Chemical Interactions at the Interface of Au on BiSe Topological Insulator.

This study explores the intricate chemical processes at the interface between the topological insulator BiSe and deposited Au. The study mainly focused on room-temperature interactions that can cause the aging of, e.g.

Giant and Tunable Out-of-Plane Spin Polarization of Topological Antimonene.

Topological insulators are bulk insulators with metallic and fully spin-polarized surface states displaying Dirac-like band dispersion. Due to spin-momentum locking, these topological surface states (TSSs) have a predominant in-plane spin polarization in the bulk fundamental gap. Here, we show by spin-resolved photoemission spectroscopy that the TSS of a topological insulator interfaced with an antimonene bilayer exhibits nearly full out-of-plane spin polarization within the substrate gap.

Silica Coated BiSe Topological Insulator Nanoparticles: An Alternative Route to Retain Their Optical Properties and Make Them Biocompatible.

Localized surface plasmon resonance (LSPR) is the cause of the photo-thermal effect observed in topological insulator (TI) bismuth selenide (BiSe) nanoparticles. These plasmonic properties, which are thought to be caused by its particular topological surface state (TSS), make the material interesting for application in the field of medical diagnosis and therapy. However, to be applied, the nanoparticles have to be coated with a protective surface layer, which prevents agglomeration and dissolution in the physiological medium.

Metallated Isoindigo-Porphyrin Covalent Organic Framework Photocatalyst with a Narrow Band Gap for Efficient CO Conversion.

Photocatalytic CO reduction into formate (HCOO) has been widely studied with semiconductor and molecule-based systems, but it is rarely investigated with covalent organic frameworks (COFs). Herein, we report a novel donor-acceptor COF named composed of isoindigo and metallated porphyrin subunits that exhibits high catalytic efficiency (∼50 μmol formate g h) at low-power visible-light irradiation and in the absence of rare metal cocatalysts. Density functional theory calculations and experimental diffuse-reflectance measurements are used to explain the origin of catalytic efficiency and the particularly low band gap (0.

Enhancing the Mechanical Properties of Biodegradable Mg Alloys Processed by Warm HPT and Thermal Treatments.

In this study, several biodegradable Mg alloys (Mg5Zn, Mg5Zn0.3Ca, Mg5Zn0.15Ca, and Mg5Zn0.

The Role of Substrate on Thermal Evolution of Ag/TiO Nanogranular Thin Films.

In multicomponent thin films, properties and functionalities related to post-deposition annealing treatments, such as thermal stability, optical absorption and surface morphology are typically rationalized, neglecting the role of the substrate. Here, we show the role of the substrate in determining the temperature dependent behaviour of a paradigmatic two-component nanogranular thin film (Ag/TiO) deposited by gas phase supersonic cluster beam deposition (SCBD) on silica and sapphire. Up to 600 °C, no TiO grain growth nor crystallization is observed, likely inhibited by the Zener pinning pressure exerted by the Ag nanoparticles on the TiO grain boundaries.

Oxygen Vacancy-Related Cathodoluminescence Quenching and Polarons in CeO.

We used cathodoluminescence (CL) spectroscopy to characterize the oxygen vacancies (V) in ceria (CeO). The effects of the processing atmosphere and thermal quenching temperature on the nature and distribution of the intrinsic defects and on the spectroscopic behavior were investigated. The presence of polarons and associates of the polarons with the oxygen vacancies such as (V -Ce ) is demonstrated.

Inherent Surface Properties of Adsorbent-Free Ultrathin BiSe Topological Insulator Platelets.

We report on a hydrothermal synthesis of hexagonal ultra-thin BiSe platelets, which was performed without any organic reactants. The synthesis resulted in the particles with a surface, clean of any organic adsorbents, which was confirmed with a high-resolution transmission electron microscopy, zeta-potential measurements and thermogravimetric measurements coupled with a mass spectroscopy. Due to the absence of the adsorbed organic layer on the BiSe platelet surface, we were able to measure their inherent surface and optical properties.

Electronic and surface properties of PbS nanoparticles exhibiting efficient multiple exciton generation.

Ultrafast transient absorption measurements have been used to study multiple exciton generation in solutions of PbS nanoparticles vigorously stirred to avoid the effects of photocharging. The threshold and slope efficiency of multiple exciton generation are found to be 2.5 ± 0.

Controlled synthesis of tuned bandgap nanodimensional alloys of PbS(x)Se(1-x).

Truly alloyed PbS(x)Se(1-x) (x = 0-1) nanocrystals (∼5 nm in size) have been prepared, and their resulting optical properties are red-shifted systematically as the sulfur content of the materials increases. Their optical properties are discussed using a modified Vegard's approach and the bowing parameter for these nanoalloys is reported for the first time. The alloyed structure of the nanocrystals is supported by the energy-filtered transmission electron microscope images of the samples, which show a homogeneous distribution of sulfur and selenium within the nanocrystals.