Transformation of Plasmonic MoO3–x Nanoparticles into Dielectric MoS2 Nanoparticles

Transformation from plasmonic to dielectric properties allows for control over light–matter interactions, enabling the development of nanoparticles that can dynamically adjust their optical characteristics and enhance their functionalities. The exploration of the transformation aligns with the demand for applications in adaptive optics and responsive photonic devices. The transformation of metal plasmonic nanoparticles to dielectric nanoparticles typically requires a complex structure design while ensuring the preservation of their original morphology. Herein, we report on the transformation of plasmonic MoO_3–x nanoparticles into dielectric MoS₂ nanoparticles. The plasmonic properties of MoO_3–x nanoparticles, prepared by aerosol spray, were investigated at the single-particle level. A comprehensive analysis of the size-dependent electromagnetic resonances of the product nanoparticles was conducted from both experimental and simulation perspectives. The transformation process was carried out in a tube furnace under a sulfur atmosphere, allowing for a complete change in optical response from plasmonic MoO_3–x nanoparticles to dielectric MoS₂ nanoparticles. The degree of transformation can be controlled by varying the sulfurization time with the formation of (MoO_3–x core)@(MoS₂ shell) nanostructures. Our results demonstrate a potential strategy for transforming plasmonic nanoparticles into dielectric nanoparticles.