The oxygen reduction reaction (ORR) is the core process - but also the bottleneck - for the cathode reaction of energy-conversion devices like certain types of fuel cells and metal-air batteries. Nanocarbon materials are very promising alternatives for the noble metal catalysts, especially platinum, that have been used to boost this reaction. New work comprehensively reviews and correlates activity origins of nanocarbon-based ORR electrocatalysts, considering the dopants, edges, and defects. Specific doping at defective edges is expected to render practical applications for metal-free nanocarbon electrocatalysts.
Paper, probably the cheapest and most widely used flexible and eco-friendly material in daily life, is a promising substrate for making flexible devices ranging from electronics to microfluidics, energy storage and sensors. In new work, researchers have developed a new and reliable method to achieve conformal coating of individual cellulose fibers in the paper and the fabrication of a metal electrode via patterning of gold and silver layers on the coated paper.
Lanthanide dopants play an important role in desirable phase transformations of aluminum oxide (alumina) in order to achieve optimized physical and chemical properties. For example, the presence of dopants strengthens the grain boundaries of alumina, largely affecting its mechanical properties. New research indicates that there are significant structural changes to the lattice with addition of the dopant, and that understanding these effects will lead to future research for addressing these challenges.
Electrical contacts are essential components for any electrical device and when a lack of control over the final properties is present designing and optimising the system is impossible. The ability to define the contacts as Schottky or Ohmic with high or low resistance is complicated by the 2-D, 1-D or quasi 1-D nature of many nanomaterials. That's why researchers have developed a deep understanding of a unique effect at these length scales that occurs in nanowires and combines the synergistic relationship between metal nanocatalyst particles and nanowires.
Here are the 10 most popular Nanowerk Nanotechnology Spotlight articles of 2016. This year, the list includes nanotechnology in textiles; nanotechnology for next-generation inkjet color printing; graphene-based smart contact lens works as self-powered biosensor; nanotechnology's tiny steps toward atomic-scale 3D fabrication; stick-on epidermal electronics tattoo to measure UV exposure; a nanotechnology approach to scavenging wind and solar energy in cities; 3D printing highly conductive nanocomposites; using household items to make a multi-sensory 'Paper Skin'; an analogue smart skin that is self-powered; and writing nanotubes with a nano fountain pen.
Great effort has been applied on the controllable synthesis of ideal carbon nanotubes (CNTs). However, it's almost impossible to directly synthesize pure semiconducting CNTs by an in situ catalytic reaction alone, without any post-separation, when only small amounts of metallic CNTs may cause catastrophic device shorting failures. That is why the synthesis of CNTs with consistent chirality and high density is facing a bottleneck. A group of researchers in China have creatively proposed a novel method by entangling an individual decimeter-long CNT with a diameter of 2 nm into a large tangle with high density and consistent chirality.
Maximizing light absorption of nanomaterials has been an emerging research field in the recent years due to its attractiveness in a wide range of applications that involves conversion or utilization of solar energy. However, most of the concepts reported are based on multi-layered architecture inspired by optical impedance matching concepts that requires complicated non-scalable fabrication process such as electron beam lithography. Efforts on maximizing light absorption via nanostructuring remain scarce. Researchers have now reported such a material - a nanolayer of black gold.
With the exponential rise of power dissipation in electric devices such as integrated circuits or micro/nano electro mechanical systems (MEMS/NEMS), new thermal management solutions are in high demand. Thermal switches, being devices capable of controlling the temperature flow between two surfaces, are one of the solutions capable of effectively tackling this problem. In new work, researchers demonstrate an innovative magnetically actuated thermal switch based on nanofluids capable of controlling both the magnitude and direction of the heat flux. This device takes advantage of the thermal conductivity increase in magnetic nanofluids when submitted to an applied magnetic field parallel to the temperature gradient.