Surface and shape unification of excimer pulse irradiated Ag nanoparticles and associated surface-enhanced Raman scattering properties

Uniform, spherical Ag nanoparticles (NPs) were produced using nanosecond excimer pulsed laser ablation of a colloid target, which had been previously prepared using silver nitrate reduction. After the irradiation experiment, the surface condition and morphology of the samples were revealed by transmission electron microscopy, and the changes in the NPs characteristics caused by different laser fluences were confirmed using optical transmission measurements with an ultraviolet–visible-infrared spectrophotometer. A considerable narrowing of the surface plasmon extinction band was achieved at 300–450 mJ laser irradiation condition, and a quantitative concept of “circularity” was put forward to estimate the degree of optimization. In addition, the effect of light-pressure explains the cause of slight collision and fusion among the nanoparticles. An analysis of these characteristics offers direct evidence of good dispersion and a change in surface shape from irregular to an ideal spherical form. A surface-enhanced Raman scattering (SERS) experiment was proposed, based on the substrate of an irradiated Ag nanoparticle, and this showed new optimized properties for SERS detection. It also involves using a heat-melting mechanism to effect change, which assumes a solid–liquid–solid phase change chain and can be explained simply by triggering the photon absorption of electrons and their coupling to the Ag lattice, which is then terminated by a heat release to the solvent.