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Quantum properties of NV centers in diamond: towards optimized industrial protocols
No full textInternational audienceBecause of their high sensitivity, quantum materials are extremely promising for new technologies. The main challenge lies in maintaining a sufficiently quantum coherence times for quantum computation or quantum sensing systems. NV centers in diamond which are point defects consisting of a substitutional nitrogen atom neighboring an atomic vacancy, where an electron pair can reside in a triplet state – are ideal candidates for the development of industrial-scale quantum systems. These spin states exhibit ms-long coherence times at room temperature and can be manipulated optically, hence opening interesting perspectives for sending magnetic fields with high sensitivity1.At HiQuTe Diamond, we take up the challenge of mastering the entire nitrogen-doped diamond production chain synthesized by Microwave Plasma-Assisted Chemical Vapor Deposition (MPACVD). We aim at creating affordable diamonds specially engineered to achieve long coherence times with high NV density and high doping uniformity. This quest require to overcome the impact of several external factors that contribute to electron spin decoherence. First, the chemical composition of the diamond, specifically the types and concentrations of impurities within the diamond matrix (such as substitutional nitrogen NS, NV centres, mono-vacancies and clusters, hydrogen, etc.), as well as their electrical charge states (NS⁰, NS⁺, NV⁰, NV⁻) should be carefully controlled. Thanks to extensive scientific research conducted over the past decade, combined with our own R&D efforts, we are now able to quantify these parameters using experimental techniques compatible with industrial applications (Raman and UV-Vis spectroscopy) and compare our results with key performance indicators2. Second, we study the relationship between coherence (T2*) and strain inhomogeneities in our diamond layers, which we analyse using birefringence measurements. Our findings demonstrate our capability to produce CVD diamond layers with reduced strain and extended defect and confirm that strain could be a critical limiting factor for T2*.In this poster, I will review the efforts carried out at HiQuTe Diamond to develop specific material that is well suited for quantum sensing applications.References1.Barry, J. F., Schloss, J. M., Bauch, E., Turner, M. J., Hart, C. A., Pham, L. M., & Walsworth, R. L. (2020). Sensitivity optimization for NV-diamond magnetometry. Reviews of Modern Physics, 92(1), 015004.2.Langer, J. (2022). Quantum-grade diamond for cavity-based solutions. Fraunhofer Verlag
Antiproliferative effects, Mechanism of Action and Tumor Reduction Studies in a Lung Cancer Xenograft Mouse Model of an Organometallic Gold(I) Alkynyl Complex
No full textInternational audienceOrganometallic complexes offer a wide range of properties like structural variety, reaction kinetics, tunable lipophilicity and alternate mechanisms of activation under physiological conditions compared to platinum chemotherapeutics and are thus being explored for their potential anticancer applications. In this regard, gold(Ⅰ) organometallics hold a pivotal position for their ability to act on biological targets different from DNA (which is the primary target of platinum therapeutics), such as thioredoxin reductase. Here, we report on the stability, in vitro antiproliferative effects, protein binding, cellular uptake, mechanism of action, effects on mitochondrial respiration of cancer cells as well as in vivo tolerance, toxicity and tumor reduction in a A549 lung cancer xenograft mouse model of an organometallic gold(Ⅰ) complex (1) bearing 4-ethynylanisole and triethylphosphane as ligands. The complex, which was stable in DMSO and reactive towards N-acetylcysteine, triggered strong antiproliferative effects in various cancer cell lines, and had a protein binding of approximatively 65% that reduced its generally efficient uptake into tumor cells. Antimetastatic properties were indicated for 1 in a scratch assay and strong inhibition of thioredoxin reductase (TrxR) was confirmed for the purified enzyme as well as in A549 lung cancer cells, which strongly overexpress TrxR. Real time monitoring of oxygen consumption rate in multiple cancer cell lines, using Seahorse Mitostress assay, demonstrated that mitochondrial respiration was severely disrupted, showing a significantly low oxygen consumption rate. Other respiratory parameters, such as proton efflux, spare respiratory capacity and maximal respiration were also attenuated upon treatment with 1. The complex was well tolerated in vivo in mice at a dose of 10 mg/kg and showed tumor reduction compared to the control group of animals in a lung cancer xenograft model of nude mice. In summary, complex 1 represents a novel organometallic anticancer drug candidate with a mechanism related to TrxR inhibition and mitochondrial respiration inhibition that shows efficient in vivo antitumor efficacy
Synthesis, Characterization and Stability of {Mo 132 }-type Capsules Containing Phosphorus Oxo Anion Ligands
No full textInternational audienceThis article deals with a set of {Mo 132 }-type capsules containing phosphorus oxo anions as ligands.Two of them, with hypophosphite and phosphate ligands, respectively, were prepared and characterized by IR spectroscopy and X-ray diffraction in Bielefeld more than two decades ago. We extended this pioneering work to phosphite and methylphosphonate ligands. All these capsules were prepared by ligand exchange in the acetate-containing {Mo 132 } capsule and some of them contain residual acetate, depending on the incoming ligand and the pH of the reaction mixture. All of them were characterized by 1 H and 31 P NMR spectroscopy in D 2 O and one by single-crystal X-ray diffraction. These studies showed that side reactions occur. On the one hand, degradation of the {Mo 132 } framework leads to the release of fragments that can be trapped as {MoO 3 H} + units by the ligands inside capsules. This was known for phosphate and is also observed for methylphosphonate.On the other hand, monitoring by NMR spectroscopy revealed that capsules slightly transform over time in solution as well as in the solid state, as evidenced by growth of characteristic signals of R. T. Deceased on December 5, 2022 2 Strandberg-type complexes and reduced Keggin-type molybdophosphates. Decomposition, however, remains fairly low over a few months. 2-, IUPAC name H-phosphonate, noted HPhos), methylphosphonate (MePO 3 2-, noted MePhos) and phosphate (HPO 4 2-, noted Phos). {Mo 132 }-type porous capsules, which Müller proposed to name Keplerates, 1 consist of 12 pentagonal {(Mo VI )Mo VI 5 O 21 (H 2 O) 6 } 6-units positioned at the vertices of an icosahedron while being connected by 30 {Mo V 2 O 4 } 2+ linkers. One of their most noteworthy features is the presence of 20 well-defined and flexible {Mo 9 O 9 } pores (diameter ca. 0.35 nm) allowing controlled matter exchange between the inside and the outside. 2 They most often incorporate 30 internal bidentate anionic ligands that are weakly bound 3 to the inner surface of the {Mo 132 O 372 (H 2 O) 72 } 12-shell and are readily replaced by other ligands. Compounds 1 1,4 and 2 5 ({Mo 132 (OAc)} and {Mo 132 (SO 4 )}, respectively, in simplified notations; see formulae in Table 1) are two representative examples. Though {Mo 132 (hypo)} (3) 4,6 and {Mo 132 (Phos)} (4a and 4b) 7 capsules were prepared very early from 1 by substituting hypophosphite or phosphate for acetate, they have since received little attention in comparison to other members of the {Mo 132 } family, specifically 2. 2Recent reports yet focused on encapsulation of Gd 3+ 8 and first-row transition metals (M = Mn 2+ , Co 2+ , Fe 2+ ) 9 in 4b, with views to assess the potential of the resulting host-guest systems as MRI contrast agents 8 and to develop catalytic and photocatalytic reactions in confined space. 9 For our part we have extended the {Mo 132 (POA)} set of capsules to {Mo 132 (HPhos)} (5) and {Mo 132 (MePhos)} (6). We report herein their synthesis, the single-crystal X-ray diffraction characterization of one of them (6b'), and a set of solution 1 H and 31 P NMR studies related to synthesis monitoring and characterization of 3, 4, 5 and 6 while providing insight in their stability, which is a crucial issue from the perspective of possible applications
Cover Feature: Experimental and Computational Analysis of Slurry‐Based Manufacturing of Solid‐State Battery Composite Cathode (Batteries & Supercaps 2/2025)
No full textInternational audienceThe Cover Feature showcases the manufacturing journey of solid-state battery composite electrodes, capturing the transition of the microstructure across key stages: slurry, drying, and calendering. It features a modeling workflow for battery cathodes composed of LiNi0.8Mn0.1Co0.1O2 and Li6PS5Cl, unveiling the impact of processing on microstructural evolution, with results validated against experimental data
Tracking solid electrolyte interphase dynamics using operando fibre-optic infra-red spectroscopy and multivariate curve regression
No full textInternational audienceAs batteries drive the transition to electrified transportation and energy systems, ensuring their quality, reliability, lifetime, and safety is crucial. While the solid electrolyte interphase (SEI) is known to govern these performance characteristics, its dynamic nature makes understanding its nucleation, growth, and composition an ambitious, yet elusive aspiration. This work employs chalcogenide fibres embedded in negative electrode materials for operando Infra-red Fibre-optic Evanescent Wave Spectroscopy (IR-FEWS), combined with Multivariate Curve Resolution by Alternating Least Squares (MCR-ALS) algorithms for spectra analysis. By establishing molecular fingerprints that can be used to identify reaction products, IR-FEWS combined with MCR-ALS enables improved understanding of SEI evolution during cell formation with notable differences stemming from electrolyte or anode material. For example, despite operating at an elevated potential, lithium titanate's SEI has intrinsic instability, evidenced by continued carbonate formation. This approach leads the hunt for the SEI down a new path, giving empirical formulations theoretical roots
Preferential fatigue cracking at basal twist grain boundary (BTGB) in bimodal Ti-5Al-4V alloy: Dislocation activities and crack initiation
No full textInternational audienceIn recent years, (0001) twist grain boundaries (BTGBs) located in primary α grain clusters were identified as fatigue crack nucleation sites in different Ti alloys. In the present study, crack initiation was investigated in a bimodal Ti-5Al-4 V alloy subjected to low-cycle fatigue and dwell-fatigue loadings at room temperature. The low fraction of primary α grains was not associated with a lack of sensitivity to BTGB cracking. Transmission electron microscopy and electron back-scattered diffraction were used to characterize BTGBs in the initial microstructure. The fatigue mechanisms were then analyzed with a focus on dislocation activity. αp grains adjacent to cracked BTGBs contained a high dislocation density. It was primarily composed of planar slip bands of 〈a〉 dislocations. In addition, 〈c + a〉 dislocations were noticed in the vicinity of cracked BTGBs. They supposedly pertain to crack tip plasticity during growth, and no evidence of a role of an incoming slip event in crack nucleation was obtained. Also, basal slip bands extending across adjacent grains were found to emerge from BTGBs. This feature provides an easier path for crack extension when growth along the grain boundary becomes difficult owing to a deviation from the basal plane. Atom probe tomography analyses evidenced V and Fe segregation at a grain boundary with a significant deviation from the BTGB configuration. This suggests a possible contribution of local solute segregation to the high cracking resistance of general αp / αp grain boundaries. This work provides new insights into the mechanisms involved in cracking of BTGB in Ti alloys subjected to cyclic loadings
The electrochemical performance of Ta2O5 thin films in ionic liquid and ionogel electrolytes
No full textInternational audienceIn this work, we present a new cell design for miniaturized energy storage devices by realizing a hybrid microcapacitor, which uses for the first time a TaN/ Ta 2 O 5 thin film electrode in combination with a MnO 2 composite electrode. In this proof of concept study, the electrochemical performance of the dielectric material Ta 2 O 5 was of main interest. Therefore, various tantalum oxide films with different thicknesses from 23 to 80 nm have been tested in combination with a pseudocapacitive oversized MnO 2 composite electrode. This was done with two model electrolytes, namely the ionic liquid Emim FSI and the solid-state ionogel Emim FSI: PVdF 80:20. Surface capacitance values up to 1.94 µF cm -2 in Emim FSI and 2.84 µF cm -2 in IG Emim TFSI: PVdF 80:20 have been reached at high scan rates (100 mV s -1 ) with no significant distortion of the voltammograms. When films of 47 and 80 nm thickness of Ta 2 O 5 are used, stable cycling with scan rates of up to 5000 mV s -1 at a cell voltage of 20 V can be achieved even in solid-state ionogel electrolyte. This performance highlights the promising characteristics of these materials and cell concept for miniaturized high power energy storage application and opens the way for further investigations to improve this needed technology
The spontaneous passivation of multi principal element alloys II: The effect of Mn in the CoCrFeNiMn family
No full textInternational audienceThe influence of at% Mn on the polarization and spontaneous passivation of (CoCrFeNi)100-xMnx (at%) alloys in aerated 0.1 M H₂SO₄ was investigated using atomic emission spectroelectrochemistry. At 0 – 6.5 at% Mn, spontaneous passivation occurred but at ≥ 10 at% Mn, the beneficial effect of Cr was completely negated. Spontaneous passivation could be predicted from Evans diagrams in which total current was decoupled into anodic dissolution and the cathodic components. Passivation occurred in two stages: rapid reaction with significant Cr enrichment; slower reaction with less enrichments. Differences between spontaneous and potentiodynamic passivation are discussed and interpreted with rate vs. free potential curves
Design and synthesis of glycofullerene derivatives as novel photosensitizer for potential application in PDT to treat cancer
No full textInternational audienceCancer is one of the most aggressive diseases known to humanity, characterized by low survival rates and poor prognoses. Currently, platinum-based anticancer drugs and traditional photosensitizers used in photodynamic therapy (PDT) are the most widely employed treatment modalities. However, the platinum-based medications, particularly cisplatin, the most commonly used agent, have several drawbacks. These drawbacks may include systemic toxicity, which can manifest as nephrotoxicity, neurotoxicity, ototoxicity, or emesis during treatment. Such side effects can severely impair patients and significantly diminish the overall effectiveness of therapeutic interventions. In contrast, photodynamic therapy does not present these disadvantages. PDT offers numerous benefits, including reduced long-term morbidity, minimal systemic toxicity, low invasiveness, negligible drug resistance, and temporal and geographic selectivity, all of which enhance patients' quality of life. Consequently, the search for novel, effective, and practical photosensitizers is essential. Fullerenes possess unique physicochemical properties that make them highly suitable as photosensitizers. In this study, we developed a comprehensive and straightforward synthesis for two water-soluble sugar fullerene derivatives, designated as 12 and 13. Multiple analytical techniques, including 1 H NMR, 13 C NMR, high-resolution mass spectrometry (HRMS), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet-visible (UV-Vis) spectroscopy, collectively confirmed the chemical structures of these derivatives and validated their successful synthesis. Upon exposure to white light irradiation at an intensity of 2.5J/cm², compound 13 demonstrated significant biological activity against three distinct tumor cell lines: HepG2, MKN45, and RPMI 4788, with IC 50 values of 5.65μM, 2.43μM, and 1.82μM, respectively. This study establishes a foundation for the development of innovative clinical photosensitizers
Modulating carbon dots from aggregation-caused quenching to aggregation-induced emission and applying them in sensing, imaging and anti-counterfeiting
No full textInternational audienceAggregation Induced Emission Carbon Dots (AIE-CDs) address the problem of conventional CDs being quenched in the solid-state. However, there are still challenges in comprehending the luminescence mechanism. This work proposed a strategy for preparing green, yellow, and near-infrared CDs by modifying the functional groups on the precursor from hydroxyl and amino to p-methylenediamine, in which electronic supply capacity determined the redshift. Additionally, The CDs' properties transformed from Aggregation-Caused Quenching (ACQ) to AIE was realized by substituting non-rotatable hydroxyl or amino groups with the rotatable p-methylenediamine on the precursor. The resulting CDs were then applied in multifield.C-CDs was used for ratiometric detection of Al 3+ and F -in pure water through three methods including fluorometer, test strip and smartphone. R-CDs was used for imaging cell nucleus and zebrafish. NIR-CDs (λ em = 676 nm) exhibits dual emission, AIE and phosphorescent characteristics was used for triple anti-counterfeiting and binary information encryption. In summary, our finding presented a strategy for preparing multicolor CDs, proposed a mechanism for the transition of CDs from ACQ to AIE, and explore their multiple applications in anti-counterfeiting, information encapsulation, sensing and imaging.</p