Bistable hybrid nanostructures – NanoHybrid

This project emerges at the crossroads of several new ideas based on our recent results, which were obtained in the frame of different national and international projects arriving to their final stages. At present, we possess a unique know-how at the international level in the synthesis of spin crossover nanomaterials, thin films and other nano-objects, as well as in the optical and electrical addressing of these materials at room temperature. The present project is built on these advances, but in a completely new context, where the aim is to construct new hybrid nanoparticle / molecule structures giving rise to novel synergistic physical properties between the two components. We wish to elaborate two kinds of hybrid systems: (1) metallic (primarily Au) nanoparticles functionalised by spin crossover molecules, and (2) core-shell systems with a metallic core and an active (spin crossover) shell or, vice versa, a coordination nanoparticle core with a metallic shell. These types of hybrid systems based on spin crossover molecules or coordination networks are novel very original. Their integration into photonic, electronic and magnetic devices is thus unprecedented and of considerable interest.
To exploit this idea we have initiated a consortium of 4 partners with complementary know-how in Chemistry and in Physics, each team with cutting-edge expertise in their respective fields at the international level. We have organised the project, as shown in the schema below, around 4 complementary and well defined tasks, where the focal point in each case is synthetic chemistry, which is oriented along two main directions: mixed systems consisting of bistable molecules and metallic nanoparticles as well as core-shell systems. In the first case, we will develop protocols based on exchange/precipitation by introducing molecules, functionalized by anchoring groups, into a colloidal solution of the particles, while in the second case we will use a synthesis method, recently developed in the consortium, which is based on the re-growth of cyano-bridged coordination networks on metallic nanoparticles.
The synthesis of the same hybrid nano-systems will open the door for the investigation of different physical properties. Using the facilities of the local nanotechnology platform (LAAS-CNRS) and different assembly methods already developed in the consortium we will organise the nano-hybrides within the electrode gaps either as extended particle networks or dimers for the transport measurements. This type of measurement is a novel alternative method to access the transport properties of single-molecules. In addition the magneto-transport properties of these compounds are so far unexplored and we anticipate uncovering interesting new properties. On the other hand we wish to investigate the optical properties of the same hybrid nano-objects, in particular by means of surface plasmon resonance based spectroscopic methods. In fact, these hybrids belong to the emerging group of active plasmonic systems as their plasmonic properties (dielectric permittivity) can be either reversible switched or continuously modulated between two states by different external stimuli, such as the temperature, the pressure or light irradiation. Last but not least we endeavour also the investigation of the nano-magnetic and nano-photomagnetic properties of our nano-hybrides. Thanks to the development of a novel, ultra-sensitive micro-magnetometer we hope to be able to achieve the unprecedented task to investigate single, isolated nano-objects displaying thermally or photo-induced phase transitions at room temperature.