Surface-enhanced Raman scattering (SERS) enhancement using hybrid gold nanoparticle-carbon nanodot substrate for herbicides and mercury detection
- UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
- Naghmeh Aboualigaledari (Creator)
- Institution
- The University of North Carolina at Greensboro (UNCG )
- Web Site: http://library.uncg.edu/
- Advisor
- Jianjun Wei
Abstract: Functionalized nanomaterials are increasingly being utilized for development and innovation in a wide range of industrial fields. Specifically, functional organic/inorganic hybrid nanomaterials and nanocomposites, which have both physicochemical properties of organic and inorganic materials, has potential for use as advanced nanomaterials in various fields. Briefly, hybrid materials are a result of constituting with two or more components, which can interact weakly through van der Waals, electrostatic, or hydrogen bonds between the organic and inorganic components or they can be held together by strong interactions, such as covalent or ionic-covalent bonds. Hybrid nanoparticles not only have the characteristics of both inorganic and organic nanomaterials but can also have unique properties that surpass those of the original components. Carbon nanomaterials have received considerable attention as SERS-active substrates. Compared with conventional semiconductor quantum dots and semiconductors, carbon nanodots have benefits of low toxicity, excellent biocompatibility, low cost, and simple synthesis. Thus, there is an emerging opportunity to design and create multi-functional hybrid nanomaterials based on carbon nanomaterials with various organic/inorganic materials at the nanoscale or molecule level, for the electronics, catalysis, sensors and energy conversion and storage application. Interaction of light with metal nanostructures show unique properties given rise to an emergent field called plasmonic. Plasmonic is an optical phenomenon that is very sensitive to the near surface dielectric constant (refractive index, RI) and refers to interaction between free electrons and electro-magnetic fields in metallic materials. Interaction between adsorbed molecules and surface of plasmonic nanostructures have important influence on SERS. SERS substrates should have abundant free electrons, which is beneficial for the creation of plasmonic hot-spots and ultimately leads to the increase in Raman intensity. Typical metals as SERS substrates are gold and silver nanostructures because they have LSPR-related absorption bands covering most of, visible and near-infrared (NIR) wavelength regimes, which used to excite Raman modes. This dissertation includes three research thrusts using hybrid carbon nanomaterials. 1) We investigate SERS using a hybrid gold nanoparticles@carbon nanodots substrate for herbicide detection. The hybrid SERS substrate shows excellent signal uniformity compared to AuNPs or CNDs alone. Also, the AuNPs@CNDs illustrates remarkable key parameters of SERS sensor including, repeatability, reproducibility, and stability, which provide the promising application of SERS sensor for ultra-sensitive determination of organic compounds in water and food. 2) We applied 4-Mercaptopyridine (MPY)-functionalized AuNPs@CNDs for mercury detection. The lowest concentration that our MPY-functionalized AuNPs@CNDs nanosensor can detect is 0. 05 nM, which is lower than concentration of Hg2+ in drinking water permitted by WHO (6ppb). The sensor had good reproducibility and repeatability and sensitivity for mercury detection. 3) We determine the localization and characteristics of nanoparticles inside cells for sensing application, using hyperspectral-enhanced dark field microscopy (HEDFM). We selected AuNPs and AuNPs@CNDs as a candidate for HEDFM evaluation owing to their unique plasmonic properties. We reported that nano hybrid Unascends and AuNPs can be applied for HEDFM evaluation of herbicides in cell specimen. We hope this research can promote the development of new hybrid materials and composites for sensing of toxic materials in water and foods, so we can benefit human health and environment.
Surface-enhanced Raman scattering (SERS) enhancement using hybrid gold nanoparticle-carbon nanodot substrate for herbicides and mercury detection
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Created on 8/1/2024
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Additional Information
- Publication
- Dissertation
- Language: English
- Date: 2024
- Keywords
- Goldnanoparticles, Herbicide detection, Hybrid nanostructure, Nitrogen doped carbon nanodots, Plasmonic nanohybrid, Surface enhanced Raman scattering
- Subjects
- Raman effect, Surface enhanced
- Nanostructured materials
- Plasmonics