Polymer solar cell (PSC) technology is amongst the most powerful and promising in terms of processing cost and simplicity compared to other photovoltaic technologies. There are still, unfortunately, low power conversion efficiency limitations and a major source of instability due to the use of fullerene derivatives as acceptor materials. In the last two years, however, polymer solar cells using a new class of acceptor materials, referred as non-fullerene acceptors (NFA) have gain extremely high attention in the field of PSCs. Indeed, unprecedented increase in power conversion efficiency from 6% to 12% within 18 months, with additional demonstration of fast exciton dissociation at low driving forces at the donor :acceptor interface, demonstrates a high potential of NFA to push PSCs technology for industrial developments. Even more recently, it was shown that limitation of binary donor-acceptor blend approaches can be surpassed by multi-material blend approaches (ternary blends), evidencing the potential of carefully designed complex material associations in the PSCs over the different parameters (increase in open-circuit voltage, photocurrent and very recently also fill factor are improved). In this context, the aim of the NFA-15 project is therefore to develop new highly performing NFA molecules together with appropriate designed ternary blend approaches to reach 15 % of power conversion efficiency at lab level. Furthermore, transfer of lab processes to industrially relevant NFA PSCs printing in air, with efficiency at module level of 10% (8-9% after burn-in) will be developed, which would be an essential step towards a larger range of PSCs application in industry. All these effort in increasing efficiency will be combined with stability study to evaluate and improve the NFA-based solar cells lifetimes to reach long time stability of 7-10 years in products.

The recent decades have shown that nanocrystals (NCs) can play an important role in a lot of different fields such as biology, catalysis, and magnetism. From a sustainable point of view it is necessary to limit the use of rare metal (platinum, palladium etc..) as catalyst. Due to their low cost and low toxicity, cobalt NCs and their derivatives are appealing materials. However, to gain valuable electronic and chemical properties, a careful design of the nano-object is required, i.e. its shape, size, phase and composition. In several industrial domains, the production of nanomaterials used as catalysts in fuel cells, batteries, etc.. needs to be improved. This calls for a better understanding of their structure at the atomic level in relation with their properties, not only in vacuum, but also in real conditions. Nevertheless, despite important research efforts in the field of colloid chemistry, the understanding of the growth mechanisms of nanomaterials is still incomplete, because of i) the impossibility of directly visualizing dynamical processes at the nanoscale in liquids, ii) the complexity of the chemicals reaction itself due to the number of components and of the role of the chemical byproducts. Therefore, the influence of the physical and chemical parameters (concentration of precursors, time of reaction, temperature, role of organic ligands…) are still in debate. At the same time, modern studies of nanoscale materials are being revolutionized by in-situ and operando characterization. Indeed, it is now possible to follow in real-time the reactivity and evolution of nanomaterials in response to chemical, thermal, mechanical, or electrical stimuli i.e, in operando conditions, but also the growth of NCs in solution or the atomic structure of NCs in liquids. These cutting-edge techniques (E-TEM, NAP-XPS, in situ STM) should lead to advanced understanding of the mechanisms of nanomaterials synthesis with functional properties, e.g. nanoalloys or core-shell nanoparticles. Thus the aim of this project is to study in situ the nucleation and growth process of metallic and bimetallic NCs, and their further reactivity in paradigmatic reactions, starting from a very simple one-pot synthesis of metallic hcp cobalt NCs recently patented.

Pi-Conjugated oligomers and polymers based on a planar backbone of sp2-bonded carbon atoms have attracted increasing interest in recent years owing to their potential application for electronic devices. For example, light-emitting diodes (OLEDs) for display based on polymer technology are commercialized since 2002. However, research in this field is still needed especially toward the development of optimized materials for white-LEDs. This type of devices is of tremendous interest since they can potentially replace traditional incandescent white light sources generating enormous energy saving. The aim of this project is the development of highly luminescent hybrids which can be used for the development of optoelectronic devices like light-emitting diodes (LEDs). To develop these new materials, we will graft Aggregation-Induced Emission organic fluorophores (AIE) on inorganic nanoparticles like ZnO, ZrO2... The grafting, via an anchoring group part of the pi-system, will concentrate a large number of chromophores at the surface and particularly freeze the motion of the molecules to reduce non-radiative deactivations. One of our objectives concerns the development of a synthetic method, easy to implement, reproducible and permits to obtain large quantities of modified nanoparticles. In particular, phospholes, siloles and tetraphenylethylene, which AIE properties have already been demonstrated on “all organic” system will be studied. One objective will be to prepare AIE fluorophores emitting different wavelengths in the visible range. Furthermore, we will study in detail the interactions between the organic fluorophore and the nanoparticle by varying different parameters (nature and position of the grafting function, shape of the nanoparticle (sphere, rod...), and introduction of different substituents on the fluorophore). Finally, introduction of these new hybrid materials with tunable emission into specific LEDs structures using wet techniques to simplify the manufacturing processes of these devices is the main target of the project to develop white LEDs for lighting.