Molecular Antennas and Photoactive Nanomaterials based on Energy Transfer Processes

Abstract

The scope of this thesis deals is the development and description of photoactive nanomaterials and novel multichromophoric systems as artificial antenna systems. To this aim, the photophysical signatures of luminescent fluorophores (with absorption and emission at different regions of the visible electromagnetic spectrum) encapsulated into inorganic and organic hosts, or assembled in supramolecular structures have been exhaustively characterized. These systems are able to harvest the light over a broad spectral region (ultraviolet-visible) and transfer it to the target place and with a specific energy via successive energy transfer hops. As consequence the excitation can be performed far away from the emission region, improving the photostability of the acceptor emitting dye and a lowering the background interferences. In pursuit of such antennas, different alternatives have been considered, (i) Hybrid materials based on LTL zeolites doped with laser dyes working in the blue, green or red parts of the visible. (ii) Latex nanoparticles doped simultaneously with luminescent fluorophores, leading to stable aqueous colloids. (iii) Molecular cassettes based on energy donor and acceptor dyes covalently linked. All of them undergoing efficient and tunable energy transfer processes, the key factor for a successful development of luminescent antennas. In conclusion, the herein reported approaches (photoactive materials and novel dyes) towards the development of luminescent antennas are shown to be properly applied in photonic fields such as tunable dye lasers, light modulators or polarity probes