ACS Publications Prizes will award cash prizes to the best works from the event. The RSC Award, from the Royal Society of Chemistry, will award the top 6 posters with vouchers to purchase books. Submission of extended abstracts to participate in the awards can be made after abstract approval, until July 19th. Know more.

– Plenary and memorial lectures. Eight world-renowned scientists will speak on bioinspired materials, characterization of materials with high degree of structural disorder, superconductors, microfluidic technologies, bioelectronics, inverse design, organic semiconductors and plasmonic nanocomposites. See names and bios, titles and abstracts on the website´s home page.

– Other activities. In addition to the symposium and plenary sessions, the event will feature workshops and discussion panels on writing and presenting scientific papers; under-representation of gender, race and geographic distribution in science; perovskites and photovoltaic industry. Know more.

Registration. Early registration discount is available until July 30th. Check the fees, here.

– Support and sponsorship. This virtual edition of the event offers several possibilities for companies and entities interested in connecting with the community and exhibiting their products and services. Interested parties can contact Alexandre Alves at comercial@sbpmat.org.br.

Event website: https://www.sbpmat.org.br/19encontro/

News from B-MRS Members

Professor Hellmut Eckert (IFSC-USP), B-MRS member, was honored in early May with a special issue of The Journal of Physical Chemistry C, which pays tribute to his scientific work in the area of nuclear magnetic resonance applied to materials. Know more.

Eckert

Note of Condolences

B-MRS expresses deep regret for the death of Sérgio Mascarenhas Oliveira, retired Professor at the University of São Paulo (USP). Mascarenhas passed away on May 31, at the age of 93. In 2012, B-MRS honored him with the “Memorial Lecture Joaquim da Costa Ribeiro” for his impact on the Brazilian Materials research community. At this moment, the B-MRS Board would like to remember him as a great scientist who encouraged new talents and believed in collaborative work and in the entrepreneurial and creative capacity of the Brazilian people.

To know more about Prof Sergio Mascarenhas, read the text written by Prof Roberto Mendonça Faria (IFSC-USP), former B-MRS president of B-MRS.

Advocacy

– B-MRS subscribed the letter to the Minister of Science, Technology and Innovations, requesting a series of measures for the release of FNDCT resources.

– B-MRS and dozens of entities endorsed a letter to Paulo Guedes, Minister of Economy, requesting information on the additional R$ 5 billion to the budget that, according to him, were received by the Ministry of Science, Technology and Innovations.

– B-MRS was present at the Forum of Scientific Societies Affiliated to SBPC, which brought together, virtually, the representatives of 120 scientific societies to discuss actions and strategies for 2021. President Mônica Cotta and scientific director Andrea de Camargo represented B-MRS.

Reading Tips

– Scientists synthesize, for the first time, two-dimensional biphenylene sheets, a flat network of carbon atoms with electronic properties that are different from graphene properties (Science). Know more.

– Scientists break a resolution record in the visualization of atoms by solving limitations of a technique developed in 2018. The solution allows to locate individual atoms in the 3 dimensions of a sample (Science). Know more.

– Materials against water scarcity: Scientists create hydrogel microstructures inspired by the shape of cactus spines, which collect water from the air 24 hours a day (Nature Communications). Know more.

– Scientists are able to “turn on” and “turn off” the antiferromagnetism of a material, opening possibilities for the development of faster, more compact and safer memories than the current ones for data storage (Physical Review Letters). Know more.

– The United Nations General Assembly announced that 2022 will be the International Year of Glass. The initiative celebrates the social, technological, scientific, economic and artistic importance of this material. Know more.

Events

VIRTUAL. 4th International Conference on Applied Surface Science. June 29 – 30, 2021. Site.

– VIRTUAL. International Conference on Materials for Humanity (MH 21). July 6 – 9, 2021. Site.

VIRTUAL. XIX B-MRS Meeting (Encontro da SBPMat) + IUMRS ICEM (International Conference on Electronic Materials). August 30 – September 3, 2021. Site.

– 7th International Polysaccharide Conference (EPNOE 2021). Nantes (France). October, 11 – 15, 2021. Site.

7th Meeting on Self Assembly Structures in Solution and at Interfaces. Bento Gonçalves, RS (Brazil). November 3 – 5, 2021. Site.

4th Workshop on Coated Tools & Multifunctional Thin Films. Campinas, SP (Brazil). March 29 – April 1, 2022. Site.

XVIII International Small Angle Scattering Conference. Campinas, SP (Brazil). September 11 – 16, 2022. Site.

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Sergio Mascarenhas de Oliveira (1928 – 2021).


[Text by Professor Roberto Mendonça Faria (IFSC-USP), former president of B-MRS.]

Prof Sergio Mascarenhas in 2012.
Prof Sergio Mascarenhas in 2012.

The Brazilian Materials Research Society (B-MRS) invited me to write about an event that no one would like to read: the demise of professor and scientist Sérgio Mascarenhas de Oliveira.

Sérgio Mascarenhas was born on May 2, 1928 in the city of Rio de Janeiro, where he graduated in chemistry from the National Faculty of Philosophy, University of Brazil, in 1951, and in physics from the University of Rio de Janeiro, in 1952.

In 1956, he, together with his wife, Professor Yvonne Primerano Mascarenhas, decided to face the great challenge of introducing research far from the big centers, such as São Paulo and Rio de Janeiro. They began their brilliant careers as professors and scientists in São Carlos, at the São Carlos School of Engineering – the University of São Paulo. With competency and hard work, Professor Mascarenhas created the first laboratories in the area of Condensed Matter Physics, an important segment of Materials Science, following the knowledge he brought from Rio de Janeiro, where he worked with the masters Joaquim Costa Ribeiro and Armando Dias Tavares, under the inspiration of Professor Bernhard Gross.

He created the Institute of Physics and Chemistry of São Carlos (where he was professor emeritus), the Embrapa Instrumentation (CNPDIA) unit in São Carlos, and was one of those responsible for founding the Federal University of São Carlos. He was visiting professor at the Universities of Princeton, Harvard, MIT (USA), the National Autonomous University and the Center for Advanced Studies (Mexico), the Institute of Physical and Chemical Research (Japan), the London University (England), the International Center for Theoretical Physics of Trieste and University of Rome (Italy). He was director of the Adib Jatene Research Foundation (Institute of Cardiology Dante Pazzanese SP), he also coordinated projects at the Institute of Advanced Studies at USP, and was a member of the Brazilian Academy of Sciences and the Academy of Sciences of the State of São Paulo. Professor Mascarenhas was decorated CNPq Researcher Emeritus, and received numerous awards: Commander of the National Order of Scientific Merit of the Presidency of the Republic, Guggenheim Award (USA), Fulbright Award (USA), Yamada Foundation Award (Japan), the National Order of Scientific Merit award – Grand Cross, among other honorary distinctions.

Professor Mascarenhas leaves a legion of students and former students who continue his work supporting the scientific development of Brazil.

Prof. Roberto Mendonça Faria.

Sergio Mascarenhas Oliveira: note of condolences.


B-MRS expresses deep regret for the death of Sérgio Mascarenhas Oliveira.

He was professor (retired) at the University of São Paulo (USP), and passed away on May 31, at the age of 93.

In 2012, B-MRS honored him with the “Memorial Lecture Joaquim da Costa Ribeiro” for his impact on the Brazilian Materials research community.

At this moment, the B-MRS Board would like to remember him as a great scientist who encouraged new talents and believed in collaborative work and in the entrepreneurial and creative capacity of the Brazilian people.

Featured paper. Synergy between graphene oxide and quantum dots for more sensitive devices.


Nowadays, new functional materials of very small dimensions are welcome to face the interest in increasingly smaller and better performing devices. Even more so if their properties can be refined to meet the needs of each application.

A Brazilian scientific team developed a nanocomposite consisting of two-dimensional sheets of reduced graphene oxide (rGO) and ultra-small quantum dots, and found a way to adjust its electrical and optical properties, taking advantage of the synergy between both components. The discovery brings possibilities for using this nanomaterial in the development of more sensitive devices with new features, for areas like energy and health.

“With the surprising and innovative results of this work, the development of new nanocomposites emerges, aimed at training human resources and with wide applicability of the technology,” says Professor Noelio Oliveira Dantas (UFAL and UFU), corresponding author of the article who reports the finding in The Journal of Physical Chemistry C.

From Minas to Alagoas

The research began in 2016 in the Brasilian state of Minas Gerais, at the Federal University of Uberlândia (UFU), within the PhD of Rosinildo Fideles do Nascimento, under the guidance of professors Noelio Dantas and Anielle Christine Almeida Silva, researchers with vast experience in new nanostructured materials, including relevant contributions to the synthesis of quantum dots.

At the Institute of Physics of UFU, more precisely at the Laboratory of New Insulating and Semiconductor Materials, reduced graphene oxide (a graphene derivative that has been widely used in and outside academia) and ultra-small quantum dots (particles of less than 5 nm with unique optical and electronic properties, due to the quantum phenomena that occur at this dimensional scale) were synthesized and characterized. A good conductor of electricity, reduced graphene oxide, however, does not have a semiconductor behavior. On the other hand, the large surface area of two-dimensional sheets of rGO can homogeneously accommodate good amounts of semiconductor particles, such as quantum dots.

But going back to the history of this work, the researchers prepared quantum dots composed of a core of cadmium selenide (CdSe) of about 1.5 nm and a shell of cadmium sulfide (CdS) of less than 1 nm. The next step was carried out in Alagoas. In fact, in 2018, professors Noelio and Anielle were transferred to the federal university of that state, UFAL, where they created the Laboratory of New Nanostructured and Functional Materials. At UFAL, Rosinildo and his advisors used the nanomaterials prepared there to develop the nanocomposite.

In order to investigate the effect of the concentration of quantum dots on the optical and electrical properties of the nanocomposite, they produced and characterized four versions of the material, each with a specific proportion of rGO and quantum dots. The nanocomposites were obtained using a method that activates groups of atoms that are present in rGO (carboxyls) and predisposes them to interact with groups in the shells of quantum dots (hydroxyls). At the end of the process, the two components are strongly bonded through the sharing of pairs of electrons (covalent bond), forming the nanocomposite.

On the left, the figure represents the structure of the nanocomposite, with the ultra-small quantum dots (in yellow and red) interspersed in the structure of reduced graphene oxide (blue). On the right, the graphs showing the electrical response of the samples.
On the left, the figure represents the structure of the nanocomposite, with the ultra-small quantum dots (in yellow and red) interspersed in the structure of reduced graphene oxide (blue). On the right, the graphs showing the electrical response of the samples.

Synergy between nanomaterials

After synthesizing the materials, the researchers used the infrastructure available at three laboratories of the Institute of Physics at UFAL to experimentally investigate the influence of the concentration of quantum dots on the properties of the nanocomposites. This part of the work involved the collaboration of professors, doctoral students and a postdoc from four university research groups.

Based on the results of this collaborative study, Rosinildo and his advisors confirmed that, in the nanocomposite, quantum dots transfer charge carriers (electrons and holes) to the rGO. However, the main contribution of the study was to demonstrate that the rate of this transfer of charge carriers can be adjusted by increasing or decreasing the concentration of quantum dots in the material.

“With the appropriate concentration of quantum dots, we have a greater electrical response of the nanocomposite, enabling to develop new, more sensitive and functional devices,” highlights Professor Anielle Christine Almeida Silva, who is also corresponding author of the paper.

Applications

By illuminating the nanocomposite with a suitable radiation, the quantum dots absorb light, which excites and mobilizes their charge carriers, which are transferred to the rGO. The effect stops when the light is removed. With these characteristics, one of the most distinct applications of the nanocomposite is in quantum dot solar cells. In these devices, which are still experimental but whose efficiency has increased yearly, quantum dots that absorb radiation in the solar light range are used. The high transfer of loads to the rGO is, in this case, a differential.

However, other uses are also promising. Professors Noelio Dantas and Anielle Christine Almeida Silva count on the collaboration of researchers specialized in the development of sensors and biomedical applications. “We are concluding new works that demonstrate the excellent potential of these nanocomposites in improving the electrical response in sensors, as well as their biocompatibility and the development of new theranostic tools,” reveals professor Anielle Christine Almeida Silva. Theranostic platforms are systems, usually nanometric, capable of diagnosing, treating and monitoring health problems.

“The use of these nanocomposites is enormous, from technological applications (solar energy, sensors) to nanobiotechnological applications (biological sensors, theranostic tools),” says Professor Noelio Dantas. According to this researcher “Brazil needs to invest in research that directly contributes to the development of technology, as well as creating programs that bring together and encourage partnerships between companies and researchers.”

Main authors of the paper. From the left: Noelio Dantas, Anielle Almeida and Rosinildo do Nascimento.
Main authors of the paper. From the left: Noelio Dantas, Anielle Almeida and Rosinildo do Nascimento.

Paper: Tuning the Optical and Electrical Properties of rGO-CdSe/CdS Ultrasmall Quantum Dot Nanocomposites. Rosinildo Fideles do Nascimento, Anielle Christine Almeida Silva, Tasso O. Sales, Artur F. Sonsin, Eduardo Jorge da Silva Fonseca, Samuel T. Souza, Ygor M. de Oliveira, Fabiane C. de Abreu, and Noelio Oliveira Dantas. The Journal of Physical Chemistry C 2021 125 (12), 6805-6811. https://doi.org/10.1021/acs.jpcc.0c09813

Contacts: Profa Anielle Christine Almeida Silva – acalmeida@fis.ufal.br. Prof. Noelio Oliveira Dantas – noelio@fis.ufal.br.


B-MRS Member is honored with a special edition in a prestigious scientific journal.


Prof Hellmut Eckert
Prof Hellmut Eckert

Professor Hellmut Eckert, a member at B-MRS, was honored in early May with a special issue of The Journal of Physical Chemistry C (ACS Publications) which pays tribute to his scientific work in the area of nuclear magnetic resonance applied to materials. Over more than four decades of work, this scientist has produced more than 500 articles published in international peer-reviewed journals.

The edition brings together 53 papers by authors from various institutions around the world in the field of magnetic resonance, in addition to a tribute from the guest editors and an autobiography.

Hellmut Eckert is currently professor in USP, at the São Carlos Institute of Physics (IFSC-USP, Brazil) and a collaborator at the Westfälische Wilhelms Universität Münster (WWU Münster, Germany).

See the special virtual edition: https://pubs.acs.org/page/jpccck/vsi/eckert-festschrift.