Carbon nanostructure (0-3 dimensional) supported isolated gold nanoparticles as an effective SERS substrate

The present work reports a comparative surface enhanced Raman scattering (SERS) study of nanohybrids of spatially isolated gold nanoparticles (Au NPs) with different carbon nanostructures (CNS). For a meticulous comparative analysis, different CNS covering from zero dimensional to three dimensions were used. SERS activities of developed nanohybrids platforms were evaluated with a Raman marker i.e. Mercaptobenzoic acid (4-MBA, 1 mu M). Synergistic Raman signal enhancement from each Au NP (electromagnetic enhancement) and underlying CNS matrix (chemical enhancement) was observed in nanohybrid enabling detection of very small concentration of 4-MBA i.e. 1 mu M convincingly. Among the different underlying matrix, GQDs-Au NPs based SERS platform have shown highest SERS enhancement by a factor of 10(7), followed by GO-Au NPs combination (similar to 3 x 10(6)) and others. Enhanced SERS activity of GQDs-Au NPs -4-MBA nanohybrid platform is attributed to the D and G bands of GQDs, overpowering the strong fluorescent background of GQDs alone. Reported nano hybrids; specially GQDs-Au NPs offers numerous possibilities to be used as sensitive and reproducible SERS platform for the detection of other biologically/chemically important analytes, showing potential for standardization in near future.