MnO2/Au hybrid nanowall film for high-performance surface-enhanced Raman scattering substrate

Surface-enhanced Raman scattering (SERS) technology has been investigated for long time because of its tremendous potential in chemical and biomolecular detection. One of the challenging works in this field is to fabricate fantastic substrates with high sensitivity, stability, and reproducibility. This work reports a novel SERS substrate based on MnO2/Au hybrid nanowall film prepared by simple and cheap hydrothermal method combined with subsequent vacuum thermal evaporation process. Enhanced SERS enhancement factor (EF) with increased thickness of gold layer was observed and a significant increase of EF up to 8 orders of magnitude has been achieved. Finite-difference time-domain (FDTD) simulations have been carried out to elucidate the origin of the enhancement and the distribution of the “hot spots”. Experimental evidences indicate that the as-prepared substrate possesses excellent SERS sensitivity, good stability and high reproducibility. Our results provide a novel MnO2/Au hybrid nanowall film as a convenient and robust SERS-active substrate for detecting biomolecules.