Researchers at the Universities of Basel and Valencia have reported important advances in the development of next generation lighting technologies in the journal “Chemical Science”.
Lighting technology is in a state of change. The old-fashioned light-bulb, which was more efficient at converting electricity into heat than light, is currently being replaced by fluorescent devices and it is expected that light emitting diodes (LEDs) will be the technology of choice in the mid-term future.
The research group lead by Basel professors Catherine E. Housecroft and Edwin C. Constable describes the design of new molecular components and strategies for the preparation of light-emitting electrochemical cells (LECs) with remarkable lifetimes.
Simpler and less demanding LECs
LEDs have the disadvantage that they are complex, multilayered devices that require high-vacuum and high temperature techniques for their preparation. They also need to be rigorously protected from exposure to air or water. LECs are much simpler devices, comprising only one layer of active material, which can be solution-processed in ambient conditions.
To date, LEC devices have had relatively short lifetimes which have precluded serious commercial investigation. The Basel and Valencia teams have shown that devices with lifetimes exceeding 2500 hours can now be prepared using molecular components stabilized by so-called aromatic rings.
The team has built metal complexes decorated with rings that arrange themselves to form a shell around the molecule. “It is a little bit like a flower closing up at night – the flat, petal-like rings fold up about the metal to make a compact and robust structure”, says Constable.
These supramolecular interactions make the complexes exceptionally stable. Furthermore, molecular tuning of the components allows a tuning of the color of light emitted, bringing the goal of white-light emitting devices one step closer.
Andreas M. Bünzli, Edwin C. Constable, Catherine E. Housecroft, Alessandro Prescimone, Jennifer A. Zampese, Giulia Longo, Lidón Gil-Escrig, Antonio Pertegás, Enrique Ortí and Henk J. Bolink
Exceptionally long-lived light-emitting electrochemical cells: multiple intra-cation π-stacking interactions in [Ir(C^N)2(N^N)][PF6] emitters
Chem. Sci., 2015, 1-10 | doi: 10.1039/c4sc03942d
Edwin C. Constable, Department of Chemistry, University of Basel, Tel. +41 61 267 10 01, Email: firstname.lastname@example.org
Catherine E. Housecroft, Department of Chemistry, University of Basel, Tel. +41 61 267 10 08, Email: email@example.com
Olivia Poisson | Universität Basel
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The pyrenoid is a carbon-fixing liquid droplet
22.09.2017 | Max-Planck-Institut für Biochemie
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
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Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
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For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
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