Featured paper: Nanomembrane microtubes and hybrid materials for advanced electronic devices.

Some of the challenges of the next generation of smartphones, sensors and other electronic devices can be solved with the help of nanomembrane microtubes (sheets made from various materials with nanometric thicknesses and micrometric lateral dimensions, which can be self-rolled and form microtubes).

In the city of Campinas (São Paulo State), at the Brazilian Nanotechnology National Laboratory of the National Center for Research in Energy and Materials (LNNano / CNPEM), a group of scientists has developed expertise in processes for the synthesis, manufacture and characterization of nanomembranes and their applications. In papers published in January and February of this year in the journals Nano Letters and Nature Communications, the authors explore some nanomembrane potentials, mainly related to their flexibility and dimensions, to develop new memristors and transistors – two widely used electronic devices.

More precisely, the LNNano researchers show that nanomembrane microtubes can be key parts in the manufacture of promising components using organic and hybrid materials (organic-inorganic) such as memristors and transistors. Thus, the novelties proposed in the articles can contribute to the development of even smaller, flexible, portable, cheaper devices and equipment that combine better performance and more low energy consumption features.

In an interview with the B-MRS Newsletter, Carlos Cesar Bof Bufon, corresponding author of both articles, talks about the scientific, technological and social impact of the research and about the skills and infrastructure involved in carrying it out. Bufon is a researcher and head of the Devices Division at LNNano/CNPEM.

B-MRS Newsletter: The articles present advances, developed at LNNano, in technologies for electronic devices (transistors and memristors). In your opinion, what are the main technological and/or scientific contributions of these articles?

Carlos Cesar Bof Bufon: The work entitled “Ambipolar Resistive Switching in an Ultrathin Surface-Supported Metal–Organic Framework Vertical Heterojunction” published in Nano Letters (DOI: 10.1021/acs.nanolett.9b04355), reports the development of a new type of memristor using structures called Surface-Supported Metal-Organic Frameworks (SURMOFs). SURMOFs are hybrid structures composed of metallic ions connected by organic ligands. The structure is highly organized on surfaces covered with chemically active self-assembled monolayers (SAMs). There are more than 70 thousand types of metal-organic structures (MOFs) that can be prepared as SURMOFs to confer new features to electronic devices. In addition to the unique properties, its considerable mechanical flexibility and low cost arouse interest in the scientific community for applications. However, in the case of a hybrid material consisting of organic and inorganic elements, the integration of this class of nanomaterials becomes a technological challenge. To circumvent this limitation, this work presents a new architecture for the integration of these SURMOFs structures for the development of a new type of memristor. The proposed architecture is based on the upper electrical contact of SURMOF HKUST-1 ultrathin films using self-rolled metal nanomembranes (microtubes). The SURMOF films explored in this work have thicknesses of the order of 20 nanometers. This new architecture opens up promising paths in the area of electronic devices based on SURMOFs, as well as providing a technological platform for conducting studies not yet reported in the literature for this class of materials. For example, the investigation of how electrical charges are conducted in layers of ultrathin SURMOFs.

Photograph of a microchip fabricated using photolithography, and illustration of the electrical contact on the SURMOF performed by the strained metallic nanomembrane after the rolled-up process. The chip has 81 mm2 and contains 32 memristors.
Photograph of a microchip fabricated using photolithography, and illustration of the electrical contact on the SURMOF performed by the strained metallic nanomembrane after the rolled-up process. The chip has 81 mm2 and contains 32 memristors.

The work entitled “Edge-driven nanomembrane-based vertical organic transistors showing a multi-sensing capability” published in Nature Communications (doi: 10.1038/s41467-020-14661-x) presents the development of a vertical organic transistor platform. Transistors are the main components for electronic circuits and processors. Compared to inorganic transistors, the organic ones have the advantages of low-cost and easy fabrication, which makes them attractive for flexible electronic devices in several areas. A significant advantage of vertical transistors is their easy integration with light-emitting devices and photodetectors in the formation of integrated optoelectronic systems. The devices presented in this work were processed entirely using conventional microfabrication and photolithography techniques, which is an advantage of technological feasibility. One of the main differences of these new transistors is related to the use of self-rolled metallic nanomembranes as drain electrodes, thus promoting the formation of a smooth mechanical contact with the organic semiconductor layer. In this architecture, the organic semiconductor layer can reach thicknesses below 50 nanometers. The manufactured devices showed high current densities (~ 0.5 A / cm2) with low operating voltages (≤ 3 V). Based on our theoretical study, it was possible to predict an improvement in the structure of the transistor, resulting in projections of devices with current densities of up to 10 A / cm2. Such values, obtained at low operating voltages on a platform composed of active organic layers, highlights the potential of these devices to be integrated with flexible and portable electronic applications in the future. Besides, the new transistors were able to detect different levels of humidity and light, thanks to the device platform based on self-rolled nanomembranes. Therefore, the developed transistors also have great potential for advancing next-generation sensor technology.

 Scanning electron microscopy image (artificially colored) of the vertical organic transistor based on rolled nanomembrane (yellow tones). The incident radiation and the water molecules (artificially placed) illustrate the multiple sensitivity characteristics of the new electronic device.

Scanning electron microscopy image (artificially colored) of the vertical organic transistor based on rolled nanomembrane (yellow tones). The incident radiation and the water molecules (artificially placed) illustrate the multiple sensitivity characteristics of the new electronic device.

B-MRS Newsletter: How could the results of the articles impact people’s daily lives (social impact)? Do you think that the proposed technologies could replace those currently used or create new applications? If so, what would be the advantages of these new technologies developed at LNNano? Would it still need many steps to bring the results of the articles to the market?

Carlos Cesar Bof Bufon: Memristor is considered one of the four fundamental electronic components. On a computer, it is capable of performing information processing and storage functions. In this work, the behavior of a memristor was observed in conditions of high relative humidity (between 90-70%). Analogous to a sponge, the water molecules present in the environment are absorbed by SURMOF nanopores. In a given electric field, these molecules facilitate the conduction of electrons within the material by changing its electrical resistance. The difference in electrical resistance can reach 1 million times using low operating voltages, less than 2 V. In a practical application, this difference can correspond to the binary states 0 and 1. The total fabrication of the device was carried out with conventional techniques photolithography, compatible with industrial scale production. The fact that it depends on the humidity for its operation does not limit its commercial application, as this can be easily bypassed through encapsulation processes, common in the electronic device industry.

The manufacture of organic transistors in vertical architecture using curled nanomembranes as drain electrodes allows the reduction of the region of interest to less than 50 nanometers (more than a thousand times less than the thickness of a hair). This implies a significant advance in the electronics industry, because the portability of electronic applications, such as smartphones, computers and televisions, depends on the reduction in the number and size of transistors. The mechanism of operation of the device reported in this work expands the current understanding of vertical organic transistors, showing that current densities can be improved by performing careful manipulations in the spatial structure of the intermediate metallic electrode (source). Besides, the preparation of transistor microchips was carried out using microfabrication techniques compatible with the industrial scale. Thus, these devices can be easily integrated into electronic applications with a few additional steps, such as encapsulating microchips, to prevent degradation of organic materials.

The two concepts of devices based on nanomembranes expand the possibilities for the use of hybrid materials in electronics. As much as there is a tendency to substitute one technology for another, the concepts developed in our works seek to open new frontiers and possibilities through the design of functional structures from their fundamental elements such as atoms and molecules.

All the technologies that we develop in the area of devices at LNNano/CNPEM are firmly grounded in two focus: the understanding of the fundamental concepts that govern the properties of the components, and their technological application. These two papers started fundamentally from scratch. In terms of technology readiness level (TRL), the devices have reached the functional validation of the components in the laboratory environment. Within the TRL scale, we achieved the fourth level out of a total of 9 – the latter being commercialization. It is also worth mentioning that the next level of development must involve the participation of the productive sector, which is who can accelerate the research towards the market.

B-MRS Newsletter: Briefly tell us the story of the works reported in the two articles: how and when the idea came up, whether it was necessary to gather very different skills, the infrastructure used, curiosities etc.

Carlos Cesar Bof Bufon: The works are the result of different stories, but were developed in the same research group sharing the idea of exploring the potential of nanomembranes in the area of functional devices. This theme is part of my Young Researcher project financed in 2016 by FAPESP. The idea of applying SURMOFs as a memristor, using nanomembranes as the top contact, was developed together with the post-doctorate Dr. Luiz Gustavo Simão Albano. Our research group started evaluating the feasibility of using SURMOFs as functional materials in devices about 3 years ago. Since then, the group has been continuously establishing the implementation of synthesis and integration routes for applications in the areas of electronic components. The work was carried out entirely at LNNano/CNPEM, and has a list of co-authors who actively contributed to making this work possible: Tatiana P. Vello (growth of SURMOFs), Davi HS de Camargo (manufacture of devices and illustrations), Ricardo ML da Silva (device manufacturing), Dr. Antonio CM Padilha (DFT simulations) and Prof. Dr. Adalberto Fazzio (DFT simulations).

The work with the transistor follows the same pattern as the memristor – a combination of functional materials and nanomembranes. About 15 years ago, I became interested in the potential of using nanostructured layers as fundamental blocks in vertical electronics. Once I was aware of the work of Prof. Ivo Humlegem, from UFPR (died 2018), in the area of vertical transistors, a series of advantages and challenges caught my attention. The idea of the work came by anticipating that an improvement of the performance of vertical transistors could be achieved with the use of a drain electrode based on nanomembrane combined with a patterned intermediate electrode (source) using photolithography. In May 2018, Dr. Ali Nawaz (a former student of Prof. Ivo!), started the execution of the project at LNNano/CNPEM. Being a complex project, the advanced infrastructures for processing and characterizing LNNano/CNPEM devices were essential. And like the memristor, the research depended on a set of varied expertise. During the project, Dr. Leandro Merces provided critical assistance in the investigation of the theoretical aspects of the devices, while collaborators Davi Camargo (specialist in microfabrication) and Denise de Andrade (graduate trainee at the State University of Ponta Grossa), provided the entire work the necessary technical support.

Main authors of the papers. From the left: Carlos Cesar Bof Bufon, Luíz Gustavo Simão Albano and Ali Nawaz.
Main authors of the papers. From the left: Carlos Cesar Bof Bufon, Luíz Gustavo Simão Albano and Ali Nawaz.

 

[Papers: Ambipolar Resistive Switching in an Ultrathin Surface-Supported Metal–Organic Framework Vertical Heterojunction. Luiz G. S. Albano, Tatiana P. Vello, Davi H. S. de Camargo, Ricardo M. L. da Silva, Antonio C. M. Padilha, Adalberto Fazzio, Carlos C. B. Bufon. Nano Lett. 2020, 20, 2, 1080-1088. https://doi.org/10.1021/acs.nanolett.9b04355 and Edge-driven nanomembrane-based vertical organic transistors showing a multi-sensing capability. Ali Nawaz, Leandro Merces, Denise M. de Andrade, Davi H. S. de Camargo & Carlos C. Bof Bufon. Nature Communications volume 11, Article number: 841 (2020). https://www.nature.com/articles/s41467-020-14661-x ].

People in the Materials community: interview with Rodrigo Fernando Bianchi.

Rodrigo Fernando Bianchi.

In the month when the SBPMat University Chapters program completes two years of existence, we interviewed its coordinator, Professor Rodrigo Fernando Bianchi of the Federal University of Ouro Preto (UFOP), scientific director of SBPMat.

Curious since his childhood to understand the phenomena of nature, Rodrigo Bianchi chose Physics as his undergraduate major, which he studied between 1992 and 1995 in his native city, at the São Carlos Institute of Physics of the University of São Paulo (IFSC-USP). Research opportunities appeared and later he earned a master’s and doctoral degree in the area of Materials, also in the IFSC-USP, under the guidance of Professor Roberto Mendonça Faria. He received his master’s degree in 1997. In 2000, during the doctorate program, he spent six months doing research in United States, at the University of North Carolina at Chapel Hill, (a research stage known as a “doctoral sandwich” program). In 2002, he received the degree of Doctor of Science at IFSC-USP.

During his undergraduate studies, Bianchi complemented his academic activities with tutoring at USP, until he became a teacher at the Electronic Systems Engineering Department in 2004. In 2006, he became a professor in the Physics Department of UFOP. That same year he created the Laboratory of Polymers and Electronic Properties of Materials (LAPPEM). From 2011 to 2013 he was a visiting researcher at the Department of Electrical Engineering and Computer Sciences at the University of California, Berkeley, USA. Between 2013 and 2014, he was the coordinator of the Center for Technological Innovation and Entrepreneurship of UFOP.

Since the creation of LAPPEM, the research and development work carried out by the research group and collaborators of the laboratory have produced scientific papers, patents and enterprises, and have received national-level awards.  For example, in 2008, the group was awarded 3rd place in the Werner von Siemens Technology Innovation Award in the “Health” modality and the Incentive Award in Science and Technology for SUS, given by the Ministry of Health for the development of neostickers. Designed for blue light phototherapy to treat neonatal jaundice, the neostickers are organic light-emitting diode sensors that indicate the optimum point of blue light accumulation for the treatment.

Another one, among the several recognitions that took place earlier this year, was a project created by LAPPEM members to introduce to the market a development conducted in the laboratory, which was classified in fourth place among 1.500 startups in Brasil in the ranking “100 Open Startups”. In this case, the product was an adhesive, also based on organic luminescent material, which allows to monitor the level of ultraviolet (UV) radiation absorbed by human skin.

Currently, and since 2014, Rodrigo Bianchi is scientific director of SBPMat. When he took over the direction, he received the assignment to create and lead the SBPMat University Chapters (UCs) program, which currently has eight participating groups based in universities of five Brazilian states. Bianchi is also dean of Planning and Development of UFOP and permanent professor of the postgraduate programs in Materials Engineering and Science: Physics of Materials.

Awarded a level 2 CNPq productivity scholarship, Bianchi is the author of 7 filed patents and more than 40 articles published in international indexed journals. He has supervised 19 master dissertations and six doctoral theses.

The following is an interview with the researcher.

SBPMat Newsletter: – Tell us why you became a scientist and what led you to work in the Materials area.

Rodrigo Bianchi: – I was always a curious child trying to understand the phenomena of nature. This “curiosity” has accompanied me throughout my journey as a scientist, from the basic and secondary cycles, through my studies in Physics in the Institute of Physics of São Carlos, USP, and postgraduate studies in Materials Science and Engineering, also at USP, up to the research lines that I coordinate at UFOP, in polymeric electronic devices applied to healthcare. The research opportunities in polymers I had since my undergraduate years led me to work closer in the applied area. As a result, from Physics I went to Materials Science and Engineering, and today I consider myself a “physicist – materials engineer” with research lines focused on both the fundamental study of charge transport phenomena in organic electronic devices, as well as the idealization of sensors applied to neonatology, to the food area and to the monitoring and control of radiation.

SBPMat Newsletter: – In your assessment, what are the main contributions to the Materials area? Please also tell us of the cases in which you participated to transform scientific knowledge into products.

Rodrigo Bianchi: – Without a doubt I believe that the main contribution was to use the phenomena that made organic electronic devices not feasible for the market, such as photodegradation, that led to low durability and poor performance of organic light emitting diodes (OLEDS), to develop innovative sensors. Something like knowing the principles of operation and limitation of devices that were still in the maturation phase to create new sensors with different applications. An example of this strategy was the use of color change of the OLEDs, generated by the exposure of oxygen and light, which precluded many of the commercial applications of these systems, to develop colorimetric radiation sensing in the form of nanofibers, films and gels. In other words, develop 1, 2 and 3D scale sensors to use in different health areas: from phototherapy control for neonatal jaundice to monitoring UV radiation for sunbathers and construction and rural workers, up to the monitoring of cobalt processes, radiotherapy and food irradiation. So, encouraged by such research, partnerships and guidelines, besides our group in UFOP, there are currently other research groups working in the area in Brazil and abroad. Furthermore, our group is currently composed of physicists, chemists, food engineers, pharmacists and many students and professionals focused on developing multidisciplinary research in the field of organic electronics. The group has generated dozens of articles, patents and guidelines, with a focus to always understand the fundamental phenomena in order to develop innovative organic devices. Due to this characteristic, our team members have been awarded important innovation awards, as for instance by the Ministry of Health, Siemens and the Government of the State of Minas Gerais.

From a technological point of view, the As31 startup, created by students to market these products, was recently in fourth place in the ranking of the 100 Open Brazilian Startups, and regularly meets with major companies to establish B2B partnerships (business-to-business) to launch products into the market. This was the second startup created by members of our research group. The lesson we learned is that there are many difficulties related to creating technological and innovative products. Therefore, the first step to launch a startup involves having a well-trained and competent scientific and technological team. However, having the courage to change and modify the direction of the company is fundamental.  For example, today the As31 has two Smart Tags as driving-force products: one to indicate to the consumer possible raw meat contamination processes, caused by temperature variations during its shelf-life, and another to indicate when bathers, especially children, should reapply sunscreen. two applications that emerged from the observation of the problems of OLEDs for more than ten years and which are currently very up to date.

SBPMat Newsletter: – The SBPMat University Chapters (UCs) program, which you have coordinated from the beginning, celebrates its two year anniversary this month. Give us your personal assessment of the results achieved to date and tell us about your plans for the program going forward.

Rodrigo Bianchi: – About the SBPMat UC program, I have to say it has been a great pleasure to participate in this creation and in the work done. It’s a challenge and not an easy task setting up a work routine and the involvement of students who are the future of the materials area in the country. We now have materials groups spread out and concentrated in all regions of the country, from north to south, from east to west. Then, it is very important to unite these students in a single cause, and as a result provide them their value in society. How to do this? Our strategy was to encourage students to form their groups, and this included numerous lectures and disseminations of UCs across the country. Once the UC program were created, most important thing was to encourage students to organize a symposium at the annual SBPMat meeting, in which students had a leading role in society by getting involved in establishing the program and also in organizing the event. An innovation, because I don’t know of any other materials entity that has provided such an opportunity until now. This happened in Rio de Janeiro in 2015 and the involvement and success of the students was clearly seen. These were high-level scientific lectures involving not only materials science themes, but also ethics and scientific writing, for example. In other words, themes that interest directly the students, who are the future of the Materials area in the country. For the next meeting in Campinas, the students are organized to again coordinate this symposium. Regarding the future? The answer is to encourage the formation of new groups, interaction among students and consolidate the participation of everybody in SBPMat.

SBPMat Newsletter: – We always ask the person interviewed in this section of the newsletter to leave a message for those who are beginning their scientific careers. Would you like to say something in particular to these future scientists / junior scientists?

Rodrigo Bianchi: – As a final message to the readers, especially the younger ones: “the Materials area is extremely rich and gives us the opportunity to interact with various themes and professionals from many fields of knowledge. So, enjoy this significant feature. Get involved with competent and motivating people, and have the courage to innovate and bring your ideas into the market. Brazil needs this and you can make a difference!”

SBPMat´s community people: interview with Roberto Mendonça Faria.

The interviewee of this edition of the newsletter of the Brazilian Materials Research Society Newsletter (SBPMat) is Professor Roberto Mendonça Faria, who has just handed over the SBPMat Presidency after four years in office (although he promises to remain active in the society).

Roberto Mendonça Faria was born in Adamantina, a small town on the west side of the State of São Paulo (Brazil), on May 1952. At the beginning of his secondary studies, already oriented towards “hard sciences” and stimulated by a great physics teacher, he started to look at science as a potential profession. In 1976, Faria concluded his bachelor’s degree in physics at the São Paulo University (USP).

In the same year, still passionate about physics, in which humanity was taking great steps towards knowledge, Faria began his academic career. He started teaching in undergraduate courses at USP and began his master´s course in physics at the same university. There, supervised by Professor Bernhard Gross, a pioneer in Materials research in Brazil, Faria learnt the pillars of scientific activity and developed a fascination for uncovering mysteries of materials (in this case, the conductivity induced via radiation in a polymer known as Teflon). Right after obtaining the master’s degree, in 1980, Faria began the doctorate course in physics at USP, once again having Professor Gross as supervisor. In 1984, Faria defended his dissertation about dielectric absorption and induced conductivity via radiation in the polymer PVDF.

In 1985, Faria started lecturing in postgraduate courses at USP. Between 1987 and 1989, he stayed in France on a post-doctorate internship at Université Montpellier 2. In 1990, he obtained the Associate Professor title at USP after defending a thesis about phase transitions in ferroelectric copolymers. In 1999, he became Full Professor of the São Carlos Institute of Physics (IFSC) at USP, where he occupied several management positions throughout the years, such as the head of the Department of Physics and Materials Science (1994-1996), the coordination of the postgraduate program in physics (1997-1998) and the IFSC general direction (2002-2006).

Roberto Faria also was the coordinator of two large scale projects at a national level. The first project was the “Multidisciplinary Millennium Institute of Polymeric Materials”, one of 17 projects selected within the program “Institutes of the Millennium” of the Brazilian Ministry of Science, Technology and Innovation (MCT). This institute gathered around 140 researchers from 17 institutions from Brazil’s five regions, and existed between 2002 and 2008. The second project continued one of the research focuses of the first one – the study of electronic polymers and their applications. Starting in 2009, the Brazilian National Institute for Organic Electronics was approved and established in the context of the Brazilian National Institutes of Science and Technology (INCTs) from the MCT.

Going beyond the frontiers of his scientific area, Faria was the coordinator, between 2010 and 2014, of the São Carlos pole of the Institute of Advanced Studies (IEA) at USP, an organization intended for broad and interdisciplinary research and discussion of fundamental issues on science and culture. In addition, in the context of his interest in contributing with the economical development of his country through research, Faria coordinated the making of the book “Science, technology and innovation for a competitive Brazil”, published in 2012.

In the last few years, Faria has been having an active participation in international scientific entities in the Materials area. In 2014, he was one of the general coordinators of the “Spring Meeting of the European Material Research Society – 2014”, which took place in the French city of Lille.  In 2015, he was elected second vice-president of the International Union of Materials Research Societies (IUMRS).

Faria is a member of the Academy of Sciences of the State of São Paulo and the Brazilian Academy of Sciences and belongs to the editorial board of the journal “Materials Science – Poland”. In 40 years of scientific research on polymeric materials, particularly those with electronic activity and their applications in devices, Professor Faria has produced around 180 articles published in indexed journals, having about 2,000 references, and has supervised 47 master´ss and doctorate thesis.

An interview with the researcher follows below.

SBPMat Newsletter: – Tell us what made you become a scientist and work in the field of Materials.

Roberto Mendonça Faria: – Before High School, I imagined I was going to follow my studies in the “hard sciences” area (engineering, physics, chemistry, mathematics, etc.). But I didn’t have any intention to follow a scientific career, even less so to be a scientist. However, in the first year of High School I started to change my mind, stimulated by an excellent physics teacher, Roberto Stark. I graduated in Physics and soon after I was lucky to be supervised by two great masters: Professor Bernhard Gross and Professor Guilherme Fontes Leal Ferreira. As any newly-graduated person in physics at the time, I was passionate about the extraordinary experimental and theoretical advances of the 20th century physics.  However, my first research study was about an apparently modest theme: the interaction of ionizing radiation with thin films of insulating polymers. Under the supervision of Professor Gross, I definitely learnt how to approach a scientific issue and also how to handle the methodological strictness needed to discover the effects and the phenomena arising from the experiments performed. Those first years of research were crucially important to my career. I never again lost the fascination in discovering the properties and the enigmas of the condensed matter, and I’m happy because materials science and engineering is extremely important for the development of Brazil.

SBPMat Newsletter: – In your assessment, which are your main contributions to the field of Materials?

Roberto Mendonça Faria: – There are different ways to measure the contributions made to the advance of scientific and technological knowledge. The most objective and internationally followed view is the bibliometric, conduced by the Journal of Citation Reports (JCR) from Thomson Reuters. This metric has many merits, but it’s too much focused on numbers. Another fact influencing scientific assessments comes from the pragmatism of the present world. Today, it is required that scientific works aim at specific applications. In this context, researches involving more fundamental studies tend to lose the visibility they deserve. That is, many times scientific works of great value have little mentions. An analysis of my production from JCR may lead to the conclusion that my most relevant contributions are connected to applications, but I particularly believe that my greatest contributions are more related to fundamental works in the areas of phase transitions of ferroelectric polymers and electrical transportation mechanisms in electronic polymers.

One of the interesting areas I have been working on in the last few years is the organic solar cells. I believe that, with my research group, we gave a significant contribution to the understanding of phenomena involving the transportation of electrical carriers inside the cell. Since 2013 we published two works where we developed an analytical equation which rules the electrical current curve in function of the voltage of a solar cell when under lighting. This analytical equation works very well in special cases and has explained many of the optoelectronic effects of the devices we built and measured in our laboratories. One of the works was published in the Applied Physics Letters journal in 2013, and the other was published on Solar Energy Materials and Solar Cells in 2015.

On the other hand, I always dedicated myself to assembling research laboratories and forming human resources. I also have been contributing with several post-graduation programs, directly and indirectly, and for more than 20 years I have been dedicating myself to strengthening the area of Organic Electronics in the country, especially in the formation of a research network in this area: the National Institute of Science and Technology of Organic Electronics. Whenever possible, I try to encourage projects in partnership with private enterprises and research institutes that aim towards applied projects. In the public policies area, I believe my greatest participation was coordinating a document from CAPES (the Brazilian agency in charge of post-graduate programs) and SBPC (Brazilian Society for the Advancement of Science), called “Science, technology and innovation for a competitive Brazil”, which has contributed to the creation of the Brazilian Company of Industrial Research and Innovation (EMBRAPII).

SBPMat Newsletter: – You have just finished your tenure as President of SBPMat. Share with our readers an analysis of the results achieved by the boards you have headed during the last four years.

Roberto Mendonça Faria: – SBPMat is a relatively new society, but it has an important mission to fulfill for the development of the country. Brazil has an extraordinary richness offered to it by nature. However, the country does not take advantage of this richness because it places little knowledge over its natural resources. There was a revolution in agriculture after the country decided to put knowledge over this blessing that nature has offered to it. Today, agribusiness is one of the pillars, perhaps the strongest one, of our economy. We have to do the same with the raw matters that abound in our territory. The publication “Science Impact – A special report on materials science in Brazil”, in partnership with the Institute of Physics (IOP), was one of the projects that worked and gratified me very much. This type of initiative helps raising awareness that Brazil has a natural gift to be a leader in several materials-related segments and to generate a lot more richness than it currently does.

Another valuable contribution that the two previous SBPMat administrations gave to materials science and engineering in Brazil was the definite consolidation and internationalization of the annual meeting, which always take place at the end of September.

I must highlight that the creation of the bilingual electronic newsletter was a realization that worked, especially because of the capability it has been produced with.

SBPMat Newsletter: – You just took over, for two years, the second vice-presidency of IUMRS. Talk about your plans, expectations…

Roberto Mendonça Faria: – I’m starting this activity. My plans are, first of all, to increasingly insert the Brazilian Materials Science in the international scenario. At the same time, I intend to use the IUMRS support to stimulate materials research in other Latin American countries. Brazil and Latin America have many problems that come from their still deficient economies. I have conviction that research studies in the materials area are valuable instruments to improve the living conditions of these populations. Today, as a member of the SBPMat council, I want to take this discussion not only in Brazil, but in several Latin American countries with the help from IUMRS.

SBPMat Newsletter: – Leave a message for the readers that are starting their scientific careers.

Roberto Mendonça Faria: – I decided to register here that one of the fulfillments (still in progress) that makes our administration proud was the creation of the University Chapters program. I’m going to ask the council to allow me to work with Professor Rodrigo F. Bianchi within this program. I have no doubts that the more researchers we form, the more Brazil will gain with this.

I believe that the work with young people starting scientific activity is one of the most valuable works for a senior researcher. It is our duty to show young people how important the work of “manufacturing knowledge” is for the country, especially in scientific and technological areas. There isn’t one example of a country that has eradicated poverty without the development of strong education and competitive science and technology. Therefore, the message to young people is: believe in your work and always try to make it in the most competent way possible.

SBPMat newsletter. English edition. Year 3, issue 1.

 

Brazilian Materials Research Society (SBPMat) newsletter
News update from Brazil for the Materials community

English edition. Year 3, issue 1. 

SBPMat news: XV Meeting - Campinas (SP), Sept 25-29, 2016 

Simposia: Symposia proposals on subjects of Materials Science and Technology can be submitted up to February 11 (extended deadline).  The submission is open to the international scientific community. Read more.

Venue: Visit the site of event and watch the video about the city of Campinas and the folder on the Expo D. Pedro convention center. 

Organization: This edition of the event is chaired by UNICAMP Professors Ana Flávia Nogueira (Institute of Chemistry) and Mônica Alonso Cotta (Institute of Physics “Gleb Wataghin”). Find the members of the local committee here.

Featured paper 

The performance of organic solar cells, devices that are able to produce electricity from sunlight, can now be assessed more accurately thanks to research entirely conducted at the São Carlos Institute of Physics of the University of São Paulo (IFSC-USP). The study included a series of experiments and the development of an analytical model, and led to the publication of a paper on the journal Solar Energy Materials and Solar Cells. Read our story about the study. 

 

People in the Materials community 

We interviewed Osvaldo Novais de Oliveira Junior, Professor at the São Carlos Institute of Physics (USP), who took office as SBPMat’s president on last Friday. We discussed his life history, career and plans for SBPMat. Osvaldo Novais does not belong to the group of people who discover early a professional vocation, but this has not impede the developing a scientific career with great results, such as an H index of 53. Passionate about knowledge, he made important contributions to the field of Materials, particularly for the study and application of Langmuir films and the development of electronic tongues, in addition to participating in the creation of the first software for grammar revision in Portuguese, as well as studying and promoting how to write good papers in English. In his message to the youth, the scientist stressed the importance of language proficiency (Portuguese, English, Mathematics) as base for lifelong learning. Read our interview. 

Edgar D. Zanotto and Victor C. Pandolfelli, both Full Professors of the Materials Engineering Department at the Federal University of São Carlos (UFSCar), received special honors from the Rector, Professor Targino de Araújo Filho, at the closing ceremony of UFSCar’s 45th anniversary celebrations. 

 

Reading tips

  • Borophene, a two-dimensional metallic, conductive material made of boron atoms (based on Science paper). Here.

  • Strange, but real: structures that expand volumetrically, both when streched and compressed (based on paper on Nature Materials, section “News and Views”). Here.
  • Healthcare materials: responding to UV light stimulus, hydrogel capsules can release RNA “on demand” (based on Advance Healthcare Materials paper). Here.
Opportunities

  • Postdoctoral fellowship in confocal microscopy and cell membrane models. Here.

Events

  • 5th International Conference on Surface Metrology. Póznan (Poland). April, 4 to 7, 2016.  Site.
  • 43rd International Conference on Metallurgical Coatings and Thin Films (ICMCTF). San Diego (USA). April, 25 to 29, 2016. Site.
  • 9th Brazilian-German Workshop on Applied Surface Science. Maresias, SP (Brazil). April, 10 to 15, 2016. Site.
  • 40th WOCSDICE ‐ Workshop on Compound Semiconductor Devices and Integrated Circuits held in Europe & 13th EXMATEC ‐ Expert Evaluation and Control of Compound Semiconductor Materials and Technologies. Aveiro (Portugal). June, 6 to 10, 2016. Site.
  • Photonic Colloidal Nanostructures: Synthesis, Properties, and Applications (PCNSPA Conference 2016). Saint Petersburg (Russia). June, 27 to July, 1, 2016.  Site.
  • XXV International Conference on Raman Spectroscopy (ICORS2016). Fortaleza, CE (Brazil). August, 14 to 19, 2016.  Site.
  • XV Encontro da SBPMat. Campinas, SP (Brazil). September, 25 to 29, 2016. Site.
  • Aerospace Technology 2016. Stockholm (Sweden). October, 11 to 12, 2016. Site.

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Interviews with plenary speakers of the XIV SBPMat Meeting: George Malliaras.

Advances in understanding brain activity and in the diagnosis and treatment of neurological diseases such as epilepsy and Parkinson’s may arise with the help of Materials Science and Engineering. More precisely, of organic electronics.  In fact, organic materials with electronic properties are great interfaces between the signals sent by the brain and the outside, whether to study the brain or to interact with it.

The subject will be addressed in a plenary talk during the XIV SBPMat Meeting, given by Professor George Malliaras, head of the Department of Bioelectronics at the Ecole Nationale Supérieure des Mines de Saint-Étienne, where physicists, material engineers, electronic engineers, biologists and neuroscientists work together.

Malliaras graduated in Physics in 1991 from Aristotle University (Greece). After that, he entered the doctoral program in Mathematics and Physical Sciences at the University of Groningen, in the Netherlands. His thesis on photorefractivity in polymers earned him a distinction in the university (cum laude). After receiving his Doctoral degree, defended in 1995, he moved away to the United States. For two years, he held a postdoctoral fellowship at the IBM Almaden Research Center, to then become a Professor of the Department of Materials Science and Engineering at Cornell University, in New York. From 2006 to 2009, he worked as head of a national laboratory linked to the university, the Cornell NanoScale Science & Technology Facility.  In 2009, he founded the company Orthogonal, which operates in the field of organic electronics. In the same year, he returned to Europe as Professor of the Ecole Nationale Supérieure des Mines de Saint-Étienne, where he remains to this day.

Malliaras, whose h-index is 64, according to Google Scholar, has authored over 200 scientific papers, with more than 13,000 citations. His work with organic electronics and bioelectronics has received awards from the New York Academy of Sciences, U.S. National Science Foundation and the company DuPont, to name a few entities. He has given over 230 invited lectures and organized several events, for instance, the 2015 MRS Fall Meeting, in which he served as Meeting Chair.

He is a member of scientific boards in research centers in Germany, Ireland and Sweden. He is also an associate editor of Science Advances, an open access, peer-reviewed journal, released this year by the AAAS, which also publishes Science.

In his plenary talk at the XIV SBPMat Meeting, the scientist will address devices based on organic materials with electronic properties, bringing examples and opportunities.

What follows is a mini-interview with this plenary speaker of the XIV SBPMat Meeting.

Conducting polymer transistor array placed on rat cortex.

SBPMat newsletter: – In your opinion, what are your most significant contributions in the field of organic electronics/bioelectronics? Please explain them, very briefly, and share references from the resulting articles or books, or comment if these studies have produced patents, products, spin-off companies etc.

George Malliaras: – In the field of organic electronics it would be the co-development, together with Chris Ober at Cornell University, of orthogonal lithography. This is a set of processes that allows the microscale patterning of organic films using photolithography, the golden standard in microelectronics. Orthogonal lithography relies on the use of fluorinated photoresists that do not damage organic films. It allows the microfabrication of devices, including high resolution displays, using standard equipment that already exists in industry. There is a company (Orthogonal, Inc.,www.orthogonalinc.com) that has commercialized the photoresists and is pursuing commercialization of this technology. In bioelectronics, the work is too recent and I would have to wait for the benefit of hindsight. A trend that was emerging when I joined the field involved a transition from the use of organic coatings to the use of organic devices. The latter undoubtedly offer more capabilities to the interface with biology. My group is contributing to this trend by demonstrating that organic electrochemical transistors bring several benefits as transducers of biological phenomena, such as large amplification which enables high quality recordings of brain activity.

References:

  • J. Rivnay, R.M. Owens, and G.G. Malliaras, “The rise of organic bioelectronics”, Chem. Mater. 26, 679 (2014).
  • D. Khodagholy, T. Doublet, P. Quilichini, M. Gurfinkel, P. Leleux, A. Ghestem, E. Ismailova, T. Herve, S. Sanaur, C. Bernard, and G.G. Malliaras, “In vivo recordings of brain activity using organic transistors” Nature Comm. 4, 1575 (2013).
  • J. Rivnay, P. Leleux, M. Ferro, M. Sessolo, A. Williamson, D.A. Koutsouras, D. Khodagholy, M. Ramuz, X. Strakosas, R.M. Owens, C. Benar, J.-M. Badier, C. Bernard, and G.G. Malliaras, “High Performance Transistors for Bioelectronics Through Tuning of Channel Thickness”, Sci. Adv. 1, e1400251 (2015).
Ultra-conformable microelectrode array for electrocorticography.

SBPMat newsletter: – Which are, in your opinion, the main challenges for materials scientists and engineers about organic electronics interfacing with the brain?

George Malliaras: – To find the right collaborator who helps them formulate the right questions. I believe that embarking on an interdisciplinary field alone is a recipe for producing low impact work. The key to high impact work in this field is to formulate questions that are interesting to both neuroscientists and to us materials scientists and engineers. From our end, we need to be able to elaborate what are the advantages that organics offer and then figure out how to best employ them to address specific problems neuroscientists face. In my experience, it is often a combination of advantages (mixed conductivity, biocompatibility, “soft” mechanical properties) rather than a single one that gives the advantage to organics.

SBPMat newsletter: – If you wish, leave a message or an invitation to your plenary talk to the readers who will attend the XIV SBPMat Meeting.

George Malliaras: – I often quote a statement by Tadahiro Sekimoto, former president of Nippon Electric Corporation: “those who dominate materials, dominate technology”. It highlights the importance of materials research in our world and shows the dangers of moving to a “service” economy.

 

More

Prof. George Malliaras´ bio and abstract of his plenary lecture.

Bernhard Gross Award for best oral presentation to Juliana Eccher, for her pioneer research in Brazil on the use of liquid crystals as organic semiconductors.

Juliana Eccher received the certificate of best oral presentation from the chairman of the 2015 meeting.

Awarded work: Electrical response of a columnar liquid crystal applied in a diode structure. Juliana Eccher1, Gregorio Couto Faria2, Harald Bock3, Heinz Von Seggern4, Wojciech Zajaczkowski5, Wojciech Pisula5, Ivan H. Bechtold1; 1Universidade Federal de Santa Catarina, 2Universidade de São Paulo, 3Centre de Recherche Paul Pascal, Cnrs and Univ.Bordeaux, 4Technische Universität Darmstadt, 5Max-Planck-Institut For Polymer Research, Mainz.

The Bernhard Gross Award for the best oral presentation of the XIII SBPMat Meeting was given to a pioneer research in Brazil in its theme. “In my opinion, the main significance of awarding this work regards the dissemination of the research involving liquid crystals as organic semiconductors for applications in the field of organic electronics, especially concerning Brazil, since there are only a few groups working towards this research line in the country”, said the newly Ph.D. graduate Juliana Eccher, who presented her paper at the symposium D on materials and organic electronic devices.

Graduated in physics from the Federal University of Santa Catarina (UFSC), Juliana decided to pursue an academic career in the field of experimental physics and chose to obtain her Masters and Ph.D. degrees at UFSC, both in the field of materials, more precisely in the study of liquid crystals . “Research in materials is fascinating because it offers a broad range of study in various fields of knowledge,” said Juliana, who attended the meeting of SBPMat on three occasions. “What attracts me the most is the possibility of new discoveries and the diversity of applications,” she added.

Liquid crystals, materials used in widely marketed LCD screens, have recently been recognized as a promising class of self-organized organic semiconductors with a high electrical mobility. Some of them are called columnar because their molecules, shaped like discs, are piled on top of each other forming stable columns. When the columns are aligned perpendicularly to the substrate, there is homeotropic alignment – an ideal configuration for the application in OLEDs (organic light emitting diodes) and OPVs (organic photovoltaic devices).

Juliana Eccher´s winning work, developed during her Ph.D. in Physics, with the supervision of Professor Ivan Bechtold, studied a thin film of liquid crystal based on perylene-diimide aromatic center and proposed a relation between its electrical properties and its molecular organization. The liquid crystal was investigated within a diode structure. The work was supported by the Brazilian Federal Council for Scientific and Technological Development (CNPq), in particular through INCT/INEO , and by the Brazilian Federal Agency for the Support and Evaluation of Graduate Education (CAPES).

Juliana and the other members of the team could obtain homeotropic alignment in films deposited by spin-coating technique by subjecting them to annealing, resulting in an increase of five orders of magnitude in the electrical mobility and also a significant increase in the electroluminescence intensity of the device.

A Ph.D. research with international collaborations

The work was made possible thanks to several international collaborations. The synthesis of the organic compound was carried out by Dr. Harald Bock of the Centre de Recherche Paul-Pascal, CNRS, in France, collaborator since 2010 of the Laboratory of Organic Optoelectronics and Anisotropic Systems at the Department of Physics, UFSC, which is coordinated by Professor Bechtold. Initially in Brazil, by means of a collaboration with Professor Gregório Faria of the São Carlos Institute of Physics at USP, the team began to investigate the potential of organic material as emitting layer in a diode structure. Furthermore, in 2013, Juliana underwent a research internship in Professor Heinz von Seggern´s group at the Technische Universität Darmstadt, in Germany, where she managed to manufacture the devices and make their electrical characterization. While beeing in Germany, Juliana established a collaboration with Dr. Wojciech Pisula, of the Max-Planck-Institut for Polymer Research, which group conducted analyses by grazing incidence wide angle x-ray scattering (GIWAXS), which were fundamental to investigate the orientation of the columns with respect to the surface. Finally, with the collaboration of Professor Gregório, a theoretical model was developed for the analysis of electrical measurements of current density as a function of the applied voltage.

“The major achievement in my Ph.D. thesis was to show that, depending on the desired application, it is possible to modify and control the orientation of liquid-crystalline domains with respect to the electrodes, which significantly improved the electrical properties of the devices,” said Juliana.

To learn more about this work

– Scientific article published: J. Eccher, G. C. Faria, H. Bock, H. von Seggern, I. H. Bechtold. ACS Appl. Mater. Interfaces 5, 11935-11943 (2013).

– Juliana Eccher´s presentation at Symposium D of the XIII SBPMat Meeting:

 


SBPMat newsletter. English edition. Year 1, issue 9 – special: XIII SBPMat Meeting.

 

Brazilian Materials Research Society (SBPMat) newsletter

News update from Brazil for the Materials community

 

English edition. Year 1, issue 9. 

Greetings, .

Final arrangements for our meeting in João Pessoa!

– Read the message of the chairs of the event, which this year accepted 2,141 papers and has nearly 2,000 registrations from 28 countries so far. In the message, professors Ieda Garcia and Severino de Lima show the highlights of the program of this year’s meeting! Here.

– After lunch and before the afternoon plenary lectures, you can attend technical lectures of the meeting´s sponsors in João Pessoa: Shimadzu/Tescan will discourse about SEM with ion beam and TOF SIMS detector, and FEI will address DualBeam TEM. Learn more.

– Why is João Pessoa called “the sun door“? Learn more about the city, one of the oldest in Brazil, and its natural and cultural features. And get ready to dive into green waters at 28 °C! Read about João Pessoa.

– What to pack? Track the weather, whose temperatures should be between 20 °C and 30 °C. But pay attention, the meeting organization warns that, at the Convention Center, the air conditioner will make the room fresh … Link to weather in João Pessoa.

– Registration: here.

Program at a glance: here.

Detailed schedule. Search for times and locations of symposia presentations: here.

–  Some options of accommodation, car rental, transfers from the airports of the region, transportation from hotels to convention center, and tours: see on the home page of the site of the event.

– And what about the conference party? This year, it will be held on Wednesday evening at Espaço Caixa Econômica Federal in Cabo Branco. Tickets may be purchased in the information desk as of Monday 1 p.m..

 

Interviews with our plenary speakers

We interviewed Robert Chang, professor of the first department of Materials Science in the world at Northwestern University. Besides having a remarkable career as a researcher (his H index is 56), “Bob” has dedicated the past 20 years guiding the development of the Materials World Modules program, which develops educational, interactive and playful material (for example, card games) on Materials and Nanotechnology for pre-college students and their teachers. In his plenary lecture at the XIII SBPMat Meeting, Professor Chang will try to mobilize citizens of the world to solve global problems together. See our interview with the scientist.

We also spoke with Professor Colin Humphreys, a professor at the University of Cambridge.  Among other honors, the scientist was knighted by the Queen of England for his services to science. Besides being the author of over 600 publications, the professor developed materials for the industry that currently fly in aircraft engines and created low cost LEDs based on gallium nitride, material on which he specialized. In João Pessoa, he will show, among other issues, how gallium nitride could reduce electricity consumption by 25% in the world. See our interview with Colin Humphreys.


We interviewed the German physicist Karl Leo, specialist in organic semiconductors. Beyond being the author of more than 550 papers with more than 23,000 citations and 50 families of patents, the scientist has already participated of the creation of 8 spin-off companies. In his lecture at the XIII SBPMat Meeting, Karl Leo will speak on highly efficient organic devices, as OLEDs and solar cells. See our interview with Karl Leo.

We also spoke with the Portuguese physicist Antonio Luis Ferreira Martins Dias Carlos, of the University of Aveiro, who will perform a lecture in our meeting in João Pessoa on luminescence applied to nanomedicine. In the interview, the professor shared with us his most prominent works in the field of Materials. He also told us about some challenges in the area of luminescence for medical applications, both in medical imaging and intra-cellular temperature mapping, and cited examples of applications of luminescent materials that have already been used in the diagnosis and treatment of various diseases. See our interview with Luis Dias Carlos.


We interviewed the French scientist Jean-Marie Dubois (Institut Jean-Lamour), specialist in quasicrystals (ordered, but aperiodic structures on solid materials) and pioneer in patenting applications for them. He told us a little about his main contributions to the field of Materials and gave a teaser on the theme of his plenary lecture in the XIII SBPMat Meeting: he will talk about quasicrystal structures, found in metallic alloys, polymers, oxides and artificial nanostructures, and their unprecedented properties. In the picture, Jean-Marie Dubois (on the left) and Dan Shechtman, who received a Nobel Prize in 2011 for the quasicrystals, using equal ties, both decorated with the Penrose tiling, an example of aperiodicity.  Read our interview with Jean-Marie Dubois here.

We also interviewed the Italian chemist Roberto Dovesi (Universita’ degli Studi di Torino), one of the creators of CRYSTAL, a computational tool for ab initio quantum calculations used in the study of several solid materials properties. The CRYSTAL code is currently used in over 350 laboratories around the world.  In his plenary lecture in the XIII SBPMat Meeting, Dovesi will attempt to demonstrate that today quantum simulations may be very useful tools to complement experiments. See our interview with Roberto Dovesi.


We have interviewed Professor Alberto Salleo, from Stanford University, who is going to give a plenary lecture on organic electronic devices in the XIII SBPMat Meeting. Young, yet holding a career that stands out internationally, Salleo told us about the work conducted by his group, which has been developing a deeper understanding on the role provided by the defects in charge transport in organic semiconductors. He also shared with us his main papers, published in Nature Materials. Finally, Salleo discussed the next challenges and applications on organic electronics, and anticipated what he is going to address in the plenary lecture, which promises to be very informative while mild enough for a wider audience. Read our interview with Alberto Salleo.

To suggest news, opportunities, events or reading recommendations items for inclusion in our newsletter, write to comunicacao@sbpmat.org.br.
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E-MRS Meeting in France: SBPMat organization and Brazilian presence at organic electronics symposium.

SBPMat was part of the organization of the E-MRS (European Materials Research Society) Spring Meeting, held from May 26th to 30th, in Lille, France. SBPMat’s President, Roberto Mendonça Faria, full professor at the Institute of Physics of the University of São Paulo (USP) was among the Conference Chairs, jointly with four European scientists.

In addition to that, SBPMat has supported one of the event’s 30 symposia, the DD “Functional materials and devices for organic electronics”, which was also assisted by the Brazilian National Institute of Science and Technology in Organic Electronics (INEO). The symposium displayed substantial Brazilian attendance. It was organized by SBPMat’s Financial Director, Professor Marco Cremona (Pontifical Catholic University of Rio de Janeiro, PUC-Rio), by SBPMat´s current Scientific Director Rodrigo Bianchi (Federal University of Ouro Preto, UFOP), and Carlos Graeff (São Paulo State University, UNESP), SBPMat´s former Scientific Director, as well as by a German and an Italian scientists.

“The symposium was a success, both regarding the researchers invited – all highly qualified and leaders in their field of expertise – as to the level of results presented in the technical sessions and the subjects approached, all current concerns in the field of organic electronics”, summarized Professor Cremona. “Not only that, but the symposium has contributed to improve the image of Brazil in this field, and to start new collaborations, while still strengthening the ones that already exist”, he adds.

Dedicated to the subject of organic electronics, the symposium comprised oral presentations, posters and 23 invited lectures in sessions on organic light-emitting devices, organic transistors, flexible devices, sensors, organic solar cells, bioelectronic devices, graphene and other transparent conductive films. Other sessions approached the relation between nanostructure and function in advanced organic devices, and the modeling, simulation, characterization methods and new horizons for materials and organic devices.  “The topics were well balanced among basic and applied researches in the field of organic electronics, including electronic devices and biosensors”, as Professor Bianchi comments.

During the four days of the symposium, over 140 studies were presented, by researchers from European Union member countries, Korea, Japan, Brazil, the United States, Russia, Australia, among others. “The presentations in the Symposium DD brought high-impact lectures to E-MRS, with great participation of Brazilian researchers, proving that the country and SBPMat have been working in fields with scientific impact, and in the knowledge frontier”, Bianchi adds. Indeed, Brazil contributed to the symposium with approximately 20 papers, and two invited lectures.

Award

The symposium also featured awards for the best three posters and two papers presented in oral form:

Oral presentations:

  • Jean Nicolas Tisserant, ETH Zürich, D-AGRL Food and Soft Materials (Zürich, Switzerland). “Growth and Alignment of Thin Film Organic Single Crystals from Dewetting Patterns”, Empa.
  • Daniele Sette, CEA, LETI, DCOS (Grenoble, France). “Influence of the Annealing Temperature on the Properties of Inkjet Printed Porous Silver Layers”.

Posters:

  • Anshuma Pathak, TU Munich, Molecular electronics (Munich, Germany),
  • Structural and Electrical Study of Organophosphonate SAMs on AlOx/Al”.
  • Jung-Hung Chang, National Taiwan University, Graduate Institute of Photonics and Optoelectronics (Tapiei, Taiwan), “All–solution processed transparent organic light emitting diodes with graphene as top cathodes”.
  • Lidiya Leshanskaya, Institute for Problems of Chemical Physics, Kinetics and Catalysis, Academician Semenov (Moscow, Russia), “Origin of the advanced charge transport properties of indigo thin films: influence of the dielectric on the crystal structure of the semiconductor”.

 

Interviews with plenary lecturers of the XIII SBPMat Meeting: Alberto Salleo (Stanford University, USA).

Professor Alberto Salleo.

“Organic electronic devices” is the subject of the plenary talk that will be given by Professor Alberto Salleo at the XIII SBPMat Meeting. Professor Salleo is the head of a research group at Stanford University (USA), working on novel materials and processing techniques for large-area and flexible electronic/photonic devices. Salleo received his Laurea degree in Chemistry in 1994 from the University of Rome La Sapienza (Italy) and his M.S. (1998) and Ph.D. (2001) in Materials Science from UC Berkeley (USA) investigating optical breakdown in fused silica. He spent 4 years at the Palo Alto Research Center (USA) before joining the Department of Materials Science and Engineering at Stanford University in December 2005. Salleo is Principal Editor of MRS Communications, Associate Editor of the Journal of Electronic Materials, and member of the Advisory Board of the Journal of Organic Electronics. Salleo was awarded the Early Career Achievement Award from SPIE, the International Society for Optics and Photonics and the 3M Untenured Faculty Award, among other honors. He has (co)/authored over 140 papers in peer-reviewed journals and 6 book chapters and has co-authored a book on flexible electronics.

Read our interview with the lecturer.

SBPMat newsletter: – Please choose some of your main publications on organic electronics to share them with our public.

Alberto Salleo: – My group has long been interested in the role defects play in transport in organic semiconductors. We combine materials characterization to correlate structure to properties and really get deep in the “Materials Science” of organic semiconductors. In 2009 we looked at the role of grain-boundary structure in charge transport in crystalline organic semiconductors [J. Rivnay, L. Jimison, J. Northrup, M. Toney, R. Noriega, T. Marks, A. Facchetti, A. Salleo, “Large Modulation of Carrier Transport by Grain Boundary Molecular Packing and Microstructure in Organic Semiconductor Thin Films.  Implications for Organic Transistor Performance”, Nature Materials 8, 952-958 (2009)]. Later, we extended this work to understanding how the microstructure of semicrystalline polymers affects carrier mobility and we outlined some basic design rules for materials [R. Noriega, J. Rivnay, K. Vandewal, F.P.V. Koch, N. Stingelin, P. Smith, M.F. Toney, A. Salleo, “A general relationship between disorder, aggregation and charge transport in conjugated polymers”, Nature Materials, 12, 1037-1043 (2013)].

In the last few years we have been interested in the fundamental processes of charge generation in organic photovoltaics. In collaboration with other groups we discovered the fundamental intermediate of the charge generation process, which is the thermalized charge-transfer state [K. Vandewal, S. Albrecht, E.T. Hoke, K.R. Graham, J. Widmer, J.D. Douglas, M. Schubert, W.R. Mateker, J.T. Bloking, G.F. Burkhard, A. Sellinger, J.M.J. Frechet, A. Amassian, M.K. Riede, M.D. McGehee, D. Neher, A. Salleo, “Efficient charge generation by relaxed charge-transfer states at organic interfaces,” Nature Materials 13, 63-68 (2014)].

Charge transport in heterogeneous polymeric microstructures is dominated by percolation through ordered regions.

SBPMat newsletter: – In your opinion, which are the organic electronics´main challenges for Materials Science and Engineering? And the main applications of organic semiconductors we´ll see in everyday life in the next decades?

Alberto Salleo: – Because these materials are bound by weak van der Waals bonds, their microstructure is very process-dependent. This is a great property for fundamental studies as it allows to generate a zoo of structures relatively easily. On the other hand, most applications require that many (sometimes thousands) of devices be integrated, which puts stringent requirements on the reproducibility of the electrical characteristics. Reaching the level of reproducibility needed to build somewhat complex circuits is still challenging.

As far as applications, it is important to think of a space that is well-matched to the unique properties of organic semiconductors. OLED displays are already commercial but maybe in the future they can be driven by organic transistors to further push flexibility and fabrication sustainability. OLEDs are also exciting as low-power, low-cost lighting sources. Of course, there is continuing progress in photovoltaics and the possibility of organics being part of tandem cells is becoming ever more realistic, while fundamental breakthroughs may also make them competitive as single junctions in specific applications where their low weight and flexibility add value. Finally, there are plenty of applications that don’t require great speed but that take advantage of the mechanical properties of organics. I am thinking of bio-electronics and wearable electronics, which are experiencing a significant growth lately. Organic devices have been used to monitor brain signals and to deliver drugs locally, as well as to measure heartbeat or oxygen content in blood.

SBPMat newsletter: – Tell us a little about the plenary lecture on organic electronic devices you are going to give at the XIII SBPMat Meeting.

Alberto Salleo – My interest is in understanding how microstructure and defects play a role in materials properties. In the end, these relationships are important for all devices, therefore I view our work as quite fundamental, regardless of applications. My goal for the lecture is to pick a device (I have a few months to decide which one!) and show exactly how the structure of the material at all length-scales affects the device behavior. This type of studies provides a nexus between scientists who make materials, those who process materials and those who design devices.