An intelligent soft material that curls under pressure or expands when stretched

Nanowerk  February 24, 2021 Existing perceptive soft actuators require complex integration and coupling between the discrete functional units to achieve autonomy and intelligently interact with humans and the environment. Researchers in China have developed actuators with embodied sensing, actuation, and control at the single-unit level by synergistically harnessing the mechanosensing and electrothermal properties of liquid metal (LM) to actuate the thermally responsive liquid crystal elastomer (LCE). They created multifunctional LM circuits on the LCE surface using a simple and facile methodology based on magnetic printing. The fluidic LM circuit can be utilized as a conformable resistive heater, and a sensory […]

Magnetic effect without a magnet

Nanowerk  February 22, 2021 An international team of researchers (Austria, Switzerland, Canada, USA – Rice University) found Ce3Bi4Pd3 produced a giant Hall effect in the total absence of any magnetic field and showed that the strange phenomenon is due to the complicated interaction of the electrons. Specific symmetries of the atoms determine the dispersion relation, the relationship between the energy of the electrons and their momentum. This complex interaction results in phenomena that mathematically look as if there are magnetic monopoles in the material which do not exist in this form in nature. But it has the effect of a […]

Breakthrough material can protect satellites from ultraviolet radiation and atomic oxygen in low-Earth orbit

Phys.org  February 16, 2021 Atomic oxygen is created when O2 molecules break apart, a process made easier in space because of the abundance of ultraviolet radiation affecting the structural integrity of space structures. An international team of researchers (UK, Germany) has developed a nano-barrier that bonds to the surface of polymer or composite materials, protecting them from erosion in low-Earth orbit without disrupting the functional performance of the space structure. The multilayered protection barrier deposited via a custom-built plasma-enhanced chemical vapor deposition system is designed to deposit all necessary layers without breaking vacuum to maximize the adhesion to the surface […]

‘Magnetic graphene’ forms a new kind of magnetism

EurekAlert  February 8, 2021 An international team of researchers ( UK, Uzbekistan, Russia, France, USA – Oak Ridge National Laboratory, Vietnam, South Korea, Czech Republic) was able to control the conductivity and magnetism of iron thiophosphate (FePS3) which undergoes a transition from an insulator to a metal when compressed. Using new techniques to measure the magnetic structure up to record-breaking high pressures, they found that magnetism survives, but gets modified into new forms, giving rise to new quantum properties in a new type of magnetic metal. The ‘spin’ of the electrons has been shown to be the source of magnetism. […]

An optical coating like no other

Nanowerk  February 5, 2021 An international team of researchers (USA – University of Rochester, Case western University, Italy) applied a 15 nanometer-thick film of germanium to a metal surface resulting in a surface capable absorbing a broad band of wavelengths. Combining it with a cavity that supports a narrowband resonance resulted in coupled cavities that exhibit Fano resonance that can reflect a very narrow band of light. The semi-transparent Fano resonance optical coationgs (FROCs) can transmit and reflect the same colour as a beam splitter filter. FROCs can spectrally and spatially separate the thermal and photovoltaic bands of the solar spectrum, […]

Scientists create armor for fragile quantum technology

Phys.org  February 8, 2021 Integration of TMDCs into practical all‐dielectric heterostructures hinges on the ability to passivate and protect them against necessary fabrication steps on large scales. An international team of researchers (Australia, Germany) has created the protective layer by exposing a droplet of liquid gallium to air, which immediately formed a perfectly even three nanometers thick layer of gallium oxide on its surface. By squashing the droplet on top of the 2D material with a glass slide, the gallium oxide layer can be transferred from the liquid gallium onto the material’s entire surface, up to centimetres in scale. Because […]

Research could dramatically lower cost of electron sources

Phys.org  February 1, 2021 An international team of researchers (USA – Los Alamos National Laboratory, Rice University, Northwestern University, France) has discovered efficient, regenerative, and low-cost electron sources based on solution-processed halide perovskites thin films when they are excited with light with energy equal to or above their bandgap. They measured a quantum efficiency up to 2.2% and a lifetime of more than 25 h. Importantly, even after degradation, the electron emission could be completely regenerated to its maximum efficiency by deposition of a monolayer of alkali antimonide and tellurides (Cs2Te, K2CsSb, Cs3Sb). The electron emission from halide perovskites can be […]

Researchers construct molecular nanofibers that are stronger than steel

MIT News  January 25, 2021 Small-molecule self-assembly is an established route for producing high-surface-area nanostructures with readily customizable chemistries and precise molecular organization. The whole structure falls apart when you remove water, particularly when any kind of external force is applied. An international team of researchers (USA – MIT, Argonne National Laboratory, France) has shown that a small-molecule platform, the aramid amphiphile overcomes these dynamic instabilities by incorporating a Kevlar-inspired domain into the molecular structure. Strong, anisotropic interactions between aramid amphiphiles suppress molecular exchange and elicit spontaneous self-assembly in water to form nanoribbons with lengths of up to 20 micrometres. […]

Solar material can ‘self-heal’ imperfections, new research shows

Phys.org  January 27, 2021 Broken bonds introduced at extended defects in covalently bonded semiconductors generally introduce deep electronic states within the gap, negatively impacting performance for applications in electronics, photochemistry, and optoelectronics. Researchers in the UK found that Sb2Se3 and Sb2S3, which show exceptional promise for photovoltaic and photoelectrochemical applications, exhibit a remarkable ability to self‐heal broken bonds through structural reconstructions, thereby eliminating the associated deep electronic states. These materials appear intrinsically resilient to the formation of dangling bonds at extended defects, which should be advantageous for a wide range of applications. They could reduce costs and improve scalability of […]

New metamaterial offers reprogrammable properties

Science Daily  January 22, 2021 Researchers in Switzerland have developed metamaterial made of silicon and magnetic powder which has a complicated structure that allows mechanical properties to vary. Each cell within the structure behaves like an electrical switch. It is possible to activate and deactivate individual cells by applying a magnetic field which modifies the internal state of the metamaterial, and consequently its mechanical properties. The programmable material is analogous to computer devices like hard drives. The devices contain bits of data that can be written to and read from in real time. The cells in this programmable metamaterial, called […]