Category Chemistry/Nanotechnology

A scanning electron microscope image shows the rigid pillar-like bristles of the FLUENCE rake, which is used to apply light-harvesting polymers to a solar cell. The distance between the pillars is 1 micrometer, about one-hundredth the diameter of a human hair. Credit: Z. Bao et al, Nature Communications

When commercialized, this advance could help make polymer solar cells an economically attractive alternative to those made with much more expensive silicon-crystal wafers. In experiments, solar cells made with the tiny rake double the efficiency of cells made without it and are 18% better than cells made using a microscopic straightedge blade.

Polymer-based photovoltaic cells are much cheaper than silicon because they’re made of inexpensive materials that can be simply painted or printed in...

Nanoparticles in the shape of cubes, octahedrons, and spheres coordinate with each other to build structures. The shapes are bound together by complementary DNA molecules on each type of particle. The structures of the resulting 3D crystals are determined by the spatial symmetry of the facets of the cubes and octahedrons, while their structural order depends on DNA-tuned interactions and the ratio of the nanoparticles’ sizes.

APPS: Directional binding for self-assembling materials made of different types of nanoparticles opens up opportunities to design unique materials that could benefit high-density energy storage devices and catalysis, among other applications.

The organization of spherical particles into lattices is typically driven by packing considerations...

It may offer an inexpensive new way to generate a freely movable microplasma, as well as yield insights into fundamental physics questions. It surprisingly also creates a mini light show, with the droplet sparking as it floats above a faint blue glowing gap. It is similar to Leidenfrost levitation — in which droplets dance on a hot vapor cushion. But by creating the vapor with a strong jolt of electricity instead of heat, the researchers found they could ionize the gas into a plasma that glowed a soft blue light.

“This method is probably an easy and original way to make a plasma,” said Cedric Poulain, a physicist at the French Alternative Energies and Atomic Energy Commission...

Experimental setup. The IR probe beam (CO2/FEL, red) is divided into two branches using a geometrical beam splitter (BS) (Au-evaporated Si wafer), which redirects part of the beam towards the s-SNOM Credit: http://www.nature.com/srep/2015/150728/srep12582/full/srep12582.html

Computer-assisted technology developed especially for this purpose combines the advantages of both methods and suppresses unwanted noise. This makes highly precise filming of dynamic processes at the nanometer scale possible eg photosynthesis or high-temperature superconductivity.

The new camera from Dresden enables unaltered optical measurements of extremely small, dynamic changes in biological, chemical or physical processes...