Theoretical Investigation on the Electron Transport Path through the Porphyrin Molecules and Chemisorption of CO

Abstract

In this report, we studied the electron transport through cyclic π-conjugated molecules. The model system consists of metalloporphyrin with two thiol groups at either 9,11-substitution (P-connection) or 1,5-substitution (D-connection) which form chemical bonds with gold electrodes. We investigated 10 typical bivalent metals as the metal-molecule-metal junctions using first principle density functional theory and nonequilibrium Green's function calculations. Due to the particular electron transport paths, all models in P-connection show similar I-V curves, indicating that the electron does not pass through the metal center in this configuration. In the D-connection, the electron takes the path through the metal center, leading to considerable difference in the I-V curves between the different metalloporphyrins. This means that the D-connected metalloporphyrin is potentially applicable in chemical sensor. We also studied a prototype for chemosensing the CO molecule theoretically at the same level.

Nonequilibrium Green’s function study on the electronic structure and transportation behavior of the conjugated molecular junction: Terminal connections and intramolecular connections

“…42 In a micro- scopic porphyrin molecule, we also demonstrated that the electron transport pathway is the one with the lowest energy barrier. 20 One question raised is how to determine the electron transport pathway in present models. Efficient electron transport is dependent on the energy barrier, which is described by barrier height and barrier length.…”

“…The specific electron transport pathway was also observed in the circular conjugated systems. 19,20 The circular conjugated molecules are promising materials in nanoelectronics. According to the ring size, the circular conjugated molecules can be classified into three catalogs.…”

Defect-induced conductivity anisotropy in MoS2monolayers

“…The directional dependence of the conductance might arise from different transmission pathways 52,53 and electron hopping within defective parts of MoS 2 -ML. 54 To date, only grain boundaries have been studied in experiment, and our results are consistent with the results reported by the Heinz group.…”

The Diversity of Electron‐Transport Behaviors of Molecular Junctions: Correlation with the Electron‐Transport Pathway

“…[30,31] Therefore, they may behave differently from other molecular wires with single electron-transport channels. Herein, we focus on the correlation between the diverse electron-transport behaviors and the molecular structures by investigating the conductance of a series of conjugated molecules wired between two Au electrodes.…”