Surface Enhanced Raman Scattering in Graphene Quantum Dots Grown via Electrochemical Process

Graphene Quantum dots (GQDs) are used as a surface-enhanced Raman substrate for detecting target molecules with large specific surface areas and more accessible edges to enhance the signal of target molecules. The electrochemical process is used to synthesize GQDs in the solution-based process from which the SERS signals were obtained from GQDs Raman spectra. In this work, GQDs were grown via the electrochemical process with citric acid and potassium chloride (KCl) electrolyte solution to obtain GQDs in a colloidal solution-based format. Then, GQDs were characterized by transmission electron microscope (TEM), Fourier-transform infrared spectroscopy (FTIR), and Raman spectroscopy, respectively. From the results, SERS signals had observed via GQDs spectra through the Raman spectra at D (1326 cm(-1)) and G (1584 cm(-1)), in which D intensity is defined as the presence of defects on GQDs and G is the sp(2) orbital of carbon signal. The increasing concentration of KCl in the electrolyte solution for 0.15M to 0.60M demonstrated the increment of Raman intensity at the D peak of GQDs up to 100 over the D peak of graphite. This result reveals the potential feasibility of GQDs as SERS applications compared to graphite signals.

Automated summary

In this study, graphene quantum dots (GQDs) were successfully synthesized via an electrochemical process and SERS signals were obtained from GQDs' Raman spectra. The D and G peaks of GQDs spectra were observed through Raman spectroscopy, with an increase in potassium chloride concentration leading to a 100-fold increase in Raman intensity at the D peak of GQDs compared to graphite. This indicates the potential feasibility of using GQDs for SERS applications compared to graphite.