[Paper Review] A review on applications of two-dimensional materials in surface enhanced Raman spectroscopy

Ming Xia|arXiv (Cornell University)|Jul 18, 2017

Gold and Silver Nanoparticles Synthesis and Applications51 references3 citations

TL;DR

This review explores the application of two-dimensional (2D) materials like graphene and MoS2 in surface-enhanced Raman spectroscopy (SERS), focusing on their intrinsic enhancement mechanisms and hybrid structures with metals. It demonstrates that bare 2D materials and metal/2D heterostructures enable significant Raman signal amplification, offering a promising platform for ultrasensitive chemical and biological sensing with tunable, substrate-free enhancement.

ABSTRACT

Two-dimensional (2D) materials, such as graphene and MoS2, have been attracting wide interest in surface enhancement Raman spectroscopy. This perspective gives an overview of recent developments in 2D materials' application in surface enhanced Raman spectroscopy. This review focuses on the applications of using bare 2D materials and metal/2D material hybrid substrate for Raman enhancement. The Raman enhancing mechanism of 2D materials will also be discussed. The progress covered herein shows great promise for widespread adoption of 2D materials in SERS application.

Motivation & Objective

• To systematically review recent advances in using two-dimensional materials for surface-enhanced Raman spectroscopy (SERS).
• To analyze the Raman enhancement mechanisms of bare 2D materials such as graphene and MoS2.
• To evaluate the performance of metal/2D material hybrid substrates in enhancing Raman signals.
• To identify key challenges and opportunities for practical implementation in sensing applications.
• To provide a comprehensive overview of the current state and future potential of 2D materials in SERS technology.

Proposed method

• Review of peer-reviewed literature from 2010 to 2017 focusing on 2D materials in SERS applications.
• Analysis of experimental and theoretical studies on Raman enhancement mechanisms in graphene, MoS2, and related 2D materials.
• Evaluation of hybrid substrates combining plasmonic metals (e.g., Ag, Au) with 2D materials to synergize electromagnetic and chemical enhancement.
• Discussion of charge transfer mechanisms as a dominant enhancement pathway in 2D materials, supported by theoretical modeling and spectroscopic evidence.
• Comparison of enhancement factors reported in literature for different 2D material systems and hybrid configurations.
• Use of schematic illustrations and data synthesis to clarify enhancement mechanisms and material performance.

Experimental results

Research questions

• RQ1 What are the dominant Raman enhancement mechanisms in bare two-dimensional materials like graphene and MoS2?
• RQ2 How do metal/2D material heterostructures improve SERS performance compared to pure metal substrates?
• RQ3 What is the role of charge transfer in enhancing Raman signals on 2D material surfaces?
• RQ4 How do the electronic and optical properties of 2D materials influence their SERS activity?
• RQ5 What are the key challenges and future prospects for integrating 2D materials into practical SERS sensing platforms?

Key findings

• Bare 2D materials such as graphene and MoS2 exhibit intrinsic chemical enhancement in SERS due to charge transfer between the analyte and the 2D material.
• Graphene-based substrates demonstrate enhancement factors on the order of 10^4 to 10^5 for certain molecules, attributed to resonant charge transfer and π-conjugation.
• Hybrid substrates combining Ag or Au nanoparticles with 2D materials show synergistic enhancement, achieving enhancement factors exceeding 10^6 in some cases.
• The 2D material layer can act as a protective and uniform coating, reducing quenching effects and improving reproducibility in SERS measurements.
• The tunability of the electronic band structure in transition metal dichalcogenides like MoS2 enables selective enhancement for specific analytes.
• The review highlights that 2D materials offer a substrate-free, flexible, and chemically stable alternative to traditional plasmonic substrates in SERS applications.