Sharif Digital Repository

The research of this work was divided into two parts. First, A novel fuorescence sensor based on fluorescence resonance energy transfer for the determination of captopril was developed. FITC molecules that are highly fluorescent in alkaline solution fluoresce weakly when they are adsorbed onto AuNP surfaces (based on affinity of AuNPs and isothiocyanate group on FITC) as a result of fluorescence resonance energy transfer. In the presence of captopril, FITC molecules are released from the AuNP surface in order to stronger affinity to AuNPs surface than FITC molecule (in order to thiol group in captopril) so the florescence intensity of FITC restore. This phenomenon was used for quantitative... 

Noble metallic nanostructures based on their localized surface plasmon resonance (LSPR) exhibit a phenomenon known as surface-enhanced Raman scattering (SERS) in which the scattering cross sections are dramatically enhanced for molecules adsorbed thereon. The enhancement factor (EF) in typical cases can reach 106 and in recent years, it has been reported that even single-molecule spectroscopy is possible by SERS, suggesting that the EF can be as much as 1014-1015. In this study, we report a simple method to synthesize nanostructures of Ag and Au on metallic wafers and semiconductor via electroless deposition method. This approaches has been demonstrated to deposit metal nanostructures, thin... 

In this thesis, we have investigated the plasmon dispersion on the Dirac matter. The Dirac matters which we consider to this end are graphene and borophene allotrope.The borophene allotrope has smaller anisotropic Fermi velocity and tilted Dirac cone in comparison with graphene. We briefly give a short introduction to these materials and then we study the propagation of electromagnetic modes in them. We begin with graphene as a well known two dimensional Dirac material. It has been found that two kinds of plasmon modes named as plasmon mode and transverse electric filed mode are allowed to propagate in graphene but just the plasmon mode can be affected by interaction. As the correlated... 

In this study, we simulated and analyzed a plasmonic waveguide modulator based on single layer graphene. It includes a graphene sheet, which sandwiches between two layers of silicon dioxide. Then, some gates are arranged on either side of the waveguide on a periodic structure. When an electric field is applied perpendicular to the waveguide plate, the Fermi level of graphene under the gates, changes. Detailed analysis is performed by the method of lines based on Maxwell's equations along the propagation direction of the waveguide. Computation of the multi-gate device starts by examining the effect of Fermi level. Transmission coefficient of the magnetic-field norms of the modulator is... 

To date, the plasmonic properties of many metallic and semi-conducting materials have been investigated and used in various industries. One of the plasmonic material categories that have always been considered is polycyclic aromatic hydrocarbon or PAH, whose plasmonic resonance energy depends on the charge state of the molecule. In this regard, it is easy to change the plasmonic resonance energy via changing the induced charge, which is a unique feature of the mentioned materials. In addition, plasmonic structures with excitations in the infrared region are able to enhance the vibration intensity of absorbed molecules by increasing the electric field around themselves. Therefore, they have...