Multi-shaped silver meso-particles with tunable morphology for surface enhanced Raman scattering

Silver meso-particles (SMPs) were successfully synthesized by a simple chemical method in the presence of L-ascorbic acid reducing agent and silver ions precursor in AgNO3. Silver meso-structures of different topographies have been synthesized by varying the concentration of the reactants such as the L-AA concentration or the Ag+ ions concentration as well as by varying the temperature reaction. The structural morphology and optical properties of SMPs were thoroughly investigated by employing different characterization methods such as ultraviolet-visible spectroscopy (UV-Vis), X-ray spectroscopy and transmission electron microscopy (TEM). The results showed that the smaller the concentration of Ag+ ions and the greater the concentration of reducing agent L-AA, the more hierarchical SMPs. This investigation is explained by the mechanism of formation and development of SMPs in the solution. The surface-enhanced Raman scattering (SERS) effects of the synthesized SMPSs are also estimated by using the detection of the Rhodamine B (RB) pigments. The investigation confirmed that the highly branched silver meso-structures exhibit a higher efficiency in enhancing surface Raman scattering in comparison with the less branched ones. The enhancement factor EF scattering at the featured peaks for 10(-6) M RB on the SMPs substrate are calculated around 10(4). Our work might give a good reference for the fabrication of SMPs, which are suitable to be applied in sensing.