Synthesis, characterization and nanostructuration of D-A systems based on Fc-PTM Dyads
- Authors
- Morales Acosta, Dayana
- Format
- DoctoralThesis
- Status
- publishedVersion
- Description
This Thesis is centered in the field of multifunctional molecular materials and more specifically in the area of Molecular Electronics and the work is focused on the design, synthesis and nanostructuration on surfaces of molecular materials based on donor?acceptor (D?A) open-shell molecules. In this work it has been studied how the electronic properties of D?A molecules are modified when moving from the 3 dimension, such as in solution and in crystals, to the 2 dimension obtained when such dipolar molecules are oriented and nanostructured on metallic surfaces as self-assembled monolayers (SAMs). Moreover, the influence of the electronic open-shell nature of such D?A molecules on the overall electronic properties of the oriented nanostructured system has been also evaluated. The second part of the Thesis has been focused on the use of different approaches to get bidimensional nanostructuration of Fc?PTM D?A molecules on gold surfaces, as SAMs, and to study its electronic properties. Initially, a two-step approach has been used which after a lot of efforts it was concluded that it is not robust enough for further reliable characterization. Then, the work was moved to the use of a onestep approach, for the nanostructuration of D?A molecules on metallic substrates. This approach yielded metallic surfaces functionalized with molecules as SAMs which were succeeded characterized using different surface analysis techniques like polarization-modulation infrared reflection adsorption spectroscopy (PM-IRRAS), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ions mass spectrometry (ToF-SIMS), contact angle (CA), atomic force microscopy (AFM) and cyclic voltammetry (CV). The stability of these SAMs was studied by CV measurements. To get further insights into the electronic structure of such SAMs of molecular oriented dipoles on surfaces, synchrotron radiation techniques (PES, RPES and NEXAFS) have been used. The influence of the open-shell electronic structure of dyad 1 in the SAMs has been analysed in comparison to the closed-shell electronic structure of 1H. We conclude that the dimensionality of a collection of Fc?PTM D?A molecules determine their electronic properties and behavior. In fact, while in 3D structures, the bistability phenomena takes place, thanks to cooperative intermolecular electrostatic interactions, with the experiments performed using solvent and temperature external stimuli to modify the electronic state of the 2D nanostructures no bistability was observed.
- Publication Year
- 2015
- Language
- eng
- Topic
- CIENCIAS EXPERIMENTALES
NANOTECNOLOG?A
CONDUCTIVITY
DONOR-ACCEPTOR SYSTEMS
- Repository
- Repositorio SENESCYT
- Rights
- openAccess
- License