Improved SERS performance of single-crystalline TiO2 nanosheet arrays with coexposed {001} and {101} facets decorated with Ag nanoparticles

In this paper, single-crystalline TiO2 nanosheet (TNS) arrays with dominant {001} facets decorated with Ag nanoparticles were synthesized on fluorine-doped tin oxide (FFO) substrate by a simple hydrothermal method and a magnetron sputtering method. Using Rhodamine 6G (R6G) as the probe molecule, we investigated the sensitivity, reversibility and uniformity of surface-enhanced Raman scattering (SERS) substrates. It is noted that the TNS with 10s Ag-sputtering achieves the highest Raman signals, and the intensity of the SERS spectra on TNS/Ag has a significant enhancement compared with Ag film. The excellent SERS performance is attributed to synergistic effect of electromagnetic mechanism (EM) and charge-transfer (CT) enhancement mechanism. Furthermore, the band bending of the adjacent region between {001} and {101} facets, provides an additional CT from Ag to TNS, which would result in strong enhancement of the SERS signal. (C) 2016 Elsevier B.V. All rights reserved.