Comparative study on surface enhanced raman scattering activity of various silver nanostructures


Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Edebiyat Fakültesi, Fizik Bölümü, Türkiye

Tezin Onay Tarihi: 2017

Öğrenci: ÖZGE DEMİRTAŞ

Danışman: ALPAN BEK

Özet:

In this work, the effect of the strong field enhancement generated in the near field of metal nanoparticles and nanowires was investigated by taking advantage of the plasmon frequencies induced by Raman laser light stimulation of free conduction electrons of these metal nanostructures. Small number of molecules that are either bound to these nanostructures or located up to a few nanometers away from the nanostructures can be detected easily through strong electromagnetic field enhancement. The aim of this work was to investigate the surface enhanced Raman scattering (SERS) effect of crystal violet (CV) and brilliant cresyl blue (BCB) molecules interacting with silver nanoparticle (Ag NP) and silver nanowire (Ag NW) that are deposited onto silicon surfaces. Statistical measurements on SERS effect, which is an application of localized surface plasmon resonance (LSPR) were acquired and corresponding enhancement factor (EF) ranges were revealed. The fact that plasmon lifetime of polyol synthesized colloidal Ag NPs and Ag NWs are long due to their smooth crystalline surfaces at the atomic level providing strong plasmon interaction of these structures. In addition, the interaction between nanostructures also depends on the number of hot spots between aggregated nanostructures, and the LSPR wavelength. Although LSPR wavelengths of nanostructures and maximum absorption wavelength of the analytes used in this work are not in resonance with the laser light, maximum EF values documented in the literature were obtained.