The development of clean light-harvesting platforms and technologies is crucial in view of the urgent energy and environmental global challenges. Plasmonic nanoparticles show great promise in light-harvesting applications, but their fabrication is typically constrained to small-area laboratory-scale methods or to highly polluting wet chemistry approaches that are not suitable for environmental applications such as waste water recycling. In this work, we propose a self-organized method to fabricate largearea (cm 2 , industrially scalable up to m 2 ) plasmonic templates. Ordered Au nanostripe arrays supported on cheap, nontoxic sodalime glass substrates are prepared, showing a tunable plasmonic response. We demonstrate enhanced photochemical reactivity and photobleaching of highly polluting methylene blue molecules promoted by this self-organized plasmonic platform. We investigate this effect by tailoring the spectral overlap between the molecule absorption band and the plasmon resonance and by tuning the monochromatized excitation wavelength. This kind of study is completely lacking in the literature for big molecules with optical absorption bands in the visible range. We demonstrate the dominant role of plasmon-enhanced near-field optical effects over hotcarrier injection in amplifying photodissociation of colored dye molecules, thus paving the way to the engineering and optimization of light-harvesting platforms for waste water treatment, dye molecule sensing devices, and a broad range of other light-harvesting applications.

LNovel Light harvesting platforms and strategies are crucial in view of renewable photon to energy conversion technologies that can answer to the compelling global energy and environmental challenges. Two-dimensional (2D)...

The urgent environmental and energy challenges require novel solutions for efficient light harvesting and conversion in new-generation ultra-thin devices. Plasmonic nanoantennas and flat optics nanogratings can promote light matter interaction at the nanoscale being very attractive for ultra-thin photonics and sensing applications. In this work we developed two light trapping solutions based on large-scale nanomaterials. The first system is a large-scale (cm2) plasmonic metasurface based on self-organized gold nanostripes. The second is based on the periodic re-shaping of ultra-thin semiconducting MoS2 layers forming large-area flat-optics nanogratings. Under this condition Rayleigh Anomalies can be resonantly excited thus promoting in-plane light confinement and photon absorption into the few-layers material. To demonstrate the impact of these nanopatterned systems in photon harvesting we probed their efficiency into a prototypal photochemical reaction: the photo-bleaching of Methylene Blue (MB). We demonstrate the resonant enhancement of the photo-bleaching of these polluting dye molecules promoted either by the localized plasmon resonance in Au nanostripes or by the Rayleigh Anomaly in flat-optics MoS2 nanogratings. We investigate this effect through a quantitative analysis of the solution photodissociation induced by a monochromatic light. These results show the strong potential of flat-optics templates for light-harvesting and energy conversion in ultra-thin photonic devices.

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