Department of Materials Science
Communicating science to the general public is a growing need to bring citizens closer to science, to create a scientific culture and, why not, inspire tomorrow’s scientists. As part of the European project SURFICE - Smart surface design for efficient ice protection and control (www.surfice-itn.eu), coordinated by prof.
The ternary Ge-Sb-Te alloys (GST) are employed as active material in non-volatile phase-change memory devices, which exploit the large difference in both electrical and optical properties between the amorphous and crystalline phases and the possibility to thermally induce a fast and reversible transition between the two phases. Recently, this technology has attracted great attention for the possible exploitation in neuromorphic computing.
The depletion of fossil fuels and ongoing ecological challenges underscore the pressing need for sustainable and environmentally friendly energy solutions. In this pursuit, fuel cells have become a focal point in current research, primarily due to their exceptional advantages, with the noteworthy aspect being the recognition of hydrogen as a green energy carrier.
Thermoelectricity is a class of physical phenomena enabling both the conversion of heat into electricity and the extraction of heat (cooling), in both cases without the use of any movable part. As such, thermoelectric generators are suitable, especially when miniaturized, to harvest low-temperature heat and to make it available as electric power (e.g. to distributed sensor networks or to portable devices). Our research activity focuses both on materials and devices for suitable applications.
Energy-selective charge carrier scattering was demonstrated to provide a route to enhance power factor of very heavily boron-doped nanocrystalline silicon films, up to the outstanding value of 40 mW/mK2. Research under way is meant to materials stabilization and to the extension of the process to n-type nanocrystalline silicon films.
Due to its high thermal conductivity, single-crystalline silicon is not suitable as such for thermoelectric applications. Nanostructuration offers effective ways to lower its thermal conductivity. Research is focused on the use of Metal-assisted Chemical Etching (MaCE) as a simple way to obtain Si nanowires (SiNWs). The process, along with the possibility of making electrical contacts localized at Si tips, discloses the opportunity of making bulk-like SiNW pads to be embedded into thermoelectric devices, either for cooling or for heat harvesting.
Photovoltaic (PV) cells only convert a fraction of the solar spectrum, releasing a significant amount of energy as heat. Threfore, solar harvesting might be improved through an accurate coupling of PV cells to thermoelectric generators. Further to energy profitability, hybrid harvesters also meet criteria of economic convenience, which is required for pairing to be practically successful. We mostly work on the direct pairing of specially designed Bi2Te3 thermoelectric generators with perovskite-based photovoltaic cells.
Thermoelectric low efficiencies are basically due to the difficulty of decoupling thermal and electrical conductivity in real systems. Nanotechnology has shown innovative ways to reach such a target. Additionally, thermal and electrical conductivities in bulk thermoelectrics may be uncoupled by operating thermoelectric generators in non-steady state mode. We are exploring how feeding time-modulated heat fluxes may enhanced conversion efficiencies at maximum power.
Prof. Dario Narducci
U5 Building, 1st Floor, Room 1032-1034
Protein misfolding and aggregation are the fundamental causes of many degenerative conditions, including Alzheimer’s and Parkinson’s disease (AD and PD) as well as type II diabetes. Misfolded proteins are usually biologically inactive; however, the dynamic equilibrium between monomeric and oligomeric aggregates may lead to cytotoxic states that induce the degenerative condition. In AD, amyloid-β (Aβ) and tau proteins misfold and form oligomers and fibrils that accumulate in the brain in pathogenic pathways leading to synaptic loss and selective neuronal cell death.