Phys.org July 2, 2021 As a proof-of-concept researchers at Kansas State University used graphene aerosol gel ink, synthesized via an energy efficient, catalyst-free, and nonhazardous chemical precursor detonation method, such as hydrocarbons (e.g., acetylene) in the presence of controlled oxygen. They used the ink to print microsupercapacitors in interdigitated electrodes (IDEs) geometry on 25-μm thick polyimide substrates using a micro plotter. The microsupercapacitors showed an aerial capacitance of 55 μF/cm2 and volumetric capacitance of 3.25 F/cm3 at a current density of 6.0 microamp/cm2 and 20 milliamp/cm3, respectively. The printed devices did not show a significant distortion in the cyclic voltammetry […]
Tag Archives: Advanced materials
The pressure is off and high temperature superconductivity remains
Phys.org July 8, 2021 The grand challenge in superconductivity research and development is no longer restricted to further increasing the superconducting transition temperature under extreme conditions and must now include concentrated efforts to lower, and better yet remove, the applied pressure required. An international team of researchers (USA – Houston University, Rice University, China) has shown such a possibility in the pure and doped high-temperature superconductor FeSe by retaining, at ambient pressure via pressure quenching, its Tc up to 37 K and other pressure-induced phases. They observed that some phases remain stable without pressure at up to 300 K and […]
Optical superoscillation without side waves
EurekAlert June 24, 2021 Optical superoscillation refers to a phenomenon of a wave packet that can oscillate locally faster than its highest Fourier component, which potentially produces an extremely localized wave in the far field. It provides an alternative way to overcome the diffraction limit and improve the resolution of an optical microscopy system. However, the optical superoscillatory waves are inevitably accompanied by strong side lobes, which limits their fields of view and, hence, potential applications. Researchers in China report both experimentally and theoretically a new superoscillatory wave form, which not only produces significant feature size down to deep subwavelength, […]
Transforming a van-der-Waals ferromagnet for future spintronics
Nanowerk June 28, 2021 An international team of researchers (Australia, China) demonstrated that ultra-high electron doping concentration (above 1021 cm-3) can be induced in the layered van der Waals (vdW) metallic material Fe5GeTe2 by proton intercalation and can further cause a transition of the magnetic ground state from ferromagnetism to antiferromagnetism. Compared to itinerant ferromagnets, antiferromagnets (AFMs) have unique advantages as building blocks of such future spintronic devices. Their robustness to stray magnetic fields makes them suitable for memory devices. All the samples showed that the ferromagnetic state can be gradually suppressed by increasing proton intercalation, and finally several samples […]
The first observation of the superscattering effect of metamaterials
Phys.org June 23, 2021 Superscattering effects, such as stopping wave propagation in an air channel, have not been verified from illusion devices physically because of the challenge of metamaterial design, fabrication, and material loss. Researchers in China have implemented a big metamaterial superscatterer, and experimentally demonstrated its superscattering effect at microwave frequencies by field-mapping technology. They confirmed that superscattering is originated from the excitation of surface plasmons. They experimentally showed that an invisible gateway integrated with superscatterer could stop electromagnetic waves in an air channel with a width much larger than the cutoff width of the corresponding rectangular waveguide. The […]
Cameras and telescopes as thin as a sheet of paper?
Nanowerk June 10, 2021 Metalenses promise to make imaging devices more compact. An international team of researchers (Canada, USA – University of Rochester) has addressed the space between the lenses which is crucial for image formation but takes up by far the most room in imaging systems, by introducing the idea of a spaceplate. They experimentally demonstrated that it is compatible with broadband light in the visible spectrum. They manipulated light based on the angle rather than the position of a light ray. Angle is a completely novel domain. They designed and experimentally demonstrated plates that compressed the space. Such […]
In a nano-optics breakthrough, researchers observe sound-light pulses in 2D materials (w/video)
Nanowerk June 10, 2021 An international team of researchers (Israel, Spain, France, USA – Kansas State University) shone pulses of light along the edge of a 2D material, producing in the material the hybrid sound-light waves. Not only were they able to record these waves, but they also found the pulses could spontaneously speed up and slow down. Surprisingly, the waves even split into two separate pulses, moving at different speeds. They developed a new technique to image the motion of light without disturbing it. According to the researchers having access to the full spatiotemporal dynamics of 2D wave packets […]
Lead halide perovskites – a horse of a different color
Nanowerk June 7, 2021 To capture the full range of the photophysical processes that occur in metal halide perovskites an international team of researchers (Sweden, Russia, Germany) has developed a novel spectroscopic technique for the study of charge carrier dynamics in lead halide perovskites. This methodology is based on the complete mapping of the photoluminescence quantum yield and decay dynamics in the 2D space of both fluence and frequency of the excitation light pulse. They offer a complete representation of the sample’s photo physics, allow examining the validity of theories by applying a single set of theoretical equations and parameters to […]
Online ‘library of properties’ helps to create safer nanomaterials
Nanowerk June 8, 2021 Under the European Union H2020-funded NanoSolveIT project an international team of researchers (Cyprus, UK) has developed a decision support system in the form of both stand-alone open software and a freely available cloud library containing full physicochemical characterisation of 69 nanomaterials, plus calculated molecular descriptors to increase the value of the available information. The dataset contains over 70 descriptors per nanomaterial. Over the last two years, this project has already presented some very impressive results with more than 30 publications, making NanoSolveIT one of the most active projects in the nanomaterials safety and informatics space. The […]
A quantum step to a heat switch with no moving parts
Science Daily June 7, 2021 Based on foundational theory a team of researchers in the US (Iowa State University, University of Ohio, University of Chicago) engineered an alloy with the elements bismuth and antimony at precise ranges. In this material electrons move like massless photons, a phenomenon theoretically predicted to exist. Under the influence of an external magnetic field some of the electrons generate energy, while others absorb energy, effectively turning the material into an energy pump resulting in 300% increase in its thermal conductivity. The mechanism is turned off if the magnet is taken away. This property, and the […]