/pdf/self-assembled-monolayers-of-thiolates-on-metals-as-a-form-1neb0hj3k4.pdf

Self-assembled monolayers of thiolates on metals as a form of nanotechnology.

Molecular conductance junctions are structures in which single molecules or small groups of molecules conduct electrical current between two electrodes. In such junctions, the connection between the molecule and the electrodes greatly affects the current-voltage characteristics. Despite several experimental and theoretical advances, including the understanding of simple systems, there is still limited correspondence between experimental and theoretical studies of these systems.

/pdf/electron-transport-in-molecular-wire-junctions-2m2v92jao5.pdf

Electron transport in molecular wire junctions.

This article summarises the industrial applications of poly-(3,4-ethylenedioxythiophene)
				(PEDT, PEDOT). The basic chemical and physical properties of PEDT are discussed to outline the fundamentals which lead to PEDT as a highly valuable electric and electronic material. PEDT applications are reviewed depending on the two different ways of preparation: in situ polymerisation of the monomer, usually carried out by the user, and applying the prefabricated polymer in the form of its water-based complex with poly(styrene sulfonic acid). Several applications like antistatic coatings, cathodes in capacitors, through-hole plating, OLED's, OFET's, photovoltaics, and electrochromic applications are discussed in detail.

Scientific importance, properties and growing applications of poly(3,4-ethylenedioxythiophene)

Self-assembled monolayers (SAMs) of alkanethiols and dialkanethiols on gold are key elements for building many systems and devices with applications in the wide field of nanotechnology. Despite the progress made in the knowledge of these fascinating two-dimensional molecular systems, there are still several “hot topics” that deserve special attention in order to understand and to control their physical and chemistry properties at the molecular level. This critical review focuses on some of these topics, including the nature of the molecule–gold interface, whose chemistry and structure remain elusive, the self-assembly process on planar and irregular surfaces, and on nanometre-sized objects, and the chemical reactivity and thermal stability of these systems in ambient and aqueous solutions, an issue which seriously limits their technological applications (375 references).

Self-assembled monolayers of thiols and dithiols on gold: new challenges for a well-known system

Creating functional electrical circuits using individual or ensemble molecules, often termed as “molecular-scale electronics”, not only meets the increasing technical demands of the miniaturization of traditional Si-based electronic devices, but also provides an ideal window of exploring the intrinsic properties of materials at the molecular level. This Review covers the major advances with the most general applicability and emphasizes new insights into the development of efficient platform methodologies for building reliable molecular electronic devices with desired functionalities through the combination of programmed bottom-up self-assembly and sophisticated top-down device fabrication. First, we summarize a number of different approaches of forming molecular-scale junctions and discuss various experimental techniques for examining these nanoscale circuits in details. We then give a full introduction of characterization techniques and theoretical simulations for molecular electronics. Third, we highlig...

Molecular-Scale Electronics: From Concept to Function

Charge transport studies across molecular length scales under symmetric and asymmetric metal-molecule contact conditions using a simple crossed-wire tunnel junction technique are presented. It is demonstrated that oligo(phenylene ethynylene), a conjugated organic molecule, acts like a molecular wire under symmetric contact conditions, but exhibits characteristics of a molecular diode when the connections are asymmetric. To understand this behavior, we have calculated current-voltage (I-V) characteristics using extended Huckel theory coupled with a Green's function approach. The experimentally observed I-V characteristics are in excellent qualitative agreement with the theory.

Metal-molecule contacts and charge transport across monomolecular layers: measurement and theory.

Charge transport across a metal−molecule−metal junction consisting of π-conjugated molecular wires in a densely packed monolayer is studied as a function of junction area. The current−voltage characteristics, measured using a crossed-wire junction at different contact forces, scale onto a single curve. The integer scaling factors, ranging from 1 to 1119, are dictated by the number of molecules contacted in each measurement. These results demonstrate that the electronic conductance of an ensemble of molecules scales directly with the number of molecules in the junction. Our results, which also imply that molecular wires connected in parallel are not strongly coupled along their molecular backbone, should aid in the future development of molecular electronic devices.

Conductance Scaling of Molecular Wires in Parallel

Optical and x-ray scattering studies of a chiral, organosiloxane smectic-A liquid crystal indicate a large field induced optical tilt of up to 31 degrees accompanied by a very small contraction of the smectic layers. This result suggests that the molecules have a nonzero tilt even with no applied field, and that the primary effect of the field is to induce long range order in the direction of the molecular tilt.

R. Shashidhar

Papers

Metal-molecule contacts and charge transport across monomolecular layers: measurement and theory.

Conductance Scaling of Molecular Wires in Parallel

Electroclinic liquid crystals with large induced tilt angle and small layer contraction

Novel ferroelectric and electroclinic organosiloxane liquid crystals

Hydroxylated secondary dopants for surface resistance enhancement in transparent poly(3,4-ethylenedioxythiophene)–poly(styrenesulfonate) thin films