Fabrication of flexible, cost-effective, and scalable silver substrates for efficient surface enhanced Raman spectroscopy based trace detection

Khan, Ghazanfar Ali
Demirtas, O. Ozge
Demir, Ahmet Kemal
Aytekin, Özlem
Bek, Alpan
Bhatti, Arshad Saleem
Ahmed, Waqqar
The fabrication and optimization of cost-effective, eco-friendly, uniform and flexible SERS platforms by facile synthesis routes has recently attracted great attention for trace detection of various analytes. Herein, we report the fabrication of interconnected Ag nanostructures on the unmodified filter paper-based flexible substrates by a facile recipe, which involves evaporation of Ag precursor solution on the filter paper followed by its reduction with a strong reducing agent, NaBH4. The fabrication process is time-efficient, reproducible, and has the potential of being scaled up. The presence of inter-connected nanostructures results in high concentration of uniformly distributed hotspots on the substrate, which in turn provide excellent and reproducible SERS sensitivity. The finite element simulation results showed that fabricated nanostructures are much more effective for field enhancement as compared to the agglomerated spherical nanoparticles. Crystal violet (CV) concentration of 10-8 M was easily detected with these substrates both via solution drying and swabbing. Similarly, AgFPS have proven effective for swab-based detection of urea nitrate (UN), a well-known constituent of homemade explosives. The C-N and NO3 - symmetric stretching modes of UN are detectable down to 1 ?M and 100 ?M concentrations, respectively. Moreover, these substrates showed SERS signal uniformity both from different spots of a single substrate, and substrates from different batches, with spot-to-spot relative standard deviation (RSD) of 15% and sample-to-sample RSD of 15?19%. This makes them excellent for reliable and quick quantitative detection. The simple synthesis strategy, flexibility, cost-effectiveness, and quantitative detection makes these substrates ideal for SERS based trace detection, especially for on-site analysis, and various sensing applications.


Development of an applied element based tool for prediction of collapse behavior of concrete dam monoliths
Hassan Zada , Hamidullah; Arıcı, Yalın; Department of Civil Engineering (2020-9-24)
In this study, conducted with the support of TUBITAK under the grant 116M524, a software framework with a web-based graphical user interface is developed for the investigation of the seismic behavior of concrete gravity dams. Using a modified discrete element technique, one of the primary goals of the developed tool is to simulate extensive cracking on concrete dam monoliths followed by sliding, rocking and loss of stability. The graphical user interface for using this engine is prepared in HTML, Java...
Optimization of nanoparticle arrays to design efficient couplers for plasmonic nanowire networks
Altınoklu, Aşkın; Ergül, Özgür Salih; Department of Electrical and Electronics Engineering (2019)
In this thesis, a novel optimization strategy for design and optimization of efficient couplers to improve nano-optical links in complex plasmonic nanowire networks is presented. Various cases involving alternative combinations of nanowire transmission lines with different types and lengths are considered. As the optimization environment, a full-wave solver based on surface integral equations and the multilevel fast multipole algorithm (MLFMA) developed for efficient and accurate solutions of plasmonic prob...
Investigation of tightly coupled arrays for wideband applications
Arda, Kaan; Dural Ünver, Mevlüde Gülbin; Department of Electrical and Electronics Engineering (2020-10)
This thesis aims to provide in depth research on tightly coupled dipole arrays to be used in ultrawideband apertures applications. First, operation principles of tightly coupled dipole arrays are investigated. Starting from the Wheeler’s current sheet aperture concept, some calculations on bandwidth and impedance concepts are conducted. B.A. Munk’s addition to the concept, use of capacitive elements between adjacent dipoles, are introduced. Array unit cell is modeled using equivalent circuit approach,...
Application of fluorescent melamine resin microspheres for use as a geothermal tracer
Salar, Mustafa; Akın, Serhat; Department of Petroleum and Natural Gas Engineering (2018)
Tracer testing of flow between injection and production wells is an effective tool to map fluid flow pathways in a geothermal reservoir. Tracer concentration curves can be used to provide insight into projected thermal drawdown in the reservoir or thermal breakthrough of re-injected fluids, estimating inter-well volumes and flow geometries. Although radioactive tracers have been used in the past, many tracer tests now use chemical tracers that are less hazardous to handle. Fluorescent organic compounds such...
Simulation of Directional Microphones in Digital Waveguide Mesh-Based Models of Room Acoustics
Hacıhabiboğlu, Hüseyin; Günel Kılıç, Banu (2010-02-01)
Digital waveguide mesh (DWM) models are time-domain numerical methods providing computationally simple solutions for wave propagation problems. They have been used in various acoustical modeling and audio synthesis applications including synthesis of musical instrument sounds and speech, and modeling of room acoustics. A successful model of room acoustics should be able to account for source and receiver directivity. Methods for the simulation of directional sources in DWM models were previously proposed. T...
Citation Formats
G. A. Khan et al., “Fabrication of flexible, cost-effective, and scalable silver substrates for efficient surface enhanced Raman spectroscopy based trace detection,” COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, pp. 0–0, 2021, Accessed: 00, 2021. [Online]. Available: https://hdl.handle.net/11511/90692.