“Plasmonic coupling in closedpacked ordered gallium Nanoparticles”
S. Catalán-Gómez, C. Bran, M. Vázquez, L. Vázquez, J.L. Pau and A. Redondo-Cubero
Scientific Reports (2020) 10:4187
DOI: doi.org/10.1038/s41598-020-61090-3 1
Plasmonic gallium (Ga) nanoparticles (NPs) are well known to exhibit good performance in applications as surface enhanced fluorescence and Raman spectroscopy or biosensing. However, to reach the optimal optical performance, the strength of the localized surface plasmon resonances (LSPRs) must be enhanced by suitable narrowing the NP size distribution among other factors. In a previous study we demonstrated the production of hexagonal ordered arrays of Ga NPs by using templates of aluminium (Al) shallow pit arrays, whose LSPRs were observed in the VIS region.
Now, by engineering the template dimensions that is by tuning Ga NPs size, we expand the LSPRs of the Ga NPs to cover a wider range of the electromagnetic spectrum from the UV to the IR regions. The factors that cause the optical performance improvement are studied with the universal plasmon ruler equation, supported with discrete dipole approximation simulations. The results allow us to conclude that the plasmonic coupling between NPs originated in the ordered systems is the main cause for the optimized optical response.
This work, performed in collaboration with the Department of Applied Physics from the Autonomous University of Madrid, has been supported by the Spanish Ministry of Economy, Industry and Competitiveness (MINECO) under project MAT2016-76824-C3-1-R and by the Regional Government of Madrid under project S2018/NMT-4321 NANOMAGCOST-CM.