Download or read book Environmental Control of Charge Transport Through Single Molecule Junctions written by Brian John Capozzi and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This technique has the potential for application in nano-scale systems beyond single-molecule junctions. These results constitute another step toward the development of single-molecule devices with commercial applications. Finally, the methods presented in this thesis offer further insights into the electronic structure of molecular junctions. We show that we can assess energy-level alignment at metal molecule interfaces– this alignment is a crucial parameter controlling the proper- ties of the interface. We also demonstrate that we can probe large regions ( 2eV) of the transmission function which governs charge transport through the junction. By being able to control level alignment, we are also able to offer preliminary studies on single-molecule junctions in the resonant transport regime. Combined, the results presented in this thesis grant new insights into electron transport at the nanoscale and provide new routes for the development of functional single-molecule devices.

Download or read book Mechanical Control of Charge Transport and Chemical Reactivity in Molecular Junctions written by Leopoldo Meja̕ Restrepo and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Charge transport plays a critical role in a wide range of molecular processes including photosynthesis, redox catalysis, energy storage, biological signaling, and the operation of molecular electronic devices. Understanding and controlling these key events requires establishing how molecular structure influences charge transport and designing physically realizable strategies to manipulate them. This thesis advances the theory, simulation, and interpretation of charge transport experiments in molecular junctions and identifies novel avenues to use external mechanical stimuli to control chemistry and physics in this nanoscale setting. The reason why we focus on molecular junction experiments is because they enable the manipulation of individual molecules and the characterization of their response to external stimuli such as mechanical forces, bias voltages, and electro-magnetic fields. Such a controllable setting is ideal to establish structure-charge transport relations at the single-molecule limit that can inform and resolve the individual molecular contributions to bulk phenomena. We first demonstrate that conductance can act as a sensitive probe of conformational dynamics during the mechanical pulling of molecular junctions. These advances offer an efficient solution to experimentally monitor conformational dynamics at the single-molecule limit. Next, we bridge molecular conductance with mechanochemistry and investigate how to mechanically onset and electrically monitor chemical reactivity in single molecules. In particular, we demonstrate mechanically controlled association and rupture reactions in molecular junctions and show that simultaneous measurements of force and conductance are able to signal reactive events that cannot be distinguished by force or conductance alone. The computations are based on atomistic molecular dynamics and nonequilibrium Green's functions computations of electron transport. At the methodological level, we clarify the utility of the Landauer equation for computing charge transport across molecular junctions immersed in a thermal environment such as solvent. The Landauer equation is central to the modeling of molecular electronics experiments. However, it supposes that the current is coherent (solely due to quantum tunneling) and does not capture the possible influence of the environment in the net current. We isolate physical conditions that require an analysis beyond Landauer and use them to identify chemical motifs capable of stabilizing coherent, incoherent, and intermediate transport mechanisms. Molecular junction experiments typically record the conductance of thousands of freshly formed junctions and report histograms of conductance events. Here, we construct a microscopic theory of such conductance histograms by merging the theory of force spectroscopy developed in biophysics with molecular conductance. The theory enhances the information that can be extracted from molecular electronics experiments, and can be employed to develop schemes to narrow the width of the histograms as desirable for spectroscopic applications and molecular device design. Further, the theory opens key opportunities to atomistically model the conductance histograms, as needed to bridge the gap between theory and experiments."--Pages viii-ix.

Download or read book Molecular Scale Electronics written by Xuefeng Guo and published by John Wiley & Sons. This book was released on 2020-07-15 with total page 408 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides in-depth knowledge on molecular electronics and emphasizes the techniques for designing molecular junctions with controlled functionalities This comprehensive book covers the major advances with the most general applicability in the field of molecular electronic devices. It emphasizes new insights into the development of efficient platform methodologies for building such reliable devices with desired functionalities through the combination of programmed bottom-up self-assembly and sophisticated top-down device fabrication. It also helps to develop an understanding of the device fabrication processes and the characteristics of the resulting electrode-molecule interface. Beginning with an introduction to the subject, Molecular-Scale Electronics: Concept, Fabrication and Applications offers full chapter coverage on topics such as: Metal Electrodes for Molecular Electronics; Carbon Electrodes for Molecular Electronics; Other Electrodes for Molecular Electronics; Novel Phenomena in Single-Molecule Junctions; and Supramolecular Interactions in Single-Molecule Junctions. Other chapters discuss Theoretical Aspects for Electron Transport through Molecular Junctions; Characterization Techniques for Molecular Electronics; and Integrating Molecular Functionalities into Electrical Circuits. The book finishes with a summary of the primary challenges facing the field and offers an outlook at its future. * Summarizes a number of different approaches for forming molecular-scale junctions and discusses various experimental techniques for examining these nanoscale circuits in detail * Gives overview of characterization techniques and theoretical simulations for molecular electronics * Highlights the major contributions and new concepts of integrating molecular functionalities into electrical circuits * Provides a critical discussion of limitations and main challenges that still exist for the development of molecular electronics * Suited for readers studying or doing research in the broad fields of Nano/molecular electronics and other device-related fields Molecular-Scale Electronics is an excellent book for materials scientists, electrochemists, electronics engineers, physical chemists, polymer chemists, and solid-state chemists. It will also benefit physicists, semiconductor physicists, engineering scientists, and surface chemists.

Download or read book Single Molecule Electronics written by Manabu Kiguchi and published by Springer. This book was released on 2016-05-23 with total page 239 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents a multidisciplinary approach to single-molecule electronics. It includes a complete overview of the field, from the synthesis and design of molecular candidates to the prevalent experimental techniques, complemented by a detailed theoretical description. This all-inclusive strategy provides the reader with the much-needed perspective to fully understand the far-reaching ramifications of single-molecule electronics. In addition, a number of state-of-the-art topics are discussed, including single-molecule spectro-electrical methods, electrochemical DNA sequencing technology, and single-molecule chemical reactions. As a result of this integrative effort, this publication may be used as an introductory textbook to both graduate and advanced undergraduate students, as well as researchers with interests in single-molecule electronics, organic electronics, surface science, and nanoscience.

Download or read book Charge Transport in Molecular Junctions written by Michele Kotiuga and published by . This book was released on 2015 with total page 195 pages. Available in PDF, EPUB and Kindle. Book excerpt: Here, we use and develop first-principles methods based on density functional theory (DFT) and beyond to understand and predict charge transport phenomena in the novel class of nanostructured devices: molecular junctions. Molecular junctions, individual molecules contacted to two metallic leads, which can be systematically altered by modifying the chemistry of each component, serve as test beds for the study of transport at the nanoscale. To date, various experimental methods have been designed to reliably assemble and mea- sure transport properties of molecular junctions. Furthermore, theoretical methods built on DFT designed to yield quantitative agreement with these experiments for certain classes of molecular junctions have been developed. In order to gain insight into a broader range of molecular junctions and environmental effects associated with the surrounding solution, this dissertation will employ, explore and extend first-principles DFT calculations coupled with approximate self-energy corrections known to yield quantitative agreement with experiments for certain classes of molecular junctions. To start we examine molecular junctions in which the molecule is strongly hybridized with the leads: a challenging limit for the existing methodology. Using a physically motivated tight-binding model, we find that the experimental trends observed for such molecules can be explained by the presence of a so-called "gateway" state associated with the chemical bond that bridges the molecule and the lead. We discuss the ingredients of a self-energy corrected DFT based approach to quantitatively predict conductance in the presence of these hybridization effects. We also develop and apply an approach to account for the surrounding environment on the conductance, which has been predominantly ignored in past transport calculations due to computational complexity. Many experiments are performed in a solution of non-conducting molecules; far from benign, this solution is known to impact the measured conductance by as much as a factor of two. Here, we show that the dominant effect of the solution stems from nearby molecules binding to the lead surface surrounding the junction and altering the local electrostatics. This effect operates in much the same way adsorbates alter the work function of a surface. We develop a framework which implicitly includes the surrounding molecules through an electrostatic-based lattice model with parameters from DFT calculations, reducing the computational complexity of this problem while retaining predictive power. Our approach for computing environmental effects on charge transport in such junctions will pave the way for a better understanding of the physics of nanoscale devices, which are known to be highly sensitive to their surroundings.

Download or read book Charge and Exciton Transport through Molecular Wires written by Laurens D. A. Siebbeles and published by John Wiley & Sons. This book was released on 2011-07-18 with total page 293 pages. Available in PDF, EPUB and Kindle. Book excerpt: As functional elements in opto-electronic devices approach the singlemolecule limit, conducting organic molecular wires are the appropriate interconnects that enable transport of charges and charge-like particles such as excitons within the device. Reproducible syntheses and a thorough understanding of the underlying principles are therefore indispensable for applications like even smaller transistors, molecular machines and light-harvesting materials. Bringing together experiment and theory to enable applications in real-life devices, this handbook and ready reference provides essential information on how to control and direct charge transport. Readers can therefore obtain a balanced view of charge and exciton transport, covering characterization techniques such as spectroscopy and current measurements together with quantitative models. Researchers are thus able to improve the performance of newly developed devices, while an additional overview of synthesis methods highlights ways of producing different organic wires. Written with the following market in mind: chemists, molecular physicists, materials scientists and electrical engineers.

Download or read book Nanogap Electrodes written by Tao Li and published by John Wiley & Sons. This book was released on 2021-08-16 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unique in its scope, this book comprehensively combines various synthesis strategies with applications for nanogap electrodes. Clearly divided into four parts, the monograph begins with an introduction to molecular electronics and electron transport in molecular junctions, before moving on to a whole section devoted to synthesis and characterization. The third part looks at applications with single molecules or self-assembled monolayers, and the whole is rounded off with a section on interesting phenomena observed using molecular-based devices.

Download or read book Charge carrier Transport Measurements Through Single Molecules written by Emanuel Marc Lörtscher and published by Cuvillier Verlag. This book was released on 2007 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Theory of Charge Transport Through Vibrating Molecules written by Yelena Simine and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Charge Transport in Single Molecule Junctions written by Claudia Benesch and published by . This book was released on 2008 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Unimolecular and Supramolecular Electronics II written by Robert M. Metzger and published by Springer Science & Business Media. This book was released on 2012-01-10 with total page 283 pages. Available in PDF, EPUB and Kindle. Book excerpt: G. C. Solomon C. Herrmann M. A. Ratner Molecular Electronic Junction Transport: Some Pathways and Some Ideas R. M. Metzger D. L. Mattern Unimolecular Electronic Devices B. Branchi F. C. Simeone M. A. Rampi Active and Non-Active Large-Area Metal–Molecules–Metal Junctions C. Li A. Mishchenko T. Wandlowski Charge Transport in Single Molecular Junctions at the Solid/Liquid Interface K. W. Hipps Tunneling Spectroscopy of Organic Monolayers and Single Molecules N. Renaud M. Hliwa C. Joachim Single Molecule Logical Devices

Download or read book Spectroscopy Fabrication and Electronic Characterization of Molecular Electronic Devices written by Andrew Paul Bonifas and published by . This book was released on 2011 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Molecular electronics is the study of charge transport through single molecules or molecular ensembles. Molecular electronic junctions consist of single molecules or an ensemble of molecules positioned between two conducing contacts. To fabricate and measure the electronic properties of molecular junctions, several techniques have been employed such as scanning tunneling microscopy, conducting probe atomic force microscopy, and vapor deposition of top contacts. Charge transport observed through molecular junctions has been shown to exhibit technologically important phenomena such as rectification, conductance switching, and orbital gating. The primary focus of the field of molecular electronics is to understand the effect of molecular properties, such as structure and molecular orbitals, on charge transport mechanisms through molecular junctions. In this dissertation, the various techniques to fabricate and characterize molecular junctions are discussed, along with an introduction to charge transport mechanisms expected to control transport through molecular junctions. More specifically, this dissertation is primary focused on the fabrication and characterization of molecular junctions fabricated through the formation of an electronic contact on a molecular layer through physical vapor deposition. A common problem with this technique is structural damage to the molecular layer or metal penetration through the molecular layer during the contact formation. To overcome these limitations, a novel fabrication technique was developed and employed to fabricate reproducible molecular junctions through a physical vapor deposition technique without molecular damage or metal penetration. Termed surface diffusion mediated deposition (SDMD), the technique remotely deposits a metallic contact adjacent to and about 10 - 100 nm away from the molecular layer. Surface diffusion causes the metallic contact to migrate towards and onto the molecular layer to form an electronic contact. With SDMD, single molecule and many-molecule junctions are fabricated and electronically characterized. To probe electronic states and molecular structure in molecule/oxide junctions, an in-situ optical absorbance spectroscopy technique was developed and employed to monitor bias induced molecular redox events in solid-state molecular junctions. Correlation of the observed spectral changes with molecular redox events allows characterization of the electronic properties of molecules which are critical in understanding charge transport through molecules. In a related application, the developed in-situ optical absorbance spectroscopy technique was used to probe doping events in polypyrrole/oxide junctions. Doping reactions in polypyrrole are shown to strongly depend on the surrounding environment. For application to both molecular and conjugated polymer junctions, in-situ absorbance spectroscopy is shown to be a useful analytical tool to determine charge transport mechanisms. Finally, a thermal oxidation technique is introduced to increase the resolution of nanoimprint lithography to fabricate nanogap electrodes for molecular junctions. The advantage of this technique is the ability to use a simple, fast, and reliable oxidation process to increase the resolution of standard nanofabrication techniques.

Download or read book Handbook of Materials Modeling written by Sidney Yip and published by Springer Science & Business Media. This book was released on 2007-11-17 with total page 2903 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first reference of its kind in the rapidly emerging field of computational approachs to materials research, this is a compendium of perspective-providing and topical articles written to inform students and non-specialists of the current status and capabilities of modelling and simulation. From the standpoint of methodology, the development follows a multiscale approach with emphasis on electronic-structure, atomistic, and mesoscale methods, as well as mathematical analysis and rate processes. Basic models are treated across traditional disciplines, not only in the discussion of methods but also in chapters on crystal defects, microstructure, fluids, polymers and soft matter. Written by authors who are actively participating in the current development, this collection of 150 articles has the breadth and depth to be a major contributor toward defining the field of computational materials. In addition, there are 40 commentaries by highly respected researchers, presenting various views that should interest the future generations of the community. Subject Editors: Martin Bazant, MIT; Bruce Boghosian, Tufts University; Richard Catlow, Royal Institution; Long-Qing Chen, Pennsylvania State University; William Curtin, Brown University; Tomas Diaz de la Rubia, Lawrence Livermore National Laboratory; Nicolas Hadjiconstantinou, MIT; Mark F. Horstemeyer, Mississippi State University; Efthimios Kaxiras, Harvard University; L. Mahadevan, Harvard University; Dimitrios Maroudas, University of Massachusetts; Nicola Marzari, MIT; Horia Metiu, University of California Santa Barbara; Gregory C. Rutledge, MIT; David J. Srolovitz, Princeton University; Bernhardt L. Trout, MIT; Dieter Wolf, Argonne National Laboratory.

Download or read book Tunnelling in Molecules written by Johannes Kästner and published by Royal Society of Chemistry. This book was released on 2020-09-22 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Quantum tunnelling is one of the strangest phenomena in chemistry, where we see the wave nature of atoms acting in “impossible” ways. By letting molecules pass through the kinetic barrier instead of over it, this effect can lead to chemical reactions even close to the absolute zero, to atypical spectroscopic observations, to bizarre selectivity, or to colossal isotopic effects. Quantum mechanical tunnelling observations might be infrequent in chemistry, but it permeates through all its disciplines producing remarkable chemical outcomes. For that reason, the 21st century has seen a great increase in theoretical and experimental findings involving molecular tunnelling effects, as well as in novel techniques that permit their accurate predictions and analysis. Including experimental, computational and theoretical chapters, from the physical and organic to the biochemistry fields, from the applied to the academic arenas, this new book provides a broad and conceptual perspective on tunnelling reactions and how to study them. Quantum Tunnelling in Molecules is the obligatory stop for both the specialist and those new to this world.

Download or read book Theoretical Study of the Charge Transport Through C60 based Single molecule Junctions written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Charge Transport in Single molecule Junctions with Fullerene End groups written by Benjamin Gmeiner and published by . This book was released on 2010 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Molecular Electronics written by Ioan Baldea and published by CRC Press. This book was released on 2016-01-05 with total page 453 pages. Available in PDF, EPUB and Kindle. Book excerpt: Molecular electronics, an emerging research field at the border of physics, chemistry, and material sciences, has attracted great interest in the last decade. To achieve the ultimate goal of designing molecular electronic devices with the desired functionality and experimental manipulation at the single-molecule level, theoretical understanding of