Investigation of 1D Siliver Nanoparticle Arrays for Use as Molecule Concentration‐Specific SERS Substrates

Abstract

One-dimensional arrays of silver nanoparticles with a particle size of 10.5 nm and interparticle spacing of 8.5 nm were fabricated by depositing nanoparticles in gas phase on block copolymer self-assembled templates. The substrate showed a surface-enhanced Raman scattering (SERS) enhancement factor as high as1×107with good reproducibility and stability. The dependence of the average enhancement factor and the SERS intensity on the packing density of the analyte molecules were investigated. For a tiny amount of analytes in the range of1×10-14to3×10-13 mol/mm2, the SERS signal showed a linear dependence on the molecule packing density on a logarithmic scale, with a slope of about 1.25. The substrates are promising for quantitative detection of trace level molecules.

A New Spin-Correlated Plasmon in Novel Highly Oriented Single-Crystalline Gold Quantum Dots

“…Intriguingly, strong SERS signals (Figure 5) are observed when 10 μM (1.8 ppm) of BPE dripped and dried on the Spin-SERS chip was excited using laser with photon energy of 633 nm (∼1.96 eV), which is resonant at the spin correlated-plasmon. We observe Raman peaks at (i) 1020 cm −1 due to (C−N) and (C−C) stretching modes, (ii) 1200 cm −1 due to (C r −C b ) stretching and rocking modes where C r is a ring-carbon bonded to a bridging carbon and C b is a bridgingcarbon, 38 (iii) 1335 cm −1 due to (CC) bending modes, and last (iv) 1607 and 1635 cm −1 , which are BPE characteristic peaks due to (C−C) stretching modes. 39 In contrast, no SERS signal is observed using SERS-substrate of Au thin film or quartz slide with the same analyte further signifying the unique role of the spin correlated-plasmon generated in HOSG-QDs and not in continuous Au thin film (Figure S7).…”