Researchers of the Optoelectronics and Measurement Techniques Unit (OPEM) at the University of Oulu [Finland] have invented a new method of producing ultra-sensitive hyper-spectral photodetectors. At the heart of the discovery are colloidal quantum dots, developed together with the researchers at the University of Toronto, Canada.
Quantum dots are tiny particles of 15-150 atoms of semiconducting material that have extraordinary optical and electrical properties due to quantum mechanics phenomena.
By controlling the size of the dots, the researchers are able to finetune how they react to different light colors (light wavelengths), especially those invisible for the human eye, namely the infrared spectrum.
-Naturally, it is very rewarding that our hard work has been recognized by the international scientific community but at the same time, this report helps us to realize that there is a long journey ahead in incoming years. This publication is especially satisfying because it is the result of collaboration with world-class experts at the University of Toronto, Canada. This international collaboration where we combined the expertise of Toronto’s researchers in synthesizing quantum dots and our expertise in printed intelligence resulted in truly unique devices with astonishing performance, says docent Rafal Sliz, a leading researcher in this project.
Mastered in the OPEM unit, inkjet printing technology makes possible the creation of optoelectronic devices by designing functional inks that are printed on various surfaces, for instance, flexible substrates, clothing or human skin. Inkjet printing combined with colloidal quantum dots allowed the creation of photodetectors of impresive detectivity characteristics. The developed technology is a milestone in the creation of a new type of sub-micron-thick, flexible, and inexpensive IR sensing devices, the next generation of solar cells and other novel photonic systems.
-Oulus’ engineers and scientists’ strong expertise in optoelectronics resulted in many successful Oulu-based companies like Oura, Specim, Focalspec, Spectral Engines, and many more. New optoelectronic technologies, materials, and methods developed by our researchers will help Oulu and Finland to stay at the cutting edge of innovation, says professor Tapio Fabritius, a leader of the OPEM.
Graphene has undoubtedly been the most popular research subject of nanotechnology during recent years. Made of pure carbon, this material is in principle easy to manufacture: take ordinary graphite and peel one layer off with Scotch tape. The material thus obtained is two-dimensional, yielding unique properties, different from those in three-dimensional materials.
Graphene, however, lacks one important property, semiconductivity, which complicates its usage in electronics applications. Scientists have therefore started the quest of other two-dimensional materials with this desired property.
Molybdenum disulfide, MoS2 is among the most promising candidates. Like graphene, MoS2 consists of layers, interacting weakly with one another. In addition to being a semiconductor, the semiconducting properties of MoS2 change depending on the number of atomic layers.
For the one or few layer MoS2 to be useful in applications, one must be able to join it to other components. What is thus needed is such a metallic conductor that electric current can easily flow between the conductor and the semiconductor. In the case of MoS2, a promising conductor is provided by nickel, which also has other desired properties from the applications point of view.
However, an international collaboration, led by the Nano and molecular systems research unit at the University of Oulu has recently discovered that nanoparticles made of nickel do not attach to MoS2. One needs gold, which ‘glues’ the conductor and the component together. Says docent Wei Cao of NANOMO: “The synthesis is performed through a sonochemical method.” Sonochemistry is a method where chemical reactions are established using ultrasound. NANOMO scientist Xinying Shi adds: “The semiconductor and metal can be bridged either by the crystallized gold nanoparticles, or by the newly formed MoS2-Au-Ni ternary alloy.”
The nanojunction so established has a very small electrical resistivity. It also preserves the semiconducting and magnetic properties of MoS2. In addition, the new material has desirable properties beyond those of the original constituents. For example, it acts as a photocatalyst, which works much more efficiently than pure MoS2. Manufacturing the golden nanojunction is easy and cheap, which makes the new material attractive from the applications point of view.
Here’s a link to and a citation for the paper,
Metallic Contact between MoS2 and Ni via Au Nanoglue by Xinying Shi, Sergei Posysaev, Marko Huttula, Vladimir Pankratov, Joanna Hoszowska, Jean‐Claude Dousse, Faisal Zeeshan, Yuran Niu, Alexei Zakharov, Taohai Li. Small Volume 14, Issue22 May 29, 2018 1704526 First published online: 24 April 2018 https://doi.org/10.1002/smll.201704526
This paper is behind a paywall.
There is a pretty illustration of the ‘golden nanojunctions’,
Golden nanoglue (Courtesy of the University of Oulu)
Science communicators can choose to celebrate June 2015 in Nancy, France and acquaint themselves with the latest and greatest in communication at the Science & You conference being held from June 1 – 6, 2015. Here’s the conference teaser being offered by the organizers,
The 2015 conference home page (ETA May 5, 2015 1045 hours PDT: the home page features change) offers this sampling of the workshops on offer,
No less than 180 communicators will be lined up to hold workshop sessions, from the 2nd to the 5th June in Nancy’s Centre Prouvé. In the meantime, here is an exclusive peek at some of the main themes which will be covered:
– Science communication and journalism. Abdellatif Bensfia will focus on the state of science communication in a country where major social changes are playing out, Morocco, while Olivier Monod will be speaking about “Chercheurs d’actu” (News Researchers), a system linking science with the news. Finally, Matthieu Ravaud and Fabrice Impériali from the CNRS (Centre National de Recherche Scientifique) will be presenting “CNRS Le journal”, the new on-line media for the general public.
– Using animals in biomedical research. This round-table, chaired by Victor Demaria-Pesce, from the Groupement Interprofessionnel de Réflexion et de Communication sur la Recherche (Gircor) will provide an opportunity to spotlight one of society’s great debates: the use of animals in research. Different actors working in biomedical research will present their point of view on the subject, and the results of an analysis of public perception of animal experimentation will be presented. What are the norms in this field? What are the living conditions of the animals in laboratories? How is this research to be made legitimate? This session will centre on all these questions.
– Science communication and the arts. This session will cover questions such as the relational interfaces between art and science, with in particular the presentation of “Pulse Project” with Michelle Lewis-King, and the Semaine du Cerveau (Brain Week) in Grenoble (Isabelle Le Brun).
Music will also be there with the talk by Milla Karvonen from the University of Oulu, who will be speaking about the interaction between science and music, while Philippe Berthelot will talk about the art of telling the story of science as a communication tool.
– Science on television. This workshop will also be in the form of a round table, with representatives from TVV (Vigyan Prasar, Inde), and Irene Lapuente (La Mandarina de Newton), Mico Tatalovic and Elizabeth Vidal (University of Cordoba), discussing how the world of science is represented on a mass media like television. Many questions will be debated, as for example the changing image of science on television, its historical context, or again, the impact these programmes have on audiences’ perceptions of science.
Science & You seems to be an ‘umbrella brand’ for the “Journées Hubert Curien” conference with plenaries and workshops and the “Science and Culture” forum, which may explain the variety of dates (June 1 – 6, June 2 – 5, and June 2 – 6) on the Science & You home page.
Here’s information about the Science & You organizers and more conference dates (from the Patrons page),
At the invitation of the President of the Université de Lorraine, the professors Etienne Klein, Cédric Villani and Brigitte Kieffer accepted to endorse Science & You. It is an honour to be able to associate them with this major event in science communication, in which they are particularly involved.
Cédric Villani, Fields Medal 2010
Cédric Villani is a French mathematician, the Director of the Institut Henri Poincaré and a professor at the Université Claude Bernard Lyon 1.
His main research interests are in kinetic theory (Boltzmann and Vlasov equations and their variants), and optimal transport and its applications (Monge equation).
He has received several national and international awards for his research, in particular the Fields Medal, which he received from the hands of the President of India at the 2010 International Congress of Mathematicians in Hyderabad (India). Since then he has played the role of spokesperson for the French mathematical community in media and political circles.
Cédric Villani regularly invests in science communication aiming at various audiences: conferences in schools, public conferences in France and abroad, regular participation in broadcasts and current affairs programmes and in science festivals.
Etienne Klein, physicist and philosopher
Etienne Klein is a French physicist, Director of Research at the CEA (Commissariat à l’énergie atomique et aux énergies alternatives – Alternative Energies and Atomic Energy Commission) and has a Ph.D. in philosophy of science. He teaches at the Ecole Centrale in Paris and is head of the Laboratoire de Recherche sur les Sciences de la Matière (LARSIM) at the CEA.
He has taken part in several major projects, such as developing a method of isotope separation involving the use of lasers, and the study of a particle accelerator with superconducting cavities. He was involved in the design of the Large Hadron Collider (LHC) at CERN.
He taught quantum physics and particle physics at Ecole Centrale in Paris for several years and currently teaches philosophy of science. He is a specialist on time in physics and is the author of a number of essays.
He is also a member of the OPECST (Conseil de l’Office parlementaire d’évaluation des choix scientifiques et technologiques – Parliamentary Office for the Evaluation of Scientific and Technological Choices), of the French Academy of Technologies, and of the Conseil d’Orientation (Advisory Board) of the Institut Diderot.
Until June 2014, he presented a weekly radio chronicle, Le Monde selon Etienne Klein, on the French national radio France Culture.
B. L. Kieffer is Professor at McGill University and at the Université de Strasbourg France. She is also Visiting Professor at UCLA (Los Angeles, USA). She develops her research activity at IGBMC, one of the leading European centres of biomedical research. She is recipient of the Jules Martin (French Academy of Science, 2001) and the Lounsbery (French and US Academies of Science, 2004) Awards, and has become an EMBO Member in 2009.
In 2012 she received the Lamonica Award of Neurology (French Academy of Science) and was nominated Chevalier de la Légion d’honneur. In December 2013 she was elected as a member of the French Academy of Sciences.
In March 2014, she received the International L’OREAL-UNESCO Award for Women in Science (European Laureate). She started as the Scientific Director of the Douglas Hospital Research Centre, affiliated to McGill University in January 2014, and remains Professor at the University of Strasbourg, France.
Following on the 2012 conference, this project will bring together all those interested in science communication: researchers, PhD students, science communicators, journalists, professionals from associations and museums, business leaders, politicians… A high-level scientific committee has been set up for this international conference, chaired by Professor Joëlle Le Marec, University of Paris 7, and counting among its members leading figures in science communication such as Bernard Schiele (Canada) or Hester du Plessis (South Africa).
The JHC Conference will take place from June 2nd to 6th at the Centre Prouvé, Nancy. These four days will be dedicated to a various programme of plenary conferences and workshops on the theme of science communication today and tomorrow.
You can find the Registration webpage here where you can get more information about the process and access the registration form.