Molecular interfaces for innovative sensors and data storage devices

Nanowerk October 20, 2021 To better understand electronic and magnetic properties and understanding the mechanisms that govern the interactions at the interface an international team of researchers (Germany, Austria, Switzerland, Italy) coupled nickel-porphyrin with copper. Using theoretical and experimental spectro-microscopy approach they showed that the charge transfer occurring at the interface between nickel tetraphenyl porphyrins and copper changes both spin and oxidation states of the Ni ion. The chemically active Ni(I), even in a buried multilayer system, can be functionalized with nitrogen dioxide, allowing a selective tuning of the electronic properties of the Ni center that is switched to a […]

Tuning transparency and opacity

Phys.org  October 18, 2021 Recently, a new type of wavefront shaping was introduced where the extinction is manipulated instead of the scattered intensity. The underlying idea is that upon changing the phases or the amplitudes of incident beams, the total extinction will change due to interference described by the cross terms between different incident beams. Researchers in the Netherlands have experimentally demonstrated the mutual extinction and transparency effects in scattering media a human hair and a silicon bar. They sent two light beams with a variable mutual angle on the sample. Depending on the relative phase of the incident beams, they […]

Deadly virus’s pathway to infect cells identified

Science Daily  September 23, 2021 Rift Valley fever virus (RVFV) is a zoonotic pathogen with pandemic potential. RVFV entry is mediated by the viral glycoprotein (Gn), but host entry factors remain poorly defined. An international team of researchers (USA – Washington University, University of Pittsburgh, Harvard University, MIT, Canada) conducted genome-wide CRISPR screen and identified low-density lipoprotein receptor-related protein 1 (mouse Lrp1/human LRP1), heat shock protein (Grp94), and receptor-associated protein (RAP) as critical host factors for RVFV infection. RVFV Gn directly binds to specific Lrp1 clusters and is glycosylation independent. Exogenous addition of murine RAP domain 3 (mRAPD3) and anti-Lrp1 […]

Lead-free rare-earth-based double perovskite nanocrystals with near-infrared emission

Nanowerk  September 9, 2021 Researchers in China synthesized all-inorganic rare-earth-based Cs2NaEr1−xBxCl6 double perovskite nanocrystals. The Cs2NaErCl6 NCs showed good air stability and emitted a sharp NIR photoluminescence at telecommunication wavelength of 1543 nm and its average lifetime is 35.7 µs. For Cs2NaEr0.5Sb0.5Cl6 nanocrystals NIR photoluminescence could be enhanced 23-fold with the lifetime being 119.1 µs. Femtosecond transient absorption measurements proved that a long-lifetime trap state promotes NIR emitting in the mixed Sb/Er double perovskite nanocrystals…read more. TECHNICAL ARTICLE 

New form of carbon in a mesh tantalizes with prospects for electronics

Nanowerk August 27, 2021 Biphenylene network is highly conductive and may prove able to store more electrical energy than even graphene. However, their syntheses remain challenging given the lack of reliable protocols for generating nonhexagonal rings during the in-plane tiling of carbon atoms. An international team of researchers (Germany, Finland, Japan) has grown an ultraflat biphenylene network with periodically arranged four-, six-, and eight-membered rings of sp2-hybridized carbon atoms through an on-surface interpolymer dehydrofluorination (HF-zipping) reaction. The characterization of this biphenylene network by scanning probe methods reveals that it is metallic rather than a dielectric. They expect the interpolymer HF-zipping […]

Achilles heel of graphene exposed

Nanowerk July 19, 2021 The quantum Hall effect is the seminal example of topological protection as charge carriers are transmitted through one-dimensional edge channels where backscattering is prohibited. In conventional Hall bar geometries, topological protection of graphene edge channels is found less robust than in high mobility semi-conductors. An international team of researchers (Belgium, Germany, Japan) exploring graphene quantum Hall regime at the local scale revealed that the detrimental influence of antidots along the graphene edges, mediating backscattering towards upstream edge channels triggering topological breakdown. The finding is a major step forward in the understanding of the quantum Hall effect […]

Nanostructures enable record high-harmonic generation

Phys.org July 21, 2021 Resonantly enhanced High harmonic generation (HHG) from hot spots in nanostructures is an attractive route to overcoming the well-known limitations of gases and bulk solids. An international team of researchers (USA – Cornell University, Ohio State University, Singapore) demonstrated an ultra-thin resonant gallium phosphide platform for highly efficient HHG driven by intense mid-infrared laser pulses. The gallium-phosphide material permits harmonics of all orders without reabsorbing them, and the specialized structure can interact with the laser pulse’s entire light spectrum. The enhanced conversion efficiency facilitates single-shot measurements that avoid material damage and pave the way to study […]

Graphene additive manufacturing for flexible and printable electronics

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 […]

Bending light for safer driving; invisibility cloaks to come?

Nanowerk June 15, 2021 Perfect optical cloaking requires the total scattering of electromagnetic waves around an object at all angles, all polarizations, over a wide frequency range, irrespective of the medium. By simplifying the invisibility requirements, pioneering work on spherical transformation cloaks, carpet cloaks, plasmonic cloaks, and mantle cloaks has been realized in narrowband microwave, infrared, and even optical wavelengths. In a tutorial a team of researchers in the US (University of Michigan, industry) review the theoretical basis for invisibility cloaking, from spherical transformational optics to non-Euclidian cases, and discuss their limitations. Because the human eye is insensitive to the […]

Surpassing the lower limit on computing energy consumption

Phys.org April 20, 2021 Researchers in Australia have confirmed the potential for topological materials to substantially reduce the energy consumed by computing. They demonstrated that the subthreshold swing of a topological transistor in which conduction is enabled by a topological phase transition via electric field switching, can be sizably reduced in a noninteracting system by modulating the Rashba spin–orbit interaction. By developing a theoretical framework for quantum spin Hall materials with honeycomb lattices, they showed that the Rashba interaction can reduce the subthreshold swing by more than 25% compared to Boltzmann’s limit in currently available materials but without any fundamental […]