A three dimensional porous diamond-multilayer graphene nanohybrid film for surface-enhanced Raman spectroscopy

Development of excellent surface-enhanced Raman scattering (SERS) substrate with high sensitivity, low limit of detection (LOD), good uniformity and high stability are still challenging in practical application. Herein, we prepared a diamond-multilayer graphene nanohybrid (DMGN) film with unique three-dimensional (3D) porous wall-like morphology as a new SERS substrate, through a microwave plasma chemical vapor deposition (MPCVD) method. A simple wet-chemical oxidation treatment performed on DMGN substrate resulted in an obvious improvement in LOD value, from 10 9 mol/L to 10(-11) mol/L, and enhancement factor (EF), from 4.2 x 10(4) to 3.9 x 10(6), for the detection of Rhodamine B (RhB), simultaneously along with good homogeneity and long-term stability. More importantly, the oxidized DMGN (ODMGN) substrate also exhibited good SERS performance for the detection of a real explosive (FOX-7), including low LOD of 10(-6) mol/L and large EF of 527. Finally, first-principles density functional theory (DFT) simulation revealed that SERS enhancement of ODMGN substrate was mainly attributed to the transfer electron between HN- functional group of FOX-7 and the -OH and -O-functional groups of ODMGN substrate. These unique 3D porous nanohybrid films showed momentous potential to realize a SERS substrate with excellent performance.