SERS Background Imaging – a Versatile Tool Towards More Reliable SERS Analytics

Surface-enhanced Raman scattering (SERS) is a highly selective and sensitive straightforward analytical method, which is however not yet established in routine analysis due to a lack of reliability and reproducibility. Here we utilise the broad SERS continuum background (SERS-BG) accompanying every SERS measurement as a versatile tool towards more reliable SERS analytics. We apply a heterogeneous gold SERS substrate immersed with an adenosine triphosphate solution to show that the integrated SERS-BG distinctly correlates with the intensity of the analyte signals in the SERS spectrum. Based on this relationship we introduce an easy-to-handle, automatable and more reliable SERS measurement procedure starting with fast and high-contrast imaging of the SERS substrate followed by hot spot localisation and recording of highly enhanced SERS spectra at the centre of the diffraction-limited spot. We further demonstrate the applicability of SERS-BG imaging by combining it with other optical modalities and electron microscopy to assess structure-property relationships. Additionally, we perform Monte-Carlo simulations to evaluate the sampling error in SERS experiments highlighting the advantages of our method over conventional SERS experiments.