Organic electronics have great potential that rests on the ability to engineer the wave-function through molecular synthesis, and hence properties of the resultant devices. Understanding the mechanism in charge transport through large area tunneling junction, largely based on self-assembled monolayers (SAMs), offers great promise in advancing molecular/organic electronics. Despite the fact that large efforts have been put into understanding the structure-property relations in charge transport, little is known about the effect of dipoles and related stereo-electronic molecular properties on charge transport. Previous work has, however, indicated that the steric orientation of the SAM molecules, or a single moiety, affects the rate of charge tunneling, as demonstrated by the odd-even effect. A reliable physical-organic study on delineating the effect of dipole on charge transport, should entail strategies to minimize steric effects. We, therefore, use thiocarboranes-based SAMs to decouple the two effect of dipoles and steric on the rate of charge transport. The packing density, orientation and thickness of SAMs derived from meta-1-carboranethiolates and meta-9-carboranethilates on ultra-flat Au are similar. These SAMs, however, have significant differences in the magnitude and orientation of their dipoles, and, therefore, they are ideal candidates to delineate the effect of dipole on charge transport. BY comparing odd-even effect in n-alkanethiolate SAMs and differences in tunneling rates through structurally similar thiocarboranes, we infer that the rate of charge transport through large area tunneling junctions is dependent on the stereo-electronic properties of the SAM.

Stereo-electronic effects on charge transport across large area tunneling junction

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.