Fabrication of Steady Junctions Consisting of α,ω-Bis(thioacetate) Oligo(p-phenylene vinylene)s in Nanogap Electrodes

Abstract

For obtaining molecular devices using metal-molecule-metal junctions, it is necessary to fabricate a steady conductive bridge-structure; that is stable chemical bonds need to be established from a single conductive molecule to two facing electrodes. In the present paper, we show that the steadiness of a conductive bridge-structure depends on the molecular structure of the bridge molecule for nanogap junctions using three types of modified oligo(phenylene vinylene)s (OPVs): alpha,omega-bis(thioacetate) oligo(phenylene vinylene) (OPV1), alpha,omega-bis(methylthioacetate) oligo(phenylene vinylene) (OPV2), and OPV2 consisting of ethoxy side chains (OPV3). We examined the change in resistance between the molecule-bridged junction and a bare junction in each of the experimental Au-OPV-Au junctions to confirm whether molecules formed steady bridges. Herein, the outcomes of whether molecules formed steady bridges were defined in terms of three types of result; successful, possible and failure. We define the ratio of the number of successful junctions to the total number of experimental junctions as successful rate. A 60% successful rate for OPV3 was higher than for the other two molecules whose successful rates were estimated to be approximately 10%. We propose that conjugated molecules consisting of methylthioacetate termini and short alkoxy side chains are well suited for fabricating a steady conductive bridge-structure between two facing electrodes.

Biphenyl Sulfonic and Disulfonic Acids with Perfluorinated Alkyl Residues

“…para ‐( tert ‐Butylthio)benzene boronic acid ( 2a ) was literature known and prepared accordingly from the respective para ‐bromo thioether 4 by lithium–halogen exchange, reaction with B(OMe 3 ) and subsequent hydrolysis. Respective bis( tert ‐butyl)benzene derivative 2b was not literature known.…”

“…Melting points were obtained with a Gallenkamp device; values are uncorrected. Compounds 4 , 5 , 6 and 9 were prepared according to literature protocols. All other starting materials were commercially available.…”

Evaluation of Nanoimprinting Multilayer Lift-off Process using Spin-on-glass for Nanogap Electrode Array

“…Nanogap electrodes consist of two metal electrodes separated from each other by nanometers. These electrodes can be used to investigate the electrical properties of nanoscale materials such as molecules and nanoparticles [1][2][3]. In addition, nanogap electrodes have been found to exhibit various characteristic phenomena such as surface plasmon enhancement, magnetic resistance, and field emission [4][5][6].…”

The Challenge of Synthesizing Oligomers for Molecular Wires

“…In recent years, many efforts have been made in order to produce molecular wires, with the prospect of creating nanoelectronics and of better understanding what happens at the molecular level in conductive processes [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. Most of these previous studies have focused on preparation and examination of relatively small molecules (<3-4 nm), but such molecules have limited applications because of their relatively small size.…”