Formation Regularities of Plasmonic Silver Nanostructures on Porous Silicon for Effective Surface-Enhanced Raman Scattering.

Hanna V Bandarenka,Vitaly P Bondarenko,Sergei N Terekhov,Kseniya V Girel,Andrei Yu Panarin,Inna A Khodasevich

doi:10.1186/s11671-016-1473-y

Abstract

Plasmonic nanostructures demonstrating an activity in the surface-enhanced Raman scattering (SERS) spectroscopy have been fabricated by an immersion deposition of silver nanoparticles from silver salt solution on mesoporous silicon (meso-PS). The SERS signal intensity has been found to follow the periodical repacking of the silver nanoparticles, which grow according to the Volmer–Weber mechanism. The ratio of silver salt concentration and immersion time substantially manages the SERS intensity. It has been established that optimal conditions of nanostructured silver layers formation for a maximal Raman enhancement can be chosen taking into account a special parameter called effective time: a product of the silver salt concentration on the immersion deposition time. The detection limit for porphyrin molecules CuTMPyP4 adsorbed on the silvered PS has been evaluated as 10−11 M.

Highlights

Surface-enhanced Raman scattering (SERS) spectroscopy is widely recognized as a label-free high-sensitive method for applications in analytical chemistry [1, 2], biomedicine [3,4,5], and various sensor devices [6,7,8,9]
Based on the analysis of the regularities of the Ag nanostructures growth and corresponding kinetics of SERS-signal intensity change, we revealed a parameter crucial for the formation of the SERS-active substrates, which can be defined as a product of the Ag salt concentration by the immersion deposition time
Morphological and optical properties of the fabricated Ag films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–Vis reflectance spectroscopy

Summary

Introduction

Surface-enhanced Raman scattering (SERS) spectroscopy is widely recognized as a label-free high-sensitive method for applications in analytical chemistry [1, 2], biomedicine [3,4,5], and various sensor devices [6,7,8,9]. SERS is observed for analyte molecules adsorbed on the noble metal surfaces with nanoscale roughness, so-called SERS-active substrates [10, 11]. An enormous level of Raman signal in SERS is mainly attributed to the strong enhancement of the local electromagnetic field near the metallic nanostructures or junctions between them [12, 13], resulted from the excitation of surface plasmon resonance (SPR)—the coherent oscillations of electrons at metaldielectric interfaces [14, 15].

Methods

Results

Conclusion