Entries with tag nanocrystals.

Researchers Create Silicon-Based LEDs

Scientists from Karlsruhe Institute of Technology and the University of Toronto report that they have made silicon-based LEDs using silicon nanocrystals that are able to emit various colors of light. These LEDs are free of heavy metals, which means the devices are not toxic. To date, scientists have been able to make silicon-based LEDs that emit only red light. The ability to produce LEDs capable of multicolored displays “is an absolutely novelty,” said Florian Maier-Flaig, a doctoral student at the Karlsruhe School of Optics and Photonics. The new system adjusts the color of light by separating the nanoparticles in the LED based on size, which helps their operational stability. Using multiple sizes of nanoparticles together typically triggers short circuits, but because the devices use a uniform size of nanoparticles, this technique also increases operational life. The researchers published their work in the journal Nano Letters. (PhysOrg)(Karlsruhe Institute of Technology)(Nano Letters)

New Technique Makes Nanocrystal Films Useful for Electronics, Displays

MIT researchers have developed a new way to make defect-free patterns of nanocrystal films, which could enable their use in electronic or photonic circuits, as well as high-resolution displays. Typically, nanocrystal films are difficult to place on a surface and often crack which limits their usefulness. The MIT researchers controlled the shape and position during the production of the nanocrystals and also created patterns able to emit visible light, making the crystals easier to see using an optical microscope. They say their film is about 180 times more electrically conductive than conventional films. In addition to emitting light, the scientists say, their patterning approach could absorb light, which could be useful in solar cells and detectors able to screen people for toxins or medical conditions. They published their work in the journal Nano Letters. (PhysOrg)(MIT News Office)(Nano Letters)

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