Quantum-confined bismuth iodide perovskite nanocrystals in mesoporous matrices.

Bismuth iodide perovskite nanocrystals are considered a viable alternative to the Pb halide ones due to their reduced toxicity and increased stability. However, it is still challenging to fabricate nanocrystals with a small and controlled size, and their electronic properties are not well understood. Here, we propose the growth of Bi iodide perovskite nanocrystals using different mesoporous silica with ordered pores of controlled diameter as templates.

Dryland Endolithic Chroococcidiopsis and Temperate Fresh Water Synechocystis Have Distinct Membrane Lipid and Photosynthesis Acclimation Strategies upon Desiccation and Temperature Increase.

An effect of climate change is the expansion of drylands in temperate regions, predicted to affect microbial biodiversity. Since photosynthetic organisms are at the base of ecosystem's trophic networks, we compared an endolithic desiccation-tolerant Chroococcidiopsis cyanobacteria isolated from gypsum rocks in the Atacama Desert with a freshwater desiccation-sensitive Synechocystis. We sought whether some acclimation traits in response to desiccation and temperature variations were shared, to evaluate the potential of temperate species to possibly become resilient to future arid conditions.

Flexible, Transparent, and Cytocompatible Nanostructured Indium Tin Oxide Thin Films for Bio-optoelectronic Applications.

Electrical stimulation has been used successfully for several decades for the treatment of neurodegenerative disorders, including motor disorders, pain, and psychiatric disorders. These technologies typically rely on the modulation of neural activity through the focused delivery of electrical pulses. Recent research, however, has shown that electrically triggered neuromodulation can be further enhanced when coupled with optical stimulation, an approach that can benefit from the development of novel electrode materials that combine transparency with excellent electrochemical and biological performance.

Practice of electron microscopy on nanoparticles sensitive to radiation damage: CsPbBr nanocrystals as a case study.

In-depth and reliable characterization of advanced nanoparticles is crucial for revealing the origin of their unique features and for designing novel functional materials with tailored properties. Due to their small size, characterization beyond nanometric resolution, notably, by transmission electron microscopy (TEM) and associated techniques, is essential to provide meaningful information. Nevertheless, nanoparticles, especially those containing volatile elements or organic components, are sensitive to radiation damage.

(De)Lithiation and Strain Mechanism in Crystalline Ge Nanoparticles.

Germanium is a promising active material for high energy density anodes in Li-ion batteries thanks to its good Li-ion conduction and mechanical properties. However, a deep understanding of the (de)lithiation mechanism of Ge requires advanced characterizations to correlate structural and chemical evolution during charge and discharge. Here we report a combined X-ray diffraction (XRD) and Li solid-state NMR investigation performed on crystalline germanium nanoparticles (c-Ge Nps) based anodes during partial and complete cycling at C/10 Li metal.

Room-Temperature Doping of CsPbBr Nanocrystals with Aluminum.

B-site doping is an emerging strategy for tuning the emission wavelength of cesium lead halide ABX nanocrystals. We present a simple method for the postsynthetic doping of CsPbBr nanocrystals with aluminum at room temperature by exposing them to a solution of AlBr in dibromomethane. Despite the much smaller ionic radius of Al compared to that of Pb, nominal doping levels in a range from 8.

Unveiling the multiscale morphology of chemically stabilized proton exchange membranes for fuel cells by means of Fourier and real space studies.

We recently presented the elaboration and functional properties of a new generation of hybrid membranes for PEMFC applications showing promising performances and durability. The strategy was to form, inside a commercial sPEEK membrane, sol-gel (SG) synthesis, a reactive SG phase able to reduce oxidative species generated during FC operation. In order to understand structure-properties interplay, we use a combination of direct space (AFM/3D FIB-SEM) and reciprocal space (SANS/WAXS) techniques to cover dimensional scales ranging from a hundred to few nanometers.

Doped Bilayer Tin(IV) Oxide Electron Transport Layer for High Open-Circuit Voltage Planar Perovskite Solar Cells with Reduced Hysteresis.

Tin oxide (SnO ) is an emerging electron transport layer (ETL) material in halide perovskite solar cells (PSCs). Among current limitations, open-circuit voltage (V ) loss is one of the major factors to be addressed for further improvement. Here a bilayer ETL consisting of two SnO nanoparticle layers doped with different amounts of ammonium chloride is proposed.

Analysis of the Calcium Phosphate-Based Hybrid Layer Formed on a Ti-6Al-7Nb Alloy to Enhance the Ossseointegration Process.

This paper reports on hybrid, bioactive ceramic Ca-P-based coating formation on a Ti-6Al-7Nb alloy substrate to enhance the osseointegration process. The Ti alloy was anodized in a Ca(PO) suspension and then the additional layer was formed by the sol-gel technique to obtain a mixture of the calcium phosphate compounds. The oxide layer was porous and additional ceramic particles were formed after sol-gel treatment (scanning electron microscopy analysis coupled with energy-dispersive x-ray spectroscopy).

Multi-scale quantification and modeling of aged nanostructured silicon-based composite anodes.

Advanced anode material designs utilizing dual phase alloy systems like Si/FeSi nano-composites show great potential to decrease the capacity degrading and improve the cycling capability for Lithium (Li)-ion batteries. Here, we present a multi-scale characterization approach to understand the (de-)lithiation and irreversible volumetric changes of the amorphous silicon (a-Si)/crystalline iron-silicide (c-FeSi) nanoscale phase and its evolution due to cycling, as well as their impact on the proximate pore network. Scattering and 2D/3D imaging techniques are applied to probe the anode structural ageing from nm to μm length scales, after up to 300 charge-discharge cycles, and combined with modeling using the collected image data as an input.

Nano-Architectured Composite Anode Enabling Long-Term Cycling Stability for High-Capacity Lithium-Ion Batteries.

Failure mechanisms associated with silicon-based anodes are limiting the implementation of high-capacity lithium-ion batteries. Understanding the aging mechanism that deteriorates the anode performance and introducing novel-architectured composites offer new possibilities for improving the functionality of the electrodes. Here, the characterization of nano-architectured composite anode composed of active amorphous silicon domains (a-Si, 20 nm) and crystalline iron disilicide (c-FeSi , 5-15 nm) alloyed particles dispersed in a graphite matrix is reported.

Eu: A suitable substituent for Pb in CsPbX perovskite nanocrystals?

Eu is used to replace toxic Pb in metal halide perovskite nanocrystals (NCs). The synthesis implies injection of cesium oleate into a solution of europium (ii) bromide at an experimentally determined optimum temperature of 130 °C and a reaction time of 60 s. Structural analysis indicates the formation of spherical CsEuBr nanoparticles with a mean size of 43 ± 7 nm.

Impact of kinetics on the growth of GaN on graphene by plasma-assisted molecular beam epitaxy.

The growth of GaN on graphene by molecular beam epitaxy was investigated. The most stable epitaxial relationship, i.e.

Multiscale Multiphase Lithiation and Delithiation Mechanisms in a Composite Electrode Unraveled by Simultaneous Small-Angle and Wide-Angle X-Ray Scattering.

The (de)lithiation process and resulting atomic and nanoscale morphological changes of an a-Si/c-FeSi/graphite composite negative electrode are investigated within a Li-ion full cell at several current rates (C-rates) and after prolonged cycling by simultaneous synchrotron wide-angle and small-angle X-ray scattering (WAXS and SAXS). WAXS allows the probing of the local crystalline structure. In particular, the observation of the graphite (de)lithiation process, revealed by the LiC Bragg reflections, enables access to the respective capacities of both graphite and active silicon.

Gallium - a versatile element for tuning the photoluminescence properties of InP quantum dots.

With the goal to tune the emission properties of colloidal InP quantum dots, the incorporation of Ga was explored. Unexpectedly, depending on the nature of the gallium precursor, the photoluminescence shifted either to the red (gallium oleate) or to the blue (gallium acetylacetonate). In the first case, larger-sized InP/GaP core/shell nanocrystals were formed, while in the second case the formation of an InGaP alloy structure enabled the blue range of emission (475 nm) to be accessed.

Activation Energy of Organic Cation Rotation in CHNHPbI and CDNHPbI: Quasi-Elastic Neutron Scattering Measurements and First-Principles Analysis Including Nuclear Quantum Effects.

The motion of CHNH cations in the low-temperature phase of the promising photovoltaic material methylammonium lead triiodide (CHNHPbI) is investigated experimentally as well as theoretically, with a particular focus on the activation energy. Inelastic and quasi-elastic neutron scattering measurements reveal an activation energy of ∼48 meV. Through a combination of experiments and first-principles calculations, we attribute this activation energy to the relative rotation of CH against an NH group that stays bound to the inorganic cage.

Growth Mechanism and Surface State of CuInS Nanocrystals Synthesized with Dodecanethiol.

Ternary metal chalcogenide nanocrystals (NCs) offer exciting opportunities as novel materials to be explored on the nanoscale showing optoelectronic properties tunable with size and composition. CuInS (CIS) NCs are the most widely studied representatives of this family as they can be easily prepared with good size control and in high yield by reacting the metal precursors (copper iodide and indium acetate) in dodecanethiol (DDT). Despite the widespread use of this synthesis method, both the reaction mechanism and the surface state of the obtained NCs remain elusive.

Evidence for spin-to-charge conversion by Rashba coupling in metallic states at the Fe/Ge(111) interface.

The spin-orbit coupling relating the electron spin and momentum allows for spin generation, detection and manipulation. It thus fulfils the three basic functions of the spin field-effect transistor. However, the spin Hall effect in bulk germanium is too weak to produce spin currents, whereas large Rashba effect at Ge(111) surfaces covered with heavy metals could generate spin-polarized currents.

Large magnetic anisotropy enhancement in size controlled Ni nanowires electrodeposited into nanoporous alumina templates.

A large enhancement of the magnetic anisotropy of Ni nanowires (NWs) embedded in anodic aluminium oxide porous membranes is obtained as a result of an induced magnetoelastic (ME) anisotropy contribution. This unusual large anisotropy enhancement depends on the diameter of the NWs and exceeds the magnetostatic (MS) contribution. As a consequence, it leads to effective magnetic anisotropy energies as large as 1.

Silver Accumulation in the Green Microalga Coccomyxa actinabiotis: Toxicity, in Situ Speciation, and Localization Investigated Using Synchrotron XAS, XRD, and TEM.

Microalgae are good candidates for toxic metal remediation biotechnologies. This study explores the cellular processes implemented by the green microalga Coccomyxa actinabiotis to take up and cope with silver over the concentration range of 10(-7) to 10(-2) M Ag(+). Understanding these processes enables us to assess the potential of this microalga for applications for bioremediation.

Direct Synthesis of Highly Conductive tert-Butylthiol-Capped CuInS2 Nanocrystals.

tert-butylthiol (tBuSH) is used as the sulfur source, surface ligand and co-solvent in the synthesis of CuInS2 nanocrystals (NCs). The presented method gives direct access to short-ligand-capped NCs without post-synthetic ligand exchange. The obtained 5 nm CuInS2 NCs crystallize in the cubic sphalerite phase with space group F-43m and a lattice parameter a=5.

Synthesis, Internal Structure, and Formation Mechanism of Monodisperse Tin Sulfide Nanoplatelets.

Tin sulfide nanoparticles have a great potential for use in a broad range of applications related to solar energy conversion (photovoltaics, photocatalysis), electrochemical energy storage, and thermoelectrics. The development of chemical synthesis methods allowing for the precise control of size, shape, composition, and crystalline phase is essential. We present a novel approach giving access to monodisperse square SnS nanoplatelets, whose dimensions can be adjusted in the range of 4-15 nm (thickness) and 15-100 nm (edge length).

Enhanced charge separation in ternary P3HT/PCBM/CuInS2 nanocrystals hybrid solar cells.

Geminate recombination of bound polaron pairs at the donor/acceptor interface is one of the major loss mechanisms in organic bulk heterojunction solar cells. One way to overcome Coulomb attraction between opposite charge carriers and to achieve their full dissociation is the introduction of high dielectric permittivity materials such as nanoparticles of narrow band gap semiconductors. We selected CuInS2 nanocrystals of 7.

Bistable coupling states measured on single Co nanoclusters deposited on CoO(111).

We describe novel features of the induced magnetic anisotropy in Co nanoclusters coupled with a CoO(111) layer. Individual cluster magnetism was studied using new microbridge superconducting quantum interference devices. Intrinsically, the Co clusters are single domains with an effective anisotropy constant K(F)≈1.