Phys.org October 7, 2024 An international team of researchers (UK, Turkey) developed an experimentally informed predictive framework for autonomous sensing architected materials, combining theoretical and computational methodologies. The model incorporates stress-dependent electrical resistivity, geometric, and contact nonlinearities. It captures architecture-dependent piezoresistive responses of lattice composites produced via additive manufacturing of polyetherimide (PEI)/carbon nanotube (CNT) nanoengineered feedstock. The PEI/CNT composite exhibited exceptional strength, stiffness, and strain sensitivity, translating into remarkable piezoresistive characteristics for the PEI/CNT lattice composites, surpassing existing works. It accurately predicts both macroscopic piezoresistive responses and the influence of architectural and topological variations on electric current paths. According to […]
Tag Archives: Materials science
Nanoscale method boosts materials for advanced memory storage
Phys.org October 7, 2024 Hierarchical assemblies of ferroelectric nanodomains can exhibit exotic morphologies that lead to distinct behaviours. Controlling these super-domains reliably is critical for realizing states with desired functional properties. A team of researchers in the US (Oak Ridge National Laboratory, University of Texas at Arlington, UC Berkeley, Lawrence Berkeley National Laboratory, Rice University) described the super-switching mechanism by using a biased atomic force microscopy tip of a model ferroelectric Pb0.6Sr0.4TiO3. They demonstrated that the writing process was dominated by a super-domain nucleation and stabilization process. A complex scanning-probe trajectory enabled on-demand formation of intricate centre-divergent, centre-convergent and flux-closure […]
Light momentum turns pure silicon from an indirect to a direct bandgap semiconductor
Phys.org September 20, 2024 Photons do not carry sufficient momentum to induce indirect optical transitions in semiconducting materials, such as silicon, necessitating the assistance of lattice phonons to conserve momentum. Therefore, silicon is a less attractive material for a wide variety of optoelectronic applications. An international team of ranchers (Russia, Israel, USA – UC Irvine) introduced an alternative strategy to fulfill the momentum-matching requirement in indirect optical transitions. They demonstrated that when confined to scales below ∼3 nm, photons acquired sufficient momentum to allow electronic transitions at the band edge of Si without the assistance of a phonon. Confined photons […]
2D silk protein layers on graphene pave the way for advanced microelectronics and computing
Phys.org September 18, 2024 A team of researchers in the US (Pacific Northwest National Laboratory, University of Washington, Lawrence Berkeley National Laboratory, North Carolina State University) developed highly ordered two-dimensional silk fibroin (SF) films grown epitaxially on van der Waals (vdW) substrates. They showed that the films consisted of lamellae of SF molecules that exhibited the same secondary structure as the nanocrystallites of native silk. Increasing the SF concentration resulted in multilayers that grew either by direct assembly of SF molecules into the lamellae or, at high concentrations, along a two-step pathway beginning with a disordered monolayer that crystallizes. They […]
First flexible perovskite solar cells on polycarbonate films
Nanowerk September 14, 2024 Despite its widespread use in many applications, poor chemical resistance and roughness of polycarbonate (PC) has hindered its adoption as a substrate in solar cell technologies. An international team of researchers (Italy, Germany, Iran) developed a solution-processed planarizing layer using a commercial ambient-curable refractory resin through blade coating. Blade coating decreased film roughness from 1.46 µm to 23 nm, lowered water vapor transmission rates (WVTR) by a half, and significantly improved solvent resistance enabling deposition of precursor inks. The power conversion efficiency (PCE) reached 13.0%. The unencapsulated PSCs retained 80% of initial PCE after 1776 h […]
New method improves understanding of light-wave propagation in anisotropic materials
Phys.org September 17, 2024 Although structurally anisotropic materials are ubiquitous in several application fields, their accurate optical characterization remains challenging due to the lack of general models linking their scattering coefficients to the macroscopic transport observables and the need to combine multiple measurements to retrieve their direction-dependent values. An international team of researchers (Italy, Slovenia, Germany) developed an improved method for the experimental determination of light-transport tensor coefficients from the diffusive rates measured along all three directions, based on transient transmittance measurements and a generalized Monte Carlo model. They applied their method to the characterization of light-transport properties in two […]
Research team uses terahertz pulses of light to shed light on superconducting disorder
Phys.org September 16, 2024 Inhomogeneities crucially influence the properties of quantum materials, yet methods that can measure them remain limited and can access only a fraction of relevant observables. However, complementary techniques that can resolve higher-order correlations are needed to elucidate the nature of the inhomogeneities. And local tunnelling probes are often effective only far below the critical temperature. An international team of researchers (Germany, USA – Brookhaven, Harvard University, Cornell University, Stony Brook University, Switzerland, UK) developed a two-dimensional terahertz spectroscopy method to measure Josephson plasmon echoes from an interlayer superconducting tunnelling resonance in a near-optimally doped cuprate. The […]
This screen stores and displays encrypted images without electronics
Nanowerk September 17, 2024 While computation functions have been demonstrated in mechanical systems, they rely on compliant mechanisms to achieve predefined states, which impose inherent design restrictions that limit their miniaturization, deployment, reconfigurability, and functionality. Researchers at the University of Michigan describe a metamaterial system based on responsive magnetoactive Janus particle (MAJP) swarms with multiple programmable functions. They designed MAJPs with tunable structure and properties in mind, that is, encoded swarming behavior and fully reversible switching mechanisms, to enable programmable dynamic display, non-volatile and semi-volatile memory, Boolean logic, and information encryption functions in soft, wearable devices. According to the researchers […]
Novel glass-forming liquid electrolyte shows glass transition across broad range
Phys.org September 4, 2024 Recently new ionic fluids such as super-concentrated electrolyte solutions, solvate ionic liquids and deep eutectic solvents have attracted much attention in the field of liquid electrolytes for next-generation electrochemical devices and processes. The basic composition of these new ionic fluids is similar among them; a solvent and a large/excess amount of salt mixtures, though the solvent is sometimes a solid at ambient temperatures. Researchers in Japan found and demonstrated that LiTFSA (TFSA = (CF3SO2)2N−) mixtures with 1,3-propane sultone (PS) or tetrahydrothiophene-1,1-dioxide (SL) yielded a homogeneous liquid at room temperature within a wide range of compositions. In […]
Study of disordered rock salts leads to battery breakthrough
MIT News August 23, 2024 Co- and Ni-free disordered rock salt cathodes utilize oxygen redox to increase the energy density of lithium-ion batteries, but it is challenging to achieve good cycle life at high voltages >4.5 V. An international team of researchers (USA – MIT, Pennsylvania State University, Argonne National Laboratory, Lawrence Berkeley National Laboratory, Brookhaven National Laboratory, South Korea, Canada, China, Taiwan) found a family of Li-excess Mn-rich cathodes that integrates rock salt- and polyanion-type structures. Following design rules for cation filling and ordering, they demonstrated the bulk incorporation of polyanion groups into the rock salt lattice. This integration bridged […]