Facile synthesis of large-scale TiO2 nanorod arrays decorated with Ag nanoparticles as sensitive 3D SERS substrates

A facile and green synthesis strategy is employed to prepare uniform three-dimensional (3D) nanostructure as surface-enhanced Raman scattering (SERS) sensors by decorating Ag nanoparticles (AgNPs) on TiO2 nanorod arrays. The results of XPS, SEM and TEM analyses indicate that AgNPs are distributed homogeneously on the surface of TiO2 nanorods. The 3D hybrid substrate presents sensitive SERS signals of rhodamine 6 G (R6G). The relative standard deviation (RSD) for the main Raman vibration modes (611, 776, 1189 and 1651 cm-1) is less than 7%. Further UV-vis absorption spectra and FDTD simulation jointly illustrate that the interaction between AgNPs with symmetrical distribution in three dimensions generated intensive hot spots, which greatly improved the performance and spatial uniformity of SERS. The substrate also exhibits excellent SERS ability in detecting adenine molecule. The results show that the two-steps synthesis is a promising strategy for preparing 3D hybrid nanostructure substrate for SERS.