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Unveiling surface reactivity: the crucial role of auxiliary ligands in gallium amidinate-based precursors for atomic layer deposition
No full textInternational audienceTwo novel gallium ALD precursors, LGaMe2 and LGa(NMe2)2 with L = amidinate, were prepared. The auxiliary ligand (methyl vs . amido) dictates the growth: while LGaMe2 halted growth after 3 cycles, LGa(NMe2)2 enabled Ga 2 O 3 /Ga 2 S 3 deposition with H 2 O/H 2 S
Direct recycling of NMC-cathode Scrap: Relithiation in aqueous solution following by low-temperature annealing
No full textInternational audienceWith the rise of electric mobility, the growing demand for batteries is expected to generate a significant stock of end-of-life batteries, making recycling an interesting solution to reduce environmental impact. Here, we propose a direct regeneration process in two steps based on a hydrothermal relithiation and post-annealing at moderate temperature. Two NMC-materials went through chemical delithiation and subsequent relithiation: NMC from scrap, which is recovered with the conductive carbon from its original formulation and reference NMC for comparison. The results demonstrate that relithiation was effective during the first solution step, leading to a partially active material. The post-annealing treatment enhances electrochemical performances and the best ones are obtained for the samples annealed at 400°C. Therefore, the results confirm that the presence of residual carbon does not impact relithiation or compromise its efficiency. The latter conserves its conductive properties after the relithiation process. However, an amount of the carbon has been lost during the second step; then this loss was compensated with an addition of fresh carbon, providing satisfactory electrochemical performances
Electrocatalytic CO<sub>2</sub> to CO and Methanol Conversion Using a Molecular Cobalt Corrole Complex
No full textInternational audienceTriphenylcorrole (Cor)Co III (DMSO), (Cat 1), was investigated for its electrochemical CO₂ reduction catalysis, facilitating 2-, 4-, and 6-electron transfer processes. Cat 1 was identified as an active molecular catalyst for CO₂-to-CO (2e⁻, 2H⁺) conversion under homogeneous conditions in CH3CN, using water as the proton source. Under heterogeneous conditions, Cat 1@E (Cat 1 immobilized on multi-walled carbon nanotubes (MWCNTs) and coated on carbon paper) demonstrated CO2-to-CO conversion with near-perfect Faradaic efficiency (FECO) ~97%, and high stability at near-neural pH in single-cell setup. When the electrode was transitioned to a flow-cell configuration, the jCO significantly improved to 47.5 ± 0.5 mA cm⁻², while maintaining a high FECO of ~95%. Applying a higher jtot of -200 mA cm⁻², led to the formation of CH3OH (6e⁻, 6H⁺) with FECH3OH of ~2%, representing a sevenfold increase compared to the single-cell configuration (FECH3OH ~0.34%) and jCH3OH of ~3.84 mA cm⁻² with trace amounts of HCHO (4e⁻, 4H⁺) in parallel. Metal-bound CO, i.e., [M n+ -CO], was identified as a key intermediate for CH3OH formation, as replacing CO2 with CO in the feed gas further promotes the FE of the liquid products, reaching ~4 to 5% for both CH3OH and HCHO under a singlecell configuration. The demonstration that simple Co corrole can drive CO2RR up to 6 electrons illustrates that multi proton-electrons activation with molecular catalysts is a more general possibility than anticipated
Biobased styrene copolymers prepared from mixtures of molecules fromlignin depolymerization
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Unveiling the Critical Influence of EDTA Additives on Modulating Solvation Structure and Solid Electrolyte Interphase Formation in Water‐in‐Salt Electrolytes for Aqueous Batteries
No full textInternational audienceAbstract Water‐in‐salt ( WIS ) electrolytes confer a wide voltage window to aqueous batteries. However, the dynamic solid electrolyte interphase ( SEI ) is adversely affected by LiTFSI precipitation/dissolution and continuous reforming issues, causing electrolyte dryness. Here, the aminopolycarboxylic (Ethylenediaminetetraacetic acid, EDTA ) additive is introduced to WIS electrolytes. An intriguing solvation phenomenon is observed wherein EDTA exhibited insolubility in a low‐concentrated (7m) solution while achieving certain solubility in a high‐concentrated (21m) one. The assembled full cell with EDTA exhibited good cycling stability at a low 0.5 C. To elucidate the unique solvation phenomenon and unravel the mechanism of SEI formation, experimental characterizations, and simulations are conducted. Molecular Dynamics ( MD ) and physical measurements disclosed that sufficient Li + acts as a bridge connecting EDTA with TFSI − ‐H 2 O . The simulated electrode/electrolyte interface investigated the dynamics, showing the difference in the activity and density of molecules after adding EDTA . Density Functional Theory ( DFT ) calculations together with physical measurements discovered EDTA ‐ species are prone to facile reduction during cycling, and the products facilitated the formation of a robust fluorine–oxygen–sulfur‐based SEI , outstanding critical roles of EDTA in forming the interphase compared with the unstable dynamic SEI . This work directs an alternative way and clear formation mechanism of the interphase for building stable aqueous batteries
Commutation multi-étape de l'état de spin avec rupture de symétrie et photocommutation ON/OFF dans un complexe de fer (II)
No full textInternational audienceIn recent world advancement and the quest for smart multi-functional material, stimuli-responsive molecular bistable systems offer unique opportunities to explore their applicability in molecular switches, data storage, and sensing technologies. Multi-stimuli responsive stepwise Spin Crossover (SCO) systems stand tall in this area. While the effects of external stimuli, particularly thermal variations and photoirradiation on the magneto-structural properties of SCO systems have been extensively studied, the area of pressure-modulated stepwise spin crossover and its associated magneto-structural changes remains lesser explored. Herein, we report a mononuclear iron(II) complex containing tetradentate macrocyclic ligand with -diimine-based bidentate coligand, [Fe(L)(bik*)](BPh4)2 (1) (L = N,N'-di-iso-propyl-2,11-diaza[3,3](2,6)pyridinophane and bik* = bis(1-ethyl-1H-imidazol-2-yl)ketone)) undergoing a reversible stepwise thermo-induced spin-state switching with the presence of three spin-states HS, LS, and an ordered HS-LS with the exciting re-entrant symmetry breaking during the spin-state switching process. The influence of external pressure on the structure and magnetic response is thoroughly studied, where the pressure-induced modification in the intermolecular interactions leads to enhanced cooperativity and a hysteretic stepwise spin state switching. The versatility of the systems is further explored where 1 displays a reversible ON/OFF photo-switching between a photo-induced paramagnetic metastable HS and diamagnetic LS states under light irradiations at low temperatures along with light-induced excited spin state trapping (LIESST).Grâce aux progrès récents et à la quête de matériaux multifonctionnels intelligents, les systèmes moléculaires bistables sensibles aux stimuli offrent des opportunités uniques pour explorer leur applicabilité aux commutateurs moléculaires, au stockage de données et aux technologies de détection. Les systèmes à croisement de spin (SCO) multi-étape et multi-stimuli sont particulièrement performants dans ce domaine. Si les effets des stimuli externes, notamment les variations thermiques et la photo-irradiation sur les propriétés magnéto-structurales des systèmes SCO ont été largement étudiés, le croisement de spin multi-étape modulé par la pression et les modifications magnéto-structurales associées restent moins explorés. Ici, nous décrivons la commutation d'état de spin thermo-induite multi- étapes et réversible avec la présence de trois états de spin HS, LS et un HS-LS et avec la rupture de symétrie rentrante pendant le processus de commutation d'état de spin d'un complexe mononucléaire de fer(II) coordonné par un ligand macrocyclique tétradentent et par un coligand bidentent à base de -diimine, [Fe(L)(bik*)](BPh4)2 (1) (L = N,N'-di-iso-propyl-2,11-diaza[3,3](2,6)pyridinophane et bik* = bis(1-éthyl-1H-imidazol-2-yl)cétone)). L'influence de la pression externe sur la structure et la réponse magnétique est étudiée en profondeur, où la modification induite par la pression dans les interactions intermoléculaires conduit à une coopérativité améliorée et à une commutation d'état de spin par étapes hystérétique. La polyvalence des systèmes est explorée plus en détail lorsque 1 présente une photo-commutation ON/OFF réversible entre un état HS métastable paramagnétique photo-induit et un état LS diamagnétique sous irradiations lumineuses à basse température ainsi qu'un piégeage d'état de spin excité induit par la lumière (LIESST)
Ethyl 4-Ene-4-ferrocenyl-5,5-bis-(4-hydroxyphenyl)-pentanoate
No full textInternational audienceThe ferrociphenol family is a group of molecules in which a ferrocenyl moiety is connected to at least one 4-hydroxyphenyl group through a C-C double bond. Among them, ferrocidiphenols in which the double bond is substituted by two gem 4-hydroxyphenyl groups have been largely studied, demonstrating interesting anticancer properties. The fourth available position of the double bond could be substituted by a simple ethyl group (1a) inherited from Tamoxifen, but also by ethyl or methyl acetate, propionate, butanoate, pentanoate (1b-g), hydroxyethyl or hydroxypropyl (1h–i). Ethyl 4-ene-4-ferrocenyl-5,5-bis-(4-hydroxyphenyl)-pentanoate 1e shows an IC50 on the MDA-MB-231 breast cancer cell line very close to that of 1a. These compounds were synthesized in moderate to good yields by McMurry coupling reaction from the corresponding ketones. Ethyl 4-ene-4-ferrocenyl-5,5-bis-(4-hydroxyphenyl)-pentanoate (1e) was fully characterized by 1H NMR (including COSY), 13C NMR (including DEPT135), low resolution mass spectrometry, HRMS, infrared spectroscopy, elemental analysis, and X-ray diffraction (XRD). The data of already published crystal structures of five structurally related ferrocidiphenols are also included for comparison purposes
Physics‐Based Machine Learning Electroluminescence Models for Fast yet Accurate Solar Cell Characterization
No full textInternational audienceElectroluminescence analyses of solar cells and modules allow for fast, cost‐effective, and nondestructive spatial characterization of devices at different stages of their development and use. Voltage‐dependent electroluminescence (ELV) measurements have been shown to mimic diode voltage–current characteristics. A derived physical model enables the determination of two local pseudoparameters from ELV data measured on silicon solar cells: a pseudorecombination current and a pseudoseries resistance . Local characteristics of the solar cells, such as the series resistance or the dark saturation current , can be deduced from these pseudoparameters. ELV measurements are stored in large data cubes, typically containing a few hundred thousand pixels. Pixel‐wise regression is commonly achieved through nonlinear least squares (NLLS) minimization; knowing that a luminescence image of a 6 ′ ′ silicon solar cell contains about 1 Mpix, this method is time‐consuming, necessitating a trade‐off between sample size, spatial resolution, fitting accuracy, and computation duration. We hence propose to replace NLLS fitting with machine learning (ML) techniques, known for their efficiency in rapidly processing large datasets. We compare the regression performances of a multilayer perceptron (MLP) with the ones of a convolutional neural network (CNN) called modified U‐NET (mU‐NET). The first ML model conducts a pixel‐wise analysis of the data cube and the second processes the entire data cube in a single step. We present a comprehensive characterization of prediction accuracy, objectively assessing the advantages and limitations of the proposed techniques. Our first step is to ensure that the prediction precision is sufficient for a valid comparison of the analysis duration. The deviation of accuracy of these models compared to NLLS is almost negligible for MLP and of 3.1 % when employing mU‐NET, demonstrating their relevancy for operational application. Both ML models are fast and efficient: the time required for regression decreases by a factor of 240 with the MLP and by a factor of 1200 with the mU‐NET, compared to the NLLS method
Cysteine-selective [ 188 Re]Re(V) radiolabelling of a Nanobody ® for targeted radionuclide therapy using a “chelate-then-click” approach.
No full textInternational audienceIn this study, we present the first reported use of bioorthogonal click chemistry with rhenium-188 (188Re) for radiolabelling of an anti-c-Met VHH Nanobody®. We employed a "chelate-then-click" strategy, wherein a bifunctional chelator was designed in two parts, which were subsequently joined post-labelling and post-conjugation via the strain-promoted azide-alkyne cycloaddition (SPAAC) reaction. Cysteine-selective conjugation of the VHH was achieved through thiol-Michael addition, forming a VHH-DBCO construct. Radiolabelling of the azide-functionalised chelator with [188Re]Re(V) was optimised to achieve a radiochemical conversion of ~70%, despite challenges associated with maintaining the azide functionality under reducing conditions. The final product, [188Re]Re-VHH, demonstrated high radiochemical purity and good in vitro stability over 48 h. In vitro cell-binding studies against U87MG and BxPC3 cell lines proved the retention of c-Met binding post-labelling. In vivo biodistribution studies on mice bearing BxPC3 tumour xenografts, however, exhibited suboptimal tumour uptake, likely a result of the low molar activity (1.4 – 3.3 MBq/nmol) of the radioconjugate. This work illustrates the potential of bioorthogonal click chemistry for radiolabelling biomolecules with 188Re, although further optimisation or alternative radiolabelling strategies to enhance the molar activity are necessary to improve pharmacokinetics
Opto-RF transduction in Er3+:CaWO4
No full textInternational audienceWe use an erbium doped CaWO crystal as a resonant transducer between the RF and optical domains at 12 GHz and 1532 nm respectively. We employ a RF resonator to enhance the spin coupling but keep a single-pass (non-resonant) setup in optics. The overall efficiency is low but we carefully characterize the transduction process and show that the performance can be described by two different metrics that we define and distinguish: the electro-optics and the quantum efficiencies. We reach an electro-optics efficiency of -84 dB for 15.7 dBm RF power. The corresponding quantum efficiency is -142 dB for 0.4 dBm optical power. We develop the Schrödinger-Maxwell formalism, well-known to describe light-matter interactions in atomic systems, in order to model the conversion process. We explicitly make the connection with the cavity quantum electrodynamics (cavity QED) approach that are generally used to describe quantum transduction