Category Chemistry/Nanotechnology

Scientists inserted helium ions into a thin crystalline film (gold) to controllably increase the out-of-plane crystal dimension, while the underlying substrate (black) fixed the in-plane directions. The red balloon represents one helium atom in the crystalline lattice. Credit: Oak Ridge National Laboratory

With just a bit of helium, the lighter-than-air element that makes balloons float, scientists have done what was once thought impossible – they stretched a crystal lattice in just one dimension, allowing them to tune the structure’s electronic and magnetic properties. To achieve this elongation, scientists devised a new method called “strain doping.” Scientists implant helium ions into a crystal. The helium gently pushes up against the structure, like a balloon under a sheet...

Researchers have found a way to make the valuable chemical ethyl acetate while generating H2 gas to power fuel cells.
CREDIT
Nanfeng Zheng

Hydrogen is widely regarded as a promising and clean alternative energy source. The traditional source of hydrogen (H2) for fuel cell use is water, which is split into H2 and oxygen (O2). But O2 is a low-value product. So, this week in ACS Central Science, researchers report a new approach and a new catalyst that can produce not just hydrogen but also valuable chemicals, including the most common ingredient in nail polish.

Nanfeng Zheng and colleagues recognized that to produce H2, it is necessary to have a source that contains both hydrogen and oxygen. Although water is the typical source, other substances could also fit the bill...

An example of 3D printed food, created by one of Professor Hod Lipson’s students. Credit: Timothy Lee Photographers/Columbia Engineering

Prof. Lipson and his students have been developing a 3D food printer that can fabricate edible items through computer-guided software and the actual cooking of edible pastes, gels, powders, and liquid ingredients – all in a prototype that looks like an elegant coffee machine.”Food printers are not meant to replace conventional cooking – they won’t solve all of our nutritional needs, nor cook everything we should eat,” says Lipson, a pioneering roboticist who works in the areas of artificial intelligence and digital manufacturing at Columbia Engineering ...

A new method of cubic phase synthesis: Hexagonal-to-cubic phase transformation. The scale bars represent 100 nm in all images. (a) Cross sectional and (b) Top-view SEM images of cubic GaN grown on U-grooved Si(100). (c) Cross sectional and (d) Top-view EBSD images of cubic GaN grown on U-grooved Si(100), showing cubic GaN in blue, and hexagonal GaN in red. Credit: University of Illinois

Researchers have developed a new method for making brighter and more efficient green light-emitting diodes (LEDs). Using an industry-standard semiconductor growth technique, they have created gallium nitride (GaN) cubic crystals grown on a silicon substrate that are capable of producing powerful green light for advanced solid-state lighting.

“The union of solid-state lighting with sensing (e.g...