SELF-ASSEMBLY AND LASER SINTERING OF SILVER NANOWIRE FILMS PREPARED BY THE MODIFIED COFFEE-RING EFFECT FOR SURFACE ENHANCED RAMAN SCATTERING

摘要

The fabrication of sensitive plasmonic arrays for surface enhanced Raman scattering applications is among prominent research topics. Here we report that large-scale orientation silver nanowire films can be fabricated by controlling the coffee-ring effect through titling the substrates during the film deposition and laser irradiation can be used to improve the film quality for enhanced Raman scattering signals. The experiment shows that the silver nanowires were oriented in parallel to the outer periphery through the solvent evaporation and the coffee-ring effect. Then the self-assembled films were sintered by UV laser. The laser sintering induces the joining and melting of nanowires, and silver nanoparticles were generated under the laser sintering. The morphology changes were analyzed quantitatively. We obtained the strongest Raman signal on the film irradiated by the pulse of 110.2 mJ/cm~2. The experiment reveals that the irradiation leads to the formation of lots of chained silver nanoparticles with the average size of 133 nm and the width of joint with the average size of 148 nm. Under the excitation of 532 nm wavelength laser, the strongest signal can be obtained on the film with nanostructures of the size around 120 nm. Our experiment results indicate that this technique is promising in the production of dense silver nanowires films with tunable properties for the surface enhanced Raman scattering. This indicates an effective way to prepare and improve surface enhanced Raman scattering substrate.