So far, it has been generally accepted knowledge that boron nitride nanotubes (BNNTs) are highly inert to oxidative treatments and can only be covalently modified by highly reactive species. By contrast, oxidation of carbon nanotubes has been proven very convenient and fundamentally important to modify the nanotube structure and morphology via controlled corrosive effects. Now, researchers have discovered a convenient method to disperse and chemically modify the morphology of BNNTs by sonication in aqueous ammonia solutions.
DNA is constantly being damaged in our cells by radiation and other random sources. One of the major forms of this damage is called depurination, or the selective loss of A and G bases from the double helix structure. In our cells, there is a system in place to fix depurination. It usually is quite successful at repairing the damage, but can sometimes make mistakes that result in mutations. As a result, depurination is directly linked to a host of diseases, including anemia and cancer. In new work, researchers show that DNA depurination can be detected electrically using solid-state nanopores.
A three-dimensional crumpled graphene-encapsulated nickel sulfide electrode is reported as a superior high-energy lithium storage material. Compared with an electrode without crumpled graphene encapsulation, the optimized electrode yields significant improvements, especially in the cycling stability and rate capability. This enhanced performance is attributed to the 3D framework providing high continuous electron pathway and more free space for charge and mass transfer, and the stabilizing effect of the crumpled graphene based stretchy shell.
Sulfur is a very intriguing solution for the design of high energy density storage devices. The lithium-sulfur battery theoretically delivers an energy density which is 3-5 times higher than traditional lithium-ion batteries. Unfortunately, several obstacles so far have prevented the practical demonstration of sulfur-based cathodes for Li-S batteries. Among them, the most important one is the rapid capacity fading. Researchers have now developed a novel strategy towards highly stable Li-S batteries by building a strongly coupled interface between surface- mediated carbon hosts and various sulfur-containing guests.
Researchers have now shown that, by varying the shape of magnetite nanoparticles, they can control the nature of the self-assembled structures as the nanoparticles assemble. This new work provides guidelines for the design of new self-assembled materials. Self-assembly of nanoparticles driven by competing forces can result in truly unique structures, the diversity and complexity of which could be particularly striking if the building blocks were simultaneously coupled by short- and long-range forces of different symmetries.
Researchers present an efficient design for a triple-junction organic tandem solar cell featuring a configuration of bandgap energies designed to maximize the tandem photocurrent output. The key innovation in this study is the demonstration of organic materials being able to mimic the record-setting efficiency of triple-junction structures in III-V solar cells. The team set out to determine a practical combination of bandgap energies for triple junctions to develop an efficient organic tandem solar cell structure.
It seems that computer memory technology is coming full circle. Pioneers in the early 19th century, such as Charles Babbage, first proposed the use of paper memory (albeit non-electronic), where a bit was stored as the presence or absence of a hole in a paper card. State-of-the-art research today again is proposing the use of paper as memory devices. This time, although he paper may be very similar, the bits are not crudely punched holes but nanofabricated device structures. In new work, researchers demonstrated a paper-based, nonvolatile memory device. Theyused a combination of inkjet and screen printing to fabricate resistive RAM memory cells on commercial printing paper.
Ever since its discovery in 2004, graphene has been considered a relatively stable, high surface area platform to anchor nanostructured catalyst materials for various electrochemical and photocatalytic applications. The emergence of solution-based graphene in the form of graphene oxide has enabled new wet-chemistry approaches to the creation of graphene-based nanocomposites. A new study raises questions about the long-term stability of reduced graphene oxide in an aqueous environment where hydroxyl radicals can be present as part of the photocatalytic reaction cycle.