Non-resonance: SERS effects of silver colloids with different shapes

Shape-controlled synthesis of metal nanostructures has opened many new possibilities to design ideal building blocks for future nanodevices. By solution-based method, three kinds of silver colloids, nanospheres, triangular nanoprisms and nanorods have been synthesized. Non-resonant surface-enhanced Raman scattering (SERS) spectra of Rhodamine 6G on as-prepared silver nanostructures of various shapes were measured and their shape-dependent properties were evaluated. The intensity of the SERS signal was the smallest for the silver nanorod and nanoprism exhibits the strongest SERS signals. The great differences of the SERS spectra for different shape Ag colloids confirmed that like electromagnetic enhancement, chemical enhancement also plays a very important role on SERS signal enhancement. (C) 2007 Elsevier B.V. All rights reserved.