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Surface - enhanced raman scattering from a layer of silver nanoparticles

We studied to prepare silver nanoparticle substrate for Surface-Enhance Raman Scattering (SERS). Silver nanoparticles were produced by laser ablation of silver plate in ethanol. The average size of silver nanoparticles is 15nm. The silver nanoparticle colloid was allowed to dry on a silicon wafer to prepare SERS substrate. Using the silver nanoparticle substrates we could obtain SERS spectrum of Rhodamine 6G molecules adsorbed on silver nanoparticles. The Raman signal was enhanced strongly by our SERS substrate. This result demonstrates that the metal nanoparticles synthesized by laser ablation in clean liquid can be used to prepare SERS substrate for molecular detection in our laboratory. | Nguyễn Quang Đông và Đtg Tạp chí KHOA HỌC & CÔNG NGHỆ 90(02): 15 - 19 SURFACE - ENHANCED RAMAN SCATTERING FROM A LAYER OF SILVER NANOPARTICLES Nguyen Quang Dong1*, Nguyen The Binh2, Vu Thi Khanh Thu2 1 College of medicine and farmacy - TNU 2 VNU University of Science ABSTRACT We studied to prepare silver nanoparticle substrate for Surface-Enhance Raman Scattering (SERS). Silver nanoparticles were produced by laser ablation of silver plate in ethanol. The average size of silver nanoparticles is 15nm. The silver nanoparticle colloid was allowed to dry on a silicon wafer to prepare SERS substrate. Using the silver nanoparticle substrates we could obtain SERS spectrum of Rhodamine 6G molecules adsorbed on silver nanoparticles. The Raman signal was enhanced strongly by our SERS substrate. This result demonstrates that the metal nanoparticles synthesized by laser ablation in clean liquid can be used to prepare SERS substrate for molecular detection in our laboratory. Key words: Surface plasmon, plasmon resonance, laser ablation, Raman Scattering, silver nanoparticle INTRODUCTION* The Surface-Enhanced Raman scattering (SERS) technique is widely used as a high sensitive analytical tool for molecular detection and characterization of a wide range of adsorbate molecules down to the single molecule detection limit [1]. Estimated enhancement factors for the Raman signals in SERS started from modest factors of 103 to 10 5 in the initial SERS experiments. For excitation laser wavelengths in resonance with the absorption band of the target molecule, surface-enhanced resonance Raman scattering (SERRS) can result in higher total effective Raman cross sections. Enhancement factors on the order of about 1010 to 1011 for Rhodamine 6G and other dyes adsorbed on colloidal silver and excited under molecular resonance conditions have been reported [2,3,4]. The large enhancement of the Raman scattering intensity has been explained by two mechanisms: the electromagnetic and chemical .