Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Enhanced plasmonic behavior of bimetallic (Ag-Au) multilayered spheres | Pena-Rodriguez and Pal Nanoscale Research Letters 2011 6 279 http content 6 1 279 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Enhanced plasmonic behavior of bimetallic Ag-Au multilayered spheres Ovidio Pena-Rodriguez 1 and Umapada Pal2t Abstract In this article we study the plasmonic behavior of some stable highly biocompatible bimetallic metal-dielectric-metal MDM and double concentric nanoshell DCN structures. By simply switching the material of the inner structure from Au to Ag the intensity of their surface plasmon resonance could be increased in the optical transparency region of the human tissues up to 20 and 60 percent for the MDM and DCN respectively while the biocompatibility is retained. The obtained results indicate that these novel structures could be highly suitable for surface enhanced Raman scattering and photothermal cancer therapy. Background Surface plasmon resonance SPR which comes from the collective oscillation of conduction electrons dominates the optical spectra of metallic nanoparticles NPs making them attractive for many potential applications. For example the dependence of their SPR frequency on the dielectric constant of embedding medium 1 can be used for cancer treatments 2 3 and biological or chemical sensing 4-6 . Moreover the intense electromagnetic fields produced by the SPR in the surroundings of the nanoparticle are essential in surface-enhanced Raman scattering SERS 7 which in turn has important applications in areas such as medical diagnostics 8 and immunoassay 9 10 . Traditionally gold and silver have been the preferred materials for the synthesis of nanoparticles 11-14 and both of them have some advantages and disadvantages. Gold NPs are easier to synthesize have better biocompatibility and long-term stability but silver NPs have a more intense SPR which is of great advantage for SERS and sensing applications. On the other hand it can be attractive 15 to use bimetallic .
