Tailoring Surface Properties for the Development of Functional Hybrid Materials

Abstract

This thesis focuses on the development of strategies for the covalent functionalization of surfaces to create new hybrid materials with applications in optoelectronics, catalysis, and molecular electronics. Specifically, self-assembled monolayers (SAMs) were prepared on gold surfaces using a photo- and redox-active molecule with a terminal alkyne as an anchoring group, forming a covalent C-Au bond. Charge transport measurements on molecular junctions (metal-molecule-metal) based on these SAMs were carried out using a liquid metal, a eutectic of gallium-indium (EGaIn) alloy, as the top electrode. Additionally, the same molecular switch was used to functionalize gold nanoparticles, which were assembled at the liquid-liquid interface, forming films with electrocatalytic activity for dye degradation in water. Furthermore, the EGaIn was not only used as an electrode in molecular junctions but also to prepare nanoparticles of this material. The surface functionalization of these particles with phosphonic acid derivatives has proven to be an efficient methodology to provide colloidal stability and control over size and morphology. Finally, in this Thesis, we also explored nanographenes as active nanomaterials for forming SAMs that are incorporated into molecular junctions, focusing on the relationship between molecular structure and electrical response. Moreover, nanographene derivatives with a distorted non-planar structure have demonstrated chiroptical properties that can be modulated by external stimuli such as pH and voltage, making them suitable for applications as molecular switches and spin filters. In summary, the work developed in this Thesis highlights the versatility of surface engineering in the development of responsive functional hybrid materials.

Date of Award	31 Jan 2025
Original language	English
Supervisor	Nuria Crivillers Clusella (Director)