There is growing consensus that mineral crystallization from ionic solutions involves a liquid-liquid phase separation (LLPS), where a reactant-rich liquid separates from water, just as in organic crystallization. However, mineral LLPS remains elusive because of the short lifetime of the liquid phases prior to solid precipitation. TITANS will provide fundamental knowledge on mineral LLPS by addressing the most debated questions in order to: 1) assess how liquid are the reactant-rich structures, 2) determine if they are a metastable thermodynamic phase or a kinetic pattern, and 3) rationalize the intricate evolutions of the liquid, the amorphous solid and the crystal. We will combine advanced fast microfluidic mixers, in situ characterization of structure, chemistry and dynamics at the synchrotron and in the laboratory, and in and out-of-equilibrium modeling. TITANS will thus provide a reliable depiction of the ubiquitous soft matter processes preceding the crystallization of carbonates, oxalates and sulfates.

Solid Oxide Fuel/Electrolysis Cells are electrochemical devices based on ceramics which operate at high temperature, typically 600-800 °C. This high temperature is needed to ensure fast diffusion and reaction rates i.e. to allow for high power efficiency. Unfortunately, coupled with extreme operating conditions, high working temperatures lead to fast degradation. Materials discovery efforts have thus targeted new electrolyte and electrode materials with improved ionic and/or electronic conductivity and electrochemical activity, able to operate at a lower temperature. Other strategies concerned the development of new types of solid oxide cells, based on new charge carriers. Among these, Proton Conducting Cells, which can operate at a temperature below 600°C, are particularly promising. With typical performances of 0.3 W/cm2 at 600 °C in 2013, they can now reach 1.3 W/cm2 at 600 °C as reported in 2018. This is an increase of more than 300% in five years, which represents a significant acceleration. To achieve such a performance, materials have been designed with complex compositions having typically 4-5 different cations, whose relative ratios were determined empirically. Still, the exploration of new or optimized compositions remains limited by the highly time-consuming tasks to fully characterize such materials. Thus, in the highly competitive international context of cells development and fabrication, new approaches allowing a fast screening of many compositions might constitute an efficient strategy to fasten the development of high-performing cells. The objective of AutoMat-ProCells project is precisely to combine advanced research tools for screening efficiently the intrinsic properties of oxide materials for proton-conducting oxide cells. It is based on a high-throughput experimental approach. More concretely, our project couples the development of combinatorial deposition for the preparation of materials library bu pulse laser deposition, their exhaustive structural/chemical characterization in a highly efficient way including synchrotron-based techniques, and the measurement of electrolyte/electrode properties through electrical, isotope exchange and nuclear probe measurements. From this, we will obtain unique information on structure, stability, hydration, conductivity, electrochemical activity, the kinetics of ionic species transfer and diffusion, this for an extensive range of compositions. Through AutoMat-ProCells, we will also pave the path toward a renewed strategy for a very efficient exploration of materials for SOCs. From AUTOMAT-PROCELLS, we expect the following results: - a validation of the High-Throughput approach for the study and discovery of materials for PCFCs/PCECs, including the characterization of hydration and transport properties, stability and structural-chemical features, - the production of exhaustive information (hundreds of different compositions tested) on important phase diagrams for proton-conducting solid oxide cells : BaZr0.8Y/Yb0.2O3-d- BaCe0.8Y/Yb0.2O3-d- BaSn0.8Y/Yb0.2O3-d ; LSM-LSC-LSF, or doped BaCo0.4Fe0.4Zr0.2FeO3-d, - the identification of original compositions with optimized exchange, transport and electrochemical properties for proton-conducting solid oxide cells, - the creation of technical advances in the field of High-throughput Experiments for materials discovery like (i) the design and fabrication of a furnace for large samples particularly adapted to the characterization of materials library (ii) the development of a low-cost route for combinatorial deposition of oxide materials (see below) (iii) the adaptation of SIMS for the characterization of combinatorial films. - to help for the emergence of a dynamic in the French materials science community (starting from the application on fuel cells) toward the use of automated and parallelized approaches in research.

The project “Graphene quantum dots and nanoribbons for advanced optics” (GRANAO) will focus on the development of the chemical synthesis of graphene quantum dots (GQDs) and graphene nanoribbons (GNRs) and their detailed optical characterizations for the next-generation of nano- and quantum optical applications. The properties of the obtained nanographenes will be investigated through experiments at the single object level. To this end, the consortium gathers two groups of chemists and one group of physicists. The main goal will be to synthesize new GQDs and GNRs structures with original electronic and optical properties and to make the link between these properties and their structure. The main challenges of the field are to push the gap of the nanographene towards the near infrared and to be able to add them new functionalities. To address these challenges, we propose to synthesize GQDs with original shapes and to use porphyrins as building blocks to synthesize new GQD and GNRs. The fabrication of these GQDs and GNRs will be achieved through close collaborations between the German and French chemistry groups. Finally, the nanographenes will be studied by advanced optical experiments. In particular spectroscopy experiments at the single molecule level and as a function of temperature will be used to analyze the quantum states at the origin of the light emission and to relate them to the structure of the object. Likewise, tools of quantum optics such as intensity correlation measurements or optically detected magnetic resonance experiments will be used to investigate the spin physics, as for instance the intersystem crossing between singlet and triplet states. At longer term, the GRANAO project intends to address “on demand” fabrication of well-adapted nanographene materials for particular applications, such as optoelectronics, photonics, and (bio)labelling in bulk scales, as well as a wide range of cutting-edge applications, including quantum emitters for cryptography, telecommunication, and quantum sensing.

The HighEneCh ANR project aims to initiate and organize collaborative work between specialists of electron spectroscopy and instrumentation at large-scale facilities (SOLEIL, UPMC – LCP-MR), radiation chemistry (CEA - NIMBE), microfluidic systems (CEA – NIMBE) and ab initio molecular dynamics simulations (UPMC - IMPMC), with the goal of extending the boundaries of fundamental knowledge of the different mechanisms involved in the chemistry in aqueous environments triggered by high-energy photons. Using complementary approaches, the HighEneCh project consortium wants, over the 48 months’ duration of the project, to achieve a global view of the radiolysis of pure water and of water/biomolecule mixtures irradiated with soft X-ray and hard X-ray synchrotron light, with a special focus on the chemical effects of core ionizations. Irradiation with high-energy photons (x-ray) produces charged and neutral species which can both influence the production of the damage caused by the radiation via direct and indirect processes, respectively. The original approach of our consortium is to combine state-of-the-art quantification methods for the detection of radical species with photo/Auger electron spectroscopy on liquids, supported by ab initio molecular dynamics simulations to elucidate the fundamental mechanisms of the interaction of high energy photons with biological material surrounded by a liquid. Detection of radicals will be based on chemical scavenging methods that will be used to quantify the production of OH and HO2 radicals, under different irradiation conditions. In the first experiments, irradiation studies will be carried out in part with an up-graded version of an existing movable experimental set-up (IRAD set-up), which be upgraded with a microfluidic cell, and used under anaerobic conditions. Photo/Auger electron spectroscopy studies of liquids will utilize a new portable apparatus (MultiSpec Set-up), where a recycling liquid microjet will be used in vacuum. Recovering the irradiated sample is crucial for our project to be able to perform off-line analytical measurements (fluorescence yield, mass spectrometry) on the same sample measured by electron spectroscopy. We also plan to recycle sample in a closed loop system in order to progressively increase the average dose and follow its chemical evolution. Electron coincidence techniques will be used on the liquids to associate the photoelectron and Auger spectra, and thus have a better understanding of the effects of the environment during the decay processes of the initial core hole. Our studies will extend from pure water to solutions of sugar phosphates such as 5 ribose phosphate and 2-deoxyribose 5-monophosphate, a biomimetic molecule of the DNA backbone. A close collaboration with theoreticians will be a valuable component of the consortium. We will investigate the early stages of the dissociation of core ionized water or sugar-phosphate molecules, embedded in liquid water, at the femto to picosecond time scale, using ab initio Molecular Dynamics (MD) simulation. To support the experimental findings for the production of superoxide radicals in pure water, we will first model the dynamics induced by an oxygen-K ionization, starting from configurations in which one water molecule is doubly ionized and another one, localized within one nanometer, is singly ionized. Such an event is highly probable since, after Auger decay, the core-ionized water molecule will carry a double vacancy. Moreover, the photo and Auger electrons are ejected with a few hundred electronvolts kinetic energy and can ionize a neighbouring water molecule with a high probability since their mean free path is only a few nanometers in water. The results will be used as input data for the Kinetic Monte-Carlo simulation to extend to the chemistry occurring on a time scale of microseconds.

Nuclear Magnetic Resonance (NMR) is a sophisticated and powerful analytical method with numerous applications in research, health care, and industry. However, its use is limited by the low intrinsic sensitivity of inductive detection (owing to a low energy difference between nuclear spin states, even above 1 Tesla) and by the low polarisation that is established at thermodynamic equilibrium (i.e., the relative difference in populations for states with opposite spin orientations). Hyperpolarisation is relevant when a strong boost in sensitivity is needed. Polarisation enhancement factors can reach several orders of magnitude. This has paved the way to advances in science and applications. Laser-polarised noble gases have found applications in functional lung imaging and biomedicine, as well as in basic research. Optical pumping techniques have been extensively studied at low magnetic field (1 - 10 mT). But detection of the NMR signal at high field is usually needed, for increased sensitivity (thanks to operation at high frequency) and spectral resolution (large chemical shifts). It allows a more detailed analysis of the system, at the expense of polarisation losses due to gas handling and transfer into the NMR apparatus. Hyperpolarisation of noble gases at high magnetic field lies at the heart of the HELPING project. Scarcely explored up to now, it is of fundamental interest (it can shed light on polarisation build-up and decay processes) and it can help reduce, or even eliminate, the dead time for gas transportation in practice. New features are expected, owing to field-dependent atomic level structures, collisional interactions, and nuclear relaxation processes. Overall optimisation of polarised gas delivery also requires meeting inherent technical constraints (bore size, magnetic susceptibility of materials). The HELPING project mainly deals with hyperpolarisation of spin-1/2 atoms, 129Xe et 3He, and includes tests with quadrupolar isotopes, 21Ne (spin 3/2) et 83Kr (spin 9/2). Xenon strongly interacts with its surrounding and 129Xe exhibits a wide range of frequency chemical shifts that are particularly relevant for NMR spectroscopy. Helium, smaller in size, interacts weakly with nearby atoms hence 3He has low nuclear relaxation rates; it is also an excellent gas probe for systems with nanoscale void spaces. 21Ne et 83Kr can both provide additional information in NMR studies in various materials or media, through data that are more easily interpreted (21Ne) or more sensitive to surface properties (83Kr). The HELPING project relies on in-depth studies, with combined optical and NMR measurements, that are made possible by the recent implementation, at CEA Saclay, of a purchased 7 T NMR spectrometer/imager. It capitalises on the almost unique features of the instrument (a super-wide bore magnet, ratings for high quality MRS and 3-axes MRI, multi-channel detection). Work will focus, first, on hardware developments for noble gas hyperpolarisation in, or very close to, the measurement area. It will, then, consist in experimental investigations aiming at: 1- In-depth study of spin exchange optical pumping (SEOP) of 129Xe in alkali vapours and SEOP tests with 83Kr, 2- Assessment of the limits of metastability exchange optical pumping (MEOP) in pure 3He, extension to 3He-4He gas mixtures, and MEOP tests at cryogenic temperatures, 3- In-depth study of a new (non-optical) hyperpolarisation scheme, recently discovered in 3He gas discharges, called PAMP (Polarisation of Atoms in a Magnetised Plasma). Computational models and simulations will be jointly developed to rationalise experimental results and propose novel sets of experimental parameters that may allow gas delivery with optimal nuclear polarisation or magnetisation (the product of polarisation and atom number density) for the selected isotopes. Finally, work will be applied to NMR characterisation of porous materials and magnetometry.