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.

Determining the conformation of a small molecule inside a huge molecular weight structure is crucial for the understanding of the fundamental molecular processes that drive the interactions. Many of these complexes are neither crystalline nor soluble and are thus difficult to study by classical methods such as NMR, X-ray diffraction etc. To the best of our knowledge, a limited number of atomic structures of such systems were reported to date. In our project, we propose a new strategy based on the synergetic combination of organic synthesis (chimio-, regio- and stereo-specific tritium labeling; carbon-13 and nitrogen-15 labeling), solid state NMR and molecular modeling as a novel unique tool-kit to determine the conformation of a small molecule embedded in a high molecular and non-crystalline assembly. To develop our strategy we choose a model small molecule, the Phe-Phe dipeptide that forms either crystals or self-assembled nanotubes depending on the solvent. If the crystalline atomic structure of Phe-Phe has been solved, the structure of the self-assembled nanotubes of Phe-Phe is still unknown. To solve such structure, precise intra- and intermolecular distances should be determined to get not only the conformation of the molecule but also its packing within the assembly. We will develop our strategy (chemical synthesis, solid state NMR and molecular modeling) on Phe-Phe crystal. This strategy will be then applied to determine the atomic structure of Phe-Phe nanotubes. The result of this project is expected to pave the way for numerous forthcoming applications such as pharmacology, biology (determination of a ligand structure bounded to its receptor, self-assembled molecules) and nanotechnology (determination of the conformation and the precise position of a small molecule within a supramolecular architecture).

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.

Perovskite solar cells (PSCs) have become a trending technology in photovoltaic research due to a rapid increase in efficiency in recent years. In 2020, a record efficiency of 25.5% close from Shockley-Queisser theoretical limit of 30% was reported. Tandem solar cells offer an alternative to go beyond but stability still remains an issue. In our project, we will bring together our complementary expertise in molecular and macromolecular syntheses, thin film morphology tuning and cell device engineering to improve the stability of highly efficient inverted perovskite cells using new electron transport layers (ETL) with high electron mobility and high stability. We will design and synthesize new n-type fullerene free semiconductors. Introduction of cross-linkable groups will lead to stabilized ETLs by thermally-induced cross-linking after film formation. The efficiency and stability of these ETLs will be finally evaluated through their incorporation in tandem configuration.