中科院固体物理研究所知识库

Spherical MoS2 nanoparticles are fabricated by laser ablation of MoS2 target in water. The obtained nanoparticles are mostly nearly perfectly spherical in shape with smooth surface, and tens to hundreds of nanometers in diameters. Such spherical MoS2 nanoparticles are built by concentrically curved {002} planes and show onion-like structure. Further examination has revealed that there exist shrinkage cavities (or voids) in the central part of the MoS2 nanoparticles or small pores dispersed in the particles and a few tadpole-like long-tailed nanoparticles in the products, indicating the marks of melting and molten liquid droplets' solidification during laser ablation. A model is thus presented based on laser-induced MoS2 liquid droplets' generation and inward {002}-oriented growth via radial solidification, which reveals the growth mechanism of the spherical MoS2 nanoparticles with onion-like structure. Interestingly, such onion-like structured spherical MoS2 nanoparticles have exhibited much higher surface enhanced Raman scattering (SERS) effect than the MoS2 nanoplates prepared by conventional methods. This work not only presents the route to the spherical MoS2 nanoparticles with onion-like structure but also reveals the formation process for the MoS2 nanoparticles in laser ablation in water.