Strain-induced Mn valence state variation in CaMnO/substrate interfaces: electronic reconstruction oxygen vacancies.

This study investigates the nanoscale crystalline and electronic structures of the interfaces between CaMnO and substrates such as SrTiO (001) and LaAlO (001) by employing advanced transmission electron microscopy and electron energy loss spectroscopy techniques. The objective is to comprehend the influence of different strains on the Mn valence state. Our findings reveal that the Mn valence state remains relatively stable in the region of a weakly tensile-strained interface, whereas it experiences a significant decrease from Mn to Mn in the region of a strongly tensile-strained interface.

Thermally Driven Structural Order of Oligo(Ethylene Glycol)-Terminated Alkanethiol Monolayers on Au(111) Prepared by Vapor Deposition.

To probe the effects of deposition temperature on the formation and structural order of self-assembled monolayers (SAMs) on Au(111) prepared by vapor deposition of 2-(2-methoxyethoxy)ethanethiol (CHO(CH)O(CH)SH, EG2) for 24 h, we examined the surface structure and electrochemical behavior of the resulting EG2 SAMs using scanning tunneling microscopy (STM) and cyclic voltammetry (CV). STM observations clearly revealed that EG2 SAMs vapor-deposited on Au(111) at 298 K were composed of a disordered phase on the entire Au surface, whereas those formed at 323 K showed improved structural order, showing a mixed phase of ordered and disordered phases. Moreover, at 348 K, uniform and highly ordered EG2 SAMs on Au(111) were formed with a (2 × 3√3) packing structure.

Vertically-Oriented WS Nanosheets with a Few Layers and Its Raman Enhancements.

Vertically-oriented two-dimensional (2D) tungsten disulfide (WS) nanosheets were successfully grown on a Si substrate at a temperature range between and 550 °C via the direct chemical reaction between WCl and S in the gas phase. The growth process was carefully optimized by adjusting temperature, the locations of reactants and substrate, and carrier gas flow. Additionally, vertically-oriented 2D WS nanosheets with a few layers were tested as a surface-enhanced Raman scattering substrate for detecting rhodamine 6G (R6G) molecules where enhancement occurs from chemical enhancement by charge transfer transition from semiconductor).

Relation between work function and structural properties of triangular defects in 4H-SiC epitaxial layer: Kelvin probe force microscopic and spectroscopic analyses.

To understand the relationship between the work function and structural properties of sufficiently expanded triangular defects (size: ∼250 μm) in the 4H-SiC epitaxial layer, Kelvin probe force microscopy (KPFM) and spectroscopic [micro-Raman spectroscopy and photoluminescence (PL)] analyses were performed. Spectroscopic analysis demonstrated that the triangular defects mostly comprise the 3C polytypes and that it experiences internal stress, defects, and defect-induced carrier generation. The distinguishable areas in the triangular defects had surface potential values different from those of the 4H-SiC matrix; this could be explained by the work function difference, which arises from variations in the electron affinity of the 3C polytype as well as the positional variations of the Fermi energy level in terms of electron concentration.

Modulation of metal-insulator transitions of NdNiO/LaNiO/NdNiO trilayers via thickness control of the LaNiO layer.

Over the last few decades, manipulating the metal-insulator (MI) transition in perovskite oxides (ABO) via an external control parameter has been attempted for practical purposes, but with limited success. The substitution of A-site cations is the most widely used technique to tune the MI transition. However, this method introduces unintended disorder, blurring the intrinsic properties.

Bi-Stability and Orientation Change of a Thin α-FeO Layer on a ε-FeO (004) Surface.

This study reports the key ingredients that influence the orientation and stability of a α-FeO layer that grows on a metastable ε-FeO during pulsed laser deposition. Depending on the substrate temperature, two different α-FeO orientations arise on the ε-FeO (004) surface. At 800 °C, (2-10)-oriented α-FeO is stabilized, whereas at 700 °C, (006) orientation occurs.

Side chain engineering in DTBDT-based small molecules for efficient organic photovoltaics.

A new small-molecule donor with a dithieno[2,3-d:2',3'-d']-benzo[1,2-b:4,5-b']-dithiophene (DTBDT) core and both alkyl and alkylthio substituents is designed and synthesized to improve the miscibility between DTBDT-based small molecules and [6,6]-phenyl-C71-butyric acid methyl ester (PCBM). The alkyl substituent on the 4-position and the alkylthio substituent on the 5-position of the substituted thiophene are expected to improve intermolecular interactions and prevent severe aggregation of the small molecules. The new small molecule, DTBDT-S-C8-TTR, exhibits a homogenous blend morphology with small domains and edge-on-oriented crystalline structures in blends with PCBM, and give a maximum power conversion efficiency (PCE) of 8.

Correction: Single phase of spinel CoRhO nanotubes with remarkably enhanced catalytic performance for the oxygen evolution reaction.

Correction for 'Single phase of spinel CoRhO nanotubes with remarkably enhanced catalytic performance for the oxygen evolution reaction' by So Yeon Kim et al., Nanoscale, 2019, 11, 9287-9295.

Single phase of spinel CoRhO nanotubes with remarkably enhanced catalytic performance for the oxygen evolution reaction.

We report the effective crystal growth for a unique single phase of spinel cobalt rhodium oxide (Co2RhO4) nanotubes via the electrospinning process combined with the thermal annealing process. In the spinel structure of the electrospun Co2RhO4 nanotubes, Co3+ cations and Rh3+ cations randomly occupy the octahedral sites, while the remaining half of the Co2+ cations occupy the centres of the tetrahedral sites as proved by microscopic and spectroscopic observations. Furthermore, electrospun spinel Co2RhO4 nanotubes exhibit excellent catalytic performances with the least positive onset potential, greatest current density, and low Tafel slope which are even better than those of the commercial Ir/C electrocatalyst for the oxygen evolution reaction (OER) in alkaline solution.

Ordered Mesoporous C N with a Combined Triazole and Triazine Framework and Its Graphene Hybrids for the Oxygen Reduction Reaction (ORR).

Mesoporous carbon nitrides (MCN) with C N stoichiometry could find applications in fields ranging from catalysis, sensing, and adsorption-separation to biotechnology. The extension of the synthesis of MCN with different nitrogen contents and chemical structures promises access to a wider range of applications. Herein we prepare mesoporous C N with a combined triazole and triazine framework via a simple self-assembly of 5-amino-1H-tetrazole (5-ATTZ).

Urine IP-10 as a biomarker of therapeutic response in patients with active pulmonary tuberculosis.

Background: Prior to clinical trials of new TB drugs or therapeutic vaccines, it is necessary to develop monitoring tools to predict treatment outcomes in TB patients. Urine interferon gamma inducible protein 10 (IP-10) is a potential biomarker of treatment response in chronic hepatitis C virus infection and lung diseases, including tuberculosis. In this study, we assessed IP-10 levels in urine samples from patients with active TB at diagnosis, during treatment, and at completion, and compared these with levels in serum samples collected in parallel from matched patients to determine whether urine IP-10 can be used to monitor treatment response in patients with active TB.

A critical role of catalyst morphology in low-temperature synthesis of carbon nanotube-transition metal oxide nanocomposite.

The effect of the catalyst morphology on the growth of carbon nanotubes (CNT) on nanostructured transition metal oxides was investigated to study a novel low-temperature synthetic route to functional CNT-transition metal oxide nanocomposites. Among several nanostructured manganese oxides with various morphologies and structures, only exfoliated 2D nanosheets of layered MnO acted as an effective catalyst for the chemical vapor deposition of CNT at low temperatures of 400-500 °C, which emphasizes the critical role of the catalyst morphology in CNT growth. Heat treatment of the MnO nanosheets under a CH flow induced the deposition of CNT, as well as a phase transition to a 2D ordered assembly of MnO nanoparticles.

Chemical Vapor Deposition of Bernal-Stacked Graphene on a Cu Surface by Breaking the Carbon Solubility Symmetry in Cu Foils.

The synthesis of Bernal-stacked multilayer graphene over large areas is intensively investigated due to the value of this material's tunable electronic structure, which makes it promising for use in a wide range of optoelectronic applications. Multilayer graphene is typically formed via chemical vapor deposition onto a metal catalyst, such as Ni, a Cu-Ni alloy, or a Cu pocket. These methods, however, require sophisticated control over the process parameters, which limits the process reproducibility and reliability.

A 2D Metal Oxide Nanosheet as an Efficient Additive for Improving Na-Ion Electrode Activity of Graphene-Based Nanocomposites.

An efficient way to improve the Na-ion electrode activity of graphene-based nanocomposite is developed by employing exfoliated metal oxide nanosheet as an additive. The titanate-nanosheet-incorporated Na-SnS -reduced graphene oxide (rG-O) nanocomposites can be synthesized by the electrostatically derived restacking of the colloidal mixture of SnS , rG-O, and titanate nanosheets with the Na cation. The incorporation of titanate into the Na-SnS -rG-O nanocomposites is effective in improving the nanoscale mixing of component nanosheets and the porosity of the composite structure.

Highly Efficient Silver-Cobalt Composite Nanotube Electrocatalysts for Favorable Oxygen Reduction Reaction.

This paper reports the synthesis and characterization of silver-cobalt (AgCo) bimetallic composite nanotubes. Cobalt oxide (CoO) nanotubes were fabricated by electrospinning and subsequent calcination in air and then reduced to cobalt (Co) metal nanotubes via further calcination under a H/Ar atmosphere. As-prepared Co nanotubes were then employed as templates for the following galvanic replacement reaction (GRR) with silver (Ag) precursor (AgNO), which produced AgCo composite nanotubes.

Structural Stability and Phase Transitions of Octanethiol Self-Assembled Monolayers on Au(111) in Ultrahigh Vacuum.

To understand the structural stability of as-prepared octanethiol (OT) self-assembled monolayers (SAMs) with a fully covered c(4 x 2) phase on Au(111) in ultrahigh vacuum (UHV) conditions of 3 x 10(-7) Pa at room temperature, we examined OT SAM samples obtained as a function of storage period using scanning tunneling microscopy (STM). STM imaging revealed that phase transition of OT SAMs after storage in UHV for 3 days occurs from the c(4 x 2) phase to the mixed phase containing ordered c(4 x 2) and disordered phases. It was also observed that the disordered phase was mainly located at around vacancy islands and near step edges of Au(111) terraces, implying that desorption of OT molecules chemisorbed on Au(111) in UHV occurs more quickly in these regions compared with in the closely packed and ordered domains.

Implementing Room-Temperature Multiferroism by Exploiting Hexagonal-Orthorhombic Morphotropic Phase Coexistence in LuFeO3 Thin Films.

Room-temperature multiferroism in LuFeO3 (LFO) films is demonstrated by exploiting the orthorhombic-hexagonal (o-h) morphotrophic phase coexistence. The LFO film further reveals a magnetoelectric coupling effect that is not shown in single-phase (h- or o-) LFO. The observed multiferroism is attributed to the combination of sufficient polarization from h-LFO and net magnetization from o-LFO.

A Conductive Hybridization Matrix of RuO2 Two-Dimensional Nanosheets: A Hybrid-Type Photocatalyst.

A universal methodology to efficiently improve the photocatalyst performance of semiconductors was developed by employing exfoliated RuO2 two-dimensional nanosheets as a conducting hybridization matrix. The hybridization with a RuO2 nanosheet is easily achieved by crystal growth or electrostatically derived anchoring of semiconductor nanocrystals on the RuO2 nanosheet. An enhanced chemical interaction of inorganic semiconductor with hydrophilic RuO2 nanosheet is fairly effective in optimizing their photocatalytic activity and photostability by the enhancement of charge separation and charge mobility.

Carrier trapping and confinement in Ge nanocrystals surrounded by Ge3N4.

We investigated the optical properties of Ge nanocrystals surrounded by Ge3N4. The broad emission ranging from infrared to blue is due to the dependence on the crystal size and preparation methods. Here, we report high resolution Photoluminescence (PL) attributed to emission from individual Ge nanocrystals (nc-Ge) spatially resolved using micro-photoluminescence and detailed using temperature and power-dependent photoluminescence studies.

Unusually Huge Charge Storage Capacity of Mn3O4-Graphene Nanocomposite Achieved by Incorporation of Inorganic Nanosheets.

Remarkable improvement in electrode performance of Mn3O4-graphene nanocomposites for lithium ion batteries can be obtained by incorporation of a small amount of exfoliated layered MnO2 or RuO2 nanosheets. The metal oxide nanosheet-incorporated Mn3O4-reduced graphene oxide (rGO) nanocomposites are synthesized via growth of Mn3O4 nanocrystals in the mesoporous networks of rGO and MnO2/RuO2 2D nanosheets. Incorporation of metal oxide nanosheets is highly effective in optimizing porous composite structure and charge transport properties, resulting in a remarkable increase of discharge capacity of Mn3O4-rGO nanocomposite with significant improvement of cyclability and rate performance.

Topological modification of the electronic structure by Bi-bilayers lying deep inside bulk Bi₂Se₃.

We observe the modified surface states of an epitaxial thin film of a homologous series of (Bi2)m(Bi2Se3)n, as a topological insulator (TI), by angle-resolved photoemission spectroscopy measurements. A thin film with m : n  =  1 : 3 (Bi8Se9) has been grown with Bi2 bilayers embedded every other three quintuple layers (QLs) of Bi2Se3. Despite the reduced dimension of continuous QLs due to the Bi2 heterolayers, we find that the topological surface states stem from the inverted Bi and Se states and the topologically nontrivial structures are mainly based on the prototype of 3D TI Bi2Se3 without affecting the overall topological order.

Highly Durable and Active PtFe Nanocatalyst for Electrochemical Oxygen Reduction Reaction.

Demand on the practical synthetic approach to the high performance electrocatalyst is rapidly increasing for fuel cell commercialization. Here we present a synthesis of highly durable and active intermetallic ordered face-centered tetragonal (fct)-PtFe nanoparticles (NPs) coated with a "dual purpose" N-doped carbon shell. Ordered fct-PtFe NPs with the size of only a few nanometers are obtained by thermal annealing of polydopamine-coated PtFe NPs, and the N-doped carbon shell that is in situ formed from dopamine coating could effectively prevent the coalescence of NPs.

The Changes of Psychometric Profiles after Medical Treatment of Lower Urinary Tract Symptoms Suggestive of Benign Prostatic Hyperplasia.

Objective: To investigate the relationship of somatization and depression with the degree of lower urinary tract symptoms suggestive of benign prostate hyperplasia (LUTS/BPH) and changes in psychometric profiles including somatization and depression after treatment of LUTS/BPH.

Methods: Subjects were evaluated at baseline and at week 12 following routine treatment for LUTS/BPH using the International Prostate Symptom Score (IPSS) to measure the severity of LUTS/BPH, the Overactive Bladder Symptom Score (OABSS) to measure the severity of OAB, the Patient Health Questionnaire-9 (PHQ-9) to assess depression, and the Patient Health Questionnaire-15 (PHQ-15) to evaluate somatization. The correlation of somatization and depression with the degree of LUTS/BPH symptoms at baseline and changes in somatization and depression after LUTS/BPH treatment were assessed using relevant statistical analyses.

A Study on the Rectification Property of Self-Assembled Viologen Single Molecules Using a Scanning Tunneling Microscopy.

An ultrahigh vacuum scanning tunneling microscopy (UHV-STM) and a scanning tunneling spectroscopy (STS) are used measure the rectification property of self-assembled viologen single molecules (VC8SH, VC10SH, HSC8VC8SH, and HSC10VC10SH) in the previous study. Using STM we observe viologen single molecules in the self-assembled octanethiol (OT) SAM matrix. In the OT matrix a mixed phase that includes a c(4 x 2) superlattice of high-density standing up-phase is observed.

Ripple-Free Graphene Sheets on Alkanethiol Self-Assembled Monolayers Provided from Unzipped Multi-Walled Carbon Nanotubes.

Octanethiol (C8S, CH3(CH2)7SH) self-assembled monolayers/Au(111) were utilized as an inert surface to provide ripple-free graphene oxide layers provided from chemically unzipped multi-walled carbon nanotubes (MWCNTs). The resulting graphene oxide monolayers were characterized with atomic resolution by UHV-STM. The honeycomb structure for the graphene monolayer and "three-for-six" triangular pattern for the multi-layer graphene sheets on C8S SAMs were clearly observed without ripples by the high-resolution UHV-STM.