Two-dimensional (2D) materials, such as graphene and many others that can be obtained from three-dimensional crystalline species with a layered structure, represent a very versatile platform on which to perform chemical modifications in order to obtain more complex nanostructures. The two-sided (Janus) nature of these 2D crystals allows different functionalities to be introduced on opposite sides, asymmetrically. In nature, organisation in asymmetrical assemblies is a key strategy to allow high efficiency and selectivity of transformation processes: for example, in photosynthesis, asymmetry is used to separate the light-harvesting units from the site where the charge separation takes place, preventing undesirable recombination processes from occurring.
The JANUS BI (All-liquid phase JANUS BIdimensional materials for functional nano-architectures and assemblies) project - coordinated by Professor Teresa Gatti of the Department of Applied Science and Technology - DISAT of the Politecnico di Torino and funded by the European Research Council with an ERC Starting grant - will produce highly asymmetrical nano-architectures containing 2D materials with different functionalities on the two opposite sides.
The project envisages an innovative protocol that proceeds completely in liquid suspensions, thus also paving the way for the scale production of these innovative nanotechnological objects. To achieve this, methods belonging to colloidal science and chemical synthesis will be used in its initial phase, while it will move in the direction of photocatalysis and optoelectronics to complete the ultimate goal of realising artificial functional nanosystems, in which light conversion processes inspired by nature are implemented.
“In JANUS BI, my team will explore the concept of exploiting flat 2D materials as separation barriers between light-absorbing nanocrystals or dyes and the charge-accepting/catalytic units, in order to hinder the recombination of electrical charges that have previously been separated by the action of light – explains Professor Gatti – At the same time, the central 2D material, with its unique and tunable electronic properties, will be exploited to facilitate charge and energy transfer processes between the two spatially separated units. The perfection of natural systems will be imitated in simple and easy-to-make photoactive nanostructures, allowing us to move forward considerably in the control of matter at the nanoscale through synthetic methods”.