6 research outputs found
Supramolecular Rotor and Translator at Work: On-Surface Movement of Single Atoms
A supramolecular nanostructure composed of four 4-acetylbiphenyl molecules and self-assembled on Au (111) was loaded with single Au adatoms and studied by scanning tunneling microscopy at low temperature. By applying voltage pulses to the supramolecular structure, the loaded Au atoms can be rotated and translated in a controlled manner. The manipulation of the gold adatoms is driven neither by mechanical interaction nor by direct electronic excitation. At the electronic resonance and driven by the tunneling current intensity, the supramolecular nanostructure performs a small amount of work of about 8 Ă 10<sup>â21</sup> J, while transporting the single Au atom from one adsorption site to the next. Using the measured average excitation time necessary to induce the movement, we determine the mechanical motive power of the device, yielding about 3 Ă 10<sup>â21</sup> W
Unimolecular Logic Gate with Classical Input by Single Gold Atoms
By a combination of solution and
on-surface chemistry, we synthesized an asymmetric starphene molecule
with two long anthracenyl input branches and a short naphthyl output
branch on the Au(111) surface. Starting from this molecule, we could
demonstrate the working principle of a single molecule NAND logic
gate by selectively contacting single gold atoms by atomic manipulation
to the longer branches of the molecule. The logical input â1â
(â0â) is defined by the interaction (noninteraction)
of a gold atom with one of the input branches. The output is measured
by scanning tunneling spectroscopy following the shift in energy of
the electronic tunneling resonances at the end of the short branch
of the molecule
Persulfurated Coronene: A New Generation of âSulflowerâ
We report the first
synthesis of a persulfurated polycyclic aromatic
hydrocarbon (PAH) as a next-generation âsulflower.â
In this novel PAH, disulfide units establish an all-sulfur periphery
around a coronene core. The structure, electronic properties, and
redox behavior were investigated by microscopic, spectroscopic and
electrochemical methods and supported by density functional theory.
The sulfur-rich character of persulfurated coronene renders it a promising
cathode material for lithiumâsulfur batteries, displaying a
high capacity of 520 mAh g<sup>â1</sup> after 120 cycles at
0.6 C with a high-capacity retention of 90%
Tuning the Planarity of an Aromatic Thianthrene-Based Molecule on Au(111)
Nonplanar aromatic molecules are interesting systems
for organic
electronics and optoelectronics applications due to their high stability
and electronic properties. By using scanning tunneling microscopy
and spectroscopy, we investigated thianthrene-based molecules adsorbed
on Au(111), which are nonplanar in the gas phase and the bulk solid
state. Varying the molecular coverage leads to the formation of two
different kinds of self-assembled structures: close-packed islands
and quasi-one-dimensional chains. We found that the molecules are
nonplanar within the close-packed islands, while the configuration
is planar in the molecular chain and for single adsorbed molecules.
Using vertical tip manipulation to isolate a molecule from the island,
we demonstrate the conversion of a nonplanar molecule to its planar
configuration. We discuss the two different geometries and their electronic
properties with the support of density functional theory calculations