Compact optical components are crucial to realize miniaturized optical systems and integrated optoelectronic devices. Plasmonic metasurfaces - structured materials in 2D with rationally designed, subwavelength-scale building blocks - have drawn great interest because they can control light based on subwavelength structures. These planar devices are attractive for applications ranging from high resolution imaging to 3D holography. New work describes the design and prototyping of single-crystalline TiN plasmonic metasurfaces based on subwavelength hole arrays.
Liquid crystals used in modern devices such as laptops, tablets and smartphones typically contain a small fraction of ionic contaminants. These ion contaminants can originate from multiple sources during the chemical synthesis of materials, in the process of assembling the device, and in its daily use.
In the case of LCDs, mobile ions in liquid crystals lead to such undesirable effects as image sticking, image flickering, and slow response. A promising solution to reduce the concentration of mobile ions in liquid crystal devices can be found by merging liquid crystals and nanotechnology.
Frost and ice accumulation result in significant decreases in the performance of ships, wind turbines, and heat exchangers. The use of active chemical, thermal, and mechanical methods of ice removal is time consuming and costly in operation. The development of passive methods to inhibit condensation, frost and ice formation is an attractive alternative. Examples are anoengineered anti-frost and anti-icing superhydrophobic and lubricant impregnated surfaces.
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.
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.
Following up on previous theoretical predictions, researchers now have demonstrated two high-yield methods for fabricating antimonenes - wide-band-gap semiconductors that under strain become direct band-gap semiconductors. Such dramatic transitions of electronic properties could open a new door for nanoscale transistors with high on/off ratio, blue/UV optoelectronic devices, and nanomechanical sensors based on new ultrathin semiconductors. The new approach is generic for various transparent conducting oxides as well as other oxide nanocrystal inks.