Development and Application of Dual SPR-SERS Plasmonic Sensors

Surface Plasmon Resonance (SPR) sensing is a real-time and label-free detection technique which is sensitive to the changes of refraction index on the metal surface. However, SPR is not suitable for molecular identification. On the other hand, Surface-Enhanced Raman Scattering (SERS) is a highly specific technique to identify molecules. By combining both SPR and SERS, quantification and qualification analysis can be accomplished on single biosensor. In this study, Nanoimprinting technique was used to transfer nanostructures on COP plastic substrate. By changing the design of structures and using the oblique angle deposition technique, we made two kinds of dual SPR-SERS plasmonic sensors. Gold nanoslit structures are used for SPR sensing in our previous study. By adding nanohole with specific arrangement and quantities to the nanoslit structures, SERS effect can be enhanced due to the increase of Raman hot spots, and SPR effect can be remained and be enhanced. Nanoslit structures with rough metal surfaces were made by oblique angle deposition. Rough metal surfaces can produce many raman hot spots and make SERS effect strongly enhanced. The highest enhancement is achieved by the situation that deposition direction is horizontal to the slit direction and optimized deposition thicknessis240nm. Meanwhile, SPR detection can also be done by observing the shift of resonant dip. Further, Raman detection of chlorpyrifos, acetone gas and ethanol gas is demonstrated.