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    Category Technology/Electronics

    Team Builds 1st Quantum Cascade Laser on Silicon

    April 20, 2016, Categories  Physics, Technology/Electronics

    3-D artistic depiction of multiple Quantum Cascade Lasers integrated above silicon waveguides. Credit: Alexander Spott

    3-D artistic depiction of multiple Quantum Cascade Lasers integrated above silicon waveguides. Credit: Alexander Spott

    The advance will have many uses including chemical bond spectroscopy and gas sensing, to astronomy and free-space communications. Integrating lasers directly on silicon chips is challenging, but it is much more efficient and compact than coupling external laser light to the chips. The indirect bandgap of silicon makes it difficult to build a laser out of silicon, but diode lasers can be built with III-V materials such as InP or GaAs. By directly bonding an III-V layer on top of the silicon wafer and then using the III-V layers to generate gain for the laser, this same group has integrated a multiple quantum well laser on silicon that operates at 2 µm...

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    Researchers develop new Semiconducting Polymer for forthcoming Flexible Electronics

    April 20, 2016, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology

    While high-mobility p-type conjugated polymers have been widely reported, high-mobility n-type conjugated polymers are still rare. In the present work, we designed semifluorinated alkyl side chains and introduced them into naphthalene diimide-based polymers (PNDIF-T2 and PNDIF-TVT). We found that the strong self-organization of these side chains induced a high degree of order in the attached polymer backbones by forming a superstructure composed of “backbone crystals” and “side-chain crystals”. This phenomenon was shown to greatly enhance the ordering along the backbone direction, and the resulting polymers thus exhibited unipolar n-channel transport in field-effect transistors with remarkably high electron mobility values of up to 6.50 cm2 V–1 s–1 and with a high on–off current ratio of 105.

    While high-mobility p-type conjugated polymers have been widely reported, high-mobility n-type conjugated polymers are still rare. In the present work, we designed semifluorinated alkyl side chains and introduced them into naphthalene diimide-based polymers (PNDIF-T2 and PNDIF-TVT). We found that the strong self-organization of these side chains induced a high degree of order in the attached polymer backbones by forming a superstructure composed of “backbone crystals” and “side-chain crystals”. This phenomenon was shown to greatly enhance the ordering along the backbone direction, and the resulting polymers thus exhibited unipolar n-channel transport in field-effect transistors with remarkably high electron mobility values of up to 6...

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    Nano-Magnets produce 3D images

    April 19, 2016, Categories  Physics, Technology/Electronics

    This is a 3-D wireframe-cube image of nano-magnetic pixels above a real nut.

    This is a 3-D wireframe-cube image of nano-magnetic pixels above a real nut.

    Toyohashi Tech has developed a wide-view 3D holographic display composed of nano-magnetic pixels. This 3-D display, with 1-µm-pitch pixels, can show holographic images at viewing angle of over 30°. This display is an attractive option for visualizing 3-D objects with a smooth motion parallax and without using special glasses.

    Conventional 3D displays, such as stereo displays with glasses and glass-free autostereoscopic displays, show 2D images for each eye. Therefore, users experience incongruity and eyestrain owing to these pseudo-3D images. A holographic display produces an exact copy of the wave front of scattered light from an object, and hence, a realistic 3D display is expected...

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    Cheap, Efficient and Flexible Solar cells: New World Record for Fullerene-free Polymer solar cells

    April 19, 2016, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology

    Polymer solar cells manufactured using low-cost roll-to-roll printing technology, demonstrated here by professors Olle Inganäs (right) and Shimelis Admassie. Credit: Stefan Jerrevång/Linkoping university

    Polymer solar cells manufactured using low-cost roll-to-roll printing technology, demonstrated here by professors Olle Inganäs (right) and Shimelis Admassie. Credit: Stefan Jerrevång/Linkoping university

    Polymer solar cells have in recent years emerged as a low cost alternative to silicon solar cells. In order to obtain high efficiency, fullerenes are usually required in polymer solar cells to separate charge carriers. However, fullerenes are unstable under illumination, and form large crystals at high temperatures.

    Now, a team of chemists led by Professor Jianhui Hou at the CAS set a new world record for fullerene-free polymer solar cells by developing a unique combination of a polymer called PBDB-T and a small molecule called ITIC...

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