Conductance Behavior of Tetraphenyl-Aza-BODIPYs

Abstract

We studied the electrical conductance of single-molecule junctions formed from molecular wires with 4 anchor groups. Three tetraphenyl-aza-BODIPYs with 4 or 2 thiomethyl anchor groups were synthesized and their single-molecule conductance measured using breakjunction-STM. Using DFT based calculations these compounds were shown to contain a combination of constructive and destructive quantum interference, depending on the molecule's connectivity in the junction. A scissor correction is employed to obtain the corrected HOMO-LUMO gaps and a tight binding model (TBM) is used to highlight the role of quantum interference in the tetraphenyl-aza-BODIPY central unit.

Gating the conductance of a single-molecule junction with ion-π interaction

“…Due to the uncertainties of the gold electrode contact configuration and solution environment, and the inherent limitations of DFT calculations, the calculated Fermi level often deviates from the experimental value, and thus E F is usually treated as a free parameter and shifted towards the gap center. [42][43][44] This treatment fits well with the assumption that transport occurs near the centre of the HOMO-LUMO gap (shaded region). 45 As shown in Fig.…”

Electrostatic Fermi level tuning in large-scale self-assembled monolayers of oligo(phenylene–ethynylene) derivatives

“…self-assembled monolayers (SAMs). [17][18][19][20][21][22][23][24][25][26][27][28][29] The central challenge for single-molecule electronics is the uncertainty in the binding geometry of single molecules located between two electrodes. This uncertainty is reduced in SAMs, because molecules are fixed in specific conformations due to intermolecular forces between neighbouring molecules.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16] The testbeds for molecular-electronic measurements are either single-molecule junctions or large-scale molecular thin films formed from selfassembled monolayers (SAMs). [17][18][19][20][21][22][23][24][25][26][27][28][29] The central challenge for single-molecule electronics is the uncertainty in the binding geometry of single molecules located between two electrodes. This uncertainty is reduced in SAMs, because molecules are fixed in specific conformations due to intermolecular forces between neighbouring molecules.…”

Electrode effects on the observability of destructive quantum interference in single-molecule junctions

“…The additional contacts increase the number of potential transmission channels and QI patterns can emerge within individual or between different channels, thereby increasing the complexity of the analysis. Junctions with multiple anchors can display either a low-or a high-conductance, depending on the connectivity of the molecule, 99 which can be electrochemically controlled. 100,101 A systematic investigation of multiplecontact junctions can open new avenues to exploit QI effects in the framework of graphene nanoelectronics.…”