Self-assembly is the most suitable approach to obtaining peptide-based materials on the nano- and mesoscopic scales. Applications span from peptide drugs for personalized therapy to light harvesting and electron conductive media for solar energy production and bioelectronics, respectively. In this study, we will discuss the self-assembly of selected model and bioactive peptides, in particular reviewing our recent work on the formation of peptide architectures of nano- and mesoscopic size in solution and on solid substrates. The hierarchical and cooperative characters of peptide self-assembly will be highlighted, focusing on the structural and dynamical properties of the peptide building blocks and on the nature of the intermolecular interactions driving the aggregation phenomena in a given environment. These results will pave the way for the understanding of the still-debated mechanism of action of an antimicrobial peptide (trichogin GA IV) and the pharmacokinetic properties of a peptide drug (semaglutide) currently in use for the therapy of type-II diabetes.

The aggregation of semaglutide was followed from the early time steps to the late formation of mesoscopic dendrimeric structures.

Among the emerging photovoltaic (PV) technologies, Dye-Sensitized Solar Cells (DSSCs) appear especially interesting in view of their potential for unconventional PV applications. In particular, DSSCs have been proven to provide excellent performances under indoor illumination, opening the way to their use in the field of low-power devices, such as wearable electronics and wireless sensor networks, including those relevant for application to the rapidly growing Internet of Things technology. Considering the low intensity of indoor light sources, efficient light capture constitutes a pivotal factor in optimizing cell efficiency. Consequently, the development of novel dyes exhibiting intense absorption within the visible range and light-harvesting properties well-matched with the emission spectra of the various light sources becomes indispensable. In this review, we will discuss the current state-of-the-art in the design, synthesis, and application of organic dyes as sensitizers for indoor DSSCs, focusing on the most recent results. We will start by examining the various classes of individual dyes reported to date for this application, organized by their structural features, highlighting their strengths and weaknesses. On the basis of this discussion, we will then draft some potential guidelines in an effort to help the design of this kind of sensitizer. Subsequently, we will describe some alternative approaches investigated to improve the light-harvesting properties of the cells, such as the co-sensitization strategy and the use of concerted companion dyes. Finally, the issue of measurement standardization will be introduced, and some considerations regarding the proper characterization methods of indoor PV systems and their differences compared to (simulated) outdoor conditions will be provided.

KuQuinones constitute a new class of quinoid compounds, characterized by a broad absorption spectrum in the visible region, mainly due to their pentacyclic, highly conjugated structure, and a very low reduction potential. These properties make them promising candidates as sensitive material in photoelectrochemical devices. To this purpose, photocurrent generation measurements have been performed, in presence of an electron donor species in solution, using two different derivatives, 1-(9-hydroxynonyl)KuQuinone (KuQ(CH₂)₉OH) and 1-methylKuQuinone (KuQCH₃), as photoactive species on indium-tin oxide surface. Electrodes have been functionalized by Langmuir–Blodgett technique, which allowed to easily prepare homogeneous mono- and multilayers of such molecules. Promising results in terms of Incident Photon to Current Efficiency values (IPCE%) and internal quantum efficiency (Φ%) have been achieved. Furthermore, the significance of the organization of the thin film obtained for the efficiency of the electron transfer process has been evidenced.