D'ANGELO Giovanna

Analysis of the structural, vibrational, thermal and optoelectronic properties of functional materials for energy applications, even under extreme conditions (low temperatures, high pressures) These research areas are fundamental to fully understand the role of several physico-chemical processes in determining the performances of functional materials used in energy applications. In particular, these studies concern: dynamics of charge transport, electron-phonon interaction, anharmonicity, soft phonons and the role of disorder. These aspects deeply influence the resulting structural, vibrational, thermal and optoelectronic properties, so their accurate characterization allows to derive fundamental information on the processes that limit them. For example, in hybrid perovskites, the organic components contribute to the vibrational response of the material with low-energy phonon modes, which affect the electron-phonon interaction processes and the thermal conductivity of such materials. In addition, these studies are also carried out under extreme conditions (low temperatures, up to 1 K and high pressures, up to 20 GPa), with the aim of investigating processes otherwise masked by environmental conditions. An interesting example is the onset of superconductivity and charge density waves in some transition metal dichalcogenides at high pressures and/or low temperatures.

Collective dynamics of biosystems and their hydration water. This line is aimed at investigating the collective dynamics and low energy vibrational properties (terahertz frequencies) of model biological systems (phospholipid membranes, proteins). Particular attention is paid to the influence of the dynamics of the aforementioned systems on their hydration water and viceversa, i.e. to the biosystem-solvent dynamic coupling, and to the contribution of solvent dynamics to biomolecular functionality.

Detection and Identification of microplastics in fish species and marine waters. Microplastics are the major problem linked to contamination by synthetic polymers present in the sea. These microparticles have the ability to enter and bioaccumulate in the food chain, which makes them highly toxic for organisms and humans, potentially causing chronic effects such as genetic mutations, endocrine dysfunctions and possible carcinogenesis. The aim of this interdisciplinary research is the characterization of the microplastics and microfibers identified in demersal fish species in the Central Mediterranean area, in order to identify their composition to distinguish plastic fibers from non-plastic ones. The use of specific analytical techniques is an essential tool for acquiring a view of the level of pollution from microplastics

Experimental study of mechanical properties of solid materials, including glasses and polymers and segmental dynamics in polymeric systems. This research activity is centered on the experimental analysis, theoretical understanding and predictive modeling of the mechanical response of glassy and polymeric materials as a function of their microstructure, with particular interest in the physics of deformations, and the temperature dependence of structural relaxation times (fragility) as a function of the composition (glasses), the length of the constituent polymer chains and their segmental mobility (polymers).

Experimental study of the dynamic and microreological properties of “smart systems”. The aim of this research is the understanding of the basic mechanisms of the diffusion processes of polysaccharide hydrogels and the "self assembling" polymeric systems which (thanks to their high degree of biocompatibility, combined with a particular sensitivity to variations in physical and chemical quantities such as temperature, pH and ionic strength) lend themselves effectively to their use in the field of biomaterials. The use of experimental methods such as dynamic light scattering and diffusive correlation spectroscopy allows not only a microstructural characterization of the systems considered but also the monitoring of phase changes and the gelation of materials. In particular, microreology makes it possible to probe the heterogeneities in the structures and mechanics that may be at the basis of non-linear behavior of materials.

Fabrication and characterizarion of some types of solar cells, devices for solar-to-fuel energy conversion and supercapacitors. The realization of devices is a key aspect to identify which materials and strategies need to be improved for the diffusion (on an industrial scale) of innovative energy technologies. Specifically, the group has experience in the production of electrodes for supercapacitors, perovskite solar cells and photo-electrodes for solar-to-fuel energy conversion (such as H2 and products of CO2 and N2 reduction). Such devices are generally produced by exploiting liquid phase deposition techniques, thus allowing the potential large-scale and low-cost realization of the obtained prototypes. Moreover, these devices are characterized by means of electrical, electrochemical and electronic experimental techniques, in order to evaluate their performances and identify possible improvement strategies.

Line 2. Experimental study of low energy vibrational dynamics and thermal properties at low temperatures in disordered glasses and solids. The aim of this research line is to link the atomic and molecular vibrational dynamics of disordered systems to macroscopic mechanical and thermal behavior. Current projects are focused on the description of phononic, vibrational and thermal properties in amorphous materials with a degree of disorder controlled by compositional changes or densification processes (annealing at high temperatures and / or application of high pressures).

Single-particle dynamics of phospholipids in model membranes. This study aims at investigating the diffusive and local dynamics of model phospholipid membranes and at verifying the changes induced on the structural organization and the dynamics of membrane lipids by the presence of alcohols with chains of various length and of pore-forming oligopeptides.