PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 11971794

Charging effects, forces, and conduction in molecular wire systems.

Eldon G Emberly·George Kirczenow
View original source ↗Export metadata ↓

Abstract

Recently, experiments have shown that effects arising from charging and conformational changes in a molecular wire due to an applied voltage bias can have a significant influence on the transport characteristics of the system. We introduce a tractable theoretical approach based on Landauer theory and total energy methods that treats transport nonlinearities, conformational changes, and charging effects in molecular wires in a unified way. We apply this approach to molecular wires consisting of short chain molecules with different electronic and structural properties bonded to metal contacts. We find that the nonlinear conductance characteristics of these systems are remarkably similar and can be understood in terms of a single physical mechanism. We predict that negative differential resistance should occur at high bias in such molecular wires due to the combined effects of charging and conformational changes on their electronic structure.

Explore related subjects

Electric ConductivityElectric ImpedanceElectrochemistryElectronsModels, StatisticalTemperatureJournal ArticleResearch Support, Non-U.S. Gov't

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Eldon G Emberly, George Kirczenow. 2002. Charging effects, forces, and conduction in molecular wire systems.. https://doi.org/10.1111/j.1749-6632.2002.tb03028.x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2007

Conductance-controlled point functionalization of single-walled carbon nanotubes.

We used covalent attachments to single-walled carbon nanotubes (SWNTs) to fabricate single-molecule electronic devices. The technique does not rely on submicrometer lithography or precision mechanical manipulation, but instead uses circuit conductance to monitor and control covalent attachment to an electrically connected SWNT. Discrete changes in the circuit conductance revealed chemical processes happening in real time and allowed the SWNT sidewalls to be deterministically broken, reformed, and conjugated to target species. By controlling the chemistry through electronically controlled electrochemical potentials, we were able to achieve single chemical attachments. We routinely functionalized pristine, defect-free SWNTs at one, two, or more sites and demonstrated three-terminal devices in which a single attachment controls the electronic response.

Electric Conductivity↗
PubMed2007

A model explaining genotypic and ontogenetic variation of leaf photosynthetic rate in rice (Oryza sativa) based on leaf nitrogen content and stomatal conductance.

BACKGROUNDS AND AIMS: Identification of physiological traits associated with leaf photosynthetic rate (Pn) is important for improving potential productivity of rice (Oryza sativa). The objectives of this study were to develop a model which can explain genotypic variation and ontogenetic change of Pn in rice under optimal conditions as a function of leaf nitrogen content per unit area (N) and stomatal conductance (g(s)), and to quantify the effects of interaction between N and g(s) on the variation of Pn. METHODS: Pn, N and g(s) were measured at different developmental stages for the topmost fully expanded leaves in ten rice genotypes with diverse backgrounds grown in pots (2002) and in the field (2001 and 2002). A model of Pn that accounts for carboxylation and CO diffusion processes, and assumes that the ratio of internal conductance to g(s) is constant, was constructed, and its goodness of fit was examined. KEY RESULTS: Considerable genotypic differences in Pn were evident for rice throughout development in both the pot and field experiments. The genotypic variation of Pn was correlated with that of g(s) at a given stage, and the change of Pn with plant development was closely related to the change of N. The variation of g(s) among genotypes was independent of that of N. The model explained well the variation in Pn of the ten genotypes grown under different conditions at different developmental stages. Conclusions The response of Pn to increased N differs with g(s), and the increase in Pn of genotypes with low g(s) is smaller than that of genotypes with high g(s). Therefore, simultaneous improvements of these two traits are essential for an effective breeding of rice genotypes with increased Pn.

Electric Conductivity↗