Materials formed by atomic thin layers constitute a common topic of interest in physics, chemistry and materials science, with van der Waals (vdW) heterostructures playing a central role as they offer the opportunity to study fundamental physical phenomena, while developing applied research towards the design of novel materials and devices. In Mol-2D a molecular approach to 2D materials is developed, which aims at designing metal-organic 2D magnets and fabricating magnetic heterostructures showing emergent properties. In particular, a new class of heterostructures is created by combining functional magnetic molecules with 2D materials with the aim of tuning/improving the properties of the “all surface” 2D material through the interactions established with the molecular system. As molecules, we concentrate on bistable spin crossover complexes able to switch between two spin states upon the application of external stimuli (temperature, light, pressure, electrical field, etc.). The driving idea is that of tuning the properties of the 2D material via an active control of the hybrid interface. As distinguished from a conventional chemical functionalization, our approach makes a strong effort to prepare high-quality molecular/2D heterostructures suitable in nano/microelectronics.
This approach has provided an entire new class of 2D molecule-based magnets and smart heterostructures of direct application in highly topical fields like electronics, spintronics or energy storage. We have pioneered on the one hand the design of chemically stable metal-organic layered magnets, which can be exfoliated and characterized down to the monolayer, while tuning their structures and magnetic properties by varying their chemical composition. On the other hand, an exquisite control over the properties of a 2D material has been achieved by fabricating twisted magnetic heterostructures exhibiting tunable magneto-transport properties, or by combining stimuli-responsive spin crossover (SCO) molecules with graphene and other 2D materials to obtain smart devices whose properties can be tuned by applying an external stimulus. This has allowed us to prepare for the first time twisted magnetic bilayers affording ultrathin spin valve devices, robust electronic devices based on spin crossover/2D heterostructures, and energy storage devices based on magnetic/graphene nanocomposites showing a giant enhancement of the capacitance when a small magnetic field is applied.
