Metal-free SERS: Where we are now, where we are heading

¹ Department of Chemistry, The University of Tokyo - 113-0033, Tokyo, Japan
² Institute for Quantum Life Science, National Institute for Quantum and Radiological Science and Technology 263-8555, Chiba, Japan
³ Institute of Technological Sciences, Wuhan University - Hubei, 430072, PRC
⁴ Department of Bioengineering, University of California - CA 90095, Los Angeles, USA

^(a) xiaoth@chem.s.u-tokyo.ac.jp (corresponding author)
^(b) goda@chem.s.u-tokyo.ac.jp

Received: 30 November 2021
Accepted: 20 January 2022

Abstract

In the recent years, the emergence of metal-free surface-enhanced Raman scattering (SERS) substrates has provided promising alternatives for reliable, high-sensitivity Raman spectroscopy due to their potential to realize highly tuneable, biocompatible, and reproducible Raman enhancement. In this perspective article, we discuss recent developments and anticipate new opportunities for metal-free SERS. Specifically, we review the theory of metal-free SERS, including electromagnetic enhancement and chemical enhancement, and introduce promising substrates developed recently, including MXenes, transition metal dichalcogenides, and carbon-based substrates. Moreover, we clarify challenges, provide potential solutions, and discuss unexploited applications. This perspective provides not only a broad and detailed view of metal-free SERS at the current stage, but also a roadmap for its future advancement.