The SWITCH project is a European doctoral network that is currently being built to support the transition from the known synthesis of switchable molecules to their implementation into operative devices. For that purpose, a consortium of experts in spin crossover systems (chemistry, properties and modelization) has started to be built and needs to be reinforced to cover as much as possible the main current challenges of molecular materials sciences for chemosensors, molecule-based electronics and barocaloric refrigeration. The scientific complementarity of the partners will be an asset for both the success of the various challenges tackled as well as for the high-level training of the doctoral candidates hired in the frame of this project. Indeed, up to fifteen doctoral candidates are planned in chemistry, physics and theoretical laboratories. Various actions will be planned to level-up their skills and create a network of young researchers for future collaborations. The MRSEI action will help building this doctoral network project by funding travels and a graphic designer to improve the quality of the project presentation.

Refrigeration systems used in our daily lives (air conditioners, refrigerators...) consumed up to 20% of the global electricity production in 2019 and are responsible for 8% of global greenhouse gas emissions. Alternatives are therefore actively sought, in particular through the compression of solids (mechanocaloric effect). This requires materials with significant structural changes, such as in spin conversion phenomenon which is accompanied by large volume changes under pressure. In this context, the BRef project aims at elaborating densified spin crossover pellets using sintering technic to study their thermal conductivity and cooling efficiency for further integration into barocaloric refrigeration devices. The project lies on the unique convergence of expertise of the Switchable Molecules and Materials team of the ICMCB on the elaboration of such densified materials and their characterization under pressure.

Sodium layered oxides NaxMO2 (where x is comprised between 0 and 1 and M is a 3d cation) were initially studied thirty years ago for use as positive electrode materials in secondary batteries. However, competing lithium based battery technology soon showed more promise and research on sodium compounds for battery applications was largely neglected. More recently, sodium batteries are once again generating interest, in part because sodium is much less expensive than lithium and it is widely available around the world. Numerous studies over the past few years have examined the structure and properties of sodium layered oxide systems, including their performance as electrode materials in sodium battery technologies for stationary applications. Moreover, some phases in these systems exhibited fascinating physical properties such as superconductivity, high thermoelectric power, and metal-insulator transitions. Therefore it appears very attractive to explore new systems in sodium layered oxides. In this project, we aim to explore new phase diagrams in sodium layered oxide systems NaxMO2 with 4d cations (in a first step with M = Mo, then with M = Nb, Ru or Rh) and to study the structure and the transport and magnetic properties of the single phases existing in these systems. This project is based on an innovative synthetic approach; the controlled electrochemical deintercalation/ intercalation of sodium ions in a battery by fixing the Fermi level of the targeted NaxMO2 phase versus the Na+/Na redox couple. It will be organised in three main work packages. The first package will be the synthesis of the new materials by solid state chemistry, either as powder or as single crystals, followed by the controlled sodium electrochemical deintercalation/ intercalation at room temperature. The electronic and the magnetic properties of single phases obtained in the first package will be systematically examined in the second package as a function of temperature. Thirdly, the structure of new phases with the most promising physical properties (high electronic and ionic conductivity, superconductivity, high thermoelectric power...) will be studied in detail using multiple complementary probes including crystallographic diffraction techniques (X-rays, neutrons or electrons) and local-scale probes such as Pair Distribution Function (PDF) analysis or solid state Nuclear Magnetic Resonance (NMR) Spectroscopy, to elucidate the composition-structure-property relationships. Whereas the NaxMO2 phases that I propose to study in this project may not find immediate wide spread use as active positive electrode materials in commercial sodium-ion batteries due to their cost and a high atomic weight / charge ratio for the incorporated 4d transition metals, the gained fundamental knowledge of composition-structure-properties relationships is of paramount importance to understand the mechanisms occurring in the positive electrode during the cycling process of all sodium layered oxide based battery technologies. Finally, this project might allow discovering new materials with exceptional electronic properties.

Materials scientists and engineers know for a long time the advantages offered by combining two or more materials of different natures and characteristics to obtain a single material with superior properties compared with their bare counterparts. The composite materials (e.g. reinforced concrete) are probably the best known example. In composites, structural building-blocks (e.g. particles, fibers) are combined with a matrix, each component remaining separate and distinct within the finished structure. Glass-ceramic materials may sometimes be considered as composites. They indeed consist in crystals dispersed in a glassy network and usually exhibit improved properties if compared to glass (e.g. mechanical resistance). However, they should be distinguished from composites as they are generally produced by crystallization from a single glass. Another type of materials that takes advantage of combining different components can be found in nature (e.g. bone or nacre): the inorganic-organic hybrid materials. As the distribution of the inorganic and organic building-blocks is assured on the molecular or nanoscale, such materials may offer a fine tailoring of their properties. Independently of the type of material, i.e. glass-ceramics, composites or hybrids, many investigations and developments have been carried out up to date. Nevertheless, few of them are related to optics and photonics._x000D_ Decreasing the size of the building-blocks incorporated into an optically transparent matrix to sub-micron/nanoscale and engineering their organization at different scales can favor enhanced and new optical properties, paving the way to a myriad of photonic applications for communication, health and medicine, energy and environment or security and housing. To this end, oxyhalide glasses appear as an ideal candidate whose potential is worth exploring. They constitute a special class of glasses as they intrinsically tend to host phase separation between the oxide and halide components, offering high optical contrast for the fabrication of artificial materials (e.g. photonic crystal structure) highly desirable for photonic technologies. Oxyhalide glasses are also promising for developing hybrid materials since they can offer characteristic temperatures compatible with the addition of molecular compounds. _x000D_ _x000D_ In the VERCINGÉTORIX project, we aim at implementing an innovative and original approach for developing transparent oxyhalide glass compositions, further hosting optically active nano-objects in view of producing new glass-ceramics, composites and hybrids for photonic applications._x000D_ Four work packages (WP) will be conducted in parallel: _x000D_ WP-1: The glass-ceramic approach, where the nano-objects will be generated from inside the oxyhalide glass by controlled demixtion and crystallization techniques._x000D_ WP-2: The composite approach, where the nano-objects (inorganic nano-particles), previously synthesized by local partners, will be incorporated into the oxyhalide glass by encapsulation and co-sintering techniques. _x000D_ WP-3: The hybrid approach, where molecular units will be incorporated into designed low-Tg oxyhalide glass compositions._x000D_ WP-4: The material functionalization, where multi-scale structuration processing through direct laser writing or thermal poling will be applied to the prepared glass-ceramics, composites and hybrids._x000D_ _x000D_ The VERCINGÉTORIX project addresses the challenge of developing new materials (multi-scale structured glass-ceramics, composites and hybrids) on one hand and of proposing new and innovative ways to manufacture the future NIR and Mid-IR photonic components on the other hand. In the long-term, objectives are to find novel solutions in the design of compact photonic systems in a cutting-edge area where international competition is very intense. In this regard, the VERCINGÉTORIX project aims to enable the ICMCB, the LAPHIA and the UBx to maintain and consolidate their leadership in the promising field of photonics and lasers.

Active plasmonic devices have recently emerged as smart electronic and light management technologies with tunable optical characteristics. Highly doped metal oxide nanocrystals exhibit charge carrier densities leading to pronounced localized surface plasmon resonances (LSPR) in the near-infrared (NIR) spectral range. The resonance of free carriers can then be modulated through an electrochemical gating process, and the change in carrier concentration induces a shift in the LSPR frequency as well as a change in optical absorption, giving rise to plasmonic electrochromism. Such nanomaterials, well-known for their original and promising exploitation in advanced glazing devices (especially as smart windows), also present a strong potential for smart display and labelling devices typically involved in applications related to intelligent packaging, environmental monitoring, disposable diagnostics and dynamic road signs, among others. So far, many electrochromic label systems are based on organic and polymer compounds: despite their easy processability, versatility and high control on optical properties, these somehow lack of robustness and their stability to long-term on/off commutation as well as recyclability are questionable, especially in harsh environments (heat, humidity, stress). In this context, there is a critical need for more durable formulations, increased chemical, thermal and mechanical stability as well as higher levels of coloration efficiency and stability tenue. The PECLABEL project aims at developing an innovative technology of smart electrochromic labelling for intelligent packaging and other electronics-related applications, based on inorganic metal oxide nanomaterials. Plasmonic electrochromic nanostructures based on aluminium-doped zinc oxide AZO, tin-doped indium oxide ITO, and substoichiometric tungsten oxide WO3-x will be chemically synthesized and characterized for being processed into thin functional films onto flexible substrates (including bio-based candidates), then manufactured into active demonstrator devices. Materials formulations will be obtained as printable, eco-conceived, low-toxic inks, and the manufacturing processes will be made compatible with standard graphic printing, leading to thin, flexible, robust, and ultra-low power smart labelling devices. These can be produced into a wide range of different shapes, patterns and sizes, offering many advantages for product design and integration. Such novel metal oxide inks will further be printed as workable electrochromic labelling devices, notably as colour tuneable QR codes, towards further applied integration in intelligent packaging systems. New functionality and selectivity in the NIR spectral range, with a tuning capacity being independent of the VIS behaviour, will also foster other interesting innovative developments in the fields of glazing devices (smart windows), security, military camouflages, smart textiles, (bio)sensing and telecommunications. PECLABEL relies on strongly innovative and ambitious concepts and approaches, sustaining responsible research, design and characterization of novel functional materials for smart energy- and electronic-related applications. The project involves one University (University of Liege), three research/industrial centres (CNRS-ICMCB, LEITAT and VTT) and three small- or medium-sized enterprises (Color Sensing, Optitune, NordicID) being based in four different countries (Belgium, France, Spain and Finland), therefore implying actors throughout the whole R&D process and value chain. The project has a beginning TRL of 2, starting with the formulation of the dual-band VIS-NIR smart labelling technology concept from the synthesis of novel nanostructures of plasmonic electrochromic materials. It will end with a TRL of 6, through the demonstration of the technology in an industrially-related environment by exploiting advanced approaches of upscaled demonstrator manufacturing with wireless powering aptitudes.