Flat-optics hybrid MoS₂/polymer films for photochemical conversion

Abstract

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)...

Hybrid MoS2/polymer nanoarrays for large-scale photon harvesting and enhanced molecular photo-bleaching

“…where the integer m is the diffraction order, λ 𝑚 is the resonant wavelength, θ is the incidence angle of the light, D is the periodicity of the grating, 𝑛 𝑓 is the effective refractive index of the medium at the internal/external interface of the corrugated MoS2 layer where the light is confined at the evanescent condition, and 𝑛 0 is the refractive index of the medium where light travels before interacting with the sample We demonstrate an enhancement of the photodegradation reaction rate of more than two times by effectively tuning the RA mode in resonance to the molecular absorption band (Figure 2b) [8]. These results pave the way to the optimization of the platform for applications such as waste water treatment, where the photonic anomaly can be easily tuned in resonance to a target molecule absorption band, and energy storage applications.…”

Large area van der Waals MoS2–WS2 heterostructures for visible-light energy conversion

“…Additionally, the type-II heterojunction configuration promotes photo-induced charge separation and boosts the absorption of solar light from UV to visible light, leading to improved efficiency. 36,79 Here, as a case study, we studied the photobleaching reaction of methylene blue (MB), a polluting organic molecule commonly employed as fabric dye or as a pharmaceutical, in the presence of different TMD samples immersed in MB solution. We fabricated a bilayer heterostack composed of a thicker WS 2 layer (12 nm) coated by a thinner MoS 2 outer layer (2 nm) and compared its photocatalytic performance with that of an individual 8 nm thick…”

“…32,33 Since atomically thin 2D TMD films are endowed with an extremely high surface-to-volume ratio, it is thus straightforward to foresee the potential of large area TMD-based heterostructures in photo-to-chemical energy conversion applications. [34][35][36] Although the coupling of different TMD monolayers is particularly exciting for optoelectronic applications, in the case of van der Waals heterostructures based on few-layer TMDs, the increased thickness enables a higher optical absorption and hence an enhanced photoconversion efficiency.…”

Self-Organized Plasmonic Nanowire Arrays Coated with Ultrathin TiO2 Films for Photoelectrochemical Energy Storage

“…However, the need for nonpolluting energy storage strategies, that can be easily integrated over a large scale, currently represents a crucial issue for the effective use and integration of renewable energy sources that are intrinsically intermittent (e.g., sun and wind) . Photochemical reactions, such as photocatalysis and water splitting, are receiving special attention from the scientific community since they can promote molecular degradation of organic pollutants, or energy storage via hydrogen production in view of renewable energy conversion. − Even though different hydrogen production schemes have been investigated, many challenges still need to be addressed. Among photoelectrochemical materials endowed with strong photocatalytic activity, chemical stability, and suitable electronic structure to promote O 2 and H 2 generation reactions, we can mention the family of large band gap semiconductor oxides (TiO 2 , ZnO, and WO 3 ) that only absorb a limited portion (5%) of the solar light in the ultraviolet (UV) spectrum. , Conversely, narrow band gap semiconductors, capable of absorbing a wide range of solar light in the visible spectrum, are typically limited in terms of their chemical reactivity, selectivity, and/or photochemical stability .…”