Ambient Bistable Single Dipole Switching in a Molecular Monolayer

Abstract

Reported here is a molecular dipole that selfassembles into highly ordered patterns at the liquid-solid interface, and it can be switched at room temperature between a bright and a dark state at the single-molecule level. Using a scanning tunneling microscope (STM) under suitable bias conditions, binary information can be written at a density of up to 41 Tb cm À2 (256 Tb/in 2). The written information is stable during reading at room temperature, but it can also be erased at will, instantly, by proper choice of tunneling conditions. DFT calculations indicate that the contrast and switching mechanism originate from the stacking sequence of the molecular dipole, which is reoriented by the electric field between the tip and substrate.

Reliable Computational Prediction of the Supramolecular Ordering of Complex Molecules under Electrochemical Conditions

“…The target molecules whose supramolecular ordering is considered constitute an organic salt that consists of a large, disc-shaped polyaromatic cation (PQP + ) and a much smaller, inorganic anion (perchlorate, ClO 4 – ). 4 – 600 …”

“…As a benchmark test for our approach, we have considered the above-mentioned system, studied in recent experimental investigations: the cation is PQP + (9-phenylbenzo [1,2] quinolizino [3,4,5,6-fed]phenanthridinylium, a disk-shaped polyaromatic molecule), while the anion is perchlorate, ClO 4 − ; the self-assembly of these ions on a Au(111) surface under the influence of an external electric field was studied. The high accuracy with which the ensuing energies calculated from the force field reproduce the ab initio simulation data make us confident about the applicability of the force field for the subsequent optimization step: using an optimization technique that is based on ideas of evolutionary algorithms, we have then identified the self-assembly scenarios of the ions on the Au surface, for a given set of external parameters (temperature, density, and external field).…”

Mechanistically Driven Control over Cubane Oxo Cluster Catalysts

“…The considerable templating and recognition properties of inorganic counteranions emerged from supramolecular chemistry research [28][29][30][31][32][33][34] and attracts increasing attention in bio-, environmental and inorganic chemistry. 31,[35][36][37][38][39] However, the full structure-directing potential of counteranions is still far from explored. The majority of synthetic studies are focused on solid state anion template effects on the crystal structure of (oxo) cluster materials, 40 e.g.…”