Functional hybrid organic-inorganic nanohelices: studies of exalted phenomena at nanometric scale – nanosprings

Helical nanosprings represent a new variety of nanostructures which have attracted great attention in nanotechnology and nanoscience over the past decade. One decisive advantage of helices or twisted ribbons, compared to 1D nanostructures such as nanotubes and nanowires, lies in the fact that 3D morphologies with extremely high surface to volume ratio exhibit unconventional physical properties (confinement, edge effects, nonlinearity, etc.). They can be advantageously used as building blocks in functional nanodevices such as nano piezoelectric or piezoresistive systems. These properties confer their potential applications in nano-electromechanical systems (NEMS) as sensors, resonators and triggers.Unfortunately, 3D nanostructures are hardly achievable using top-down nanofabrication techniques since they rely on 2D fabrication processes. The bottom-up approach has already led to the formation of piezoelectric carbon or zinc oxide nanohelices. The synthesis relies on spontaneous formation processes leading to a variety of orientations, shapes and sizes of the structures.However, it is still very challenging to achieve both high-yield and low cost controlled synthesis of uniform helical nanostructures (regardless of the synthesis processes, less than 10% of the obtained structures exhibit coiled shapes).
The difficulty for the precise control of the morphologies of obtained objects requires the development of more specific synthesis methods, allowing the preparation of controlled nanoscale synthetic architectures. In this project, we propose to use the structural diversity of self-assembled organic systems -based amphiphilic molecules. These systems are then used as templates for the formation of hybrid or inorganic nanomaterials with high yield synthesis of nano-scale helical objects with controlled dimension. Their subsequent modification with metal nanoparticles or semiconductor layers will lead to new properties such as piezoresistive or piezoelectric phenomena and exaltation of luminescent propeties ans SERS effect.