BINA

Speedy and selective detection of sensing targets is of great interest to researchers from diverse fields. Dominated by excitations of intramolecular and intermolecular vibrations, the emerging terahertz (THz) spectroscopy offers both molecular fingerprint information and biosensing abilities, which is excellent for speedy and selective sensing applications. In this review, we focus on THz selective sensing principles and introduce three frequently utilized methods enabled by THz fingerprints, the interaction between THz absorption of molecules and plasmonic resonances, and THz metamaterial biosensors. The recent progress of THz selective sensing implementations including detections of gas molecules, solid molecules, protein, nucleic acid, cells, and viruses are also summarized. We note that current THz sensing research is multidisciplinary and has led cross-disciplinary collaborations between physics and …

Quantum materials have a fascinating tendency to manifest novel and unexpected electronic states upon proper manipulation. Ideally, such manipulation should induce strong and irreversible changes and lead to new relevant length scales. Plastic deformation introduces large numbers of dislocations into a material, which can organize into extended structures and give rise to qualitatively new physics as a result of the huge localized strains. However, this approach is largely unexplored in the context of quantum materials, which are traditionally grown to be as pristine and clean as possible. Here we show that plastic deformation induces robust magnetism in the quantum paraelectric SrTiO3, a property that is completely absent in the pristine material. We combine scanning magnetic measurements and near-field optical microscopy to find that the magnetic order is localized along dislocation walls and coexists with …

Electrolyte solution composition strongly affects the performance of Li-ion batteries in terms of their general electrochemical properties, electrode stability, cycle life, long-term stability (especially at elevated temperatures), and safety. Additives are essential constituents of efficient electrolyte systems for advanced batteries. Their nature and chemical identity are highly diverse, and their modes of action are sometimes not fully understood, seemingly related to “alchemy”. Additives play a crucial role in stabilizing interfaces, enhancing cycle life, and significantly improving safety. Here, a wide scope of additives used in rechargeable Li batteries is examined. Various additives are surveyed emphasizing the importance of their functional groups. We examine routes for judicious optimization of electrolyte solutions by selecting suitable additives for improved rechargeable batteries. As there are many types of additives, their …

Significance A better understanding of diffusion reflection (DR) behavior may allow it to be used for more noninvasive applications, including the development of in vivo non-damaging techniques, especially for medical topical diagnosis and treatments. Aim For a bilayer opaque substance where the attenuation of the upper layer is larger than the attenuation of the lower layer, the DR crossover point () is location where the photons coming from the bottom layer start affecting the DR. We aim to study the dependency of the on absorption changes in different layers for constant scattering and top layer thickness. Approach Monolayer and bilayer optical tissue-like phantoms were prepared and measured using a DR system. The results were compared with Monte Carlo simulations. Results There is an agreement between the experiments and the simulations. correlates with the square root of the absorption coefficient ratio …

In recent years, there has been a lot of interest in biodegradable surface-engineered iron oxide nanoparticles (IONPs) because they could be used in drug delivery and other biomedical fields. This chapter gives an overview of the current state of research on how to make biodegradable IONPs, how to engineer their surfaces, and how to make them work for drug delivery and other biomedical applications. Because these nanoparticles are biodegradable, they will break down and leave the body in a safe way, reducing worries about toxicity. Also, the surface of IONPs can be changed to make them more stable, biocompatible, and able to target specific cells or tissues. This makes it easier for drugs to get to where they need to go. The review talks about how natural polymers, peptides, and targeting ligands are used to change the surface, as well as how these changes affect the physicochemical properties and …

Recent advances in DNA nanotechnology allow for the assembly of nanocomponents with nanoscale precision, leading to the emergence of DNA-based material fabrication approaches. Yet, transferring these nano- and micron-scale structural arrangements to the macroscale morphologies remains a challenge, which limits the development of materials and devices based on DNA nanotechnology. Here, we demonstrate a materials fabrication approach that combines DNA-programmable assembly with actively driven processes controlled by acoustic fields. This combination provides a prescribed nanoscale order, as dictated by equilibrium assembly through DNA-encoded interactions, and field-shaped macroscale morphology, as regulated by out-of-equilibrium materials formation through specific acoustic stimulation. Using optical and electron microscopy imaging and x-ray scattering, we further revealed the …

Due to quasi-one-dimensional confinement, nanowires possess unique electronic properties, which can promote specific device architectures. However, nanowire growth presents paramount challenges, limiting the accessible crystal structures and elemental compositions. Here we demonstrate solid-state topotactic exchange that converts wurtzite InAs nanowires into Zintl Eu3In2As4. Molecular-beam-epitaxy-based in situ evaporation of Eu and As onto InAs nanowires results in the mutual exchange of Eu from the shell and In from the core. Therefore, a single-phase Eu3In2As4 shell grows, which gradually consumes the InAs core. The mutual exchange is supported by the substructure of the As matrix, which is similar across the wurtzite InAs and Zintl Eu3In2As4 and therefore is topotactic. The Eu3In2As4 nanowires undergo an antiferromagnetic transition at a Néel temperature of ~6.5 K. Ab initio calculations …

The fundamental question of “what is the transport path of electrons through proteins?” initially introduced while studying long-range electron transfer between localized redox centers in proteins in vivo is also highly relevant to the transport properties of solid-state, dry metal–protein–metal junctions. Here, we report conductance measurements of such junctions, Au-(Azurin monolayer ensemble)-Bismuth (Bi) ones, with well-defined nanopore geometry and ~103 proteins/pore. Our results can be understood as follows. (1) Transport is via two interacting conducting channels, characterized by different spatial and time scales. The slow and spatially localized channel is associated with the Cu center of Azurin and the fast delocalized one with the protein’s polypeptide matrix. Transport via the slow channel is by a sequential (noncoherent) process and in the second one by direct, off-resonant tunneling. (2) The two …

The ratio of Sr/Ca ions in marine biogenic minerals is considered advantageous for tracking geochemical and biomineralization processes that occur in the oceans. It is debatable, though, whether the ratio in biominerals such as coral skeleton is simply related to values in the seawater environment or controlled by the organism. Recent data show that coral larvae produce partially disordered immature aragonite in Mg-containing Sr-poor calcifying fluids, which transforms into well-ordered aragonite in Mg-depleted Sr-enriched environments, upon animal metamorphosis into the sessile polyp state.Inspired by the process in young coral, we explored in vitro substitution of Ca by Sr in aragonite by exposing aragonite crystals precipitated a priori to Sr solutions with variable concentrations. The resulting biphasic material, comprised of Sr-doped aragonite and Ca-doped strontianite, was carefully analyzed for foreign …

The use of plasmonic particles, specifically, localized surface plasmonic resonance (LSPR), may lead to a significant improvement in the electrical, electrochemical, and optical properties of materials. Chemical modification of the dielectric constant near the plasmonic surface should lead to a shift of the optical resonance and, therefore, the basis for color tuning and sensing. In this research, we investigated the variation of the LSPR by modifying the chemical environment of Ag nanoparticles (NPs) through the complexation of Pt(IV) metal cations near the plasmonic surface. This study is carried out by measuring the shift of the plasmon dipole resonance of Ag nanocubes (NCs) and nanowires (NWs) of differing sizes upon coating the Ag surface with a layer of polydopamine (PDA) as a coordinating matrix for Pt(IV) complexes. The red shift of up to 45 nm depends linearly on the thickness of the PDA/Pt(IV) layer and the …

Control of catalyst morphology is important because it affects many catalytic related properties such as, active sites, surface energy, and surface area, which can lead to tunable catalytic activity. Nanoporous metallic networks (NPMs), a morphology of interest for catalysis, contain many uncoordinated atoms at the surface and highly curved ligaments that can have a large effect on catalytic performance. Nanoporous self-supported metal structures have been synthesized in the past by dealloying of a master alloy,[1] which is a wet chemical method. This technique uses an Au-Ag alloy, from which Ag is etched away and which always results in NPMs containing residual amounts of the sacrificial metal (Ag) preventing the formation of high-purity structures. It follows that the catalytic properties of pure NPMs formed by dealloying can not be studied due to metal 'impurities' remaining in the structure. Although these …

SignificanceA better understanding of diffusion reflection (DR) behavior may allow it to be used for more noninvasive applications, including the development of in vivo non-damaging techniques, especially for medical topical diagnosis and treatments.AimFor a bilayer opaque substance where the attenuation of the upper layer is larger than the attenuation of the lower layer, the DR crossover point () is location where the photons coming from the bottom layer start affecting the DR. We aim to study the dependency of the on absorption changes in different layers for constant scattering and top layer thickness.ApproachMonolayer and bilayer optical tissue-like phantoms were prepared and measured using a DR system. The results were compared with Monte Carlo simulations.ResultsThere is an agreement between the experiments and the simulations. correlates with the square root of the absorption coefficient ratio …

Significance: A better understanding of diffusion reflection (DR) behavior may allow it to be used for more noninvasive applications, including the development of in vivo non-damaging techniques, especially for medical topical diagnosis and treatments.Aim: For a bilayer opaque substance where the attenuation of the upper layer is larger than the attenuation of the lower layer, the DR crossover point (Cp) is location where the photons coming from the bottom layer start affecting the DR. We aim to study the dependency of the Cp on absorption changes in different layers for constant scattering and top layer thickness.Approach: Monolayer and bilayer optical tissue-like phantoms were prepared and measured using a DR system. The results were compared with Monte Carlo simulations.Results: There is an agreement between the experiments and the simulations. Cp correlates with the square root of the absorption …

Speedy and selective detection of sensing targets is of great interest to researchers from diverse fields. Dominated by excitations of intramolecular and intermolecular vibrations, the emerging terahertz (THz) spectroscopy offers both molecular fingerprint information and biosensing abilities, which is excellent for speedy and selective sensing applications. In this review, we focus on THz selective sensing principles and introduce three frequently utilized methods enabled by THz fingerprints, the interaction between THz absorption of molecules and plasmonic resonances, and THz metamaterial biosensors. The recent progress of THz selective sensing implementations including detections of gas molecules, solid molecules, protein, nucleic acid, cells, and viruses are also summarized. We note that current THz sensing research is multidisciplinary and has led cross-disciplinary collaborations between physics and …

Raman spectroscopy is an extremely powerful laser-based method for characterizing materials based on their unique inelastic scattering spectrum. Ultimately, the power of the technique is limited by the resolution of the spectrometer. Here we introduce a new method for achieving Super-Spectral-Resolution Raman Spectroscopy (SSR-RS), by angle-tuning a Fabry–Perot (F-P) etalon filter that we incorporated in a micro-Raman setup. A monolithically coated F-P etalon structure, only 1.686 mm in thickness, was mounted onto an angle-tunable motorized stage, and Raman spectra were automatically acquired for many different angles of the etalon. Using a low-resolution grating of 150 g/mm by itself, without the F-P etalon, we obtained a best-case Regular-Raman spectral resolution of 44 cm−1 for the characteristic Raman peak from a diamond sample. When we applied the SSR-RS technique to diamond, we …

Acoustic-directed assembly is a modular and flexible bottom-up technique with the potential to pattern a wide range of materials. Standing acoustic waves have been previously employed for patterning preformed metal particles, however, direct patterning of metallic structures from precursors remains unexplored. Here, we investigate utilization of standing waves to exert control over chemical reaction products, while also exploring their potential in the formation of multi-layered and composite micro-structures. Concentric micro-structures of gold and silver were obtained by introducing a metal precursor salt and a reducing agent into a cylindrical piezoelectric resonator that also served as a reservoir. In addition, we introduce an innovative approach to directly fabricate metallic multi-layer and composite structures by reducing different metal ions or adding nanoparticles during the reduction step. We showcased our …

Planar Hall effect (PHE) magnetic sensors are attractive for various applications where the field resolution is required in the range of sub-nano Tesla or in Pico Tesla. Here we present a detailed noise study of the PHE sensors consisting of two or three intersecting ellipses. It can be used to measure two axes of the magnetic field in the sensor plane in particular along the two perpendicular easy axes in the overlapping region for two intersecting ellipses and three easy axes at an angle of 60 degrees for three crossing ellipses. Thus, for each remanent magnetic state in the overlap area, the sensor can measure the vector component of the magnetic field perpendicular to the direction of the remanent magnetization. The two field components are measured with a field resolution ≤ 200 pT/√Hz at 10 Hz and 350 pT/√Hz at 1 Hz in the same region, while maintaining a similar size and noise level of a single-axis sensor …

Most next-generation electrode materials are prone to interfacial degradation, which eventually spreads to the bulk and impairs electrochemical performance. One promising method for reducing interfacial degradation is to surface engineer the electrode materials to form an artificial cathode electrolyte interphase as a protective layer. Nevertheless, the majority of coating techniques entail wet processes, high temperatures, or exposure to ambient conditions. These experimental conditions are only sometimes conducive and can adversely affect the material structure or composition. Therefore, we investigate the efficacy of a low-temperature, facile atomic surface reduction (ASR) using trimethylaluminum vapors as a surface modification strategy for Li and Mn-rich NCM (LMR-NCM). The results presented herein manifest that the extent of TMA-assisted ASR is temperature-dependent. All tested temperatures …

Accessing the low-energy non-equilibrium dynamics of materials and their polaritons with simultaneous high spatial and temporal resolution has been a bold frontier of electron microscopy in recent years. One of the main challenges lies in the ability to retrieve extremely weak signals and simultaneously disentangling the amplitude and phase information. Here we present free-electron Ramsey imaging—a microscopy approach based on light-induced electron modulation that enables the coherent amplification of optical near fields in electron imaging. We provide simultaneous time-, space- and phase-resolved measurements of a micro-drum made from a hexagonal boron nitride membrane, visualizing the sub-cycle dynamics of two-dimensional polariton wavepackets therein. The phase-resolved measurement reveals vortex–anti-vortex singularities on the polariton wavefronts, together with an intriguing …

The magnetic field range in which a magnetic sensor operates is an important consideration for many applications. Elliptical planar Hall effect (EPHE) sensors exhibit outstanding equivalent magnetic noise (EMN) on the order of pT/Hz, which makes them promising for many applications. Unfortunately, the current field range in which EPHE sensors with pT/Hz EMN can operate is sub-mT, which limits their potential use. Here, we fabricate EPHE sensors with an increased field range and measure their EMN. The larger field range is obtained by increasing the uniaxial shape-induced anisotropy parallel to the long axis of the ellipse. We present measurements of EPHE sensors with magnetic anisotropy which ranges between 12 Oe and 120 Oe and show that their EMN at 10 Hz changes from 800 pT/Hz to 56 nT/Hz. Furthermore, we show that the EPHE sensors behave effectively as single magnetic domains with negligible hysteresis. We discuss the potential use of EPHE sensors with extended field range and compare them with sensors that are widely used in such applications.