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The group of Prof. Carlos F. O. Graeff at Faculty of Sciences from São Paulo State University (UNESP), in Bauru (Brazil), is looking for 1 postdoctoral research scientist. The application deadline for the positions is 15/07/2022. The candidates are expected to design, produce and characterize perovskite solar cells (PSCs).
About the Project
The present project aims on comprehending the degradation mechanisms involved in PSCs, and on finding solutions to overcome the stability issues of these devices. Based on this premise, several chemical and physical aspects will be investigated which includes; synthesis of different perovskite light harvester materials, analysis of interfacial and defects phenomena, search for optimal electron and hole transport layers materials, use of promising novel techniques for materials and devices characterization and novel device configurations. These investigations will converge to the primary objective of this work which consists of proposing more stable and more efficient PSCs.
Key project aims
I. To optimize perovskite compositions in order to minimize defects during crystallization and thin-film deposition steps.
II. To design novel electron and hole transport layers as alternatives for the currently low stable used materials.
III. To characterize the structure, morphology and optical properties of nanomaterials as active components in PSCs;
IV. To study defects and their effects on PSCs by using advanced spectroscopic and electrical techniques such as photothermal deflection spectroscopy (PDS) and photo-CELIV.
Requirements and how to apply
– Ph.D. in Physics, Materials Science & Engineering, Chemistry, or related areas.
– Experience in fabrication and characterization of perovskite solar cells is necessary.
– Experience on a variety of film deposition methods (blade-coating, roll-to-roll, etc) will be positively evaluated.
– Previous experience with the characterization techniques PDS or CELIV is a plus.
– English knowledge (fluent in writing and speech).
Each selected candidate will receive a Post-Doctoral fellowship from the São Paulo Research Foundation (FAPESP) in the amount of R$ 8.479,20 monthly and a research contingency fund, equivalent to 10% of the annual value of the fellowship which should be spent in items directly related to the research activity
Candidates should contact Prof. Carlos F. O. Graeff (email@example.com) with a brief statement of research interest/cover letter, a CV, and contact information of 2-3 references. Students in their final year of Ph.D. training are encouraged to apply.
A team of researchers from the Brazilian Federal University of Paraná (UFPR) has developed a low-cost biosensor capable of detecting Covid-19 antibodies in about 30 minutes and with high sensitivity. The system has shown promise for producing handheld, disposable devices that could be used to diagnose coronavirus infection or to confirm antibody production after vaccination using just a few drops of blood.
Biosensors are systems that have a biological element (in this case, the N protein of the SARS-CoV-2 virus) responsible for chemically interacting with what you want to detect (in this case, the specific antibody for that antigen). When the interaction takes place, the chemical reaction is transformed in the device into an interpretable signal.
The biosensor developed at UFPR is based on a stainless steel mesh coated with a hybrid material which is formed by a polymer that conducts electricity (polypyrrole) and gold nanoparticles. In these nanoparticles, virus proteins are immobilized, so that antibodies from blood samples, if any, come into contact with their antigens, spontaneously react with them and become detectable.
Facing the pandemic
The idea of the research emerged at the beginning of the Covid-19 pandemic, when society needed to have systems for the detection of the virus and the antibodies generated by the infection. At that moment, Professors Dênio Souto and Marcio Vidotti, from UFPR, decided to gather their expertises in sensors and related topics and be part of the global efforts.
“We already knew from the beginning that the urgency and multidisciplinary nature of the subject would increase our challenge”, says Bruna M. Hryniewicz, first author of the article that reports this research in the journal Materials Today Chemistry. Bruna took part in the research during her PhD, still in progress, under the guidance of Professor Vidotti, both from the Research Group on Macromolecules and Interfaces at UFPR.
A detection system was built based on the doctoral thesis of Ana Leticia Soares, which has just been defended by UFPR. With the guidance of professors Marcio Vidotti and Luis Fernando Marches, the work resulted in a platform formed by a conductive polymer modified with gold nanoparticles that showed promising responses when joined to several pairs of antigens and antibodies.
More sensitivity and selectivity
Starting from this platform, the team investigated some issues that could improve the sensitivity and selectivity of the biosensor – parameters that allow reducing the amount of false positives and negatives in the detection results, even in small amounts of sample.
In this sense, the authors synthesized and characterized two polypyrrole morphologies to produce the hybrid material, the globular and the nanotubular, and found that the polymeric nanotube biosensor had a sensitivity eight times higher to detect antibodies than the globular polypyrrole system.
Another important point was the choice of the method of immobilization of the N protein in the nanoparticles. The researchers chose to promote a covalent bond (chemical bond based on the sharing of electron pairs between the atoms involved), which brings more stability and sensitivity to the system. In fact, this methodology positions the antigen in an orientation in which the sites of interaction with the antibody are available – an interaction that is further encouraged by the favorable chemical environment provided by polypyrrole. “All these characteristics allow the biosensor to present satisfactory sensitivity and selectivity responses”, says Jaqueline Volpe, also the first author of the article, who participated in the research during her master’s degree, under the guidance of Professor Dênio Souto, both from the Spectrometry, Sensors and Biosensors.
In addition to the participation of professors, post-docs and students from the Graduate Program in Chemistry at UFPR, the collaboration of researchers and physicians from UFPR and Hospital Erasto Gaertner, in Curitiba, was fundamental in the research. These collaborators quickly provided the SARS-CoV-2 N protein. They also obtained blood samples from people with and without Covid-19 who had had PCR tests (the diagnostic methodology considered the most accurate), which were used to test the performance of the biosensor.
“Taking into account that the work was carried out during the height of the pandemic, the challenges were numerous, from access to laboratories, to the exploration of a highly relevant topic, which generates greater pressure in the development of research”, comments Larissa Bach Toledo, co-author of the article.
According to the authors, the biosensor developed is promising for use on a large scale in the diagnosis of infected people and in the monitoring of antibodies due to the simple and scalable method of manufacturing the electrodes (batch synthesis), added to the low cost of the stainless steel matrix, and the high sensitivity of the system. However, to produce it commercially, it would be necessary to do many more validation tests with real samples, as well as transforming the system into a simple, miniaturized and easy to use device, in which the detection results could be interpreted by anyone.
This research was funded by the German foundation Alexander von Humboldt, UFPR through Proind 2020 and the Brazilian agencies CAPES and CNPq. The work also received support from INCTBio, of which Professor Marcio Vidotti is a member.
Reference of the paper: Development of polypyrrole (nano)structures decorated with gold nanoparticles toward immunosensing for COVID-19 serological diagnosis. B. M. Hryniewicz, J. Volpe, L. Bach-Toledo, K. C. Kurpel, A. E. Deller, A. L. Soares, J. M. Nardin, L. F. Marchesi, F. F. Simas, C. C. Oliveira, L. Huergo, D. E. P. Souto, M. Vidotti. Materials Today Chemistry. Volume 24, June 2022, 100817. https://doi.org/10.1016/j.mtchem.2022.100817.
We announce the opportunity for one (1) FAPERJ PDR (value of R$ 4,100.00/month) linked to the FAPERJ Jovem Pesquisador Fluminense grant #E-26/200.627/2022. The duration of the scholarship is 12 months, renewable for another 24 months.
The scholarship holder will work in the area of Theory, Modeling and Simulation of Nanomaterials and the project will be developed at the Department of Solids Physics at UFRJ. The project to be developed will emphasize the study of properties of 2D materials with application in catalysis and electronic properties of organic solar cells.
Technical Skills of interest:
(1) Density functional theory (DFT).
(2) Molecular Dynamics.
(3) Machine Learning (will be considered an asset).
Proficiency in English (writing, communication, presentation of seminars), ability to work in groups, ability to program in fortran, C or python.
Experiment with some of the codes: Quantum Expresso, Vasp, Siesta, ORCA, LAMMPS, GROMACS or similar.
Send email to Dr. Graziâni Candiotto (firstname.lastname@example.org), until 05/27/2022, with the title “PDR-FAPERJ Registration” and the following items:
● Curriculum vitae (CV).
● Letters of recommendation (minimum of one and maximum of two).
● Letter (maximum 1 page) describing how your experience/activities will contribute to the project goals.
This opportunity is open to candidates of all nationalities. The analysis of the CV will be based on the history of publications in the area. Candidates may be invited for an interview (in person or videoconference).
The implementation of the scholarship will be done immediately after the end of the selection process.
The candidate must have defended his Doctoral Thesis for a maximum of 5 years. Other requirements and conditions are described in the following link: http://www.faperj.br/?id=13.4
Announcement of post-doctoral FAPESP fellowship opportunity linked to FAPESP Young Investigators Award phase 2 – grant # 2021/06730-7
The Cranium lab works with the synthesis of innovative polycrystalline ceramics and develops recycling pathways for zirconia block waste to create hydrothermally stable and resistant materials for restorative applications.
The postdoctoral researcher will work on the development of syntheses methods of multilayered polycrystalline ceramics, zirconia recycling, graded infiltration, and materials characterizations.
– Experience in: 1) polycrystalline ceramics syntheses, graded infiltration, and/or zirconia recycling; 2) Microstrucutral, optical, and mechanical property (static and fatigue) characterizations, fractographic and Weibull analyses.*
* The authorship in international publications (journals of selective editorial policy and high impact factor) will be the main criteria to prove experience in the field.
– Fluent english
– Full time dedication
– Doctorate degree obtained up to 7 years before project start
E-mail to Prof. Dr. Estevam A. Bonfante – email@example.com until May 8, with Curriculum vitae (CV) attached.
This post-doc opportunity is open to candidates of all nationalities. CV analyses will focus on the candidate’s publication records. There may be an interview (personal or videocall).
The scholarship will be granted for 24 months (BRL 8,479.20 /month). A technical reserve, (15% of the annual scholarship) will be provided.
Edson Roberto Leite was an undergraduate student of materials engineering when he began to work with research in sintering. At the time, his advisor was Professor José Arana Varela, a distinguished materials scientist who died in 2016 and was founding member and president of the Brazilian Materials Research Society.
Used since antiquity, sintering is a process of agglutination of solid particles that results in a compact material. In this process, the spaces between the particles or grains (the pores) are filled by atoms that detach from the surface of the material.
“I have always been very interested in this subject and curious to know what transport is like at the atomic level during the sintering process”, recalls Edson Leite.
More than thirty years after this first scientific work, Leite, who now is the scientific director of the Brazilian Nanotechnology National Laboratory (LNNano), calmed this curiosity. Together with other researchers at LNNano, he was able to visualize, in real time and with atomic resolution, the process of eliminating pores in a nanometric zirconium oxide ceramic. The work was recently published in Nano Letters.
“Certainly Prof. Varela would be proud and enjoy this work”, says Leite, who received the José Arana Varela Award from B-MRS last year in recognition of his scientific trajectory.
The first step of the work was taken four years ago, when Leite and his team developed a methodology that allowed the preparation of monolayers of self-supported nanoparticles (without substrate). When they took these very thin films to a transmission electron microscope (TEM), the researchers noticed that the electron beam induced the transport of atoms, even at room temperature. The team then saw the possibility of studying the sintering process in situ. That is, being able to follow the changes in pore filling under the microscope, step by step and without having to remove the sample in the middle of the process.
The possibility took shape in LNNano’s high-resolution TEM, an HRTEM, which allows one to visualize atoms. “We put together a team made up of Jefferson Bettini (researcher at LNNano), my postdoc Tanna Rodrigues Fiuza and Marlon Muniz da Silva (intern at LNNano and now a PhD student at LNLS) and started to work hard to visualize sintering at the atomic scale,” says Leite.
Initially, the team prepared ceramic films formed by nanometric grains of zirconium oxide and focused their efforts on studying the process that occurs at the end of sintering: the elimination of isolated pores that remain at the grain boundaries.
The work was as exciting as it was challenging, not only because of the hours spent at the microscope in collecting, processing and analyzing images, but mainly because of the researchers’ effort to understand what they were seeing. “In the end, we were quite happy and demonstrated the transformations that occur during the closing of pores on an atomic scale”, says Leite.
In this video, filmed by the authors of the article using HRTM, it is possible to visualize atoms migrating from adjacent grains and filling the pore:
The work should have an important academic impact, since its results show that the reality of nanometric ceramics does not fit, in some aspects, in the theoretical models that are used to explain sintering processes. “Most existing models involving sinter kinetics consider the surface energy and the energy of isotropic grain boundaries. We showed that this does not occur in nanometric ceramics”, explains Professor Leite. “In addition, we showed that a transition occurs in which a rough surface is eliminated and the appearance of faceted surfaces occurs, indicating that there may be a thermodynamic barrier, in addition to a kinetic barrier for atomic transport”, he adds. “In summary, we can say that it is necessary to modify the existing models to explain the sintering process at the nanoscale”, concludes the scientist.
According to the authors, the work should also have an impact on the ceramic industry, as a better understanding of the sintering process can lead to the development of nanostructured ceramics with controlled porosity and particle size and, therefore, with differentiated mechanical and electronic properties.
Reference of the paper: Visualization of the Final Stage of Sintering in Nanoceramics with Atomic Resolution. Tanna Elyn Rodrigues Fiuza, Marlon Muniz da Silva, Jefferson Bettini, and Edson Roberto Leite. Nano Lett.2022, 22, 1978 – 1985. https://doi.org/10.1021/acs.
Author contact: firstname.lastname@example.org
[Text by Professor Petrus Santa Cruz (DQF/UFPE), B-MRS member]
It is difficult to assess the indirect impacts of the Covid-19 pandemic, and it is even more difficult to receive, even at this point, news from direct victims, such as that of a long-time collaborator, Hernán Valenzuela, who left us on the 7th of March.
As a senior representative of the Fraunhofer ENAS Institute (Fraunhofer-Instituts für Elektronische Nanosysteme ENAS) in Latin America, nearly 20 years ago Hernán began to bring together researchers involved in the application of new materials in nanotechnologies in the Minapim Seminar, a biennial series of which Hernán has been chairman since his first edition in 2004, together with the creation of the MTM Minapim News Technology Magazine, initiatives initially supported by the Superintendence of the Manaus Free Trade Zone (SUFRAMA). In the 2018 edition of the Minapim Seminar, emphasis was given to the consolidation of the international cooperation agreement between the Fraunhofer Institute ENAS and UFPE, having interacted in events involving new technologies since the first international events in the area, in 2003 at Nanofair (Switzerland) and NanoTech (Japan).
In 2013, he gave support to the UFPE’s Workshop for the Bioterium of Nanostructured Species BEN at SUFRAMA’s headquarters (Manaus), involving discussions on Biodiversity and Bioinspiration, within the scope of the Capes Nanobiotec Brasil Project.
As a result of the collaborations catalyzed by Hernán, in March 2020 a team including the President Director of Fraunhofer ENAS at the time, Dr. Thomas Otto, visited Ponto Quantico Nanodevices (Positiva, LandFoton/UFPE), when Ponto Quantico became the Hub of the Fraunhofer ENAS Cooperation Agreement with UFPE, and the team was received by the Rector Alfredo Gomes, a few days before the Recife campus lockdown, when the WHO declared the beginning of the ongoing pandemic.
Hernán, who was a sociologist, leaves a wife, four children, five grandchildren and many friends, many of them from our scientific community.
Prof. Petrus Santa Cruz (DQF/UFPE)