Rhodium nanospheres for ultraviolet and visible plasmonics

MUÑETON ARBOLEDA, DAVID; COVIELLO, VITO; PALUMBO, ARIANNA; PILOT, ROBERTO; AMENDOLA, VINCENZO

Nanoscale Horizons

Royal of Society Chemistry

Año: 2025 vol. 10 p. 336 - 348

2055-6756

The development and understanding of alternative plasmonic materialsare crucial steps for leveraging new plasmonic technologies. Althoughgold and silver nanostructures have been intensively studied, the promisingplasmonic,chemical andphysical attributesof rhodiumremainpoorlyinvestigated. Here, we report the synthesis and plasmonic response ofsphericalRh nanoparticles (NPs)with sizes in the 20–40nmrange.Due tothe high cohesive energy of this metal, synthesis and experimentalinvestigations of Rh nanospheres in this size range have not beenreported; yet, it becomes possible here using a green and one-step laserablation in liquidmethod. The localized surface plasmon (LSP) of Rh NPsfalls in the ultraviolet spectral range (195–255 nm), but the absorption tailin the visible region increases significantly upon clustering of the nanospheres.The surface binding ability of Rh NPs towards thiolated moleculesis equivalent to that of Au and Ag NPs, while their chemical andphysical stability at high temperatures and in the presence of strong acidssuch as aqua regia is superior to those of Au and Ag NPs. The plasmonicfeatures are well described by classical electrodynamics, and the resultsare comparable toAu andAg NPs in termsof extinction cross-section andlocal field enhancement, although blue shifted. This allowed, for instance,their use as an optical nanosensor for the detection of ions of toxicmetalsin aqueous solution and for the surface enhanced Raman scattering ofvarious compounds under blue light excitation. This study explores theprospects ofRhNPs in the realms ofUV and visible plasmonics, while alsoenvisaging amultitude of opportunities for other underexplored applicationsrelated to plasmon-enhanced catalysis and chiroplasmonics.