Enhancing SERS Sensitivity in N-Graphene Hydrangea by Synergistic Charge-Transfer and Excitation Light Absorption

Surface-enhanced Raman scattering (SERS) is a versatile spectroscopic technique, which plays a crucial role in enhancing analytical sensitivity, investigating interfacial reaction mechanisms, enabling biosensing, and fostering efficient catalysis. Currently, the common SERS substrates are primarily metal nanostructures, which entail high manufacturing costs, complex processes, and the metal surface undergo change over time and with environmental conditions. These issues limit the development of SERS technology. In this work, a nitrogen-doped graphene (N-graphene) hydrangea was synthesized on a silicon (Si) substrate using plasma-assisted chemical vapor deposition (PACVD), forming an N-graphene hydrangea/Si hybrid structure as a SERS substrate. This substrate offers the advantages of high stability, ultra-sensitivity, and reusability. The three-dimensional nano-cavity structure of graphene can increase the interaction between light and graphene, resulting in an increased localized electric field. Combining theoretical simulation analysis, the introduction of nitrogen (N) elements adjusts the Fermi level of graphene, promoting efficient charge transfer. In practical scenarios, Di(2-ethylhexyl) phthalate (DEHP), a commonly used plasticizer, has raised concerns due to its potential as an endocrine disruptor and carcinogen. The as-prepared SERS substrate achieves a remarkable detection limit of as low as 10-8 m for DEHP, providing significant support for environmental conservation and human health. The nitrogen-doped graphene (N-graphene) hydrangea/Si structure, serving as a surface-enhanced Raman scattering (SERS) substrate, synergistically enhances the SERS signal through charge transfer and local surface plasmon resonance effects. With notable advantages of high stability, ultra-sensitivity, and reusability, it exhibits ultra-low detection capabilities for various molecules.image (c) 2024 WILEY-VCH GmbH