Featured paper: New ozone sensor based on nanorods of silver tungstate.

The scientific paper by members of the Brazilian community on Materials research featured this month is:

Luís F. da Silva, Ariadne C. Catto, Waldir Avansi, Laécio S. Cavalcante, Juan Andrés,  Khalifa Aguir, Valmor R. Mastelaro and Elson Longo. A novel ozone gas sensor based on one-dimensional (1D) α-Ag2WO4 nanostructures. Nanoscale (Print), 2014, v. 1, p. 1-2. DOI: 10.1039/C3NR05837A

New ozone sensor based on nanorods of silver tungstate

A study carried out by a research group from Brazil, with collaboration from French and Spanish scientists, has reported, for the first time, gas detection properties in nanorods of silver tungstate in its alpha phase (α-Ag2WO4).The study showed that this material can be applied as a resistive sensor, displaying great performance when detecting ozone (O3). The work was and coordinated by Elson Longo, Professor at the São Paulo State University “Júlio de Mesquita Filho” (UNESP).

Resistive gas sensors are basically built from a material capable of changing its electrical properties when molecules of a certain gas are adsorbed in its surface. In the specific case of the silver tungstate, when it is submitted to an oxidant gas such as ozone, there is an increase in its electrical resistance that is proportional to the presence and concentration of the gas.

SEM image of the nanorods inside a diagram showing the sensor performance.

In this work, the Brazilian scientists synthesized nanorods of silver tungstate and assembled a sensor based on such nanoparticles. They had put the sensor in a temperature controlled test chamber, exposed it to different concentrations of ozone gas, from 80 to 930 parts per billion (ppb), and evaluated its capacity to detect the ozone.

Present in high atmospheric layers, the ozone plays an important role protecting living beings by absorbing the solar ultraviolet radiation. The ozone is also used by people in several applications, such as, for example, cleaning water. However, the exposition to the gas in certain concentrations may lead to health issues as headache, burning and irritation in the eyes, and respiratory system problems. The World Health Organization (WHO) recommends avoiding the exposure to ozone gas above 120 ppb.

“Subjecting the compound to low amounts of ozone, we observed a fast response, as well as a very short recovering time, making its properties comparable or even better than traditional sensors as tin dioxide (SnO2), tungsten trioxide (WO3), and indium oxide (In2O3),” says Luís Fernando da Silva, first author of the article and postdoctoral fellow of the São Paulo Research Foundation (Fapesp) at UNESP’s Chemistry Institute of Araraquara.

The results were published online in the peer reviewed journal Nanoscale in the end of January this year.

Background of the paper 

The studies with silver tungstate started in the postdoctoral research of Laécio Cavalcante, currently a Professor at Piauí State University (UESPI). Cavalcante synthesized nanorods of silver tungstate using microwave-assisted hydrothermal technique (process that was also used in the synthesis of nanorods from the paper published by Nanoscale). Performing electronic microscopic analysis with the microscope of the Chemistry Institute of Araraquara, the group of scientists coordinated by Professor Longo noticed that the interaction of the electron beam with the material was stimulating the growth of metallic silver particles on the surface of the nanorods. The result of this paper led to an article published in April last year by Scientific Reports (DOI: 10.1038/srep01676).

“Since then, Professor Elson Longo has researched and encouraged the investigation of the potentiality of the α-Ag2WO4 compound”, comments Luís Fernando da Silva. Longo, his team and partners have already observed that the material holds bactericidal (J. Phys. Chem. A, 2014; Doi:10.1021/jp410564p), photoluminescent (J. Phys. Chem. C, 2014, DOI: 10.1021/jp408167v), and photocatalytic properties, with a series of possible applications.

“Based on these potential applications”, Luís Fernando da Silva adds, “I, Professor Waltir Avansi Junior from the Physics Department of the Federal University of São Carlos (UFSCar), jointly with Professor Valmor Mastelaro from the São Carlos Physics Institute of São Paulo University (USP) and his PhD student, Ariadne Catto, started investigating about the detection properties of the non-irradiated α-Ag2WO4 compound (without nanoparticles of metallic silver)”. During the experiments, Silva says, the team noticed that the material was sensitive to detect ethanol and acetone steam and, ultimately, ozone gas, even in low amounts. Assisted by Professors Khalifa Aguir from Université Aix-Marseille (Marseille, France), and Juan Andrés, from Universitat Jaume I (Castelló, Spain), they prepared the communication published by Nanoscale, a renowned journal in the nanotechnology field.

The studies concerning silver tungstate performed by the team of Professor Longo might not end there. According to Luís Fernando da Silva, the team will assess the capacities of the material to detect other gases. In addition to that, returning to the silver tungstate nanorods with nanoparticles of metallic silver, the scientists are going to study the effects of electron irradiation on the gas detection capacity of the material.

“This paper contributes to the discovering of new materials applied as gas sensors”, states the postdoctoral fellow. “However, complementary examinations are necessary in order to achieve a deeper comprehension of the mechanisms involved in the detection, adsorption and desorption processes of the gas(es)”, he concludes.

Processo seletivo para bolsa de pós-doutorado na UFSC.

Programa de Pós-Graduação em Física da Universidade Federal de Santa Catarina (UFSC-Florianópolis) anuncia a disponibilidade de uma (1) bolsa de pós-doutorado PNPD/CAPES, com duração até janeiro de 2015, com mensalidade 4.100 reais e valor de custeio anual de 12 mil reais.

O pós-doutorando deve atuar em linhas de pesquisa TEÓRICAS ou EXPERIMENTAIS em uma das seguintes áreas: Astrofísica, Física Atômica e Molecular, Física da Matéria Condensada e Mecânica Estatística, Física Nuclear e de Hádrons, Física de Partículas e Campos.

Mais informações:

Informações sobre o projeto e linhas de pesquisa.

Edital CAPES- PNPD institucional.

Inscrições:

O candidato deverá enviar e-mail para Esta imagem contém um endereço de e-mail. É uma imagem de modo que spam não pode colher., com os seguintes documentos*:

1) Curriculum Vitae Lattes atualizado;

2) Descrição de interesses científicos, incluindo projeto de pesquisa para o período (abril/2014 a janeiro/2015) com no máximo 10 páginas;

3) Nome e e-mail de duas pessoas para eventuais cartas de recomendação.

*Toda documentação deve ser enviada em um único e-mail. Os documentos 1 e 2 devem ser anexados ao e-mail, ambos em formato pdf.

Período de inscrições: 14/03/2014 a 28/03/2014

Divulgação do Resultado: até o dia 03 de abril de 2014.

 Critérios para seleção:

Os candidatos terão sua documentação avaliada pelos seguintes quesitos:

– Potencial e domínio do candidato em sua área de pesquisa;
– Diversidade de sua formação;
– Qualidade e quantidade de sua produção intelectual;
– Autonomia e maturidade científica;
– Potencialidade de interação efetiva com os grupos de pesquisa do Programa.

Requisitos do candidato à bolsa (item 4.4 do Edital da CAPES)

O candidato indicado para recebimento da bolsa do PNPD deverá atender aos seguintes requisitos:

a)   ser brasileiro ou possuir visto permanente no País. No caso de candidato estrangeiro, este deverá estar, no momento da implementação da bolsa, em situação regular no País;
b)    estar em dia com as obrigações eleitorais;
c)    possuir em seu currículo Lattes qualificações que demonstrem capacitação suficiente para desenvolver o projeto;
d)    não ser beneficiário de outra bolsa de qualquer natureza;
e)    dedicar-se integralmente e exclusivamente às atividades do projeto;
f)     não ter vínculo empregatício (celetista ou estatutário);
g)    não ser aposentado ou encontrar-se em situação equiparada;
h)    estar apto a iniciar as atividades relativas ao projeto tão logo seja aprovada a sua candidatura pela respectiva agência;
i)   ter obtido o título de doutor há, no máximo, 5 (cinco) anos,quando da implementação da bolsa, estando de posse do seu diploma. Em caso de diploma obtido em instituição estrangeira, este deverá possuir o reconhecimento de validação, conforme dispositivo legal;
j)     ter seu currículo atualizado e disponível na Plataforma Lattes.

Science without Borders Postdoctoral Fellowship for NREL-USA in Perovskite or Organic semiconductors.

The National Renewable Energy Laboratory (NREL), located at the foothills of the Rocky Mountains in Golden, Colorado is the U.S. primary laboratory for research and development of renewable energy and energy efficiency technologies.

The Science without Borders is a large scale nationwide scholarship program primarily funded by the Brazilian federal government. The program seeks to strengthen and expand the initiatives of science and technology, innovation and competitiveness through international mobility of undergraduate and graduate students and researchers.

We would like to offer the opportunity for outstanding Postdoctoral Researchers to come to NREL through the Brazil-US Consortium for Innovation in Energy Materials (CINEMA) initiative under the Brazilian Science Without Borders program to develop research activities within NREL’s Chemical Sciences and Nanoscience Division in the area of Perovskites and Organic semiconductors.

1) Our current research activities on perovskite-based PVs focuses on (a) solution processing of halide perovskites, (b) fabrication of planar and mesostructured perovskite cells, and (c) fundamental understanding of charge transport and recombination. Our objective is to understand material effects on the basic physical and chemical processes that are important to device operations. The insight learned from the basic studies will be used as guide to control material properties and to develop more effective device architectures. Examples of our recent publications on perovskites include [1] J. Phys. Chem. Lett., 5, 490–494 (2014); [2] Chem. Commun., 50, 1605–1607 (2014); [3] J. Phys. Chem. Lett., 4, 2880–2884 (2013).

2) Fundamental research topics of particular interest for organic semiconductors include the structural characterization of organic materials in the solid state by X-ray or Neutron scattering methods, transient photoconductivity for the study of photoinduced charge generation and decay dynamics in novel donor:acceptor materials and device-based methods for charge mobility and recombination studies. As to more applied device level research, we are also interested in developing novel electrical contact architectures for upscaling OPV devices. Some of our relevant publications in organic semiconductors and devices include [1] ChemPhysChem (2014), accepted. DOI: 10.1002/cphc.201301022; [2] Adv. Funct. Mater., 22 (2012) 4115; [3] Macromolecules 46 (2013) 1350; [4] Organic Electronics 12 (2011) 108.

Postdoctoral candidates from Brazil willing to develop research activities in areas relevant to the projects above are strongly encouraged to apply. Candidates will be expected to communicate their results through journal publications and conference presentations. In general, to be considered, candidates should have a demonstrated track record of success in addressing fundamental science questions and devising solutions to challenging problems, a Ph.D degree in related field and a strong record of publications/presentations will be a plus.

Send inquires to alexandre.nardes@nrel.gov and to apply, please, send CV along with a list of publications, and the names of at least three professional references to the same e-mail address (subject: “PostDoc Brazil”). Note deadlines for applications at http://www.cienciasemfronteiras.gov.br

SBPMat e-newsletter – year 1 – issue 2

 

Brazilian Materials Research Society (SBPMat) newsletter

News update from Brazil for the Materials community

 

English edition. Year 1, issue 2.

Greetings, .

SBPMat’s news

XIII SBPMat meeting:

João Pessoa, September 28th, to October 2nd.

  • Abstracts submission deadline: May 23rd. There are 18 symposia this year in which you can submit your papers.
  • Plenary talks: Five lecturers have confirmed presence.
  • Bernhard Gross Award: for best papers presented by students at the simposia (posters and oral presentations).
  • Memorial Lecture Joaquim Costa Ribeiro: Professor José Arana Varela will be honored this year.

Visit the website of the XIII SBPMat Meeting! (English version coming soon)

New SBPMat Board of Directors.

  • There was ceremony to empower the new board of directors and counselors, as well as the first meeting of the team. Learn more.
  • Get to know the new members and their roles. Here.

Featured paper with Brazilian participation

A team of three scientists managed to identify defects of atomic dimensions which exist in thin films of zinc oxide, through an interesting experiment, using the luminescence capability of this material. Initially, they prepared films with various quantities and types of defects and, systematically, they excited the samples, measured luminescence and related these data with the defects that had been introduced. The experiment was conceived and performed by a Brazilian researcher, using photon-scanning tunneling microscopy in Germany. The results have been published in The Journal of Physical Chemistry Letters. More.

(To suggest papers with Materials focus with Brazilian participation published in high impact journals for this section of our newsletter contact comunicacao@sbpmat.org.br)

History of Materials research in Brazil

We present the second part of the history of CAPES Materials Area, followed by an interview with Professor Carlos Graeff (coordinator of the area from 2009 to 2014) about the evolution of postgraduate courses in Materials in Brazil, the evaluation criteria of their scientific production and challenges for the next years, among other subjects. Here.

SBPMat’s community people

Interviewed due to Bridge Building Award of American Ceramic Society, Professor José Arana Varela has told us how he got to science of Materials and which are his most important contributions to the area of ceramic materials and his main collaborators. Arana Varela also left a message for our readers who are initiating their career. Here.

Reading recommendations

Science journalism stories based on papers published in journals with high impact factor.

  • Scientists use nanoparticle solutions as adhesive to glue gels and biological tissues (based on paper from Nature) Here.
  • Graphene bread sandwich: new technique to prepare biomolecules for electronic microscopy (based on paper from Advanced Materials) Here.
  • Organic Electronics: fastest polymeric transistor is developed. It is transparent and benzothiophene-based (based on paper from Nature Communications) Here.
  • For the first time, nanomotors travel inside living cells (see texts, images and videos) (based on paper from Angewandte Chemie International) Here.

Books, presentations, multimedia material, etc.

  • Review of  the book “Fundamental Principles of Polymeric Materials” – for beginners in polymers science and technology. Here.

Materials news from the Brazilian National Institutes of Science and Technology (INCTs).

  • Thermal nanoimprint lithography developed at Namitec with potential application to photovoltaic panels. Here.
  • From the INCT for Nanotechnology Materials: silver tungstate as ozone gas sensor. Here.
  • Very sensitive hydrogen sensor developed in Namitec is ready to be used. Here.

Upcoming events in the area.

  • VI Curso do Método Rietveld de Refinamento de Estrutura. Here.
  • 10º Encontro Brasileiro sobre Adsorção. Here.
  • 13th International Conference on Modern Materials and Technologies (CIMTEC 2014). Here.
  • 1st International Conference on Polyol Mediated Synthesis. Here.
  • 13th European Vacuum Conference + 7th European Topical Conference on Hard Coatings + 9th Iberian Vacuum Meeting. Here.
  • 19th International Conference on Ion Beam Modification of Materials. Here.
  • XIII Encontro da SBPMat. Here.(Soon, English version of the site)
  • X Brazilian Symposium on Glass and Related Materials (X-BraSGlass). Here.
To suggest news, opportunities, events or reading recommendations items for inclusion in our newsletter, write to comunicacao@sbpmat.org.br.
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Anniversary of CAPES Materials Area. Part 2.

A little more than four months after the creation of CAPES Materials Area, with Professor Lívio Amaral as pro tempore coordinator, in 12 and 13 of June 2008, the first meeting of postgraduate programs of the new field took place in the headquarters of CAPES, Brasilia. Discussions basically involved the presentation of ten programs already linked to CAPES Materials Area (from UCS, UFC, UFPE, UFRGS, UFRN, UFSC, UNESP – Bauru, UNESP – Ilha Solteira, USP-Lorena and USP São Carlos), meetings with some of the directors from CAPES and the presentation of new programs (from FATEC, FEEVALE, UFMT and UFSCar- Sorocaba). Some programs linked to other areas in CAPES (from UFVSF, UFPR and UFS) have also been invited, to assess a possible change of area. At the end of the event, there was a discussion about creating what they called “the document of the Materials Area”.

This document was finalized in the second meeting of postgraduate programs, which took place in the 5th and 6th of March 2009 at Puc-Rio. At this time, the meeting was summoned by Professor Lívio Amaral, together with SBPMat, presided then by Professor Fernando Lázaro Freire Junior. Discussions included presentation of SBPMat and work teams about the creation of the document.

Professor Carlos Graeff, coordinator of the Materials Area at CAPES, lecturing at USP in November, 2013. Photo supplied by Carlos Graeff.

In April 2009, Professor Lívio Amaral left the coordination of the Materials Area to take over as Evaluation Director at CAPES. Regarding the actions performed during his coordination, which lasted a year and two months, Professor Amaral states that theytake this time to essentially identify the postgraduate programs in the field of Materials; from this, they try to consolidate the Materials Area and include it among the other CAPES areas, in a way that could be understood by the community”. On the other hand, Amaral regrets not being able to stimulate, neither in existing programs nor in new initiatives, “the imperious need to have much more research and human resources formation in Biomaterials”, subarea which, according to the Professor, is still very critical in the country. “All you have to do is go to a MRS meeting, either American or European, and it is easy to observe the increasing research in Biomaterials”, demonstrates Amaral.

On August 12th, 2009, CAPES president, Professor Jorge Guimarães, announced through Normative Regulation 097 that Professor Carlos Frederico de Oliveira Graeff had been assigned to fulfill the role of Materials Area coordinator until 2010, concluding the period of three years started by Lívio Amaral. Graeff still remains the coordinator until June 2014, being assigned for the role for three more years.

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APPENDIX 1: About CAPES Materials Area.

The main tasks of CAPES are: evaluate and promote creating of new postgraduate programs; evaluate existing programs applying grades; evaluate scholarships and other financial support requests for students and teaching staff and for scientific events organization. Besides, CAPES coordinators are the most important interface between academic community and CAPES.

The Materials Area at CAPES is composed by a coordinator and two deputy coordinators. The job of the second deputy coordinator has been recently created, around 2013, to follow up in more detail programs of professional masters. Besides, the Evaluation Direction at CAPES has one or more technicians that help in the coordinators with internal procedures and the interface of CAPES with the community.

Coordinators in the area are chosen by the president at CAPES, after consulting post-graduate programs and technical and scientific societies connected to the area.

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Professor Carlos Graeff, coordinator of the Materials Area at CAPES, lecturing at USP in November, 2013. Photo supplied by Carlos Graeff.

APPENDIX 2: Interview with Professor Carlos Graeff, CAPES Materials Area coordinator from 2009 to 2014.

SBPMat Bulletin: – Could you summarize the quantitative and qualitative evolution of postgraduate courses in Materals in Brazil, since the creation of CAPES Materials Area?

Carlos Graeff: – The area was created in 2008 with the adhesion of 10 programs. We are 29 today, that is, we have increased 290% in 6 years. This is quantitative date, but, most importantly, the area has diversified. It is a multidisciplinary area and with new programs, new frontiers of knowledge have been embraced with interfaces related to biological and medical fields, as well as agriculture, to name a few. Besides, another important feature of this evolution was the expansion of covered areas with postgraduate programs, especially in places with no high level education programs in the field, as the Central-west and Northeast Brazilian regions.

SBPMat Bulletin: – What were the main actions and facts  during your coordination?

Carlos Graeff: – The main mark of our administration was transparency. We had a series of meetings with coordinators and, as the area is still relatively small, we could make a serious of decisions collectively, mostly relating to the evaluation of postgraduate programs. Regarding new courses, we always tried to invite new members, specialists, to the evaluation committees, for a fair examination of requests.  This measure also brought improvement of the existing knowledge concerning CAPES role. A recurring issue is related to unawareness of CAPES work; when bringing a representative number of professors to the assessment processes, there is a tendency to strengthen the relationship between the scientific community and CAPES. I hope that this interview can contribute in that sense.

Besides working in this interface with post-graduate programs, I am a full member of Conselho Técnico-Científico da Educação Superior, where I led the work team with the topic “technical products”. There is an increasing demand for stronger interaction between academic society and society in general, that is, for applied research or technological development. In fact, creating the Materials and Biotechnology Areas at CAPES was basically inspired by this approximation. However, to evaluate programs that work with this interface there is a need for tools that might measure and qualify products such as patents, prototypes, etc. Therefore, it is essential that CAPES successful in assessing intellectual production well (in the case of Materials, basically articles in scientific journals) can be extended to technical production. The discussions have been very productive and we hope that soon they will reflect both on the CAPES evaluation process.

SBPMat Bulletin: – Can you comment on the “Qualis” (CAPES system for evaluation of scientific journals) of Materials Area?

Carlos Graeff: – One of the debates in the area was how to generate a Qualis that would attend multidisciplinary. Qualis is a broadly discussed tool in academic community in general, but especially in more dynamic areas of knowledge, considering its role is one of the most important: to qualify main intellectual products generated by postgraduate programs, scientific papers. The most used method uses impact factor. However, impact factor reflects the size and dynamics of different academic communities. For instance, when we compare average impact factors in Engineering with those of Natural Sciences (Physics, Chemistry, and Biology), they are inferior. We do not want to discuss the reasons for this difference which is even more remarkable if, for instance, we enter the realm of humanities. But this difference exists and, therefore, we should take this into consideration in order to avoid distortions in the evaluation process of, for instance, postgraduate research with strong inclination to research in Materials Engineering against Materials Chemistry. Our proposal, therefore, separates journals in big groups: Materials Science, Materials Engineering and correlate areas. By doing this, we try to achieve fairness while comparing papers generated by groups of engineers or physicists that work with Materials. Obviously, our proposal needs some adjustment, but I believe we have taken a step further in this direction.

SBPMat Bulletin: – In your opinion, which are the challenges faced by the area in the next few years?

Carlos Graeff: – Brazil is going through an important time in industry where it suffers with increasingly stronger competition, due to a great opening of our market and the integration with global economy. An important path is the sophistication of our products and processes, and Materials area has a lot to contribute to a stronger and more competitive industry. Nanotechnology is increasingly more emphasized and there are expectations that it might generate a series of new products, which is a fundamental subject of Materials field. Therefore CAPES and SBPMat play an important part in this matter. Actions in this direction are being discussed both at CAPES and SBPMat. Besides great national issues, there is still a lot of room to grow in the area.  There are, for instance, the great and urgent challenges of creating a postgraduate program in the North Brazilian region, the only region with still no offer for Materials courses.

SBPMat Bulletin: – Feel free to add anything else.

Carlos Graeff: – I am honored with the generous invitation from Professor Livio Amaral to conduct the implementation of Materials Area at CAPES. I have learned a lot and I could follow changes that CAPES have been through in the last years, focusing in system improvement. We will soon have significant changes in the assessment process, among them, a new tool to collect and support evaluation called Sucupira Platform. This initiative has been taken with enthusiasm and skillfulness of Professors Amaral and Guimarães. So I would like to end thanking both of them.

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Featured paper: Luminescence measurements to identify defects in zinc oxide thin films.

The scientific paper by members of the Brazilian community in Materials research featured this month is:

Fernando Stavale, Niklas Nilius, and Hans-Joachim Freund. STM Luminescence Spectroscopy of Intrinsic Defects in ZnO(0001̅) Thin Films. J. Phys. Chem. Lett., 2013, 4 (22), pp 3972–3976. DOI: 10.1021/jz401823c.

Luminescence measurements to identify defects in zinc oxide thin films.

Zinc oxide (ZnO) is a very common material in everyday life. It can be found in screws, sunscreen, catalyzer for methanol synthesis and sophisticated optoelectronic devices, such as computer flexible screens, to name just a few. However, in order to enable some promising applications, such as transistors and new devices, it is important to control electrical properties of this semiconductor material, which are related to specific defects in its atomic structure.

Within this context, three scientists from institutions in Germany and Brazil identified specific defects in zinc oxide films through an original approach, taking advantage of luminescence capability (emission of light not resulting from heat) of zinc oxide. Researchers prepared zinc oxide thin films with different types and amounts of specific defects. Systematically, scientists measured luminescence of each film and, thus, they managed to relate peaks on the measurements with various types of defects in crystal nets. The results of this study were published in periodical The Journal of Physical Chemistry Letters (JPCL).

“In this study, we developed extremely high quality thin films of zinc oxide and we altered the amount of specific defects using thermal desorption, photo-desorption induced by laser and reduction by treatment in hydrogen controlled environment” – says Fernando Stavale, researcher for Centro Brasileiro de Pesquisas Físicas (CBPF), who signs the article as main author.

Characterization technique

In order to make the experiments, scientists used a scanning tunneling microscope (STM) in ultra high vacuum with a few peculiarities designed to generate luminescence, collect the emitted photons and obtain the measurements (spectrum) of luminescence. With this configuration, the STM is known as  photon-scanning tunneling microscope. According to Stavale, one of the main scientists in the field of development and application of this technique is Professor Niklas Nilius, correspondent author of the JPCL paper, with whom Stavale has directly worked for three years during his post-doctoral research at  Fritz-Haber Max-Planck Society, in Berlin, specifically at Physico-chemical Department led by Professor Hans-Joachim Freund, last author of the JPCL article. “The photon-scanning tunneling microscope has been employed in unprecedented manner to characterize metallic acids at the department directed by Professor Freund” – says Stavale. “The technique is still underused in Brazil and it is an essential part of the projects I develop with my research team at CBPF, situated in Rio de Janeiro” – he adds.

One of the most important features in photon-scanning tunneling microscopy is the use of electrons which are emitted by the tip of the STM to excite samples and, in the case of zinc oxide, to generate the desired luminescence. This phenomenon of emitting light generated by the impact of electrons over the material is called cathodoluminescence.

Experiment scheme in which the tip of the tunneling microscope can be observed, in the photo, exciting the zinc oxide film. The graph shows a spectrum of the oxide cathodoluminescence. At the back , the tunneling microscopy image of a zinc oxide film, with density of 20 layers (~5 nm) shows monoatomic steps and specific defects in the film’s surface. Vacancies of oxygen and zinc, specific defects, correspond to the areas indicated by arrows. The dark areas with hexagonal shape correspond to the areas where the film is noncontinuous, with depth of up to eight atomic layers.

This systematic work allowed scientists to infer that some peaks of luminescence of zinc oxide are due to defects such as vacancies of oxygen and zinc (dots in the lattice containing “vacancies”, instead of the expected oxygen and zinc atoms). “These specific defects are related to electrical properties often observed in zinc oxide, known as n-type doping” – Stavale adds.

The context of the work

The experiments of the JPCL article were conceived and conducted by Brazilian national Fernando Stavale in 2012, during his last year of post-doctoratal research with the group led by Professor Nilius, at Fritz-Haber of Max-Planck Society. Stavale joined the group in 2010 with financial support from Humboldt Institute in Germany. “For three years we have investigated for the first time the role of several dopants, such as chromium, europium and lithium in zinc and magnesium oxides, combined with ultra-thin films, raised in ultra-high vacuum with tunneling microscopy and local cathodoluminescence” – says Stavale about his post-doctoral studies.

The interpretation of results and the JPCL article redaction were performed in 2013 when Fernando Stavale became a CBPF researcher and Niklas Nilius became a Professor at University of Oldenburg, Germany.

Interview with Professor Jose Arana Varela, honored with the Bridge Building Award from American Ceramic Society.

Professor Arana Varela (to the left) receiving the award. Photo by American Ceramic Society.

On the last January 27th, in Daytona Beach (Florida, United States), during the 38th edition of International Conference and Exposition on Advanced Ceramics and Composites, the Bridge Building Award of the American Ceramic Society was given to a Brazilian for the first time, Professor José AranaVarela, president of our SBPMat from 2010 to 2011. The honor annually distinguishes people from outside the United States who have notably contributed to the field of engineering ceramics.

Graduated in Physics from University of São Paulo in 1968, Arana Varela also has a Master’s Degree in Physics for the Instituto Tecnológico de Aeronáutica (ITA), becoming a Master in 1975. He took his PhD from 1977 to 1981 at University of Washington (United States), conducting research in the field of ceramic materials.

Currently, Arana Varela is Full Professor at Universidade Estadual Paulista Julio de Mesquita Filho (UNESP) and president-director of the executive board of São Paulo Research Foundation (Fapesp), as well as member of the council for competitivity and innovation at São Paulo Federation of Industries (FIESP). Professor Arana Varela is also full member of the Brazilian Academy of Sciences (ABC), among other associations, and member of the editorial body for the journals Ceramics International, Science of Sintering, Cerâmica and Materials Research. Besides, he coordinates the innovation division at the Multidisciplinary Center for Development of Ceramic Materials.

His scientific papers gather over 6,500 citations. In the last 13 years, he has been the author of more than 500 articles, published in international journals. Up to this moment, he has advised and co-advised assignments for over 30 masters and over 40 doctoral theses.

Throughout his career, he has received more than 20 awards from organizations such as American Ceramic Society, Sociedad Española de Cerámica y Vidrio, CNPq, Associação Brasileira de Metalurgia e Materiais and Associação Brasileira de Cerâmica.

A brief interview with the researcher can be seen below:

SBPMat Bulletin: – Tell us a little bit about your story: which were the opportunities and choices that led you to become a researcher in the field of ceramic materials?

José Arana Varela: – Our choice of being a scientist in mateirals started during the Master’s at ITA, in  1972. During this period (in 1975), I met Professor O. J. Whittemore from the University of Washington, Seattle, during his visit to Universidade Federal de São Carlos for a year. As my master’s research was related to a physico-chemical view of thermal decomposition of talcum, which is a ceramic material, Professor Whittemore became interested in it and made some remarks regarding ceramic processing (his specialty). Thence the invitation for a doctorate in Seattle (from 1977 to 1981).

SBPMat Bulletin: – In your own analysis, which were your main contributions to the science and technology of materials? Specifically, can you comment on your main contributions to the field of engineering ceramics, the focus of Bridge Building Award?

José Arana Varela: — As the main theme of our doctoral theses was related to sintering models, we performed a simple study about variable effects, such as water vapor and heating rate in densification and microstructure of magnesium oxide ceramic. We created a model to take into account the structural rearrangement in sintering process.

Considering the evolution on application of ceramic materials in Microelectronics, due to functionality of these materials, we started the Electroceramic line in the 90’s. The functionality initially chosen was resistivity variation with electrical field (ceramic varistors) due to its application, mostly with lightning rods and electric circuits protectors. After understanding and contributing with varistor’s system based on zinc oxide (ZnO), we proposed to change the system considering another semi-conductor (stannous oxide). In this case, we developed throughout the years a stannous oxide varistor with properties that were much superior to traditional ZnO varistors.

Other contributions are related to development of thin ceramic films with Perovskite structure, with the purpose of optimizing their dielectric, piezoelectric and ferroelectric properties by using chemical deposition. We have advanced in the knowledge of chemical deposition, which we call polymeric precursors methods. One of the applications of these films are related to the manufacture of ferroelectric memories. With this, our students have worked in characterizing thin films with ferroelectric properties in some systems such as barium titanate, lead zirconate titanate, as well as strontium niobate and tantalate. A patent in ferroelectric memories, licensed to Panasonic, was proposed by a group led by Professor Carlos Paz de Araujo, at University of Colorado.

The latest contribution is related to sensors with nanometric structure, in collaboration with a group led by Professor Harry Tuller at MIT. Recent results were very promising and they showed great sensitivity in nanosensors based on stannous monoxide. It is important to point out that we have recently applied for patent regarding this study.

SBPMat Bulletin: – “Bridge building”, building bridges. Can you share with us a retrospective on the main bridges built throughout your career and the ones you would like to build?

José Arana Varela: — Our bridges have been built from the moment we finished our PhD at University of Washington. I continued to collaborate with Professor Whittemore for decade and I started other partnerships with Professor Gary Messing at Penn State University e then Professor Richard Bradt at University of Alabama.

Concurrently, we had joint projects in Europe with Professor João Baptista at Universidade de Aveiro, Portugal and with Doctor José Fernandez from Institute of Ceramics and Glass in Madrid, related to the subject of Electroceramics. We began to collaborate with groups in Bordeaux, France (Professor Marc Onillon), as well as André Perrin at University of Rennes. The collaborations proceeded with groups led by Professor Paolo Nanni at University of Genoa, concurrently with group led by Professor Danilo Suvorov at Josef Stephan Institute, in Slovenia and Professor Harry Tuller at MIT, in Boston.

SBPMat Bulletin: — Would you like to leave a message for our readers who are developing their academic or industry career as materials researchers?

José Arana Varela: — Science of Materials is fundamental to developing new useful technologies that will resolve society’s greatest problems. Great advancement in knowledge of ceramic materials, mostly their application in production of energy, communication, environmental control, etc., has been increasing in the past 20 years, mainly because of increased collaboration among researchers in different parts of the world. Science of Materials stopped being polarized between the United States and Europe (Germany, England and France) and it relies on contributions from other players in Asia and certainly Brazil. Fundamental knowledge of mass and charge transportation mechanisms, as well as structure of materials in nanometric scale, is essential to new developments and advances in technology.

 

New board of SBPMat directors and members of the council: investiture and first meeting.

On February 14th of this year, at 10 o’clock, the Brazilian Society of Materials Research (SPBMat) had an investiture ceremony for the Seventh Board of directors, for a two-year term beginning in January, 2014. Together with the Board of directors, four new full counselors and a deputy counselor were in role, whose term goes until 2018. The ceremony took place at Golden Park Hotel Viracopos, in the city of Campinas, in Sao Paulo. The new Board of directors and the new counselors were elected by vote at the end of 2013.

New Board of directors on the day of the investiture. From left to right, Rodrigo Bianchi, Marco Cremona, André Pasa, Ieda Garcia dos Santos, Julio Sambrano, Maria Aparecida Zaghete and Roberto Faria (president).

First meeting

The first meeting with the new Board of directors, together with the council occurred on the same day, at 2 p.m.

At the meeting, members of the board and council were appointed to take part in SBPMat’s commitee. For the Events Commitee, Professor Marco Cremona, Professor Iêda Maria Garcia dos Santos and Professor José Alberto Giacometti were assigned; for the SBPMat Bulletin Commitee, Professors Fernando Lázaro Freire Junior, André Avelino Pasa and José Antonio Eiras; and for University Chapters Commitee, Professors Rodrigo Fernando Bianchi, Antonio José Felix de Carvalho, Iêda Maria Garcia dos Santos, Maria Aparecida Zaghete and Waldemar Augusto de Almeida Macedo. As responsible for creating the document “Materials Science Impact” together with Institute of Physics, Professors Roberto Mendonça Faria, Marco Cremona and Julio Ricardo Sambrano were chosen. It is important to highlight that other SBPMat associates besides the initial members can be included.

During the meeting, scientific directors were assigned their duties.

See current members of the Board and Council and learn about our directors and their roles.

Concurso para professor adjunto na UFPE em Engenharia de Reabilitação.

O Departamento de Engenharia Biomédica da UFPE está realizando concurso para professor adjunto, com regime de dedicação exclusiva para a área de Engenharia da Reabilitação. Solicitamos a ampla divulgação do mesmo.

INSCRIÇÕES: As inscrições ocorrerão no período de 12 de Fevereiro a 14 de Março de 2014, exceto sábados, domingos e feriados, para entrega da documentação exigida.

Edital de Condições Gerais: Edital Nº 05/2014,

http://www.ufpe.br/progepe/images/progepe/documentos/CCD/edital%2005%202014%20professor%20adjunto.pdf

Edital Complementar: Biomédica: Engenharia de Reabilitação

www.ufpe.br/progepe/images/progepe/documentos/CCD/edital%20complementar%20ctg%20eng%20biomedica%20reabilitacao.pdf

UFPE – Universidade Federal de Pernambuco (www.ufpe.br)

Research center studies material applied as ozone gas sensor (Text by CDMF and INCTMN)

Developing multifunctional materials, that is, chemical compounds synthesized in labs, which may be applied in several areas, is a research field increasingly explored in the chemistry departments of universities around the world. The Center for the Development of Functional Materials (CDMF), located at Universidade Estadual Paulista (UNESP), jointly with researchers from Universidade de São Paulo (USP), Universidade Federal de São Carlos (UFSCar) and Instituto de Pesquisas Energéticas e Nucleares (IPEN) have developed an original study using the chemical compound silver tungstate (Ag2WO4) as a resistive sensor to detect small amounts of ozone gas, providing an alternative to environmental solutions.

Luis Fernando Silva, researcher at CDMF, under the supervision of Professor Elson Longo, has investigated the properties of silver tungstate as an ozone gas sensor. Ozone (O3) is an oxidant gas, used in many technological applications, such as the food industry, drinking water treatment, medicine, microelectronics cleaning processes, among others. “Ozone has been successfully used to disinfect effluents, allowing a more efficient drinking water treatment. However, when there are high amounts of this gas in the atmosphere, it becomes harmful, especially to human health, causing serious conditions as headaches, burning and stinging in the eyes, difficulties to breath and lung damages”, he said.

In 2013, researchers from CDMF identified a way to stimulate the growth of nanoparticles of silver in the silver tungstate compound itself. Thereby, the material developed a number of properties that may be used in different sectors, such as health, environment, and technology.

Encouraged by this breakthrough, the researchers studied silver tungstate as a resistive gas sensor. “The preliminary results qualified this compound as a great gas sensor. In one of our trials, we identified that silver tungstate displayed an excellent performance detecting ozone. That was the first time in which this compound was used as a resistive gas sensor”, explained the researcher. The obtained results were published on the journal Nanoscale, a renowned source on the subject.

Silva also explains that following this work, the main goal will be examining the sensibility of silver tungstate when detecting other gases, such as nitrogen dioxide (NO2), ammonia (NH3), ethanol (C2H6O), or even humidity. “These are parameters that enable the potential commercialization of this material”, he stated.

The initiative results from the interaction between CDMF and the INCTMN (National Institute of Science and Technology for Nanotechnology Materials).

Exposition to ozone gas

Ozone is a gas found in the higher layers of the atmosphere, acting as a filter against the solar ultraviolet radiation that comes down to Earth. The gas is not natural where living beings live, presenting a negative impact to health. It is formed by the reactions between gases created by combustions, as in vehicles, for example.

The World Health Organization (WHO) recommends avoiding the exposition to ozone gas above 120 ppb (parts per billion). Based on this date, the constant detection and measurement of the levels of ozone contained in the atmosphere or in certain environments remains indispensable.