The enhanced SERS effect of Ag/ZnO nanoparticles through surface hydrophobic modification

•A facile heating reflux method is presented for the fabrication of hydrophobic Ag/ZnO nanocomposites.•Surface modification was achieved through addition of stearic acid (SA) and polyvinylpyrrolidone.•A 3-fold SERS signal enhancement was observed compared to the pristine hydrophilic Ag/ZnO substrate for detecting Rh B molecules after the surface modification. Ag/ZnO nanocomposites modified by a mixture of stearic acid (SA) and polyvinylpyrrolidone (PVP) were obtained using a heating reflux method. Fourier transform infrared spectroscopy (FT-IR) suggests that organic SA/PVP was bonded onto the surface of Ag/ZnO nanocrystals, converting the wettability property of the nanostructures from hydrophilic to hydrophobic. The modified Ag/ZnO nanostructures were confirmed as effective Raman substrates, with a 3-fold signal enhancement compared to the ordinary hydrophilic Ag/ZnO substrate for detecting Rh B molecules due to the hydrophobic condensation effect. It is expected that the modified Ag/ZnO nanoparticles have potential for SERS-based rapid detection of molecules.