| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 106 === Nanostructure engineering has been proposed as a powerful and useful technology to fabricate functional materials for varying applications. In particular, plasmonic core-shell nanostructures with unique localized surface plasmon resonance, allowing surface-enhanced Raman scattering (SERS) occurred for an ultra-sensitive molecular-level detection.
Recently, graphene quantum dot (GQDs), a unique type of graphene derivatives, has stimulated a lot of attentions due to their exceptional properties including low toxicity, photostability, biocompatibility and excellent solubility. By coating a GQDs shell can significantly modify the optical properties and electronic structure. Moreover, bio-compatible Au nanostructures can generate great electromagnetic fields, leading a effective concentration of the incident light at the spatially narrow region around the nanostructures, providing a strong resonant behavior for SERS detection. Hence, the development of GQD/AuNP core-shell nanostructures can create a rational design of active materials for high sensitive SERS detection. However, the conventional approaches to prepare such nanohybrids are usually complicated, time consuming, inefficiency, and high temperature required.
Here we demonstrate a rapid synthesis method of GQD/AuNP by using atmospheric-pressure microplasmas. Microplasmas are defined as gaseous discharges formed in electrode geometries where at least one dimension is less than 1mm, which can be operated stably with an aqueous solution at atmospheric pressure. Energetic species formed in the microplasma are capable to initiating electrochemical reactions and nucleating particles in solution without chemical reducing agents. Detailed microscopic and spectroscopic characterizations indicate that the morphology and size distribution of as-produced GQDs/AuNPs core-shell nanostructures can be controlled via changing the reaction conditions. By sourcing different emissions of GQDs or adjusting core to shell ratio of GQDs/AuNPs nanostructure can further explore their optical properties for the SERS spectroscopic analysis and suggest that GQDs/AuNPs heterostructures can performed as an effective material for SERS-based biomolecular sensing.
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