The development of large components like displays requires organic coatings that emit white light and are inexpensive to produce. Previous gel- or solvent-based liquid “dyes” are easy to apply, but are often not colorfast or are barely luminescent after drying. For solids, on the other hand, processing is often too complex.
A team led by Takashi Nakanishi at the National Institute for Materials Science in Tsukaba (Japan) has taken a different approach: they use uncharged organic substances that are luminescent liquids at room temperature and require no solvent. The electronically active parts of the molecules consist of linear chains of carbon atoms linked by ð-conjugated double bonds. This means that electrons can move freely over a large portion of the molecule. The core is shielded by low-viscosity organic side chains that ensure that the core areas do not interact with each other and that the substance remains liquid.
The researchers were able to prepare a liquid that fluoresces blue under UV light. They then dissolved green- and orange-emitting dyes in this solvent-free liquid. This results in a durable, stable white-emitting paste whose glow can be adjusted from a “cool” bluish white to a “warm” yellowish white by changing the ratio of the dyes. It is possible to use this ink directly in a roller-ball pen for writing, or to apply it with a brush on a wide variety of surfaces. Application to a commercially available UV-LED allowed the researchers to produce white light-emitting diodes.About the Author
Takashi Nakanishi | Angewandte Chemie
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
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...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
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!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
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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