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    Category Physics

    Photosensitive Perovskites Change Shape when Exposed to Light

    August 28, 2017, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology

    The perovskite material changes size when exposed to light.

    The perovskite material changes size when exposed to light. Reproduced with permission from reference 1.© 2017 WILEY‐VCH Verlag GmbH & Co.

    A crystalline material that changes shape in response to light could form the heart of novel light-activated devices. Perovskite crystals have received a lot of attention for their efficiency at converting sunlight into electricity, but new work by scientists at KAUST shows their potential uses extend far beyond the light-harvesting layer of solar panels. Photostriction is the property of certain materials to undergo a change in internal strain, and therefore shape, with exposure to light...

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    Flipping the Switch on Ferroelectrics

    August 28, 2017, Categories  Physics, Chemistry/Nanotechnology

    Charge screening in ferroelectric Pb(Zr,Ti)O3 nanorods was used to control their domain pattern. The c-domain fraction markedly increased with as the rod width decreased, while the a-domain formation prevailed by metallization of their sidewall. All the observed results could be explained by the depolarizing field, arising from the imperfect charge screening. This approach could be expanded to other low-dimensional nanoscale ferroelectric systems. Credit: Tomoaki Yamada

    Charge screening in ferroelectric Pb(Zr,Ti)O3 nanorods was used to control their domain pattern. The c-domain fraction markedly increased with as the rod width decreased, while the a-domain formation prevailed by metallization of their sidewall. All the observed results could be explained by the depolarizing field, arising from the imperfect charge screening. This approach could be expanded to other low-dimensional nanoscale ferroelectric systems. Credit: Tomoaki Yamada

    Scientists have taken control of the configuration of domains in nanorod- and thin-film ferroelectric systems. Many next-generation electronic and electro-mechanical device technologies hinge on the development of ferroelectric materials...

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    New Steel Beats the Strength-Ductilitiy Trade-off

    August 26, 2017, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology

    (a) Electron backscatter diffraction (EBSD) phase image showing the lamella microstructure of layered austenite grains embedded in tempered martensite matrix. (b) The dislocation structures in martensite as enlarged in transmission electron microscopy (TEM) image. (c) TEM image showing the elongation of dislocation cell structure after the 8% tensile strain. (d) TEM image confirming the transformation of metastable austenite to martensite after 16% tensile strain. Credit: The University of Hong Kong

    (a) Electron backscatter diffraction (EBSD) phase image showing the lamella microstructure of layered austenite grains embedded in tempered martensite matrix. (b) The dislocation structures in martensite as enlarged in transmission electron microscopy (TEM) image. (c) TEM image showing the elongation of dislocation cell structure after the 8% tensile strain. (d) TEM image confirming the transformation of metastable austenite to martensite after 16% tensile strain. Credit: The University of Hong Kong

    Automotive, aerospace and defence applications require metallic materials with ultra-high strength...

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    Carbon Nanotube Pores developed to Exclude Salt from Seawater

    August 25, 2017, Categories  Physics, Technology/Electronics, Chemistry/Nanotechnology, Environment/Geology

    An artist's depiction of the promise of carbon nanotube porins for desalination. The image depicts a stylized carbon nanotube pipe that delivers clean desalinated water from the ocean to a kitchen tap. Credit: Image by Ryan Chen/LLNL

    An artist’s depiction of the promise of carbon nanotube porins for desalination. The image depicts a stylized carbon nanotube pipe that delivers clean desalinated water from the ocean to a kitchen tap. Credit: Image by Ryan Chen/LLNL

    Lawrence Livermore scientists, in collaboration with Northeastern University have developed a saltwater purification device. The team also found that water permeability in carbon nanotubes (CNTs) with diameters smaller than a nanometer (0.8 nm) exceeds that of wider CNTs by an order of magnitude. The nanotubes, hollow structures made of carbon atoms in a unique arrangement, are more than 50,000 times thinner than a human hair...

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