An efficient dual functional Raman and Fluorescence detection platform achieved by controlling the electromagnetic enhanced field in three-dimensional Ag/ZnO composited arrays

Surface-enhanced Raman scattering (SERS) and metal-enhanced fluorescence (MEF) phenomena can significantly increase spectroscopic signals, allowing sophisticated biological detection to be realized. However, integrating SERS and MEF into a single plasmonic platform is still a challenge, since the optimized distance between the analyte and the metal is different for these two detection techniques. Herein, we designed a three-dimensional (3D) electromagnetic field via decorating silver (Ag) nanoparticles on a zinc oxide (ZnO) nanorod arrays to overcome this limitation, and the ultrasensitive detection of Rhodamine 6G dye molecules at extremely low detection limits of 10 fM for SERS and 100 fM for MEF can be realized. The underlying enhancement mechanism investigated via finite-difference time-domain simulations revealed that the 3D electromagnetic field could overcome the quenching effect in MEF to achieve the simultaneous enhancement of the SERS and MEF signals. This work provides a way to apply 3D architecture to realize ultrasensitive SERS-MEF dual-mode detection.