Spatial Charge Separation as the Origin of Anomalous Stark Effect in Fluorous 2D Hybrid Perovskites

2D hybrid perovskites (2DP) are versatile materials, whose electronic and optical properties can be tuned through the nature of the organic cations (even when those are seemingly electronically inert). Here, it is demonstrated that fluorination of the organic ligands yields glassy 2DP materials featuring long‐lived correlated electron–hole pairs. Such states have a marked charge‐transfer character, as revealed by the persistent Stark effect in the form of a second derivative in electroabsorption. Modeling shows that electrostatic effects associated with fluorination, combined with the steric hindrance due to the bulky side groups, drive the formation of spatially dislocated charge pairs with reduced recombination rates. This work enriches and broadens the current knowledge of the photophysics of 2DP, which will hopefully guide synthesis efforts toward novel materials with improved functionalities.     

Rethinking Global-Regulation: world’s law meets artificial intelligence

This article takes a critical look at Machine Translation of legal text, especially global legislation, through the discussion of Global-Regulation, a state of the art online search engine of the world’s legislation in English. Part 2 explains the rationale for an online platform such as Global-Regulation. Part 3 provides a brief account of the history of the development of machine translation, and it describes some of the limits of the use of statistical machine translation for translating legal texts. Part 4 describes Neural Machine Translation (NMT), which is a new generation of machine translation systems. Finally, Parts 5 and 6 outline the ‘big sky’ thoughts on future directions for Global-Regulation.     

Experimental multiaxial fatigue tests realized with newly developed geometry specimens

In the literature there are many experimental results of multiaxial fatigue testing, usually generated by the combination of two or more cyclical loads. The cases in which samples are randomly stressed are rarer. Moreover, to generate particular stress states, the use of specific machinery for fatigue tests is usually required. For these reasons, the authors have created a particular geometry of specimens, which, when solicited by a single input of a random type, guarantees the creation of specific multiaxial stress states without using complex and costly instruments. The experimental tests were finally used for the validation of the multiaxial reduction method developed and currently utilized in the authors' design phase, though potentially used to verify all the other methodologies present in the literature.     

Superfluid Gap in Neutron Matter from a Microscopic Effective Interaction

Correlated basis function (CBF) perturbation theory and the formalism of cluster expansions have been recently employed to obtain an effective interaction from a nuclear Hamiltonian strongly constrained by phenomenology. We report the results of a study of the superfluid gap in pure neutron matter, associated with the formation of Cooper pairs in the \(^1S_0\) channel. The calculations have been carried out using an improved version of the CBF effective interaction, in which three-nucleon forces are taken into account using a microscopic model. Our results show that a non-vanishing superfluid gap develops at densities in the range \(2 \times 10^{-4} \lesssim \rho /\rho _0 \lesssim 0.1\), where \(\rho _0 = 2.8 \times 10^{14}~\mathrm{g~cm}^{-3}\) is the equilibrium density of isospin-symmetric nuclear matter, corresponding mainly to the neutron-star inner crust.     

Dopant‐Free Hole‐Transporting Materials for Stable and Efficient Perovskite Solar Cells

Molecularly engineered novel dopant‐free hole‐transporting materials for perovskite solar cells (PSCs) combined with mixed‐perovskite (FAPbI₃)_0.85(MAPbBr₃)_0.15 (MA: CH₃NH₃⁺, FA: NH=CHNH₃⁺) that exhibit an excellent power conversion efficiency of 18.9% under AM 1.5 conditions are investigated. The mobilities of FA‐CN, and TPA‐CN are determined to be 1.2 × 10^?4 cm² V^?1 s^?1 and 1.1 × 10^?4 cm² V^?1 s^?1, respectively. Exceptional stability up to 500 h is measured with the PSC based on FA‐CN. Additionally, it is found that the maximum power output collected after 1300 h remained 65% of its initial value. This opens up new avenue for efficient and stable PSCs exploring new materials as alternatives to Spiro‐OMeTAD.     

Dry powders for the inhalation of ciprofloxacin or levofloxacin combined with a mucolytic agent for cystic fibrosis patients

Objective: This study aimed to design and characterize an inhalable dry powder of ciprofloxacin or levofloxacin combined with the mucolytics acetylcysteine and dornase alfa for the management of pulmonary infections in patients with cystic fibrosis.

Methods: Ball milling, homogenization in isopropyl alcohol and spray drying processes were used to prepare dry powders for inhalation. Physico-chemical characteristics of the dry powders were assessed via thermogravimetric analysis, differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry and scanning electron microscopy. The particle size distribution, dissolution rate and permeability across Calu-3 cell monolayers were analyzed. The aerodynamic parameters of dry powders were determined using the Andersen cascade impactor (ACI).

Results: After the micronization process, the particle sizes of the raw materials significantly decreased. X-ray and DSC results indicated that although ciprofloxacin showed no changes in its crystal structure, the structure of levofloxacin became amorphous after the micronization process. FT-IR spectra exhibited the characteristic peaks for ciprofloxacin and levofloxacin in all formulations. The dissolution rates of micro-homogenized and spray-dried ciprofloxacin were higher than that of untreated ciprofloxacin. ACI results showed that all formulations had a mass median aerodynamic diameter less than 5?μm; however, levofloxacin microparticles showed higher respirability than ciprofloxacin powders did. The permeability of levofloxacin was higher than those of the ciprofloxacin formulations.

Conclusion: Together, our study showed that these methods could suitably characterize antibiotic and mucolytic-containing dry powder inhalers.     

Enhancement of the Magnetic Coupling in Exfoliated CrCl3 Crystals Observed by Low-Temperature Magnetic Force Microscopy and X-ray Magnetic Circular Dichroism

Magnetic crystals formed by 2D layers interacting by weak van der Waals forces are currently a hot research topic. When these crystals are thinned to nanometric size, they can manifest strikingly different magnetic behavior compared to the bulk form. This can be the result of, for example, quantum electronic confinement effects, the presence of defects, or pinning of the crystallographic structure in metastable phases induced by the exfoliation process. In this work, an investigation of the magnetism of micromechanically cleaved CrCl₃ flakes with thickness >10 nm is performed. These flakes are characterized by superconducting quantum interference device magnetometry, surface-sensitive X-ray magnetic circular dichroism, and spatially resolved magnetic force microscopy. The results highlight an enhancement of the CrCl₃ antiferromagnetic interlayer interaction that appears to be independent of the flake size when the thickness is tens of nanometers. The estimated exchange field is 9 kOe, representing an increase of ≈900% compared to the one of the bulk crystals. This effect can be attributed to the pinning of the high-temperature monoclinic structure, as recently suggested by polarized Raman spectroscopy investigations in thin (8–35 nm) CrCl₃ flakes.     

Electrical transport mechanisms of Neodymium-doped rare-earth semiconductors

Journal of Materials Science: Materials in Electronics - This study reports the electrical properties of Nd-doped cerium oxide (CeO2) films synthesized by microwave assisted hydrothermal using a...