Surface-Enhanced Raman Scattering and DFT Study of 4,4'-Biphenyldithiol on Silver Surface

Abstract

Surfaced-enhanced Raman scattering (SERS) of 4,4'-biphenyldithiol (BPDT) has been investigated at a silver island film. Ordinary Raman (OR) spectra of neat sample in solid state and in basic solution have also been taken for comparison. The spectral feature in the SERS spectrum was similar to that for the OR spectrum in basic solution, except for the broadening of ring stretching bands indicative of the presence of surface-phenyl ring π interaction. In contrast, only absence of the C-H stretching band with very small Raman scattering crosssection seemed not pertinent in judging the definitive orientation of molecule. The observed vibrational bands in the SERS spectrum have been assigned by referring to the normal modes and wavenumbers from density functional theory (DFT) calculations of the simple model as 4,4'-biphenyldithiolates bound to two Ag atoms at the both ends. Excellent agreement between the experimental and the calculated results was achieved, which is remarkable considering the level of theory applied.

Hyperbolic metamaterials for large-area Surface-Enhanced Raman Scattering (SERS) sensing

“…Figure 4.a) demonstrates that Raman spectra can be obtained at laser powers as low as 900 µW, in contrast to a standard Au substrate from which no spectra is obtained at the same power. The prominent peaks are observed at 1023, 1091, 1205, 1292, and 1596 cm -1 and are obtained with laser powers lower than similar studies 23 . Figure 4.b) displays that at integration times as low as 97 ms, the vibrational modes at 1094 and 1597 cm -1 can be observed 14 .…”

Raman photostability of off-resonant gap-enhanced Raman tags

“…2b(ii) and (iii)). [37][38][39] Two strong characteristic Raman bands of single-shell and double-shell BDT-GERTs at 1055 and 1555 cm À1 and one weak band at 1178 cm À1 correspond to the phenyl-ring breathing mode (C-H in-plane bending and C-S stretching), the phenyl-ring stretching motion (8a vibrational mode), and the CH bending motion (9a vibrational mode), respectively ( Fig. 2b(i) and (iv)).…”

Molecularly-induced roughness and oxidation in cobalt/organodithiol/cobalt nanolayers synthesized by sputter-deposition and molecular sublimation

“…Raman spectra from Co/BPDT/Co sandwiches (Fig. 8) exhibit the following signatures of BPDT: 24,42–44 CC stretching (1590 cm −1 ), C–C stretching (1288 cm −1 ) between, and C–H bending (1201 cm −1 ) within, the aromatic rings, and S–C stretching (1078 cm −1 ). The lack of an observable peak at 376.6 cm −1 indicates –SH moieties did not react with each other to form disulfides.…”