tailieunhanh - Báo cáo hóa học: " Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate"

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: Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate | Hao et al. Nanoscale Research Letters 2011 6 263 http content 6 1 263 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Fabrication and evolution of multilayer silver nanofilms for surface-enhanced Raman scattering sensing of arsenate Jumin Hao1t Mei-Juan HanH Zhonghou Xu1 Jinwei Li2 and Xiaoguang Meng1 Abstract Surface-enhanced Raman scattering SERS has recently been investigated extensively for chemical and biomolecular sensing. Multilayer silver Ag nanofilms deposited on glass slides by a simple electroless deposition process have been fabricated as active substrates Ag GL substrates for arsenate SERS sensing. The nanostructures and layer characteristics of the multilayer Ag films could be tuned by varying the concentrations of reactants AgNO3 BuNH2 and reaction time. A Ag nanoparticles AgNPs double-layer was formed by directly reducing Ag ions on the glass surfaces while a top layer 3rd-layer of Ag dendrites was deposited on the double-layer by selfassembling AgNPs or AgNPs aggregates which had already formed in the suspension. The SERS spectra of arsenate showed that characteristic SERS bands of arsenate appear at approximately 780 and 420 cm-1 and the former possesses higher SERS intensity. By comparing the peak heights of the approximately 780 cm-1 band of the SERS spectra the optimal Ag GL substrate has been obtained for the most sensitive SERS sensing of arsenate. Using this optimal substrate the limit of detection LOD of arsenate was determined to be approximately 5 gg-l-1. Introduction Since the discovery of surface-enhanced Raman scattering SERS in the late 1970s SERS has been extensively studied as a sensitive analytical technique for fundamental studies of surface species 1-6 . The development of SERS substrates with high sensitivity and good reproducibility has been one of the most challenging tasks. Colloidal Ag or Au nanoparticles are the most widely used SERS substrates. The aggregation of the .