Abstract
A highly sensitive and uniform surface-enhanced Raman scattering (SERS) substrate is the guarantee for reliable quantitative analysis. Herein, a three-dimensional TiO(2)-Ag SERS substrate was prepared by growing a TiO(2) nanorods (NRs) array on a TiO(2) compact layer (c-TiO(2)), followed by modification with Ag nanoparticles (AgNPs). The synergy between the c-TiO(2), semiconductor TiO(2) NRs and the plasmonic AgNPs collaboratively endowed it with high sensitivity, in which c-TiO(2) effectively blocked the recombination of electrons and holes, and the charge transfer enhancement contributed 10-fold improvement over that without the c-TiO(2) substrate. Besides the high sensitivity, the TiO(2)-Ag hybrid array SERS substrate also showed quantitative and multi-component detecting capability. The limit of detection (LOD) for crystal violet (CV) was determined to be 10(-9) M even with a portable Raman instrument. The TiO(2)-Ag composite structure was extended to detect organic pesticides (thiram, triazophos and fonofos), and the LODs for thiram, triazophos and fonofos were measured to be 10(-7) M, 10(-7) M and 10(-6) M, respectively. In addition, the realistic simulation detecting pesticide residues for a real sample of dendrobium was demonstrated. The sensitive, quantitative and multiplex analysis of the TiO(2)-Ag hybrid array substrate indicated its great potential in the rapid detection of pesticide residues in real samples.