jp7b05924_si_001.pdf (2.6 MB)
Bi-Axial Growth Mode of Au–TTF Nanowires Induced by Tilted Molecular Column Stacking
journal contribution
posted on 2017-09-25, 00:00 authored by Yanlong Xing, Eugen Speiser, Dheeraj K. Singh, Petra S. Dittrich, Norbert EsserIn this study, to
understand the molecular self-organization in
metal–organic charge-transfer nanowires, single gold-tetrathiafulvalene
(Au–TTF) nanowires were analyzed using polarized Raman spectroscopy,
combined with density functional theory (DFT) calculations. To verify
the methodology, an investigation was done for neutral tetrathiafulvalene
(TTF) bulk crystals with well-known structure. On the basis of the
DFT calculation of the molecular Raman tensor and simulation of the
angular-dependent depolarization ratio, the molecular orientation
in single TTF crystals was verified. Thereon, the combined experimental
and ab initio-simulation method was applied to study single Au–TTF
nanowires. Our results clearly demonstrate, in contrast to the commonly
accepted parallel molecular stacking model, that at least two molecules
with different orientations are located in the unit cell of the nanowire’s
crystal structure. The new tilted molecular column stacking wire model
explains also the axial and radial growth mechanism of Au–TTF
wires.