Suitable boron-doped graphene substrate for glucose Raman signal enhancement

Surface-enhanced Raman spectroscopy (SERS) is a highly sensitive and selective technique. It greatly enhances the signal of an analyte compared to classical Raman spectroscopy, due to analyte–substrate interactions. A promising substrate for SERS is boron-doped graphene (B-graphene). At low boron concentrations of ∼ 1.39 at.%, it has been shown to enhance the Raman signal of simple organic molecules such as pyridine. The potential use of high-concentration B-graphene materials for SERS remains unexplored. Therefore, in our study, we investigate the influence of dopant concentration and relative adsorbate/substrate geometry on the effectiveness of B-graphene as a SERS substrate, with glucose as the analyte. We perform Density Functional Theory simulations using the PBE functional and the DFT-D2 van der Waals correction. By combining analysis of interatomic force constants and phonon eigenvector composition, we conclude that higher doping concentrations provide a larger enhancement to the Raman signal of glucose, while the molecule’s orientation relative to the surface plays a fundamental role in the Raman response. We suggest that 12.5 at.% B-graphene represents a potential substrate for SERS-based detection of glucose. Additionally, the phonon-based analysis can be promptly applied in the search for promising substrate materials for enhanced Raman response. • β -glucose strongly binds with substrate doped at 12.5 at.% concentration. • 12.5 % boron doping provides SERS enhancement larger than low or null doping. • Relative molecule/substrate orientation affects SERS response. • Phonon analysis is necessary to correctly assign atom contributions to Raman signal.