Periodic Reporting for period 2 - REPLY (REshaping Photocatalysis via Light-Matter hYbridization in Plasmonic Nanocavities)
Berichtszeitraum: 2023-05-01 bis 2024-10-31
Photocatalytic conversion of solar energy to fuels, such as hydrogen, is a Green Deal priority, driven by the promise of addressing both energy supply and storage. Within this context, REPLY would like to shape a new generation of artificial photosynthetic devices, where the design of function through precise fabrication, synthesis and assembly will be expanded towards a richer class of hybrid materials and interfaces. In perspective this study will concur to set the stage for technological advancements in photonic devices for green energy production through water splitting.
The project aims at engineering the coupling strength between light and semiconductor photocatalysts by combining the extreme radiation confinement properties of plasmonic nanocavities with the dipole-active photocarriers typical of semiconductor nanocrystals. The long-term vision of the proposed approach will ensure a spectrally broader harvesting of the solar radiation and contribute to a better control over sunlight driven chemical reactions.
REPLY will reach this goal pursuing three objectives. Initially, the synergistic conjugation of top-down nanofabrication with self-assembly methodologies will boost the realization of a new-class of heterostructures via light-matter hybridization. The understanding of the photophysical mechanisms that regulate the energetics and the charge transfer processes will concur to gain fundamental insight and will guide the rational design and realization of advanced photo(electro)catalyst prototypes for solar-to-hydrogen conversion.
The project aims at engineering the coupling strength between light and semiconductor photocatalysts by combining the extreme radiation confinement properties of plasmonic nanocavities with the dipole-active photocarriers typical of semiconductor nanocrystals. The long-term vision of the proposed approach will ensure a spectrally broader harvesting of the solar radiation and contribute to a better control over sunlight driven chemical reactions.
REPLY will reach this goal pursuing three objectives. Initially, the synergistic conjugation of top-down nanofabrication with self-assembly methodologies will boost the realization of a new-class of heterostructures via light-matter hybridization. The understanding of the photophysical mechanisms that regulate the energetics and the charge transfer processes will concur to gain fundamental insight and will guide the rational design and realization of advanced photo(electro)catalyst prototypes for solar-to-hydrogen conversion.
During the first 3 years of the project, the research team was able to tackle a systematic investigation of a large variety of strongly-coupled platforms, including planar, vertical and nanotextured layouts. The following aspects have been addressed:
• Solution-based colloidal synthesis of semiconductor nanocrystals with different size, shape and composition.
• Numerical design and top-down fabrication of different sets of plasmonic nanocavities.
• Combination into a single platform of semiconductor nanocrystals and/or molecular aggregates with plasmonic resonators.
• Morphological and steady-state optical characterisation of the aforementioned systems.
• Ultrafast transient absorption spectroscopy of excited optical resonators, including plasmonic and Fabry Perot cavities, and their coupled counterparts with excitonic materials.
• Solution-based colloidal synthesis of semiconductor nanocrystals with different size, shape and composition.
• Numerical design and top-down fabrication of different sets of plasmonic nanocavities.
• Combination into a single platform of semiconductor nanocrystals and/or molecular aggregates with plasmonic resonators.
• Morphological and steady-state optical characterisation of the aforementioned systems.
• Ultrafast transient absorption spectroscopy of excited optical resonators, including plasmonic and Fabry Perot cavities, and their coupled counterparts with excitonic materials.
REPLY has demonstrated various breakthroughs compared to the state-of-the-art. Different plasmonic nanoresonators, with optimized electromagnetic field concentration and distribution have been extensively explored, involving numerical design, clean room based fabrication and optical/photophysical assessment. The combination with semiconductor nanocrystals and/or molecular aggregates has provided remarkable results, where the marriage between light and matter in a confined optical cavity demonstrated the formation of a richer hybrid landscape with enhanced and broadened absorption bands.
In particular, the possibility of controlling the amount of nano-objects inserted into the plasmonic cavities, via ligand exchange and/or dielectric intercalation, has been used to vary the coupling strength and consequently to manipulate the energy separation of the hybrid states.
Among the major achievements, it is worth mentioning the comprehensive investigation of long-range plasmonic arrays, with a particular focus on periodic and quasi-periodic nanotextured structures. Their unique properties in terms of extraordinary optical transmission, collective effects and near-field distribution have allowed for optimized coupling strength, with possible implications on the future photocatalytic applications. Indeed, the integration of advanced functionalities into a single and versatile device can be used for both fundamental studies as well as for technological exploitation. In summary, taking into consideration the fabrication protocols developed so far and the novel heterostructures already synthesized, the research team should be able to explore, by the end of the project, different photocatalyst architectures/reactors operating within the light-matter strong coupling regime.
In particular, the possibility of controlling the amount of nano-objects inserted into the plasmonic cavities, via ligand exchange and/or dielectric intercalation, has been used to vary the coupling strength and consequently to manipulate the energy separation of the hybrid states.
Among the major achievements, it is worth mentioning the comprehensive investigation of long-range plasmonic arrays, with a particular focus on periodic and quasi-periodic nanotextured structures. Their unique properties in terms of extraordinary optical transmission, collective effects and near-field distribution have allowed for optimized coupling strength, with possible implications on the future photocatalytic applications. Indeed, the integration of advanced functionalities into a single and versatile device can be used for both fundamental studies as well as for technological exploitation. In summary, taking into consideration the fabrication protocols developed so far and the novel heterostructures already synthesized, the research team should be able to explore, by the end of the project, different photocatalyst architectures/reactors operating within the light-matter strong coupling regime.