Síntese e caracterização de filmes de nanopartículas de ouro ancorados em eletrodo sólido transparente (FTO)

Abstract

Gold nanoparticles (AuNPs) have been widely studied due to their differentiated physicochemical properties, high chemical stability and biocompatibility. One of the most important phenomena that these nanoparticles present is the surface plasmon resonance in the visible region of the electromagnetic spectrum, which makes them very promising for applications in sensors and optoelectronic devices, to improve the sensitivity and performance of these systems. This study reports the synthesis and characterization of AuNPs films deposited on the surface of fluorine-doped tin oxide (FTO) electrodes using a heat treatment process, varying the concentrations of the metal precursor solutions and the chemical treatments of the surface of the electrodes with piranha solution. The synthesis to obtain the AuNPs films was performed in a single step, in which the functionalization of the electrode surface and the deposition of metal ions were carried out simultaneously. 3- Aminopropyltriethoxysilane (APTES) was used to anchor the metal ions on the substrate and to act as a reducing agent to obtain AuNPs via APTES pyrolysis reaction. The samples were characterized by UV-Vis spectroscopy, TEM and SEM/EDS, which made it possible to verify the formation of AuNPs and evaluate their sizes, shapes, distributions and the quality of the formed film. The synthetic route using the heat treatment process was viable, obtaining homogeneous films of AuNPs on the FTO electrode, resulting in films with predominantly spherical AuNPs. The average diameters of the obtained AuNPs were in the 5.1-6.8 nm range.