Edge-Localized Plasmonic Resonances in WS Nanostructures from Electron Energy-Loss Spectroscopy.

Localized plasmon resonances in 2D transition metal dichalcogenides (TMDs) offer a powerful means to enhance light-matter interactions at the nanoscale, making them ideal candidates for advanced optoelectronic applications. However, disentangling the complex plasmonic interactions in these materials, especially in the low-energy regime, presents significant challenges. Herein, localized plasmon resonances in chemical vapor deposition-grown tungsten disulfide (WS) nanotriangles, using a combination of advanced spectral analysis and simulation techniques, is investigated. By combining non-negative matrix factorization with electron energy loss spectroscopy, distinct plasmonic modes to provide a comprehensive analysis of the plasmonic landscape of individual and stacked WS nanotriangles are identified and characterized. Furthermore, the dispersion relation of these localized plasmon resonances is quantified and their evolution across different WS triangular geometries is evaluated. Experimental characterization of plasmonic resonances in WS through dedicated numerical simulations based on the pygdm package is validated. The findings highlight the critical role of localized plasmon resonances in modulating the electronic and optical properties of WS, offering new insights into the design and optimization of TMD-based devices for optoelectronic and nanophotonic applications.