Category Chemistry/Nanotechnology

Semiconducting Inorganic Double Helix

The new material comprising tin, iodine and phosphorus possesses a double helix structure which provides the semiconductor with extreme mechanical flexibility. Credit: Prof. Tom Nilges / TUM

The new material comprising tin, iodine and phosphorus possesses a double helix structure which provides the semiconductor with extreme mechanical flexibility. Credit: Prof. Tom Nilges / TUM

New flexible semiconductor for electronics, solar technology and photo catalysis. It is the double helix, with its stable and flexible structure of genetic information, that made life on Earth possible in the first place. Now a team from the Technical University of Munich (TUM) has discovered a double helix structure in an inorganic material. The material called SnIP, comprising tin (Sn), iodine (I) and phosphorus(P) is a semiconductor with extraordinary optical and electronic properties, and extreme mechanical flexibility.The centimeter-long fibers can be arbitrarily bent without breaking.

“This prope...

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A More Accurate Sensor for Lead Paint

The stimuli-responsive nature of molecular gels makes them appealing platforms for sensing. The biggest challenge is in identifying an appropriate gelator for each specific chemical or biological target. Due to the similarities between crystallization and gel formation, we hypothesized that the tools used to predict crystal morphologies could be useful for identifying gelators. Herein, we demonstrate that new gelators can be discovered by focusing on scaffolds with predicted high aspect ratio crystals. Using this morphology prediction method, we identified two promising molecular scaffolds containing lead atoms. Because solvent is largely ignored in morphology prediction but can play a major role in gelation, each scaffold needed to be structurally modified before six new Pb-containing gelators were discovered. One of these new gelators was developed into a robust sensor capable of detecting lead at the U.S. Environmental Protection Agency limit for paint (5000 ppm).

Developing a Gel-Based Sensor Using Crystal Morphology Prediction

A new molecular gel recipe developed at the University of Michigan is at the core of a prototype for a more accurate lead paint test to see whether a paint chip contains >5,000 parts per million of the poisonous metal that was banned from pigments in 1978. Government agencies use that threshold to define paint as “lead-based” and the EPA requires that home test kits can differentiate above and below it. Yet these home kits have a wide margin of error and they produce many false positives, the researchers say.

The new test is more clear and accurate than its counterparts. It consists of a vial that holds paint thinner and a sprinkling of certain salts that, when combined with the right concentration of lead, form a gel...

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Electron Beam Microscope directly writes Nanoscale Features in Liquid with Metal Ink

To direct-write the logo of the Department of Energy’s Oak Ridge National Laboratory, scientists started with a gray-scale image.

To direct-write the logo of the Department of Energy’s Oak Ridge National Laboratory, scientists started with a gray-scale image. They used the electron beam of an aberration-corrected scanning transmission electron microscope to induce palladium from a solution to deposit as nanocrystals. Image credit: Oak Ridge National Laboratory, U.S. Dept. of Energy

A scanning transmission electron microscope (STEM) has been harnessed for the first time to directly write tiny patterns in metallic “ink,” forming features in liquid that are finer than half the width of a human hair. The automated process is controlled by weaving a STEM instrument’s electron beam through a liquid-filled cell to spur deposition of metal onto a silicon microchip...

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Breakthrough in Materials Science: Scientists Bond Metals with nearly all Surfaces

Aluminium plates which have only been sandblasted (in the background of the picture) cannot be glued successfully. The two glued plates separate again at the interface between glue and metal – this can be seen by the fact that there is no white glue residue visible on one of the two plates. The aluminium plates in the foreground of the picture were treated with the etching process “nanoscale-sculpturing” before being glued. These plates could also be separated. But the white glue particles left on both plates demonstrate that the bond between metal and glue is not broken, but rather the glue itself. Credit: Photo/Copyright: Julia Siekmann / Kiel University

Aluminium plates which have only been sandblasted (in the background of the picture) cannot be glued successfully. The two glued plates separate again at the interface between glue and metal – this can be seen by the fact that there is no white glue residue visible on one of the two plates. The aluminium plates in the foreground of the picture were treated with the etching process “nanoscale-sculpturing” before being glued. These plates could also be separated. But the white glue particles left on both plates demonstrate that the bond between metal and glue is not broken, but rather the glue itself. Credit: Photo/Copyright: Julia Siekmann / Kiel University

Through this “nanoscale-sculpturing” process, metals such as aluminium, titanium, or zinc can permanently be joined with nearly a...

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