News from the NNI Community - Research Advances Funded by Agencies Participating in the NNI

Lithium-ion batteries work by moving lithium ions back and forth between two electrodes that temporarily store charge. Ideally, those ions are the only things moving in and out of the billions of nanoparticles that make up each electrode. But oxygen atoms leak out of the nanoparticles as lithium moves back and forth. So far, the details have been hard to pin down because the signals from these leaks are too small to measure directly. Now, researchers from Stanford University, the U.S. Department of Energy’s Lawrence Berkeley National Laboratory, the U.S. Department of Energy's SLAC National Accelerator Laboratory, and Samsung Advanced Institute of Technology in South Korea have measured the leakage by looking at how oxygen loss modifies the chemistry and structure of the nanoparticles.

Engineers at Rice University have unveiled how a popular two-dimensional material, #MolybdenumDisulfide, flashes into existence during chemical vapor deposition. Knowing how the process works will give scientists and engineers a way to optimize the bulk manufacture of molybdenum disulfide and semiconducting crystals that are good bets to find a home in next-generation electronics. Chemical vapor deposition, often associated with graphene and carbon nanotubes, has been exploited to make a variety of two-dimensional materials by providing solid precursors and catalysts that sublimate into gas and react.

Widespread adoption of hydrogen-powered vehicles over traditional electric vehicles requires fuel cells that can convert hydrogen and oxygen safely into water – a serious implementation problem. Researchers at the University of Colorado Boulder and the University of California, Los Angeles, are addressing one aspect of that roadblock by developing new computational tools and models to better understand and manage the conversion process. The researchers developed models for metal nanostructures and oxygen, water, and metal interactions that are more than 10 times more accurate than current quantum methods.

A research team from the University of Massachusetts Amherst has created an electronic microsystem that can intelligently respond to information inputs without any external energy input, much like a self-autonomous living organism. The microsystem is constructed from a novel type of electronics that can process ultralow electronic signals and incorporates a device that can generate electricity from the ambient environment. Both of the key components of the microsystem are made from protein nanowires, a "green" electronic material that is renewably produced from microbes without generating electronic waste.

About 60% of drugs on the market have hydrophobic molecules as their active ingredients. These drugs, which are not soluble in water, can be difficult to formulate into tablets because they need to be broken down into nanocrystals to be absorbed by the human body. Now, a team of MIT chemical engineers has devised a simpler process for incorporating hydrophobic drugs into tablets or other drug formulations, such as capsules and thin films. Their technique, which involves creating a nanoemulsion of the drug and then crystallizing it, allows for a more powerful dose to be loaded per tablet. 

A team of researchers at the University of Pennsylvania and the University of Michigan has developed a blueprint for designing new materials using difficult combinations of nanocrystals. The work could lead to improvements in nanocrystals already used in displays, medical imaging, and diagnostics, and could enable new materials with previously impossible properties.

Engineers at MIT have discovered a new way of generating electricity using tiny carbon particles that can create a current simply by interacting with liquid surrounding them. The carbon particles are made of high-surface-area single-walled carbon nanotube networks. The liquid, an organic solvent, draws electrons out of the particles, generating a current that could be used to drive chemical reactions or to power micro- or nanoscale robots.

Hydrogels are commonly used inside the body to help in tissue regeneration and drug delivery, but once inside the body, they can be challenging to control for optimal use. A team of researchers at Texas A&M University is now developing a new way of manipulating the gel by using light. The team is using a new class of two-dimensional nanomaterials known as molybdenum disulfide, which has shown negligible toxicity to cells and superior near-infrared light absorption. These nanosheets with high photothermal conversion efficiency can absorb and convert near-infrared light to heat, which can be developed to control thermoresponsive materials.

Researchers at the University of Southern California, Los Angeles, have shown that when water comes into contact with an electrode surface, all of its molecules do not respond in the same way. The researchers designed a unique electrode built from monolayer graphene, placed it on a cell of water, and ran a current through the electrode. The scientists observed that the top layer of water molecules closest to the electrode aligned in a completely different way than the rest of the water molecules. This discovery was unexpected and could enable more accurate simulations of how aqueous chemical reactions affect the materials they work with.

Researchers from Cornell University and Harvard University have developed a technology that uses nanoscale sensors and fiber optics to measure how much water is present inside a leaf’s surface. The engineering feat provides a minimally invasive research tool that will greatly advance the understanding of basic plant biology, and open the door for breeding more drought-resistant crops. The technology could eventually be adapted for use as an agronomic tool for measuring water status in crops in real time.