Industrially Compatible Fabrication Process of Perovskite-Based Mini-Modules Coupling Sequential Slot-Die Coating and Chemical Bath Deposition

To upscale the emerging perovskite photovoltaic technology to larger-size modules, industrially relevant deposition techniques need to be developed. In this work, the deposition of tin oxide used as an electron extraction layer is established using chemical bath deposition (CBD), a low-cost and solution-based fabrication process. Applying this simple low-temperature deposition method, highly homogeneous SnO2 films are obtained in a reproducible manner. Moreover, the perovskite layer is prepared by sequentially slot-die coating on top of the n-type contact. The symbiosis of these two industrially relevant deposition techniques allows for the growth of high-quality dense perovskite layers with large grains. The uniformity of the perovskite film is further confirmed by scanning electron microscopy (SEM)/scanning transmission electron microscopy (STEM) analysis coupled with energy dispersive X-ray spectroscopy (EDX) and cathodoluminescence measurements allowing us to probe the elemental composition at the nanoscale. Perovskite solar cells fabricated from CBD SnO2 and slot-die-coated perovskite show power conversion efficiencies up to 19.2%. Furthermore, mini-modules with an aperture area of 40 cm2 demonstrate efficiencies of 17% (18.1% on active area)

Serum and Muscle Metabolomics for the Prediction of Ultimate pH, a Key Factor for Chicken-Meat Quality

Variations in muscle glycogen storage are highly correlated with variations in meat ultimate pH (pHu), a key factor for poultry meat quality. A total of two chicken lines were divergently selected on breast pHu to understand the biological basis for variations in meat quality (i.e., the pHu– and the pHu+ lines that are characterized by a 17% difference in muscle glycogen content). The effects of this selection on bird metabolism were investigated by quantifying muscle metabolites by high-resolution NMR (¹H and ³¹P) and serum metabolites by ¹H NMR. A total of 20 and 26 discriminating metabolites between the two lines were identified by orthogonal partial least-squares discriminant analysis (OPLS-DA) in the serum and muscle, respectively. There was over-representation of carbohydrate metabolites in the serum and muscle of the pHu– line, consistent with its high level of muscle glycogen. However, the pHu+ line was characterized by markers of oxidative stress and muscle catabolism, probably because of its low level of energy substrates. After OPLS-DA multiblock analysis, a metabolic set of 15 high-confidence biomarkers was identified that could be used to predict the quality of poultry meat after validation on an independent population

Redox and Luminescent Properties of Robust and Air-Stable N‑Heterocyclic Carbene Group 4 Metal Complexes

Robust and air-stable homoleptic group 4 complexes of the type M­(L)₂ [<b>1</b>–<b>3</b>; M = Ti, Zr, Hf; L = dianionic bis­(aryloxide) N-heterocyclic carbene (NHC) ligand] were readily synthesized from the NHC proligand 1,3-bis­(3,5-di-<i>tert</i>-butyl-2-hydroxyphenyl)­imidazolinium chloride (<b>H</b>_<b>3</b><b>L,Cl</b>) and appropriate group 4 precursors. As deduced from cyclic voltammetry studies, the homoleptic bis-adduct zirconium and hafnium complexes <b>2</b> and <b>3</b> can also be oxidized, with up to four one-electron-oxidation signals for the zirconium derivative <b>2</b> (three reversible signals). Electron paramagnetic resonance data for the one-electron oxidation of complexes <b>1</b>–<b>3</b> agree with the formation of ligand-centered species. Compounds <b>2</b> and <b>3</b> are luminescent upon excitation in the absorption band at 362 nm with emissions at 485 and 534 nm with good quantum yields (ϕ = 0.08 and 0.12) for <b>2</b> and <b>3</b>, respectively. In contrast, the titanium complex <b>1</b> does not exhibit luminescent properties upon excitation in the absorption band at 310 and 395 nm. Complexes <b>2</b> and <b>3</b> constitute the first examples of emissive nonmetallocene group 4 metal complexes

Mapping the Radiative and the Apparent Nonradiative Local Density of States in the Near Field of a Metallic Nanoantenna

We present a novel method to extract the various contributions to the photonic local density of states from near-field fluorescence maps. The approach is based on the simultaneous mapping of the fluorescence intensity and decay rate and on the rigorous application of the reciprocity theorem. It allows us to separate the contributions of the radiative and the apparent nonradiative local density of states to the change in the decay rate. The apparent nonradiative contribution accounts for losses due to radiation out of the detection solid angle and to absorption in the environment. Data analysis relies on a new analytical calculation, and does not require the use of numerical simulations. One of the most relevant applications of the method is the characterization of nanostructures aimed at maximizing the number of photons emitted in the detection solid angle, which is a crucial issue in modern nanophotonics

Mapping the Radiative and the Apparent Nonradiative Local Density of States in the Near Field of a Metallic Nanoantenna

We present a novel method to extract the various contributions to the photonic local density of states from near-field fluorescence maps. The approach is based on the simultaneous mapping of the fluorescence intensity and decay rate and on the rigorous application of the reciprocity theorem. It allows us to separate the contributions of the radiative and the apparent nonradiative local density of states to the change in the decay rate. The apparent nonradiative contribution accounts for losses due to radiation out of the detection solid angle and to absorption in the environment. Data analysis relies on a new analytical calculation, and does not require the use of numerical simulations. One of the most relevant applications of the method is the characterization of nanostructures aimed at maximizing the number of photons emitted in the detection solid angle, which is a crucial issue in modern nanophotonics

Porous Nitride Light-Emitting Diodes

A porous InGaN/GaN blue light-emitting diode is demonstrated using selective area sublimation. Transmission electron microscopy reveals that the structure is porous down to the Si substrate; however, the porosity is higher in the GaN buffer, while smaller pores are observed in the active region. This change of porosity between the active region and the buffer is explained by the modification of the dislocation pattern in the heterostructure, which is evidenced by weak beam transmission electron microscopy on a nonporosified reference sample. Cathodoluminescence mapping and electron beam-induced current microscopy (EBIC) analyses are used to probe the impact of porosification on the optical and electrical properties of the structure at nanoscale dimensions. It is observed that neither the quantum well emission nor the p–n junction EBIC spatial profile was degraded after porosification with respect to the nonannealed reference sample. A light-emitting diode with a fully porous active region is fabricated using a parylene pore filling for electrical insulation, and its electroluminescence is analyzed

Onset of Multiferroicity in Prototypical Single-Spin Cycloid BiFeO₃ Thin Films

In the room-temperature magnetoelectric multiferroic BiFeO3, the noncollinear antiferromagnetic state is coupled to the ferroelectric order, opening applications for low-power electric-field-controlled magnetic devices. While several strategies have been explored to simplify the ferroelectric landscape, here we directly stabilize a single-domain ferroelectric and spin cycloid state in epitaxial BiFeO3 (111) thin films grown on orthorhombic DyScO3 (011). Comparing them with films grown on SrTiO3 (111), we identify anisotropic in-plane strain as a powerful handle for tailoring the single antiferromagnetic state. In this single-domain multiferroic state, we establish the thickness limit of the coexisting electric and magnetic orders and directly visualize the suppression of the spin cycloid induced by the magnetoelectric interaction below the ultrathin limit of 1.4 nm. This as-grown single-domain multiferroic configuration in BiFeO3 thin films opens an avenue both for fundamental investigations and for electrically controlled noncollinear antiferromagnetic spintronics

Heterozygous BTNL8 variants in individuals with multisystem inflammatory syndrome in children (MIS-C)

International audienceMultisystem inflammatory syndrome in children (MIS-C) is a rare condition following SARS-CoV-2 infection associated with intestinal manifestations. Genetic predisposition, including inborn errors of the OAS-RNAseL pathway, has been reported. We sequenced 154 MIS-C patients and utilized a novel statistical framework of gene burden analysis, “burdenMC,” which identified an enrichment for rare predicted-deleterious variants in BTNL8 (OR = 4.2, 95% CI: 3.5–5.3, P &lt; 10−6). BTNL8 encodes an intestinal epithelial regulator of Vγ4+γδ T cells implicated in regulating gut homeostasis. Enrichment was exclusive to MIS-C, being absent in patients with COVID-19 or bacterial disease. Using an available functional test for BTNL8, rare variants from a larger cohort of MIS-C patients (n = 835) were tested which identified eight variants in 18 patients (2.2%) with impaired engagement of Vγ4+γδ T cells. Most of these variants were in the B30.2 domain of BTNL8 implicated in sensing epithelial cell status. These findings were associated with altered intestinal permeability, suggesting a possible link between disrupted gut homeostasis and MIS-C-associated enteropathy triggered by SARS-CoV-2