Flexible SERS Substrate with a Ag-SiO2 Cosputtered Film for the Rapid and Convenient Detection of Thiram.

It is very important to build uniform large-area dense hotspots to improve the surface-enhanced Raman scattering (SERS) detection limit. In our research, we designed and prepared a new flexibile SERS substrate with ultradense hot spots that has the advantages of high sensitivity, good repeatability, easy fabrication, and low cost. Due to the special dense hot spot structure, the substrate reaches a SERS enhancement factor of 2.1 × 1011. Because of the excellent physical stability of polydimethylsiloxane, the substrate can be bent at will, and the SERS performance will not change with bending. This is very important to extract effective detection objects on complex surfaces. The substrate has good light transmittance and softness and can be directly attached to the detected agricultural products to realize real-time and rapid SERS monitoring. This structure exhibits extraordinary performance for thiram detection in the ultralow concentration range of 10-13 M.

Designed Growth of AgNP Arrays for Anti-counterfeiting Based on Surface-Enhanced Raman Spectroscopy Signals.

Based on etched PS sphere arrays, the different growths of Ag nanoparticles with tunable LSPR are designed when SiO2-25 nm/Ag-30 nm/SiO2-100 nm sandwich nanocavity structures are annealed at 500 °C, including the hexagonal silver nanoparticle rings, circular silver nanoparticle rings, and aggregated silver nanoparticles. The uniformity of particle size and regularity of position generate enhanced electromagnetic field and good surface-enhanced Raman spectroscopy signals as confirmed by UV-vis observation and finite difference time domain method simulation. The developed nanostructures are effectively used as stable, nonreproducible, and markable anti-counterfeiting signs.

Re(I) complex doped nanofibers for oxygen optical sensing.

In this paper, we design and synthesize a novel diamine ligand of PTO (2-(pyridin-2-yl)-5-p-tolyl-1,3,4-oxadiazole). The crystal structure, photophysical character and electronic nature of its corresponding Re(I) complex of Re(CO)(3)(PTO)Br have been investigated in detail. Experimental data and theoretical calculation suggest that Re(CO)(3)(PTO)Br owns a long-lived yellow phosphorescence which is sensitive towards molecular oxygen. By doping Re(CO)(3)(PTO)Br into a polymer matrix of polystyrene (PS), the emission response of the resulted composite nanofibers towards molecular oxygen is studied. The optimal sample with mean diameter of 600 nm shows a maximum sensitivity of 4.14 with short response time of 14s (here sensitivity is defined as the ratio of emission intensity in pure N(2) atmosphere to that in pure O(2) atmosphere). The composite nanofibers are also found to be photostable enough to experience UV radiation.