Large-Scale Atomistic Simulations of Environmental Effects on the Formation and Properties of Molecular Junctions

Abstract

Using an updated simulation tool, we examine molecular junctions composed of benzene-1,4-dithiolate bonded between gold nanotips, focusing on the importance of environmental factors and interelectrode distance on the formation and structure of bridged molecules. We investigate the complex relationship between monolayer density and tip separation, finding that the formation of multimolecule junctions is favored at low monolayer density, while single-molecule junctions are favored at high density. We demonstrate that tip geometry and monolayer interactions, two factors that are often neglected in simulation, affect the bonding geometry and tilt angle of bridged molecules. We further show that the structures of bridged molecules at 298 and 77 K are similar.

Tuning the thermoelectric properties of a single-molecule junction by mechanical stretching

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Regarding the electronic transport properties, an important point (the increasing of the conductance during stretching) was recently re-addressed. In particular, a lot of effort has been made to investigate both the low bias conductance and the thermoelectric properties of molecules coupled to gold leads.…”

Structural versus Electrical Functionalization of Oligo(phenylene ethynylene) Diamine Molecular Junctions

“…[37][38][39] We also explored different concentrations of the molecule in solution, which is a parameter mostly overlooked for this kind of experiment. 40 We included in the study a compound with long alkyl groups, for which we expect steric influence similar to that of alkoxy groups, but no significant effect on the energies and charge distributions of the OPE molecular orbitals.…”

A Detailed Experimental and Theoretical Study into the Properties of C60 Dumbbell Junctions

“…This is in part due to the lack of imaging possibilities and the large number of molecules close to the junction, required to obtain high quality statistics. This means that the most probable conductance value obtained from such measurements may sometimes correspond to more than one wired molecule 4, 14. Equally problematically, it remains difficult to control precisely how the anchor group binds to the electrodes and, hence, how the molecule(s) sits in the junction.…”