Few-layer BiOSe: a promising candidate for high-performance near-room-temperature thermoelectric applications.

Advancements in high-temperature thermoelectric (TE) materials have been substantial, yet identifying promising near-room-temperature candidates for efficient power generation from low-grade waste heat or TE cooling applications has become critical but proven exceedingly challenging. Bismuth oxyselenide (BiOSe) emerges as an ideal candidate for near-room-temperature energy harvesting due to its low thermal conductivity, high carrier mobility and remarkable air-stability. In this study, the TE properties of few-layer BiOSe over a wide temperature range (20-380 K) are investigated, where a charge transport mechanism transitioning from polar optical phonon to piezoelectric scattering at 140 K is observed.

Breaking The Permeance-Selectivity Tradeoff for Post-Combustion Carbon Capture: A Bio-Inspired Strategy to Form Ultrathin Hollow Fiber Membranes.

Thin film composite (TFC) hollow fiber membranes with ultrathin selective layer are desirable to maximize the gas permeance for practical applications. Herein, a bio-inspired strategy is proposed to fabricate sub-100-nm membranes via a tree-mimicking polymer network with amphipathic components featuring multifunctionalities. The hydrophobic polydimethylsiloxane (PDMS) brushes act as the roots that can strongly cling to the gutter layer, the PDMS crosslinkers function as the xylems to enable fast gas transport, and the hydrophilic ethylene-oxide moieties (brushes and mobile molecules) resemble tree leaves that selectively attract CO molecules.

Solution-Printable PEDOT Solid-Contact for Nitrate-Selective Electrodes: Enhanced Selectivity from Anion Dopant Exchange.

Poly(3,4-ethylenedioxythiophene)-polyethylene glycol (PEDOT:PEG) is a conductive material adopted in bioelectronics due to its biocompatibility and stability. While PEDOT has established its utility in cationic solid-contact ion-selective electrodes (sc-ISEs), its anionic counterpart remains less explored. Herein, we report the first example of PEDOT:PEG as a solution-printable solid-contact for all-solid-state nitrate-selective electrodes and a simple ion exchange treatment which can significantly enhance nitrate selectivity.

Current-induced self-switching of perpendicular magnetization in CoPt single layer.

All-electric switching of perpendicular magnetization is a prerequisite for the integration of fast, high-density, and low-power magnetic memories and magnetic logic devices into electric circuits. To date, the field-free spin-orbit torque (SOT) switching of perpendicular magnetization has been observed in SOT bilayer and trilayer systems through various asymmetric designs, which mainly aim to break the mirror symmetry. Here, we report that the perpendicular magnetization of CoPt single layers within a special composition range (20 < x < 56) can be deterministically switched by electrical current in the absence of external magnetic field.

Halogen Bonding Ionophore for Potentiometric Iodide Sensing.

Iodide (I) is an essential micronutrient for thyroid function. Hence, rapid and portable sensing is important for I quantification in food and biological samples. Herein, we report the first example of a halogen bonding (XB) tripodal ionophore () which is selective for the I anion.

On-Surface Atom-by-Atom-Assembled Aluminum Binuclear Tetrabenzophenazine Organometallic Magnetic Complex.

The Kondo effect results from the interactions of the conduction electrons in a metal bulk with localized magnetic impurities. While adsorbed atop a metallic surface, the on-surface nanoscale version of this effect is observed when a single magnetic atom or a single magnetic molecule (SMM) is interacting with the conduction electrons. SMMs are commonly organometallic complexes incorporating transition-metal atoms in different oxidation states.

Experiment and Simulation of a Selective Subwavelength Filter with a Low Index Contrast.

Subwavelength gratings have been of great interest recently due to their ability to eliminate multiple orders. However, high index contrast ( Δ n ∼ 3 ) is typically achieved using metals or high-index dielectrics surrounded by vacuum in order to maintain good optical selectivity. Here, we theoretically propose and experimentally realize a selective subwavelength grating using an index contrast of Δ n ∼ 1.

Giant Enhancements of Perpendicular Magnetic Anisotropy and Spin-Orbit Torque by a MoS Layer.

2D transition metal dichalcogenides have attracted much attention in the field of spintronics due to their rich spin-dependent properties. The promise of highly compact and low-energy-consumption spin-orbit torque (SOT) devices motivates the search for structures and materials that can satisfy the requirements of giant perpendicular magnetic anisotropy (PMA) and large SOT simultaneously in SOT-based magnetic memory. Here, it is demonstrated that PMA and SOT in a heavy metal/transition metal ferromagnet structure, Pt/[Co/Ni] , can be greatly enhanced by introducing a molybdenum disulfide (MoS ) underlayer.

Dynamic mapping of spontaneously produced HS in the entire cell space and in live animals using a rationally designed molecular switch.

Hydrogen sulfide (H2S) is a key signaling molecule in the cytoprotection, vascular mediation and neurotransmission of living organisms. In-depth understanding of its production, trafficking, and transformation in cells is very important in the way H2S mediates cellular signal transductions and organism functions; it also motivates the development of H2S probes and imaging technologies. A fundamental challenge, however, is how to engineer probes with sensitivity and cellular penetrability that allow detection of spontaneous production of H2S in the entire cell space and live animals.

Poly(ferrocenylsilane) electrolytes as a gold nanoparticle foundry: "two-in-one" redox synthesis and electrosteric stabilization, and sensing applications.

Gold nanoparticles (AuNPs) coated with responsive polymers gained considerable interest due to their controllable size, good stability, and fast environmental response suitable for biological applications and sensing. Here we report on a simple and efficient method for the synthesis of stable and redox responsive AuNPs using organometallic polyelectrolytes in aqueous solutions of HAuCl. In the redox reaction, positively or negatively charged poly(ferrocenylsilanes) (PFS/PFS) served as reducing agents, and also as stabilizing polymers.

Polarization invariant plasmonic nanostructures for sensing applications.

Optics-based sensing platform working under unpolarized light illumination is of practical importance in the sensing applications. For this reason, sensing platforms based on localized surface plasmons are preferred to their integrated optics counterparts for their simple mode excitation and inexpensive implementation. However, their optical response under unpolarized light excitation is typically weak due to their strong polarization dependence.

DNA-Directed Assembly of Nanogold Dimers: A Unique Dynamic Light Scattering Sensing Probe for Transcription Factor Detection.

We have developed a unique DNA-assembled gold nanoparticles (AuNPs) dimer for dynamic light scattering (DLS) sensing of transcription factors, exemplified by estrogen receptor (ER) that binds specifically to a double-stranded (ds) DNA sequence containing estrogen response element (ERE). Here, ERE sequence is incorporated into the DNA linkers to bridge the AuNPs dimer for ER binding. Coupled with DLS, this AuNP dimer-based DLS detection system gave distinct readout of a single 'complex peak' in the presence of the target molecule (i.

Serum Albumin Binding Inhibits Nuclear Uptake of Luminescent Metal-Complex-Based DNA Imaging Probes.

The DNA binding and cellular localization properties of a new luminescent heterobimetallic Ir(III) Ru(II) tetrapyridophenazine complex are reported. Surprisingly, in standard cell media, in which its tetracationic, isostructural Ru(II) Ru(II) analogue is localized in the nucleus, the new tricationic complex is poorly taken up by live cells and demonstrates no nuclear staining. Consequent cell-free studies reveal that the Ir(III) Ru(II) complex binds bovine serum albumin, BSA, in Sudlow's Site I with a similar increase in emission and binding affinity to that observed with DNA.

"Turn-on" fluorescence probe integrated polymer nanoparticles for sensing biological thiol molecules.

A "turn-on" thiol-responsive fluorescence probe was synthesized and integrated into polymeric nanoparticles for sensing intracellular thiols. There is a photo-induced electron transfer process in the off state of the probe, and this process is terminated upon the reaction with thiol compounds. Configuration interaction singles (CIS) calculation was performed to confirm the mechanism of this process.

Tuning the cellular uptake properties of luminescent heterobimetallic iridium(III)-ruthenium(II) DNA imaging probes.

The synthesis of two new luminescent dinuclear Ir(III)-Ru(II) complexes containing tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]phenazine (tpphz) as the bridging ligand is reported. Unlike many other complexes incorporating cyclometalated Ir(III) moieties, these complexes display good water solubility, allowing the first cell-based study on Ir(III)-Ru(II) bioprobes to be carried out. Photophysical studies indicate that emission from each complex is from a Ru(II) excited state and both complexes display significant in vitro DNA-binding affinities.

Study of single-stranded DNA binding protein-nucleic acids interactions using unmodified gold nanoparticles and its application for detection of single nucleotide polymorphisms.

We have developed a label-free homogeneous phase bioassay to characterize the DNA binding properties of single-stranded DNA binding (SSB) protein, a key protein involved in various DNA processes such as DNA replication and repair. This assay uses gold nanoparticles (AuNPs) as sensing probe and is based on the phenomenon that preformed SSB-single-stranded DNA (ssDNA) complexes can protect AuNPs against salt-induced aggregation better than SSB or ssDNA alone. With the controlled particle aggregation/dispersion as measure, this assay can be used to detect the formation of SSB complexes with ssDNA of different length and nucleotide composition and to assess their binding properties without tedious and complicated assay procedures.

Acousto-plasmonic and surface-enhanced Raman scattering properties of coupled gold nanospheres/nanodisk trimers.

This work is devoted to the fundamental understanding of the interaction between acoustic vibrations and surface plasmons in metallic nano-objects. The acoustoplasmonic properties of coupled spherical gold nanoparticles and nanodisk trimers are investigated experimentally by optical transmission measurements and resonant Raman scattering experiments. For excitation close to resonance with the localized surface plasmons of the nanodisk trimers, we are able to detect several intense Raman bands generated by the spherical gold nanoparticles.

Sensing of transcription factor through controlled-assembly of metal nanoparticles modified with segmented DNA elements.

We have developed a unique metal nanoparticle (mNPs)-based assay to detect sequence-specific interactions between transcription factor and its corresponding DNA-binding elements. This assay exploits the interparticle-distance dependent optical properties of noble mNPs as sensing element and utilizes specific protein-DNA interactions to control the dispersion status of the mNPs. The assay involves two sets of double-stranded (ds)DNA modified-mNPs, each carrying a half site segment of a functional DNA sequence for the protein of interest.

Gold-nanoparticle-based assay for instantaneous detection of nuclear hormone receptor-response elements interactions.

Gold nanoparticles (AuNPs) are widely used as colorimetric probes for biosensing, relying on their unique particle size-dependent and/or interparticle distance-dependent extinction spectrum and solution color. Herein, we describe an AuNP-based colorimetric assay to detect binding interactions between nuclear hormone receptors and their corresponding DNA-binding elements, particularly the human estrogen receptors (ERalpha and ERbeta) and their cognate estrogen response elements (EREs). We found that the protein-DNA (ER-ERE) complexes can stabilize citrate anion-capped AuNPs against salt-induced aggregation to a larger extent than the protein (ER) or the DNA (ERE) alone, due to their unique molecular size and charge properties that provide a strong electrosteric protection.

Characterization of atomic force microscopy (AFM) tip shapes by scanning hydrothermally deposited ZnO thin films.

Direct observation of tip shapes by atomic force microscopy (AFM) has been achieved using spike-like crystallites in ZnO thin films deposited on microscope glass slides by the hydrothermal deposition technique. Three types of AFM tips, e.g.

Effect of molecule-substrate interaction on thin-film structures and molecular orientation of pentacene on silver and gold.

Evaporated pentacene thin films with thicknesses from several nm to 150 nm on gold and silver substrates have been studied by ultraviolet photoelectron spectroscopy (UPS), near-edge X-ray absorption fine structure (NEXAFS), scanning tunneling microscopy (STM), and atomic force microscopy (AFM). It was found that pentacene thin-film structures, particularly their molecular orientations, are strongly influenced by the metal substrates. UPS measurements revealed a distinct change in the valence band structures of pentacene on Au compared to those on Ag, which is attributed to the different packing between adjacent molecules.

Switching in organic devices caused by nanoscale Schottky barrier patches.

We have identified a possible electronic origin of metal filaments, invoked to explain the switching behavior of organic devices. Interfaces of two representative organics polyparaphenylene (PPP) and poly(2-methoxy-5-2-ethyl-hexyloxy-1,4-phenylenevinylene) with Ag are investigated using ballistic emission microscopy. Nanometer scale spatial nonuniformity of carrier injection is observed in ballistic electron emission microscopy images of both interfaces.

Piezoelectric quartz crystal based label-free analysis for allergy disease.

This work presents a piezoelectric (Pz) quartz crystal based label-free quantification of total IgE and allergen-specific IgE in human sera for allergy testing. An evaluation of the different brands of crystals was first initiated with respect to variability in mass sensitivity, frequency measurement reliability and stability, and surface roughness. Thereafter, for total IgE quantification.

Self-assembled monolayer-based piezoelectric crystal immunosensor for the quantification of total human immunoglobulin E.

This work presents a piezoelectric (Pz) immunosensor for the quantification of total human IgE in serum samples. The anti-human IgE is deposited on the surface of the 10 M Hz AT-cut gold coated crystal resonator by self-assembled technique, and serves as a receptor layer. The highly ordered self-assembled monolayers (SAMs) ensure well-controlled surface structure and offer many advantages to the performance of the sensor.