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. 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. 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. Four work packages (WP) will be conducted in parallel: WP-1: The glass-ceramic approach, where the nano-objects will be generated from inside the oxyhalide glass by controlled demixtion and crystallization techniques. 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. WP-3: The hybrid approach, where molecular units will be incorporated into designed low-Tg oxyhalide glass compositions. 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. 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.

Fiber drawing offers a promising alternative method for adapting materials to application requirements. Here, taking full profit of the locale, fertile scientific ecosystem, we envision implementing a new capability and research activity at the University of Bordeaux (UBx) to develop innovative solution for the shaping and functionalization of hybrid materials through fiber drawing. The Phosphate-based Hybrid Fibers (PhosFyb) project encompasses four primary Tasks: Task (A) Researching on functional glasses Involves the fabrication, purification and characterization of hybrid phosphate glasses with new or interesting properties (ex. laser damage resistance, incorporation of transition ions for high nonlinearity); investigation of their structure/property relationship Task (B) Developing hybrid phosphate-based fibers for Laser gain and non-linear optic Developing promising properties linked to local partners problematic and/or with a strong potential for technological transfer (ex. high-power laser fiber, fibers for short fs/ps pulses, Kerr effect, selfphase modulation mode, 4-wave mixing, parametric effect) Task (C) Multi-material fiber processing Identifying new set of materials (glass compositions, polymers, crystalline materials…) compatible with thermal co-drawing; Developing innovative fabrication instrumentation, protocols and functionalization sequences (in-preform chemistry; in-line and off-line femtosecond laser writing; in-fiber/on-fiber chemistry) Task (D) Launching a new technological platform at UBx dedicated to fiber-drawing - During the PhosFyb project we will purchase and install dedicated equipment for the drawing of low-Tg glass systems and glass/polymer hybrid systems. In the meantime we will work in collaboration with the Prof. Smektala at the ICB / University of Bourgogne-Dijon to support advances on the drawing of multi-materials structures. The assembly of hybrid multi-materials macroscopic preforms and their drawing offers a new and exciting challenge to the teams involved in the project. Overall the objectives of the PhosFyb project are (i) to develop new fiber-based technological paradigms; (ii) to expand the range of materials suitable for co-drawing; (iii) to enhance the device packing density and interface quality; and (iv) to propose specialty fibers with new or improved functionalities that stem from altering the materials composition and arrangements. To efficiently treat the research project we will combine the adapted resources and local expertise and implement an effective management between different tasks. In order to guaranty the success of the program, the strategy will be to select the most suitable material for the targeted application, to develop the fiberization technique, to test and adopt innovative geometry and to establish correlation between fiber architectures, materials chemistry and properties. Dr. Danto will be the Project coordinator of the PhosFyb project. He is the recent laureate of a two-year post-doctoral fellowship provided within the framework of the ‘Initiative of Excellence’ (IdEx) of the University of Bordeaux. This scientific program is expected to attract high-profile candidates willing to bring an innovative insight into a mature research topic, which fits into the site’s scientific priorities, and to strengthen the international network of the UBx. In line with this program, we are requesting the support of the ANR@RAction 2014 call for three years to further strengthen the development of the fiber-drawing platform at UBx and its associated research. We are confident that funding gradually emanating from public and/or private partners will enable the development of the program over time.

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.

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.

MultiPhos project aims re-engaging with Solid State Chemistry approach. Its main goal is the search of multiferroics solids based on polyanionic frameworks investigating a synergy between non-centrosymmetric proper and magnetically-induced improper ferroelectricity. Partners from 4 institutes and divided into 4 interdependent research clusters wish to share their culture to offer a cooperation to rise to the complex challenge consisting on single crystal growth, characterize at different length scales, “understand” and tune the physical properties of novel multifunctionnal solids. Exotic magnetic properties such as chiral magnetism or hysteretic magneto capacitance effect due to the non centrosymetry nature of the nuclear cell plus improper effects are expected. MultiPhos project opens the possibility for breakthrough technological developments within sustainable development issues because multiferroic materials are of interest for energy harvesting and energy efficiency.