One-step selective formation of silver nanoparticles on atomic layered MoS2 by laser-induced defect engineering and photoreductionElectronic supplementary information (ESI) available: EDS spectrum, additional SEM images and silver ions concentration effect. See DOI: 10.1039/c7tc01863k

Two dimensional (2D) materials decorated with noble metal nanoparticles (NPs) have attracted wide attention due to their appealing chemical and physical properties. Herein, we have developed a novel approach to controllable and selective decoration of silver NPs on atomic layered molybdenum disulfide (MoS 2 ) by using one-step laser-induced defect engineering and photoreduction. By employing a focused micro-power laser beam, silver NPs can be rapidly (in seconds) anchored onto the irradiated area of MoS 2 flakes, forming 0D/2D AgNPs@MoS 2 heterostructures. The mechanism for silver growth on MoS 2 flakes was based on laser-induced defect creation in a silver ion environment and silver nucleation on laser-excited MoS 2 flake surfaces, as evidenced by a combination of techniques including Raman spectroscopy, atomic force microscopy and second-harmonic generation. We also found that the morphology and the growth rate of silver NPs are highly dependent on the layer thickness of MoS 2 and the laser irradiation power; while the size and number density of silver NPs could be precisely controlled by varying the irradiation time as well as the silver ion concentration. Finally, AgNPs@MoS 2 heterostructure micro-patterns have been successfully demonstrated via a programmed low-power laser scan, which shows great potential to be used as an efficient surface enhanced Raman scattering platform for chemical sensing. This work developed a simple, rapid approach to controllable and selective decoration of noble metal nanoparticles on atomic layered MoS 2 via a single-step micro-power laser-induced defect engineering and photo-reduction technique.