Deciphering the Potential of Multidimensional Carbon Materials for Surface-Enhanced Raman Spectroscopy through Density Functional Theory

Abstract

Surface-enhanced Raman spectroscopy (SERS) is a potent analytical tool, particularly for molecular identification and structural analysis. Conventional metallic SERS substrates, however, suffer from low reproducibility and compatibility with biological molecules. Recently, metal-free SERS substrates based on chemical enhancement have emerged as a promising alternative with carbon-based materials offering excellent reproducibility and compatibility. Nevertheless, our understanding of carbon materials in SERS remains limited, which hinders their rational design. Here we systematically explore multidimensional carbon materials, including zero-dimensional fullerenes (C60), one-dimensional carbon nanotubes, two-dimensional graphene, and their B-, N-, and O-doped derivatives, for SERS applications. Using density functional theory, we elucidate the nonresonant polarizability-enhanced and resonant charge-transfer-based chemical enhancement mechanisms of these materials by evaluating their static/dynamic polarizability and electron excitation properties. This work provides a critical reference for the future design of carbon-based SERS substrates, opening a new avenue in this field.

SERS microscopy as a tool for comprehensive biochemical characterization in complex samples

“…Other non-plasmonic materials that could be further explored in bioanalytical SERS and that use the ‘chemical’ enhancement obtained by beneficial charge transfer conditions include perovskite semiconductors that improve charge transfer through vibronic coupling, 62 ceric oxide, demonstrated for a sensitive detection of adenosine triphosphate (ATP), 63 or multidimensional carbon-based substrates. 64 The main challenge in applying the latter will be their use in the absence of any molecular resonances from probed biomolecules or without relatively high amounts of label compounds that have been added when using the chemical enhancement by carbon structures so far. 65…”

A highly simple and controllable nitrogen-doping method for carbon-based surface-enhanced Raman spectroscopy substrates

“…1–6 While traditional SERS substrates primarily consist of metal-based materials, distinguished by significant enhancement factors (EFs) and devoid of inherent SERS signals, 1–13 there has been a substantial shift toward exploring efficient metal-free alternatives, particularly those made from carbon-based materials. 14–38 Such metal-free substrates enhance the Raman signal by forming a charge-transfer (CT) complex between the analyte and the substrate. This interaction modifies the electronic energy levels and amplifies the Raman signal via the resonance Raman effect, a process known as the “chemical enhancement mechanism”.…”